Patent Application
20250207774
The disclosure generally relates to cooling systems and, more particularly, to cooling systems for combustors.
This section provides background information related to the present disclosure which is not necessarily prior art.
Rotating detonation combustors are a category of pressure gain combustors which offer a pressure gain during the combustion process. Such combustion processes can deliver more compact engine designs with potentially higher efficiency. This known system consists of two concentric cylinders through which fresh mixture is injected and detonated. A strong detonation wave consumes the fresh mixture at ˜2000 m/s (for hydrogen air mixtures), with highly unsteady but periodic pressures waves traveling around the combustors and periodic heat fluxes on the wall.
Known rotating detonation combustor test rigs around the country are either operated only during a very short duration, or water cooled, which prevents the implementation in propulsion systems.
Accordingly, there is a continuing need for a cooling system for rotating detonation combustors. Desirably, the cooling system may be light weight so that the cooling system may be applied to airbreathing and rocket propulsion applications.
In concordance with the instant disclosure, a cooling system that may be utilized with a rotating detonation combustor that permits continuous operation, has surprisingly been discovered. Desirably, the cooling system may be light weight compared to known cooling methods, thus allowing the cooling system to be applied to propulsion applications.
A cooling system of the present disclosure may be configured to lower an operating temperature of a combustor and/or cool the walls of the combustor. The combustor may include a combustor channel opening around a central axis. The cooling system includes a jacket disposed at least partially around the combustor. The jacket includes a slot having an opening oriented towards a downstream end of the combustor. It is also contemplated the opening the slot may be oriented towards an upstream end of the combustor in certain circumstances. In certain circumstances, the slot of the jacket may include a plurality of slots. The slot may include a width ranging from around 0.5% to around 100% of the width of the combustor channel opening. In a specific example, the slot may accept a coolant through the opening of the slot. The coolant may enhance the cooling capabilities of the cooling system.
The cooling system may be provided in various ways. For instance, the cooling system may be used according to a method to lower an operating temperature of a combustor having a combustor channel opening around a central axis. The method may include a step of providing the cooling system having a jacket disposed at least partially around the combustor. The jacket may include a slot having an opening oriented towards a downstream end of the combustor. A coolant may be injected into the opening of the slot. Afterwards, the combustor may be cooled.
Further areas of applicability will become apparent from the description provided herein. The description and specific examples in this summary are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure.
The drawings described herein are for illustrative purposes only of selected embodiments and not all possible implementations and are not intended to limit the scope of the present disclosure.
The following description of technology is merely exemplary in nature of the subject matter, manufacture, and use of one or more inventions, and is not intended to limit the scope, application, or uses of any specific invention claimed in this application or in such other applications as may be filed claiming priority to this application, or patents issuing therefrom. Regarding methods disclosed, the order of the steps presented is exemplary in nature, and thus, the order of the steps can be different in various embodiments, including where certain steps can be simultaneously performed. “A” and “an” as used herein indicate “at least one” of the item is present; a plurality of such items may be present, when possible. Except where otherwise expressly indicated, all numerical quantities in this description are to be understood as modified by the word “about” and all geometric and spatial descriptors are to be understood as modified by the word “substantially” in describing the broadest scope of the technology. “About” when applied to numerical values indicates that the calculation or the measurement allows some slight imprecision in the value (with some approach to exactness in the value; approximately or reasonably close to the value; nearly). If, for some reason, the imprecision provided by “about” and/or “substantially” is not otherwise understood in the art with this ordinary meaning, then “about” and/or “substantially” as used herein indicates at least variations that may arise from ordinary methods of measuring or using such parameters.
Although the open-ended term “comprising,” as a synonym of non-restrictive terms such as including, containing, or having, is used herein to describe and claim embodiments of the present technology, embodiments may alternatively be described using more limiting terms such as “consisting of” or “consisting essentially of.” Thus, for any given embodiment reciting materials, components, or process steps, the present technology also specifically includes embodiments consisting of, or consisting essentially of, such materials, components, or process steps excluding additional materials, components or processes (for consisting of) and excluding additional materials, components or processes affecting the significant properties of the embodiment (for consisting essentially of), even though such additional materials, components or processes are not explicitly recited in this application. For example, recitation of a composition or process reciting elements A, B and C specifically envisions embodiments consisting of, and consisting essentially of, A, B and C, excluding an element D that may be recited in the art, even though element D is not explicitly described as being excluded herein.
As referred to herein, disclosures of ranges are, unless specified otherwise, inclusive of endpoints and include all distinct values and further divided ranges within the entire range. Thus, for example, a range of “from A to B” or “from about A to about B” is inclusive of A and of B. Disclosure of values and ranges of values for specific parameters (such as amounts, weight percentages, etc.) are not exclusive of other values and ranges of values useful herein. It is envisioned that two or more specific exemplified values for a given parameter may define endpoints for a range of values that may be claimed for the parameter. For example, if Parameter X is exemplified herein to have value A and also exemplified to have value Z, it is envisioned that Parameter X may have a range of values from about A to about Z. Similarly, it is envisioned that disclosure of two or more ranges of values for a parameter (whether such ranges are nested, overlapping, or distinct) subsume all possible combination of ranges for the value that might be claimed using endpoints of the disclosed ranges. For example, if Parameter X is exemplified herein to have values in the range of 1-10, or 2-9, or 3-8, it is also envisioned that Parameter X may have other ranges of values including 1-9, 1-8, 1-3, 1-2, 2-10, 2-8, 2-3, 3-10, 3-9, and so on.
When an element or layer is referred to as being “on,” “engaged to,” “connected to,” or “coupled to” another element or layer, it may be directly on, engaged, connected, or coupled to the other element or layer, or intervening elements or layers may be present. In contrast, when an element is referred to as being “directly on,” “directly engaged to,” “directly connected to” or “directly coupled to” another element or layer, there may be no intervening elements or layers present. Other words used to describe the relationship between elements should be interpreted in a like fashion (e.g., “between” versus “directly between,” “adjacent” versus “directly adjacent,” etc.). As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items.
Although the terms first, second, third, etc. may be used herein to describe various elements, components, regions, layers and/or sections, these elements, components, regions, layers and/or sections should not be limited by these terms. These terms may be only used to distinguish one element, component, region, layer or section from another region, layer, or section. Terms such as “first,” “second,” and other numerical terms when used herein do not imply a sequence or order unless clearly indicated by the context. Thus, a first element, component, region, layer, or section discussed below could be termed a second element, component, region, layer, or section without departing from the teachings of the example embodiments.
Spatially relative terms, such as “inner,” “outer,” “beneath,” “below,” “lower,” “above,” “upper,” and the like, may be used herein for ease of description to describe one element or feature's relationship to another element(s) or feature(s) as illustrated in the figures. Spatially relative terms may be intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the FIG. is turned over, elements described as “below”, or “beneath” other elements or features would then be oriented “above” the other elements or features. Thus, the example term “below” can encompass both an orientation of above and below. The device may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly.
A cooling system 100 of the present disclosure may be configured to lower an operating temperature of a combustor 102 and/or reduce the temperature near a wall of the combustor 102 without lowering the core temperature of the combustor 102. As shown in
In certain circumstances, the slot S1, S2, S3 may be provided in various ways. For instance, the slot S1, S2, S3 may be substantially parallel with the central axis A. In another example, as shown in
In certain circumstances, as shown in
In certain circumstances, the coolant may be provided in various ways. For instance, the coolant may be provided in a gaseous state. The coolant may include nitrogen. In a more specific example, the coolant may include air. In another non-limiting example, the coolant may include a fuel and/or an oxidizer. The coolant may be injected in a subsonic and/or supersonic core flow. A flow of the coolant may be provided at a lower static pressure than the static pressure in the combustor 102 if injected in a high-speed region. A skilled artisan may select other suitable ways to provide the coolant, within the scope of the present disclosure.
The pressures in the rotating detonation combustor 102 vary cyclically, which means that during a certain period of time the combustor pressure might be too high to inject cooling into the combustor 102, and flow reversal can happen or the cooling slots S1, S2, S3 are blocked off. Whereas when the pressure is sufficiently low within the combustion chamber, the cooling slots S1, S2, S3 are activated and cooling may be provided to the combustor walls.
In certain circumstances, the jacket 106 may be provided in various ways. For instance, the jacket 106 may be constructed from a metal, a ceramic, a composite material, and/or a plastic. In a specific example, the jacket 106 may be constructed from milling and/or additive manufacturing. In another specific example, the jacket 106 may be made of a porous material to allow transpiration cooling to further enhance its cooling capabilities. As shown in
The cooling system 100 may be provided in various ways. For instance, as shown in
In certain circumstances, the cooling system 100 may include a combustor 102 having a central axis A and a jacket 106 disposed at least partially around the combustor 102. The jacket 106 may include a slot S1, S2, S3 having an opening oriented towards a downstream end DE of the combustor 102. In a specific example, the combustor 102 may include a hollow cylinder and/or a concentric cylinder. In a more specific example, the cylinder of the combustor 102 may include a diverging wall and/or a converging wall. In another specific example, the inner cylinder may also contain a slot or a plurality of slots to provide cooling to protect this surface. It is also contemplated that the cooling system 100 may include a combustor 102 that does not utilize a center body, such as a cylinder. One skilled in the art may select other suitable ways to provide the cooling system 100, within the scope of the present disclosure.
Advantageously, as shown in
Provided as a specific, non-limiting example, one embodiment of the cooling system 100 was experimentally tested. Thermocouples were affixed to the rear-side of all three film-cooling slots S1, S2, S3 to determine surface temperature of each cooling slot S1, S2, S3. Additionally, pressure taps were integrated into the film-cooling apparatus such that static pressures were also available for each slot S1, S2, S3.
For each test, a Phantom high-speed camera operating at 100 khz was used in conjunction with a mirror to visualize the detonation waves from the aft of the combustor 102, looking forward. Due to heat distortion from the combustor exhaust during firing, the resulting high-speed footage exhibits noticeable distortion. Nevertheless, detonation waves are still visible, as shown in
A full test matrix for this campaign is shown below in Table 1. Of note, despite 33 tests having been run, only 23 of the tests had successful ignition. The remaining were either cold-flows or failed-ignitions. For this data analysis, only the ignited tests have been considered. Test #32 is an uncooled control case.
As an initial demonstration of the cooling-slot effectiveness, the temperature profile of the uncooled control case (Test #32) is plotted alongside that of Test #33, the longest duration cooled test and is depicted in
The start and end times used here are derived from thrust measurements by virtue of a load-cell integrated into the RDC frame. Due to installation, an absolute value of the RDC thrust was not measured, however the load-cell data provides a relative comparison that enables the determination of the test window, as shown in
This method was found to be robust enough to determine test start and end points for all ignited tests. As shown in
To determine the impact of the coolant mass-flow on the cooling performance, the blowing ratio (BR) is defined as follows:
A higher value of BR indicates more cooling, for instance a value of 1 indicates cooling mass-flow is equal to propellant mass flow, whereas a value of 0 indicates an uncooled test. For these experiments, blowing ratio never exceeds 0.5, as a measure to avoid ignition/detonation difficulty due to excessive nitrogen dilution.
The slot temperature increase can be shown by the average rate of slot temperature change, expressed as the following ratio:
Where Tmax and Tinitial are the temperatures recorded at the end and at the start of the test respectively, and ttest is the test duration. The decision to use this rate instead of a direct temperature delta (Tfinal−Tinital) or ratio (Tfinal/Tinital) was made to remove the dependence on test duration.
By plotting this rate against the previously defined blowing ratio, a correlation between cooling mass-flow and slot temperature increase rate can be observed in
As can be seen, the uncooled test has the highest slot temperature change, but as cooling increases, the slot temperature change is less pronounced. For a clearer view, the slapping-mode tests have been omitted in
As shown in
With reference to
As shown through the experimental testing, the temperature readings of the cooling system 100 show the successful cooling of the hardware throughout the test matrix, also at lower blowing ratios.
Example embodiments are provided so that this disclosure will be thorough and will fully convey the scope to those who are skilled in the art. Numerous specific details are set forth such as examples of specific components, devices, and methods, to provide a thorough understanding of embodiments of the present disclosure. It will be apparent to those skilled in the art that specific details need not be employed, that example embodiments may be embodied in many different forms, and that neither should be construed to limit the scope of the disclosure. In some example embodiments, well-known processes, well-known device structures, and well-known technologies are not described in detail. Equivalent changes, modifications and variations of some embodiments, materials, compositions, and methods can be made within the scope of the present technology, with substantially similar results.
This application claims the benefit of U.S. Provisional Application No. 63/613,304 filed Dec. 21, 2023, the entirety of which is hereby incorporated by reference.
| Number | Date | Country | |
|---|---|---|---|
| 63613304 | Dec 2023 | US |
