Heat exchangers and articles
The heat exchanger with curvilinear cooling channels addresses thermal management challenges in rocket thrust chambers and nozzles by enhancing heat transfer and structural strength, reducing pressure loss in cooling systems.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- AEROJET ROCKETDYNE INC
- Filing Date
- 2025-05-14
- Publication Date
- 2026-05-19
AI Technical Summary
Existing cooling systems for rocket thrust chambers and nozzles face challenges in effectively managing high temperatures without causing damage or erosion, particularly when using cryogenic propellants.
A heat exchanger with cooling channels having varying circumferential and radial curvatures, arranged in a nested configuration, enhances thermal management by improving heat transfer efficiency and structural strength.
The curvilinear cooling channels reduce pressure loss while maintaining high heat transfer capacity and structural integrity, allowing for effective thermal management in high-temperature environments.
Smart Images
Figure 2026082616000001_ABST
Abstract
Description
Technical Field
[0001] (Statement Regarding Federally Sponsored Research and Development) This invention was made with government support under Contract No. FA8650-23-C-5709, awarded by the Air Force Research Laboratory. The government has certain rights in this invention.
Background Art
[0002] The operation of rocket motors involves very high temperatures, which can cause damage and erosion to the thrust chamber or nozzle. Therefore, liquid coolants such as propellants are used for cooling the thrust chamber and / or nozzle. For example, some or all of the propellant passes through tubes or channels provided around the thrust chamber and / or nozzle. These paths are formed, for example, by brazing cooling tubes to the thrust chamber / nozzle or by machining channels along the walls of the thrust chamber / nozzle. Propellants are often cryogenic and provide effective thermal load management. The heated propellant is then supplied to a gas generator or directly injected into the main combustion chamber.
Summary of the Invention
Problems to be Solved by the Invention
[0003] Therefore, an object of the present invention is to improve the cooling of the type described at the beginning.
Means for Solving the Problems
[0004] A heat exchanger according to an example of the present disclosure includes a wall disposed around a central axis and having a first end, a second end, a first side surrounding a chamber, and a second side opposite the first side. The first side and the second side extend from the first end to the second end. An array of a plurality of cooling channels is embedded in the wall to allow a cooling fluid to flow therethrough. Each of the cooling channels defines a flow path having a circumferential curvature that varies with respect to the axial direction.
[0005] In a further embodiment of any of the embodiments described above, the changing circumferential curvature has a periodic shape.
[0006] In any further embodiment of the above-described embodiments, the periodic shape is a sine wave.
[0007] In any further embodiment of the above-described embodiments, the periodic shape is non-sinusoidal.
[0008] In a further embodiment of any of the embodiments described above, the cooling channel defines a flow path having radial curvature that varies with respect to the axial direction.
[0009] In any further embodiment of the above-described embodiments, each cooling channel includes a first section extending from a first end to a second end, a second section extending from a second end to a first end, and a turn section at the second end that fluidly connects the first section and the second section.
[0010] In any further embodiment of the above-described embodiments, the cooling channels are fluidly separated from each other within the wall.
[0011] In any further embodiment of the above-described embodiments, each of the cooling channels defines a channel width, the waveform channel profile defines the period and amplitude, and the amplitude-to-channel width ratio is 2:1 or greater.
[0012] In any further embodiment of the above-described embodiments, the wall is cylindrical.
[0013] In any further embodiment of the above-described embodiments, the wall is frustoconical.
[0014] In a further embodiment of any of the embodiments described above, each cooling channel includes a first section extending from a first end to a second end, a second section extending from a second end to a first end, and a turn section connecting the first and second sections at the second end. These cooling channels are fluidly isolated from one another. The cooling channels have a constant cross-sectional area along the longitudinal direction from the first end to the second end. Each cooling channel defines a channel width. The waveform channel profile defines the period and amplitude, and the ratio of amplitude to channel width is 2:1 or greater.
[0015] An example of an article relating to the present disclosure includes a nozzle arranged around a central axis and formed by a wall surrounding a chamber. The wall has a first axial end, a second axial end, an inner portion surrounding the chamber, and an outer portion opposite the inner portion. An array of cooling channels is embedded in the wall to allow a cooling fluid to flow through it. Each of the cooling channels defines a flow path having a circumferential curvature that varies with respect to the axial direction.
[0016] In any further embodiment of the above-described embodiments, the cooling channels are nested circumferentially.
[0017] In any further embodiment of the above-described embodiments, the nozzle is a convergence-diffusion nozzle.
[0018] In any further embodiment of the above-described embodiments, each cooling channel includes a first section extending from a first axial end to a second axial end, a second section extending from a second axial end to a first axial end, and a turn section that fluidly connects the first section and the second section at the second axial end.
[0019] In any further embodiment of the above-described embodiments, the cooling channels are fluidly separated from each other within the wall.
[0020] In a further embodiment of any of the foregoing embodiments, the cooling channel has a constant cross-sectional area along the length direction from the first axial end to the second axial end.
[0021] In a further embodiment of any of the foregoing embodiments, each of the cooling channels defines a channel width, the wavy channel profile defines a period and an amplitude, and the ratio of the amplitude to the channel width is 2:1 or more.
[0022] The present disclosure may include any one or more of the individual features disclosed above and / or below, either alone or in any combination thereof.
[0023] The various features and advantages of the present disclosure will be apparent to those skilled in the art from the following detailed description. In the present disclosure, the same reference numbers indicate the same elements where appropriate, and reference numbers with a multiple of 100 added to the number indicate modified elements having the same features and advantages as the corresponding elements. The drawings accompanying the detailed description can be briefly described as follows.
Brief Description of the Drawings
[0024] [Figure 1] It is a diagram showing a heat exchanger. [Figure 2] It is a perspective view of the channel of the heat exchanger. [Figure 3] It is a side view of the channel of the heat exchanger. [Figure 4] It is a diagram showing a part of the channel of the heat exchanger. [Figure 5] It is a radial cross-sectional view of the heat exchanger. [Figure 6] It is a perspective view of the channel of the nozzle including the heat exchanger. [Figure 7] It is a side view of the channel of the nozzle including the heat exchanger.
Modes for Carrying Out the Invention
[0025] Figure 1 schematically shows a selected portion of the heat exchanger 20. The heat exchanger 20 may be installed in the nozzle, combustion chamber, or air breathing propulsion system of a rocket engine, but is not limited to these locations, and can be applied to any end-use product employing regenerative cooling.
[0026] The heat exchanger 20 includes a wall 22 having a first end 22a, a second end 22b, a first (inner) side 22c surrounding a chamber 24 (e.g., a combustion chamber), and a second (outer) side 22d opposite the first side 22c. As understood, the wall 22 is shown as a cylindrical shape about a central axis A so as to surround the chamber 24. However, the wall 22 may have another shape selected depending on the end application. The wall 22 defines the longitudinal direction between the ends 22a / 22b, which in this case is axial.
[0027] The wall 22 is embedded with an array of cooling channels 26 for transporting a cooling fluid (collectively represented by C) that flows through the wall 22 for thermal management. The cooling fluid is not limited and may be, for example, a propellant. Figures 2 and 3 show the channels 26 in solid form, excluding the solid portion of the wall 22, thereby revealing the shape of the channels 26, and Figure 4 shows a representative portion of one channel 26. The channels 26 can have circular, rectangular, or other cross-sectional shapes. Each cooling channel 26 defines a flow path 28 from one end 22a to the other end 22b. This profile includes curvature that can vary in the axial, radial, and circumferential directions. This profile is not linear or straight in three-dimensional space. The curvature can vary periodically. The curvature may also appear wavy. For example, in the illustrated example, the flow path 28 has periodically varying curvature. As an example, the flow path 28 has sinusoidal curvature. Alternatively, the curvature of the flow path is non-sinusoidal.
[0028] The channels 26 are arranged close together to promote good heat transfer. For example, as shown in Figure 3, the channels 26 are arranged in a nested manner in the circumferential direction. This means that the peaks of one channel interlock with the valleys of the adjacent channels. This configuration allows for a narrow spacing between the channels 26, and the heat exchange capacity can be adjusted by changing this spacing. The channels 26 within the wall 22 are fluidically separated from each other. For example, a coolant is supplied to the first section 26a of each channel 26 from the first end 22a. The coolant flows through the first section 26a from the first end 22a to the second end 22b, where it is discharged from the wall 22.
[0029] Figure 5 is a cross-sectional view taken by a radial plane passing through the wall 22, showing a typical cross-section of the channel 26. In this example, the channel 26 has a constant rectangular cross-section along its (axial) length from the first end 22a to the second end 22b, but it may be circular, elliptical, or of other shape. For example, each channel 26 defines a channel width W, and the corrugated channel profile 28 defines a period P and amplitude A1 (see Figure 4). The channel width W, period P, and amplitude A1 can be selected based on desired operating characteristics such as pressure drop and flow rate. The ratio of amplitude A1 to channel width W can be, for example, 2:1 or greater, for example, 3:1, 5:1, or 8:1. Such a ratio, for example, can reduce the scale of the channel 26 while keeping the pressure loss in the corrugated flow path of the channel 26 low.
[0030] Figures 6 and 7 show another exemplary article 120 having a wall 122 with multiple channels 126. Similar to the preceding figures, the channels 126 are shown in solid form with the solid portion of the wall 122 removed. The channels 126 have a corrugated channel profile 28 as described above. However, in this example, the wall 122 is not cylindrical but is formed as a convergent-divergent nozzle 123 having a converging frustoconical section 123a and a diverging frustoconical section 123b.
[0031] Articles 20 / 120 may be formed using additive manufacturing methods such as selective laser melting of metal alloy powders, but are not limited thereto. The alloy is not particularly limited and can be selected based on the desired performance of the end-use article. For example, the alloy may be a titanium alloy, a copper alloy, or a nickel-chromium alloy such as Inconel 625.
[0032] The configuration of channels 26 / 126 also helps to increase the strength of the walls 22 / 122 compared to straight channels. For example, the solid lands 22e between channels 26 / 126 (Figure 5) extend at an angle of approximately 45° along the corrugated inclined sides of channels 26 / 126. The 45° angle facilitates balancing the circumferential stress within the channel with the pressure stress from the coolant, resulting in an overall improvement in strength compared to straight channels and increasing flexibility in the design of article 20 / 120. Furthermore, the corrugated channel profile 28 also improves heat transfer performance. Normally, an improvement in heat transfer capacity comes with the penalty of increased pressure loss in the coolant flow. However, the corrugated channel profile 28 allows for wider channels that reduce pressure loss while enabling relatively narrow channel spacing for improved heat transfer. As a result, at least a moderate improvement in heat transfer can be achieved without the pressure loss penalty that is normally expected.
[0033] While the illustrated examples show combinations of features, it is not necessary to combine all of them to realize the advantages of the various embodiments of this disclosure. In other words, a system designed according to the embodiments of this disclosure does not necessarily include all of the features shown in any of the figures, or all of the parts schematically shown in the figures. Furthermore, selected features from one embodiment may be combined with selected features from another embodiment.
[0034] The above description is illustrative and not limiting in nature. It will be apparent to those skilled in the art that variations and modifications to the disclosed examples will not necessarily deviate from this disclosure. The scope of legal protection granted in this disclosure can only be determined by considering the following claims.
Claims
1. A wall arranged around a central axis, having a first end, a second end, a first side surrounding a chamber, and a second side opposite the first side, the first side and the second side extending from the first end to the second end, An array of cooling channels embedded in the wall to allow a cooling fluid to flow through, wherein each of the cooling channels defines a flow path having a circumferential curvature that changes with respect to the axial direction; A heat exchanger equipped with [a specific feature].
2. The heat exchanger according to claim 1, characterized in that the changing circumferential curvature has a periodic shape.
3. The heat exchanger according to claim 2, characterized in that the periodic shape is sinusoidal.
4. The heat exchanger according to claim 2, characterized in that the periodic shape is non-sinusoidal.
5. The heat exchanger according to claim 1, characterized in that the cooling channel defines a flow path having a radial curvature that changes with respect to the axial direction.
6. The heat exchanger according to claim 1, characterized in that each of the cooling channels includes a first section extending from the first end to the second end, a second section extending from the second end to the first end, and a turn section that fluidly connects the first section and the second section at the second end.
7. The heat exchanger according to claim 6, characterized in that the plurality of cooling channels are fluidly separated from each other within the wall.
8. The heat exchanger according to claim 1, characterized in that each of the cooling channels defines a channel width, the waveform channel profile defines a period and amplitude, and the ratio of the amplitude to the channel width is 2:1 or greater.
9. The heat exchanger according to claim 1, characterized in that the wall is cylindrical.
10. The heat exchanger according to claim 1, characterized in that the wall is frustoconical in shape.
11. The heat exchanger according to claim 1, wherein each of the cooling channels includes a first section extending from the first end to the second end, a second section extending from the second end to the first end, and a turn section connecting the first section and the second section at the second end, the plurality of cooling channels are fluidly separated from each other, the cooling channels have a constant cross-sectional area along the length from the first end to the second end, each of the cooling channels defines a channel width, the waveform channel profile defines a period and amplitude, and the ratio of the amplitude to the channel width is 2:1 or greater.
12. A nozzle arranged around a central axis and formed from a wall surrounding a chamber, wherein the wall has a first axial end, a second axial end, an inner portion defining the chamber, and an outer portion opposite the inner portion. An array of cooling channels embedded in the wall so as to allow a cooling fluid to flow through the wall, wherein each of the cooling channels defines a flow path having a circumferential curvature that changes with respect to the axial direction, An article equipped with.
13. The article according to claim 12, characterized in that the plurality of cooling channels are nested in the circumferential direction.
14. The article according to claim 12, characterized in that the nozzle is a convergence-diffusion nozzle.
15. The article according to claim 12, characterized in that each of the cooling channels includes a first section extending from a first axial end to a second axial end, a second section extending from a second axial end to a first axial end, and a turn section that fluidly connects the first section and the second section at the second axial end.
16. The article according to claim 15, characterized in that the plurality of cooling channels are fluidly separated from each other within the wall.
17. The article according to claim 16, characterized in that the cooling channel has a constant cross-sectional area along the length from the first axial end to the second axial end.
18. The article according to claim 17, characterized in that each of the cooling channels defines a channel width, the waveform channel profile defines a period and amplitude, and the ratio of the amplitude to the channel width is 2:1 or greater.