Patent Application
20200400377
The present disclosure relates generally to heat exchangers and more particularly to closure bars incorporated into a heat exchanger.
For heat exchangers exposed to large temperature differentials, closure bars at the heat exchanger inlet are subjected to higher temperatures than at other locations. Thermal growth of the closure bar(s) can result in significant stress and potential damage to other heat exchanger parts.
A heat exchanger includes first and second parting sheets, a cold fin extending between the first and second parting sheets, and a closure bar extending between the first and second parting sheets. The closure bar includes first, second, third, and fourth surfaces, a body, first and second ends, an inlet, and an outlet. The body forms an opening that extends from the first end to the second end of the body. The first surface faces the cold fin. The second surface is an opposite side of the body from the first surface. The third surface is in contact with the first parting sheet. The fourth surface is in contact with the second parting sheet. The inlet is disposed at the first end of the closure bar and is fluidly connected to the outlet via the opening. The outlet is disposed at the second end of the closure bar.
A method of managing thermal energy in a heat exchanger includes impinging a flow of hot air onto a closure bar of the heat exchanger. Thermal energy is transferred from the flow of hot air to the body of the closure bar. A flow of cold air is inserted into and through the opening. Thermal energy is transferred from the body of the closure bar to the flow of cold air. The flow of cold air is then ejected out of the opening.
The present summary is provided only by way of example, and not limitation. Other aspects of the present disclosure will be appreciated in view of the entirety of the present disclosure, including the entire text, claims, and accompanying figures.
While the above-identified figures set forth one or more embodiments of the present disclosure, other embodiments are also contemplated, as noted in the discussion. In all cases, this disclosure presents embodiments by way of representation and not limitation. It should be understood that numerous other modifications and embodiments can be devised by those skilled in the art, which fall within the scope and spirit of the principles of the disclosure. The figures may not be drawn to scale, and applications and embodiments of the present disclosure may include features and components not specifically shown in the drawings.
The present disclosure presents a heat exchanger closure bar that incorporates a flow path/hole with swirl vanes through the depth of the bar (along the cold flow length) to enhance heat transfer and induce mixing to preclude the development of a hot fluid layer along the surface of the cold side of the closure bar.
Closure bar 10 is a flat piece of solid material. In this example, a material of closure bar 10 includes a metal. Body 12 is a bulk of solid material of closure bar 10. First surface 14, second surface 16, third surface 18, and fourth surface 20 are exterior faces or sidewalls of body 12. First end 22 and second end 24 are opposite ends of body 12. Opening 26 is a channel or passage. In this example, a shape of opening 26 includes a cylinder or tube. Inlet 28 and outlet 30 are fluidic ports or openings. Features 32 are protrusions of solid material. In this example, features 32 include four swirl vanes that each include a helical shape. Other shapes of features 32 can include a spiral, a helicoid, or a corkscrew shape. In other non-limiting embodiments, features 32 can include more or less than four features, and can include turbulence imparting/inducing features such as airfoils, blades, vanes, or splitters. First flow F1 and second flow F2 are streams of airflow. In this example, first flow F1 is a flow of hot air and second flow F2 is a flow of cold air (i.e., second flow F2 of air has a lesser amount of thermal energy than first flow F1 of air).
Closure bar 10 is positioned between parting sheets as part of a heat exchanger. (See e.g.,
During operation of the heat exchanger, closure bar 10 functions as a barrier to prevent mixing of first flow F1 of air, second flow F2 of air, and other flows of air flowing through the heat exchanger. Body 12 absorbs thermal energy from first flow F1 of air and transfers the thermal energy from first flow F1 of air to a portion of second flow F2 of air that is passing through opening 26. Second surface 16 is in contact with first flow F1 of air and transfers thermal energy from first flow F1 of air to body 12. Opening 26 provides a fluidic through-hole through which second flow F2 of air passes through body 12. Inlet 28 provides an intake through which second flow F2 of air enters opening 26. Outlet 30 provides an output through which second flow F2 of air exits opening 26. Features 32 impart turbulence into second flow F2 of air by swirling (e.g., inducing a rotation or spin into) second flow F2 of air due to the helical shape of features 32.
Closure bar 10 with features 32 prevents the development of a hot fluid layer along first surface 14 (e.g., the cold side) of closure bar 10. Such a hot fluid layer would prevent thermal energy transfer due to a reduced temperature differential between first surface 14 and a fluid passing across first surface 14. As a result, a temperature of closure bar 10 is reduced, which reduces stresses to surrounding components due to thermal growth of closure bar 10.
First parting sheet 34 and second parting sheet 36 are planar sheets of solid material. In this example, first parting sheet 34 and second parting sheet 36 include a metallic material. Cold fin 38 is a thin sheet with a corrugated or zig-zag shape. In this example, features 32 are shown as extending radially inward relative to the generally circular shape of opening 26. Here, a height (or depth) of features is shown as extending partially towards a centerpoint of opening 26. In other non-limiting embodiments, features 32 can radially extend to or past the centerpoint of opening 26.
In this example, second flow F2 of air flows into and through opening 26 in a direction that is into the page (as shown in
During operation, a temperature of first flow F1 of air can be so high as to impart damaging temperature differentials between closure bar 10 and first and second parting sheets 34 and 36. Here, closure bar 10 with opening 26 acts to reduce the temperature differentials between closure bar 10 and first and second parting sheets 34 and 36 by increasing a rate of cooling of closure bar 10 with second flow F2 of air through opening 26. Features 32 impart swirl into second flow F2 of air thereby increasing the transfer of thermal energy between closure bar 10 and second flow F2 of air, which also prevents a hot layer of air forming at first surface 14 of closure bar 10. It can also be understood that other components that closure bar 10 is in contact with or in the vicinity of may also see a reduction of damaging temperature differentials via the improved transfer of thermal energy between closure bar 10 and second flow F2 of air.
In
First channel 140 and second channel 142 provide additional through-channels through which second flow F2 of air can flow through closure bar 10 thereby increasing the rate of transfer of thermal energy from first flow F1 of air, to closure bar 10, and to second flow F2 of air.
A heat exchanger includes first and second parting sheets, a cold fin extending between the first and second parting sheets, and a closure bar extending between the first and second parting sheets. The closure bar includes first, second, third, and fourth surfaces, a body, first and second ends, an inlet, and an outlet. The body forms an opening that extends from the first end to the second end of the body. The first surface faces the cold fin. The second surface is an opposite side of the body from the first surface. The third surface is in contact with the first parting sheet. The fourth surface is in contact with the second parting sheet. The inlet is disposed at the first end of the closure bar and is fluidly connected to the outlet via the opening. The outlet is disposed at the second end of the closure bar.
The heat exchanger of the preceding paragraph can optionally include, additionally and/or alternatively, any one or more of the following features, configurations and/or additional components.
A feature can extend from the body into the opening, wherein the feature can be configured to impart turbulence into a flow of air that passes through the opening.
The feature can comprise a swirl vane.
The swirl vane can include a helical shape.
The feature can comprise a plurality of swirl vanes.
The second surface of the body can be exposed to the hot air flow, and wherein the opening can be exposed to the cold air flow.
A first channel can be formed between the body and the first parting sheet, wherein the first channel can be parallel to the opening and/or can extend from the first end to the second end of the body.
A second channel can be formed between the body and the second parting sheet, wherein the second channel can be positioned on an opposite side of the opening as from the first channel, wherein the second channel can be parallel to the opening and/or can extend from the first end to the second end of the body.
A method of managing thermal energy in a heat exchanger includes impinging a flow of hot air onto a closure bar of the heat exchanger. Thermal energy is transferred from the flow of hot air to the body of the closure bar. A flow of cold air is inserted into and through the opening. Thermal energy is transferred from the body of the closure bar to the flow of cold air. The flow of cold air is then ejected out of the opening.
The method of the preceding paragraph can optionally include, additionally and/or alternatively, any one or more of the following steps, features, configurations and/or additional components.
The flow of air can be swirled with a feature that extends from the body into the opening.
The flow of air can be swirled with a plurality of swirl vanes that extend from the body into the opening.
While the invention has been described with reference to an exemplary embodiment(s), it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment(s) disclosed, but that the invention will include all embodiments falling within the scope of the appended claims.
This invention was made with government support under Contract #FA8626-16-C-2139 awarded by the Air Force. The government has certain rights in the invention.
