APPARATUS FOR REDUCING AIR TURBULENCE IN A FAN CHASSIS

BACKGROUND

In personal computing, the significance of fans cannot be overstated, as they constitute one of the most critical components in thermal design for effectively cooling high-power devices, such as laptops. As technology advances, laptops have steadily increased in power consumption to enhance the user experience through improved performance. Simultaneously, there is a growing demand for laptops to become thinner, quieter, and cooler so that they can be used in more places by more people. These factors impose considerable challenges on thermal solutions within confined form factors.

Advancements in fan technology have primarily focused on increasing blade count, reducing blade thickness, or introducing blade designs inspired by concepts such as volumetric resistance blowers and biomimicry (for example, drawing inspiration from natural models like owl wings). However, these endeavors have either reached their manufacturing limits or require completely new materials and manufacturing processes than standard fans. Hence their benefits to fan design are either limited or require increased cost to implement. Therefore, an improved fan design that maintains affordability and simplicity is desired.

BRIEF DESCRIPTION OF THE FIGURES

Some examples of apparatuses and/or methods will be described in the following by way of example only, and with reference to the accompanying figures, in which

FIGS. 1A and 1B show schematic images of an interior wall of a fan chassis with an incline;

FIG. 1C shows a cross-sectional view of a continuous fan wall along line A-A′ of FIG. 1B;

FIG. 1D shows a top-down view of a fan wall with various inclines;

FIGS. 2A to 2C show a schematic of a fan wall with a lean;

FIGS. 3A and 3B show schematic images of a fan wall with a step;

FIG. 3C shows a cross-sectional view of a stepped fan wall along line A-A′ of FIG. 1B;

FIGS. 4A and 4B show schematic images of a cutwater of a fan chassis with a fold;

FIG. 5 shows a visualization of noise produced by turbulence in a fan chassis a fan;

FIG. 6 show a schematic of a fan wall with opposite inclines; and

FIGS. 7A to 7D show schematics of a fan wall with an aperture and a recess.

DETAILED DESCRIPTION

Some examples are now described in more detail with reference to the enclosed figures. However, other possible examples are not limited to the features of these embodiments described in detail. Other examples may include modifications of the features as well as equivalents and alternatives to the features. Furthermore, the terminology used herein to describe certain examples should not be restrictive of further possible examples.

Throughout the description of the figures, same or similar reference numerals refer to same or similar elements and/or features, which may be identical or implemented in a modified form while providing the same or a similar function. The thickness of lines, layers, and/or areas in the figures may also be exaggerated for clarification.

When two elements A and B are combined using an “or,” this is to be understood as disclosing all possible combinations, i.e., only A, only B as well as A and B, unless expressly defined otherwise in the individual case. As an alternative wording for the same combinations, “at least one of A and B” or “A and/or B” may be used. This applies equivalently to combinations of more than two elements.

If a singular form, such as “a,” “an,” and “the” is used and the use of only a single element is not defined as mandatory either explicitly or implicitly, further examples may also use several elements to implement the same function. If a function is described below as implemented using multiple elements, further examples may implement the same function using a single element or a single processing entity. It is further understood that the terms “include,” “including,” “comprise,” and/or “comprising,” when used, describe the presence of the specified features, integers, steps, operations, processes, elements, components, and/or a group thereof, but do not exclude the presence or addition of one or more other features, integers, steps, operations, processes, elements, components and/or a group thereof.

In the following description, specific details are set forth, but examples of the technologies described herein may be practiced without these specific details. Well-known circuits, structures, and techniques have not been shown in detail to avoid obscuring an understanding of this description. “An example/example,” “various examples/examples,” “some examples/examples,” and the like may include features, structures, or characteristics, but not every example necessarily includes the particular features, structures, or characteristics.

Some examples may have some, all, or none of the features described for other examples. “First,” “second,” “third,” and the like describe a common element and indicate different instances of like elements being referred to. Such adjectives do not imply element item so described must be in a given sequence, either temporally or spatially, in ranking, or any other manner. “Connected” may indicate elements are in direct physical or electrical contact with each other and “coupled” may indicate elements co-operate or interact with each other, but they may or may not be in direct physical or electrical contact.

As used herein, the terms “operating,” “executing,” or “running” as they pertain to software or firmware in relation to a system, device, platform, or resource are used interchangeably and can refer to software or firmware stored in one or more computer-readable storage media accessible by the system, device, platform, or resource, even though the instructions contained in the software or firmware are not actively being executed by the system, device, platform, or resource.

The description may use the phrases “in an example/example,” “in examples/examples,” “in some examples/examples,” and/or “in various examples/examples,” each of which may refer to one or more of the same or different examples. Furthermore, the terms “comprising,” “including,” “having,” and the like, as used with respect to examples of the present disclosure, are synonymous.

The interaction between the blades and the fan housing or chassis is one of the main causes of fan total noise, which comprises broadband and tonal noise. Tonal noise is characterized by distinct, singular frequencies or tones, often perceived as whining or humming, whereas broadband noise encompasses a wide range of frequencies, resulting in a more diffuse, hissing, or roaring sound. Several innovative embodiments of fan chassis designs, which can be employed individually or in various combinations, are described herein. The embodiments tend to affect these blade-chassis interactions and reduce the noise generated by fans. Specifically, the embodiments aim to mitigate both tonal and broadband noise and ultimately enhance the overall acoustic performance represented by improved Iso-acoustic PQ (static pressure-volumetric characteristic) curves. In other words, employing these embodiments in a fan may either result in higher system airflow at equivalent noise levels or reduced noise emissions at the same system airflow, ensuring a more pleasant and efficient user experience.

FIGS. 1A and 1B show schematic images of an interior wall 101 of a fan chassis 108 with an incline. They generally show a swept cutwater face. FIG. 1A shows the fan chassis in a profile view. FIG. 1B shows the fan chassis in a top-down view. The interior wall may comprise a portion 110 that extends from a base 106 of the fan chassis at an acute angle to an axis orthogonal to the base.

A fan chassis 108 is the structural framework, enclosure, casing, or housing that encases fan components, such as the motor, fan assembly (including a rotor wheel or impeller 104), base 106, intake and outflow passages, and other associated parts. This chassis is typically crafted from materials such as metal or durable plastic and is designed to provide support, protection, and structural integrity to the internal components of the fan system. The design of the fan chassis 108 can include specific structures or features that shape the flow of air through the fan. Specifically, the design directs the incoming air toward the fan blades. The air is then accelerated radially and tangentially as it passes through the blades, resulting in a higher pressure output. The interior wall 110 or surfaces of the chassis can be designed to reduce turbulence within the fan. By minimizing air resistance and disruption, the chassis ensures a smoother and more efficient airflow, thereby enhancing the fan's performance.

The chassis also plays a role in dampening vibrations and reducing noise generated by the fan. This may be achieved through the use of vibration-absorbing or acoustic-dampening materials and structural design that minimizes resonant frequencies. The fan chassis may comprise these materials in whole or in part. For example, the interior wall may comprise these acoustic-dampening materials, which may include at least rubber, elastomers, polyurethane foam, composite materials such as fiberglass or reinforced plastics, and viscoelastic polymers.

A base, backplate, or baseplate 106 may be a component of the fan chassis 108 that provides structural support and stability to the fan assembly, including the impeller 104. It is usually located at the rear or bottom of the fan and serves as a mounting surface for the fan motor and other internal components. The baseplate 106 may help secure the components in place and add rigidity to the fan chassis 108.

An axis orthogonal to the base (as seen in FIGS. 1C and 3C) refers to a straight line or axis that is at a right angle (90 degrees) to the base 106 of the fan chassis or structure 108. In a three-dimensional space, if the base is positioned horizontally, the orthogonal axis would be a vertical line rising perpendicularly from that base. When a rotor wheel or impeller 104 of a fan assembly rotates, vortices shed from fan blades 142 interact with the interior wall 101 and create tonal noise. In designs without an angled wall (e.g. a wall that is substantially perpendicular to the base), all vortices from a particular blade interact with the wall in the same manner. However, by introducing an acute angle in the wall, a phase difference in interaction is created. As seen in FIG. 1A, trailing edge vortices along a blade height travel different distances before interacting with an inclined interior wall. Thus a phase difference is created resulting in a reduction in tonal noise.

FIG. 1C shows a cross-sectional view of a continuous and stepped interior wall 101 of the fan casing 108 along line A-A′ of FIG. 1B. It has an orthogonal axis Z to the base 106. A portion 110 of the interior wall 101 extends from the base 106 of the fan casing 108 at an acute angle θ to the axis orthogonal to the base Z. As shown in FIGS. 1A to 1D and 2A, the acute angle may be an inclination angle creating a “swept” design.

The axis orthogonal to the base Z may be parallel to a rotational axis of a fan mount 144 of the fan chassis 108. In particular, the fan mount 144 could be an impeller mount. A fan mount of a fan chassis may refer to the structural component designed to securely hold and position the fan's operational elements, which may include a motor and a rotor wheel or impeller, within the chassis 108. The fan mount is connected to a hub, which is the central part of the rotor wheel or impeller of the fan assembly. The hub supports blades or vanes that are attached to the hub and the wheel rotates to impart kinetic energy to the air causing its movement, pressure change, or flow acceleration (generally, airflow). Although the figures show an impeller, other types of forced-air fan assemblies where vortices are created, such as propellers, may be used.

Ensuring the orthogonal axis is parallel an axis to the fan mount ensures that the portion 110 of the interior wall 101 is lined up with the blades of the fan, resulting in better interaction with the vortices of the fan blades. If, for example, the base of the fan chassis is not generally planer, the orthogonal axis should be parallel to a rotational axis of the impeller so that a phase difference between the blades and the wall exists.

FIG. 1D shows a top-down view of a fan wall with various inclines. The inclines are shown as distance variations between the proximal and distal ends of the portion 110 of the interior wall 101. Inclination angles vary the sweep of the portion 110 interior wall 101. FIG. 1D shows sweep distances of 1 millimeter (mm), 2 mm, 2.5 mm, or −1 mm (resulting from a negative inclination angle). The creation of an inclined or swept interior wall may result in a positive impact in terms of tonal noise reduction of the order of >0.5 dBA. A dBA, or A-weighted decibel, is a unit of sound measurement that reflects the relative loudness of sounds in the air as perceived by the human ear. The “A-weighting” is an adjustment to the actual sound pressure levels across various frequencies, designed to better match the frequency response of the human ear. In essence, dBA is a way to measure sound that considers the varying sensitivity of human hearing to different frequencies.

Inclination angles that result in a negative sweep distance with respect to a base of the fan chassis are also shown in FIG. 1D. A negative distance may result in a positive impact in terms of tonal noise reduction of the order of >0.5 dBA. The negative distance would be a positive distance with respect to a lid of a fan chassis. As fan chassis are generally symmetrical with respect to their base and lid, the angle and distance of the sweep of the interior wall or cutwater of the fan chassis is more relevant than whether it is measured from the base or lid.

Tests were conducted by varying the swept distance 1 mm, 2 mm, 2.5 mm, and −1 mm. A baseline dBA of approximately 37 was measured. The sweep distance of 1 mm resulted in a tonal noise reduction of 0.24 dBA from baseline, the 2.5 mm sweep distance resulted in a reduction of 0.58 dBA from baseline, and the −1 mm sweep resulted in a reduction of 0.59 dBA from baseline. Thus, an interior wall with an acute inclination angle may result in a positive impact in terms of tonal noise reduction.

The acute inclination angle may be at least 25 degrees (or at least 30 degrees, or at least 35 degrees) and/or the acute inclination angle may be at most 85 degrees (or at most 80 degrees, or at most 75 mm). Inclination angles that approach 90 degrees may result in an interior wall that is substantially perpendicular to the base and therefore will not have a substantial phase difference between the proximal and distal portions of the wall. The resulting sweep may be at least 1 mm (or at least 2 mm, or at least 2.5 mm). An inclination angle resulting in a backward sweep may be the same.

The height of the fan chassis 108 may be at least 3.5 millimeters (or at least 10 mm, at least 7 mm, at least 2 mm, or at least 1 mm) and/or at most 15 millimeters (or at most 7 mm, at most 10 mm, at most 18 mm, or at most 20 mm). Having a fan chassis 108 with a thickness within the mentioned range may ensure the structural integrity of the fan assembly by providing a sufficient thickness to securely support and protect the internal components, such as the motor and impeller 104 of the fan assembly. The specified thickness may also contribute to the rigidity and stability of the fan chassis 108, reducing vibrations and flexing that can negatively impact performance and increase noise levels. Additionally, keeping the fan chassis 108 within this thickness range may allow for optimal space utilization, making it suitable for applications with limited space or where a compact design is desired.

For example, the height of the portion of the wall 110 of the fan chassis 108 may extend the height of the chassis. Extending the fin fix to the full height of the chassis may help to minimize air leakage or bypass, ensuring that the maximum amount of air is directed toward an outlet. This may result in enhanced efficiency and effectiveness of the fan's airflow, optimizing its performance and achieving better airflow management within the system.

More details and optional aspects of the device of FIGS. 1A to 1D may be described in connection with examples described below (e.g. FIGS. 2A to 7D).

FIGS. 2A to 2C show schematic images of an interior wall 201 of a fan chassis 208 with a lean. They generally show a leaned cutwater 220 face of a fan chassis 208. Specifically, they show a portion 210 of the fan chassis 208 where the acute angle is a lean angle. Vortices shed from an impeller of a fan interact with the interior wall or cutwater and create tonal noise. Generally, all vortices from a particular blade interact with a fan chassis wall. Similar to a swept cutwater face, an interior wall with a leaning portion or cutwater may also create a phase difference in interaction, resulting in lower tonal noise. The acute lean angle may be at least 25 degrees (or at least 30 degrees, or at least 35 degrees) and/or the acute lean angle may be at most 85 degrees (or at most 80 degrees, or at most 75 degrees). The resulting lean may be at least 1 mm (or at least 2 mm, or at least 2.5 mm). A lean angle resulting in a backward lean may be the same.

Tests were conducted by varying the lean distances by 1 mm, 2 mm, and 2.5 mm. A baseline dBA of approximately 37 was measured. The sweep distance of 1 mm resulted in a tonal noise reduction of 0.64 dBA from baseline, the 2.5 mm sweep distance resulted in a reduction of 0.31 dBA from baseline, and the −1 mm sweep resulted in a reduction of 0.28 dBA from baseline. Thus, an interior wall with an acute inclination angle may result in a positive impact in terms of tonal noise reduction.

An interior wall with swept and leaned portions or cutwaters can be combined to maximize the benefit. Sweeping and leaning individually may provide a 0.5 dBA benefit. Therefore, combining sweeping and leaning may result in ˜1 dBA noise reduction. This may translate to about 5-8% ISO acoustic performance improvement of the fan as defined by the International Organization for Standardization (ISO). Interior walls with an inclination angle and/or a lean angle may extend continuously from the base.

More details and optional aspects of the device of FIGS. 2A to 2C may be described in connection with examples described above (e.g. FIGS. 1A to 1D) or below (e.g. FIGS. 3A to 7D).

FIGS. 3A and 3B show schematic images of an interior wall of a fan chassis where a portion of the wall extends stepwise from the base. They generally show a stepped cutwater face. FIG. 3A shows the entire interior wall 301 while FIG. 3B shows an enlarged portion focused on the cutwater 320. The interior wall 310 may comprise a portion 310 that extends from the base of the fan chassis at an acute angle to an axis orthogonal to the base. The irregular surface of a stepped wall portion may disrupt the formation of vortices better than a continuous, smooth wall. This may further help to reduce tonal noise further and improve acoustics signature. A stepped interior wall may also be easier to manufacture (such as by 3D printing, which manufactures objects layer-by-layer) as compared to a continuous, smooth wall.

A stepped portion of an interior wall may also be inclined, leaned, or combined with any of the embodiments disclosed herein. Combining embodiments, such as a stepped incline and/or lean may result in increased acoustics benefits overall than any embodiment individually. FIG. 3C shows a cross-sectional view of a stepped, inclined interior wall 301 of the fan casing 308 along a line similar to A-A′ of FIG. 1B. Like FIG. 1C, FIG. 3C has an orthogonal axis Z to the base 306. A portion 310 of the interior wall 301 extends from the base 306 of the fan casing 308 in a stepwise manner. The steps' incline is at an acute angle θ to the axis orthogonal to the base Z. The acute angle and thus steps may be an inclination angle creating a swept or inclined design. The acute angle and steps may also create a leaned design or an inclined and leaned design with a stepwise, rather than continuous, extension. The irregular surface of the stepped configuration coupled with an incline and/or lean feature may disrupt the formation of vortices better than any one feature alone. A stepped wall or cutwater may further help to reduce tonal noise and improve the acoustics signature. A stepped wall in combination with an inclined, leaned, or other disclosed embodiment may compound the acoustic benefit.

More details and optional aspects of the device of FIGS. 3A to 3C may be described in connection with examples described above (e.g. FIGS. 1A to 2C) or below (e.g. FIGS. 4A to 7D).

FIGS. 4A and 4B are identical to FIGS. 1A and 1B. They show an interior wall 401 of a fan chassis 401 comprising a cutwater 420 with a fold. FIG. 4A shows the fan chassis in a profile view. FIG. 4B shows the fan chassis in a top-down view. The portion of the interior wall that extends from a base of the fan chassis may be a fold. A fold is a three-dimensional structure formed when a surface or material is bent or curved, creating a series of hinge points h₁, h_nand inflection points i₁, i_n. These hinge points are connected to define the hinge line or fold axis f, which is the primary structural element of the fold, indicating the direction of maximum continuity of the fold. The limb of the fold is the segment between a fold axis f and the adjacent inflection line il₁, il₂, where the inflection line il₁, il is the locus of inflection points i₁, i₂at which the curvature changes. Folds may be complex, three-dimensional structures with distinct geometrical properties and relationships between their elements.

An inflection point or line refers to a specific point, location, or region (e.g. a corner or a curved section) where a fold transitions from a first direction to a second direction. It can be the meeting point or a dividing point that joins or separates the fold from the rest of the interior wall or cutwater. The inflection area is an important region that marks the change in flow direction and plays a significant role in directing the fluid or airflow. Moreover, the highest turbulence and resulting noise may be found in the inflection area due to the structures that mark the transition from one outlet to another.

FIG. 4A shows a portion of the interior wall 401 that extends along a fold axis f from the base 406 of the fan casing 408 at an acute angle θ to the axis orthogonal to the base Z. As shown in FIG. 4A, the acute angle may be an inclination angle creating a “swept” design. Trailing edge vortices along a blade height of the fan assembly 404 travel different distances before interacting with the fold (for example at hinge points h₁, h_n). Thus, a phase difference is created resulting in a reduction in tonal noise. However, the fold axis may equally define a lean, an inclined lean, a stepped incline and/or lean, or any of the other embodiments disclosed herein. FIGS. 1C, 1D, 2A to 2C, and 3C all depict fold axes f representing an inflection point in the bend of an interior wall. As in FIG. 4A, each fold axis f intersects with the orthogonal axis Z creating an acute angle between the fold axis f and the orthogonal axis Z.

FIGS. 4A and 4B show a cutwater 420. A cutwater is a design feature often found in fluid flow applications, such as pumps, fans, or turbines that improves efficiency and performance. It may be a shape or structure, typically a curved or angled plate or edge, located where the air or fluid exits the fan and designed to reduce or minimize resistance caused by air or fluid flow. The cutwater may be designed to smoothly direct the flow of air or fluid from the impeller into the fan's discharge area, minimizing turbulence and flow separation and preventing excessive drag. When a cutwater is located near an outlet 452, it may be used for air compression and is sometimes known as a primary or compression cutwater. A cutwater 420 for compression in a centrifugal fan may serve to create a barrier or obstruction that redirects the airflow. It may help to increase the pressure of the air as it passes through the fan, promoting efficient compression. This design feature may enhance the fan's ability to generate higher pressures and deliver a more concentrated airflow, making it suitable for applications that require robust air compression and movement.

A cutwater's design is essential in reducing noise and vibration, and in preventing the formation of vortices or backflow, which can occur when the high-velocity air from the impeller interacts with the slower-moving air in the discharge area or outlet. An outlet 452 may be a specific opening, duct, or passage through which fluid, such as air or liquid, is discharged or expelled from a system, apparatus, or device (e.g. a fan). The outlet 452 may be designated for a particular purpose, location, or function, and may be associated with specific flow control or directionality features. By ensuring a smoother transition of airflow, a cutwater contributes significantly to the overall aerodynamic efficiency of the fan, reducing energy consumption and enhancing performance.

More details and optional aspects of the device of FIGS. 4A and 4B may be described in connection with examples described above (e.g. FIGS. 1A to 3C) or below (e.g. FIGS. 5 to 7D).

FIG. 5 shows a visualization of noise produced by turbulence in a fan chassis 508. In particular, it shows high turbulence 599 near a cutwater 529. When a rotor or impeller 504 rotates, the cutwater geometry helps to avoid high-pressure air recirculating back to a volute section of the fan. The cutwater helps to build the pressure from the minimum area point (the distance between the impeller blade and the cutwater also called a cutwater distance) towards the outlet so that, eventually, high-pressure air comes out from the fan outlet section. At the same time, cutwater also creates high turbulence due to high-pressure air impinging on the cutwater wall. This creates a recirculating flow locally which results in high turbulent kinetic energy and hence more broadband noise as shown in FIG. 5.

More details and optional aspects of the device of FIG. 5 may be described in connection with examples described above (e.g. FIGS. 1A to 4B) or below (e.g. FIGS. 6 to 7D).

FIG. 6 shows a schematic of a fan wall with opposite inclines. FIG. 6 has an enlarged view of the cutwater, where cutwater 620 comprises a fold with an increasing bend radius extending from the base of the fan chassis. A bend radius is the radius of the curvature of the fold centered on the fold axis f. As the bend radius increases, the adjacent inflection lines il₁, il₂, begin to incline away from each other at an angle. The angle of the inflection lines, along with the fold axis, may be an acute, inclination angle to an axis orthogonal to the base. A cutwater with an increasing bend radius may avoid vortices shed from the impeller that interact with the cutwater and result in tonal noise, in a similar manner as an incline or lean. However, the inclined opposite cutwater, as shown in FIG. 6, has proven to be more effective in reducing fan noise compared to an incline or a lean. Test data shows that this feature helps to reduce the noise levels by 1 to 1.5 dBA.

A fold may also have a decreasing bend radius. FIGS. 1A, 1B, 1D, 4A, and 4B show a fold with a decreasing bend radius extending from a base of the fan chassis. Thus, the inflection lines incline towards each other as seen in FIG. 4B. In FIGS. 2A to 2C, the bend radius is constant while the cutwater has a lean. Therefore, a variable bend radius may be indicative of an incline. Other possibilities exist but are not shown. For example, the bend radius could increase while centered on fold axis with an incline as discussed in previous examples. Thus the fold will get wider as the incline extends further away from the base. The opposite would be true if the bend radius decreases as the fold axis inclines. Negative inclination angles with increasing or decreasing bend radii are also possible. Further still, the fold axis could have a lean with and an increasing or decreasing bend radius. And the fold axis could have an incline and a lean with an increasing or decreasing bend radius. Hence, multiple complex, three-dimensional fold structures that avoid vortices and reduce tonal noise are possible.

More details and optional aspects of the device of FIG. 6 may be described in connection with examples described above (e.g. FIGS. 1A to 5) or below (e.g. FIGS. 7A to 7D).

FIGS. 7A to 7D show schematics of a fan wall with an aperture and a recess. FIG. 7A shows a top-down, cross-sectional view of a wall 701 of a fan chassis 708 with a passage 730. A cutwater 720 for an interior wall of a fan casing may comprise the passage 730 that extends from a proximal portion of the cutwater 720 to a distal portion of the cutwater. The cutwater may further comprise a fold between the proximal portion and the distal portion of the cutwater. The proximal portion of the cutwater may further be a first limb of a fold of the cutwater between a fold axis (at cross-sectional hinge point h) and a first inflection line (at cross-sectional inflection point in), the distal portion of the fold may further be a second limb of the fold is the segment between the fold axis and a second inflection line (at cross-sectional inflection point i₂). In other words, a passage may pass through the fold behind a fold axis or hinge point of the cutwater. It may also be located within the fold in the limbs of the fold or beyond the fold but still within the cutwater. Having a passage in the cutwater section 720, as shown in FIGS. 7A to 7D, may help to reduce the turbulence by minimizing the local recirculation.

FIG. 7B shows a cutwater 620 with a fold axis that is orthogonal to the base. In other words, there is no incline or lean. The passage 730 is an aperture through the cutwater 620. Having, one or more holes or apertures draw recirculating flow into the volute section has proven to reduce the turbulence intensity and hence broadband noise which in turn reduces overall noise. One or more apertures may provide ˜1 to 1.5 dBA lower noise levels compared to baseline geometry without holes. A diameter of the aperture may be at least 0.5 mm (or at least, 0.75 mm, or at least 1 mm). Apertures may be placed to retain the structural integrity of the of the cutwater. For example, avoiding fasteners 790.

A volute section in the context of a centrifugal fan is the portion of the fan casing that surrounds the impeller and is designed to transform the high-speed, rotational kinetic energy of the fluid or air exiting the impeller into pressure. The volute is typically a spiral-shaped casing that gradually expands in cross-sectional area as it wraps around the impeller and approaches the outlet. As the air exits the impeller at high speed, it enters the volute where the increasing area of the spiral casing allows for a gradual reduction in fluid speed, leading to an increase in static pressure. This transformation of kinetic energy to pressure is essential for the effective operation of the fan, facilitating the movement of air or fluid through the system.

An outlet may extend an edge of the chassis of the fan, it may be a main airflow direction of air output. The main airflow direction may target a direction of the outlet or be averaged over the airflow through the outlet.

The passage 730 may extend at least partially along a tangent of a curve of the interior wall 710. The tangent may be adjacent to the distal end of the face. For example, the passage may follow a tangent of a curve of the interior wall where the wall transitions (such as, at an inflection point) into the cutwater. In other words, the passage extends the course of the interior wall along a tangent of its curve through the cutwater as an aperture/tunnel or cut/recess.

Extending the passage along a tangential path or curve of the wall may reduce turbulence by directing air that was already following along the course of the wall through the passage. Thus, improving fluid flow direction, enhancing energy transfer, increasing efficiency, and reducing turbulence. Only partially extending along the path allows a controlled redirection of the fluid or airflow. By initially aligning the path tangentially with the wall, the flow can harness the initial momentum and direction provided by the impeller. The subsequent change in path allows for desired adjustments in flow direction, velocity, or distribution, enabling more precise control and optimization of the fluid dynamics within the system. This approach provides flexibility in directing the flow to specific areas or components, optimizing performance, and achieving desired flow patterns or characteristics.

The passage 730 may be tangent to a circle originating at an impeller mount of the fan chassis. Following a tangent to a circle centered on the rotational axis of the impellor may better harness the impeller's rotational motion, momentum, and direction provided by the impeller. Furthermore, a tangential path may allow for a more straightforward and streamlined design, which can simplify the manufacturing process, reduce production costs, and enhance overall production efficiency. The channel's alignment with the impeller's rotational motion facilitates a more intuitive and efficient construction of the passage and cutwater.

A distance of the passage from the base of the fan chassis may be at least 1 mm (or at least 1.5 mm, or at least 3 mm) and/or at most 6 millimeters (or at most 5 mm, or at most 3.5 mm). Having a passage closer to the base of the fan chassis may avoid turbulence from the inlet at the top of the fan chassis and benefit from increased pressure at the base.

FIG. 7C shows a cutwater with a pressure relieving slot. A passage may be a recess in the face of the cutwater. The face of the cutwater may refer to a flat or curved surface on the cutwater. It can be the visible or functional surface facing the interior of the fan chassis and the impeller. A cutwater may comprise multiple recesses. A minimal width (or average width) of the aperture or recess of the cutwater may be at least 0.5 mm (or at least, 0.75 mm, or at least 1 mm). This range allows for a balance between providing sufficient space for airflow while maintaining proper air velocity and pressure throughout the fan system. It may help to ensure efficient operation, minimize turbulence, and maximize the fan's performance in terms of airflow delivery and energy efficiency. All passages may comprise any width. Furthermore, the widths of different massages may also be different depending on the design requirements or intentions.

A recess may be easier to manufacture than an aperture or hole. FIG. 7C also shows the combination of inclined opposite cutwater of FIG. 6 with a recess. The combination of these features helps to augment the acoustics noise benefit better than one feature alone. Test data on the combined slot and opposite incline cutwater showed a noise reduction of ˜>1.5 dBA.

FIG. 7D likewise shows the combination of the inclined opposite cutwater of FIG. 6 with the aperture of FIGS. 7A and 7B. A cutwater may comprise multiple apertures. The combination of these features helps to augment the acoustics noise benefit better than one feature alone. Test data on the combined slot and opposite incline cutwater also showed a noise reduction of ˜>1.5 dBA.

More details and optional aspects of the device of FIGS. 7A to 7D may be described in connection with examples described above (e.g. FIGS. 1A to 6) or below.

As described above, various features and concepts disclosed herein can be used in combination to reduce noise and improve airflow in a fan chassis. A cutwater for an interior wall of a fan chassis may comprise a fold with an increasing and/or decreasing bend radius extending from the base of the fan chassis. The fold may extend from the base at one or more acute angles to an axis orthogonal to the base. The one or more acute angles are an inclination angle and/or a lean angle. The fold may further be located between a proximal portion of the cutwater and a distal portion of the cutwater. The cutwater may further comprise a passage extending from the proximal portion to the distal portion. The fold may extend stepwise from the base. The cutwater may also comprise an acoustic-dampening material.

The fan housing concepts discussed herein were studied using experiments on a 65 mm by 65 mm by 4 mm single outlet fan with 3D printed housing for different concepts. Acoustics data showed a reduction in overall Sound Pressure Level (SPL, a measure of the intensity or loudness of sound in decibels (dB)) up to 1.4 dBA at ISO-acoustics for inclined with hole and inclined with slot concepts. Also fan PQ data showed flow at the system operating point was better for these concepts compared to the baseline. At ISO-acoustics conditions, the net flow was increased by ˜8%. Experiment data was also compared for tonality and sharpness. Inclined with hole and inclined with slot concepts helped to reduce the tonality as well as sharpness.

Aeroacoustics simulations performed on a 65 mm by 65 mm by 3.5 mm fan at 3900 rpm for baseline and inclined with hole cutwater designs showed a reduction in tonal noise at blade pass frequency for inclined with hole design. This reduction in tonal noise resulted in a reduction in overall SPL by 1.1 dBA compared to a baseline design.

As described above, various features and concepts disclosed herein can be used in combination to reduce noise and improve airflow in a centrifugal fan. A centrifugal fan may comprise an impellor mounted in a chassis, the chassis may comprise a cutwater that extends from the base of the chassis toward a lid of the chassis, wherein a portion of the cutwater extends at one or more acute angles to a rotational axis of the impeller of the centrifugal fan.

A centrifugal fan may be any type of fan or blower that operates on the principle of centrifugal force. It consists of an impeller or rotor that rotates within a housing or chassis, creating a radial flow of the fluid. The centrifugal fan may be used to generate fluid movement, create pressure differentials, and facilitate the transfer of heat or mass in various applications. Although the figures show a centrifugal fan, other types of fans may be used, such as axial fans, crossflow fans, and vaneaxial fans, among others.

In certain high-performance laptops, gaming laptops, or other electronic devices that generate a significant amount of heat, manufacturers may opt for centrifugal fans instead of or in conjunction with axial fans. Centrifugal fans, also known as radial fans, operate by pulling air into the fan housing at the center and then redirecting it perpendicular to the axis of rotation before expelling it. This design allows for higher static pressure and improved airflow in constrained spaces, making them suitable for laptops with more demanding cooling requirements.

The fan (e.g. centrifugal fan) may comprise an impeller. An impeller may be a rotating component within a fluid handling system, typically used in pumps, fans, or turbines. An impeller may comprise blades or vanes that impart kinetic energy to the air or fluid, resulting in its movement, pressure change, or flow acceleration. It may be designed to efficiently transfer energy from the mechanical system to the fluid, enabling pumping, mixing, or propulsion. Although the figures show an impeller, other types of forced air fan assemblies may be used, such as propellers and bladeless fans.

The proximity of an impeller refers to the close distance between the impeller and other components within a fluid handling system. It signifies the spatial relationship and nearness of the impeller to surrounding elements, such as the fins, the partition structure, housing, blades, channels, or any other structures involved in the fluid flow process.

The one or more acute angles along which a portion of the cutwater extends may be an inclination angle and/or a lean angle. The cutwater of the centrifugal may comprise an aperture and/or a recess extending from a proximal portion of the cutwater to a distal portion of the cutwater. The aperture and/or the recess may extend along a tangent to a circle originating at the rotational axis of the impeller. The proximal portion may extend toward an outlet of the chassis and the distal portion may extend away from the outlet. The centrifugal fan of claims 29 to 33, wherein the lid comprises an inlet.

Any and all components of a centrifugal fan, in particular the chassis, may comprise at least one of plastic or a metal (e.g. aluminum or copper). A chassis may be made of metals such as aluminum, copper, or other highly conductive materials due to their excellent thermal conductivity. This allows for efficient heat transfer between the air and any cooling structure, such as a heat exchanger, attached to the chassis. This may enhance an overall heat exchanger performance. Additionally, metals provide durability and structural integrity to withstand the demanding operating conditions of heat exchangers, ensuring long-term reliability. Plastic may also be used due to its ease of manufacture, availability, and readiness to be shaped. The choice of these materials also facilitates manufacturing processes, enabling the chassis to be easily formed and integrated into a laptop or other computing system design.

A height of the chassis of the centrifugal fan may be at least 3.5 millimeters (or at least 10 mm, at least 7 mm, at least 2 mm, or at least 1 mm) and/or at most 15 millimeters (or at most 7 mm, at most 10 mm, at most 18 mm, or at most 20 mm. In particular, the height of the chassis may be at least 11 millimeters and at most 13 millimeters. Having a fan chassis with a thickness within the mentioned ranges may ensure the structural integrity of the fan assembly by providing a sufficient thickness to securely support and protect the internal components, such as the motor and impeller of the fan assembly. The specified thickness may also contribute to the rigidity and stability of the fan chassis 108, reducing vibrations and flexing that can negatively impact performance and increase noise levels. Additionally, keeping the fan chassis within this thickness range may allow for optimal space utilization, making it suitable for applications with limited space or where a compact design is desired.

A blade height of the impeller of the centrifugal fan may be at least 8 millimeters and at most 10 millimeters. Fan blade Z-height that is proximate to or equal to the height of the chassis may accomplished by a circumferential cutout on the fan casing or lid of the fan casing to avoid interference. The incremental z-height fan blade increase does not increase the X-Y form factor of the fan and may be accommodated in the existing real estate of the fan. Increasing the blade height of a fan may elevate laptop cooling performance with a unique fan blade design that enhances airflow by increasing blade height without altering the fan's x and y dimensions.

A centrifugal fan with taller blades may offer superior heat dissipation while maintaining the laptop's sleek form factor. Higher airflow gives more thermal stability to the system preventing throttling and thermal runaway. From the fundamental fluid dynamics principles, an increase in the fan blade height results in a proportional increase in airflow, for instance on centrifugal fans. Experimental data collected showed a 10% increase in the blade height results in a 10% increase in airflow, assuming all the other factors remain constant.

The chassis of the centrifugal fan may comprise a vibration-absorbing or an acoustic dampening material. Experimental data further revealed that, for a 40 mm by 40 mm fan, acoustic dampers combined with a fan blade height increase of up to 20% does not increase the acoustics by more than 2 dB. Beyond 20%, fan blade height may result in more airflow accompanied by higher acoustics. A laptop cooling system featuring strategically placed acoustic dampers within the centrifugal fan housing may significantly reduce fan noise while maintaining optimal thermal performance.

Vibration-absorbing or acoustic-dampening materials may minimize resonant frequencies. The fan chassis may comprise these materials in whole or in part. For example, the chassis or a cutwater of the chassis may comprise acoustic-dampening materials. These may include at least rubber, elastomers, polyurethane foam, composite materials such as fiberglass or reinforced plastics, and viscoelastic polymers.

Integrated acoustic dampers may deliver whisper-quiet operation without compromising cooling efficiency. This may be ideal for noise-sensitive environments. Experimental data was gathered from centrifugal fan casings with and without acoustic dampers. The experiments were conducted using acoustics damping material as a fan side wall or interior wall of a fan. Acoustics tests were conducted at a full range of fan operating speeds for the fan, with and without an acoustics damper. The experimental results showed a significant improvement in acoustics, with more than a 10% benefit realized using dampers. The results were found to be consistent across the full fan speed range while delivering the same flow rate.

Experimental data was gathered from fan housing concepts with various cutwater configurations and with acoustic dampening. One fan housing design that was tested comprised an inclined cutwater with holes, acoustically damped fan sidewall and cutwater material, and a preferential fan blade height. The combination of these concepts resulted in significant benefits in terms of acoustics, with an improvement of over 4 dBA, and a flow improvement of more than 10%. The net benefit may yield ˜5 to 6 dBA at the same flow rate or a 20 to 30% flow improvement at ISO-acoustics.

The aspects and features described in relation to a particular one of the previous examples may also be combined with one or more of the further examples to replace an identical or similar feature of that further example or to additionally introduce the features into the further example.

It is further understood that the disclosure of several steps, processes, operations, or functions disclosed in the description or claims shall not be construed to imply that these operations are necessarily dependent on the order described unless explicitly stated in the individual case or necessary for technical reasons. Therefore, the previous description does not limit the execution of several steps or functions to a certain order. Furthermore, in further examples, a single step, function, process, or operation may include and/or be broken up into several sub-steps, -functions, -processes, or -operations.

If some aspects have been described in relation to a device or system, these aspects should also be understood as a description of the corresponding method. For example, a block, device, or functional aspect of the device or system may correspond to a feature, such as a method step, of the corresponding method. Accordingly, aspects described in relation to a method shall also be understood as a description of a corresponding block, a corresponding element, a property, or a functional feature of a corresponding device or a corresponding system.

An example (e.g. example 1) relates to an interior wall of a fan chassis, wherein the interior wall comprises a portion that extends from a base of the fan chassis at an acute angle to an axis orthogonal to the base.

Another example (e.g. example 2) relates to a previously described example (e.g. example 1), wherein the acute angle is an inclination angle.

Another example (e.g. example 3) relates to a previously described example (e.g. example 2), wherein the inclination angle is between 25 and 35 degrees.

Another example (e.g. example 4) relates to a previously described example (e.g. example 2), wherein the inclination angle is less than 85 degrees.

Another example (e.g. example 5) relates to a previously described example (e.g. one of the examples 1-4), wherein the acute angle is a lean angle.

Another example (e.g. example 6) relates to a previously described example (e.g. example 5), wherein the lean angle is between 25 and 35 degrees.

Another example (e.g. example 7) relates to a previously described example (e.g. example 5), wherein the lean angle is less than 85 degrees.

Another example (e.g. example 8) relates to a previously described example (e.g. one of the examples 1-7), wherein the portion of the wall extends continuously from the base.

Another example (e.g. example 9) relates to a previously described example (e.g. one of the examples 1-7), wherein the portion of the wall extends stepwise from the base.

Another example (e.g. example 10) relates to a previously described example (e.g. one of the examples 1-9), wherein the axis orthogonal to the base is parallel to a rotational axis of an impeller mount of the fan chassis.

Another example (e.g. example 11) relates to a previously described example (e.g. one of the examples 1-10), wherein the portion that extends from a base of the fan chassis at the acute angle is a fold.

Another example (e.g. example 12) relates to a previously described example (e.g. example 11), further comprising a cutwater, wherein the cutwater comprises the fold.

An example (e.g. example 13) is a cutwater for an interior wall of a fan chassis, the cutwater comprising a passage that extends from a proximal portion of the cutwater to a distal portion of the cutwater.

Another example (e.g. example 14) relates to a previously described example (e.g. example 13), wherein the passage is an aperture through the cutwater.

Another example (e.g. example 15) relates to a previously described example (e.g. example 14), wherein a diameter of the aperture is at least 0.5 millimeters and at most 1 millimeters.

Another example (e.g. example 16) relates to a previously described example (e.g. example 13), wherein the passage is a recess in a face of the cutwater.

Another example (e.g. example 17) relates to a previously described example (e.g. example 16), wherein a width of the recess is at least 0.5 millimeters and at most 1 millimeters.

Another example (e.g. example 18) relates to a previously described example (e.g. one of the examples 13-17), wherein the cutwater further comprises a fold between the proximal portion and the distal portion of the cutwater.

Another example (e.g. example 19) relates to a previously described example (e.g. one of the examples 13-18), wherein the passage extends at least partially along a tangent of a curve of the interior wall.

Another example (e.g. example 20) relates to a previously described example (e.g. example 19), wherein the tangent is adjacent to the distal end of the face.

Another example (e.g. example 21) relates to a previously described example (e.g. one of the examples 13-20), wherein the passage is tangent to a circle originating at an impeller mount of the fan chassis.

Another example (e.g. example 22) relates to a previously described example (e.g. one of the examples 13-21), wherein a distance of the passage from a base of the fan chassis is at least 1 millimeter and at most 6 millimeters.

An example (e.g. example 23) is cutwater for an interior wall of a fan chassis, the cutwater comprising a fold with an increasing bend radius extending from a base of the fan chassis.

Another example (e.g. example 24) relates to a previously described example (e.g. example 23), wherein the fold extends from the base at one or more acute angles to an axis orthogonal to the base.

Another example (e.g. example 25) relates to a previously described example (e.g. example 24), wherein the one or more acute angles are an inclination angle and/or a lean angle.

Another example (e.g. example 26) relates to a previously described example (e.g. one of the examples 23-25), wherein the fold is between a proximal portion of the cutwater and a distal portion of the cutwater, and wherein the cutwater further comprises a passage extending from the proximal portion to the distal portion.

Another example (e.g. example 27) relates to a previously described example (e.g. one of the examples 23-26), wherein the fold extends stepwise from the base.

Another example (e.g. example 28) relates to a previously described example (e.g. one of the examples 23-27), wherein the cutwater comprises an acoustic dampening material.

An example (e.g. example 29) is a centrifugal fan, wherein a chassis of the centrifugal fan comprises a cutwater that extends from a base of the chassis toward a lid of the chassis, wherein a portion of the cutwater extends at one or more acute angles to a rotational axis of an impeller of the centrifugal fan.

Another example (e.g. example 30) relates to a previously described example (e.g. example 29), wherein the one or more acute angles are an inclination angle and/or a lean angle.

Another example (e.g. example 31) relates to a previously described example (e.g. one of the examples 29-30), wherein the cutwater comprises an aperture and/or a recess extending from a proximal portion of the cutwater to a distal portion of the cutwater.

Another example (e.g. example 32) relates to a previously described example (e.g. example 31), wherein the aperture and/or the recess extend along a tangent to a circle originating the rotational axis of the impeller.

Another example (e.g. example 33) relates to a previously described example (e.g. one of the examples 31-32), wherein the proximal portion extends toward an outlet of the chassis and the distal portion extends away from the outlet.

Another example (e.g. example 34) relates to a previously described example (e.g. one of the examples 29-33), wherein the lid comprises an inlet.

Another example (e.g. example 35) relates to a previously described example (e.g. one of the examples 29-34), wherein a height of the chassis is at least 3.5 millimeters and at most 15 millimeters.

Another example (e.g. example 36) relates to a previously described example (e.g. example 35), wherein the height of the chassis is at least 11 millimeters and at most 13 millimeters.

Another example (e.g. example 37) relates to a previously described example (e.g. example 36), wherein a blade height of the impeller is at least 8 millimeters and at most 10 millimeters.

Another example (e.g. example 38) relates to a previously described example (e.g. one of the examples 29-37), wherein the chassis comprises an acoustic dampening material.

An example (e.g. example 39) is a system comprising a previously described example (e.g. one of the examples 1-38).

An example (e.g. example 40) is a method for forming a previously described example (e.g. one of the examples 1-39).

The disclosed methods, apparatuses, and systems are not to be construed as limiting in any way. Instead, the present disclosure is directed toward all novel and nonobvious features and aspects of the various disclosed examples, alone and in various combinations and sub-combinations with one another. The disclosed methods, apparatuses, and systems are not limited to any specific aspect or feature or combination thereof, nor do the disclosed examples require that any one or more specific advantages be present, or problems be solved.

Theories of operation, scientific principles, or other theoretical descriptions presented herein in reference to the apparatuses or methods of this disclosure have been provided for the purposes of better understanding and are not intended to be limiting in scope. The apparatuses and methods in the appended claims are not limited to those apparatuses and methods that function in the manner described by such theories of operation.

The following claims are hereby incorporated in the detailed description, wherein each claim may stand on its own as a separate example. It should also be noted that although in the claims a dependent claim refers to a particular combination with one or more other claims, other examples may also include a combination of the dependent claim with the subject matter of any other dependent or independent claim. Such combinations are hereby explicitly proposed unless it is stated in the individual case that a particular combination is not intended. Furthermore, features of a claim should also be included for any other independent claim, even if that claim is not directly defined as dependent on that other independent claim.

APPARATUS FOR REDUCING AIR TURBULENCE IN A FAN CHASSIS

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