Combustion chamber cooling structure, combustion heater and additive manufacturing method thereof

Abstract

The present application belongs to the field of combustion chamber and additive manufacturing technology, and discloses a combustion chamber cooling structure, a combustion heater and an additive manufacturing method thereof. The combustion chamber cooling structure comprises a liquid inlet end, a liquid outlet end and a first flow channel arranged in the side wall of the combustion chamber. The liquid inlet end comprises a liquid inlet hole and a first liquid inlet chamber arranged in sequence along the liquid inlet direction. The first liquid inlet chamber extends obliquely along the liquid inlet direction to the region of the combustion chamber side wall corresponding to the gas inlet end, and the included angle between the top wall of the first liquid inlet chamber and the horizontal plane is not less than 45°. The two ends of the first liquid inlet chamber are respectively communicated with the liquid inlet hole and the first flow channel. The first flow channel is communicated with the liquid outlet end. The combustion heater comprises the combustion chamber cooling structure. The additive manufacturing method of the combustion heater is to form the combustion heater by layer-by-layer accumulation vertically upward. The present application can eliminate the cooling blind area, significantly improve the cooling effect, and realize support-free forming.

Description

Technical Field

[0001] This invention relates to the field of combustion chamber and additive manufacturing technology. Background Technology

[0002] As the core hot-end component of the heating system for hypersonic aerodynamic / propulsion ground test equipment, the combustion heater is the main area where oxidizer and fuel combustion generates high-temperature, high-pressure combustion gases. To improve the service performance of the combustion heater under high-temperature and high-pressure operating environments, the sidewalls of the combustion chamber are typically designed with multiple water-cooled channels for active cooling, which greatly increases the manufacturing difficulty.

[0003] The traditional manufacturing process for combustion heaters is welding. Due to limitations in welding technology, the cooling channel structure of the combustion chamber sidewalls should be as simple and regular as possible to facilitate welding after machining. However, a simple channel structure is insufficient to meet the cooling requirements of the combustion chamber. Therefore, to enable the fabrication of more complex cooling channels within the combustion chamber sidewall structure, additive manufacturing technology can be used to achieve the integrated forming of the combustion chamber.

[0004] Currently, due to limitations in additive manufacturing processes, the top of the manifold within the combustion chamber sidewall needs to be designed as a pointed structure to achieve integrated additive manufacturing and supportless forming. The presence of this pointed structure creates a cooling blind zone at the combustion chamber's gas inlet end, corresponding to the area of ​​the pointed structure, meaning the coolant cannot reach this area. However, this cooling blind zone is actually the area with the highest temperature and pressure. Summary of the Invention

[0005] This application provides a combustion chamber cooling structure to resolve the contradiction between additive manufacturing and cooling blind spots caused by the pointed structure.

[0006] This invention is achieved through the following technical solution:

[0007] A combustion chamber cooling structure, comprising:

[0008] The liquid inlet, liquid outlet, and first flow channel are located inside the side wall of the combustion chamber;

[0009] The liquid inlet end includes a liquid inlet hole and a first liquid inlet chamber arranged sequentially along the liquid inlet direction;

[0010] The first liquid inlet chamber extends obliquely along the liquid inlet direction to the combustion chamber sidewall area corresponding to the gas inlet end, and the angle between the top wall of the first liquid inlet chamber and the horizontal plane is not less than 45°.

[0011] The first liquid inlet chamber is connected to the liquid inlet hole and the first flow channel at both ends, respectively; the first flow channel is connected to the liquid outlet.

[0012] This invention eliminates the pointed top structure of the first liquid inlet chamber and designs it as an obliquely extending structure, so that the coolant can be guided along the first liquid inlet chamber to the combustion chamber sidewall area corresponding to the gas inlet end, thereby eliminating the cooling blind zone. Furthermore, the angle between the top wall of the first liquid inlet chamber and the horizontal plane is not less than 45°, ensuring that the first liquid inlet chamber can be formed without support during additive manufacturing.

[0013] Furthermore, the first liquid inlet chamber is an annular cavity surrounding the combustion chamber.

[0014] The first liquid inlet chamber is an annular cavity, so that the liquid inlet hole can share the first liquid inlet chamber and the first flow channel for sharing, which simplifies the structure and can also ensure that the combustion chamber side wall area corresponding to the gas inlet end is cooled in the circumferential direction.

[0015] Furthermore, the first flow channel extends along the axial direction of the combustion chamber. This allows for axial cooling of the combustion chamber sidewalls through the first flow channel.

[0016] Furthermore, several first flow channels are distributed circumferentially along the sidewall of the combustion chamber. This allows for circumferential cooling of the sidewall of the combustion chamber.

[0017] Furthermore, it also includes a second liquid inlet chamber and a second flow channel arranged sequentially along the liquid inlet direction;

[0018] The second flow channel is located outside the first flow channel; the two ends of the second liquid inlet chamber are respectively connected to the liquid inlet hole and the second flow channel; the second flow channel is connected to the liquid outlet.

[0019] The second liquid inlet chamber extends obliquely to the second flow channel along the liquid inlet direction, and the angle between the top wall of the second liquid inlet chamber and the horizontal plane is not less than 45°.

[0020] Adding a second liquid inlet chamber and a second flow channel enables differential cooling of the combustion chamber sidewall: the first flow channel is close to the inner side of the combustion chamber sidewall, and the coolant flowing through the first flow channel carries away a large amount of heat, resulting in a relatively high coolant temperature; the second flow channel is located outside the first flow channel and is relatively far from the inner side of the combustion chamber sidewall, so the coolant flowing through the second flow channel has a relatively low temperature and can carry away the heat from the outside of the first flow channel, thereby improving the overall cooling and heat dissipation effect.

[0021] Adding a second inlet chamber and a second flow channel can also reduce the pressure drop between the inlet and outlet ends: the first inlet chamber and the first flow channel, together with the second inlet chamber and the second flow channel, form a double-chamber double-row cooling structure. Compared with a single-row cooling structure, the total cross-sectional area of ​​the inner flow channel is increased, which can reduce the flow resistance of the inner flow channel, thereby allowing the coolant to be discharged from the inlet chamber more promptly.

[0022] Furthermore, the first and second flow channels are staggered along the circumferential direction of the combustion chamber sidewall. This makes the wall thickness of the combustion chamber sidewall more uniform, ensuring the strength of the combustion chamber sidewall.

[0023] Furthermore, a plurality of liquid inlet holes are distributed circumferentially along the side wall of the combustion chamber; the second liquid inlet chamber is an annular cavity surrounding the combustion chamber.

[0024] By setting several inlet holes, the liquid inlet flow rate is increased. The second liquid inlet chamber is an annular cavity for sharing, which simplifies the structure and facilitates processing and manufacturing.

[0025] Furthermore, the liquid outlet end includes a liquid outlet manifold chamber and a liquid outlet hole arranged sequentially along the liquid outlet direction; the liquid outlet manifold chamber has a pointed top structure, and the included angle of the pointed top structure is not less than 45°; the first flow channel and the second flow channel both extend to the liquid outlet manifold chamber along the axial direction of the combustion chamber, and are connected to the liquid outlet hole through the liquid outlet manifold chamber.

[0026] The first and second flow channels share a common liquid outlet manifold, simplifying the structure; the pointed structure of the liquid outlet manifold ensures supportless forming during additive manufacturing.

[0027] The present invention also provides a combustion heater, including the combustion chamber cooling structure described above.

[0028] The present invention also provides an additive manufacturing method for a combustion heater, wherein the combustion heater is formed by stacking layers vertically upwards, and the lower liquid outlet end is formed first, and the upper liquid inlet end is formed later.

[0029] The liquid outlet is formed first, followed by the liquid inlet, to ensure that the angle between the top wall of the liquid inlet chamber and the horizontal plane, as well as the angle of the pointed structure, can meet the process requirements of additive manufacturing without support.

[0030] The additive manufacturing method of the present invention achieves integrated manufacturing with high efficiency, high quality and low cost. The combustion heater processed by the additive manufacturing method of the present invention can eliminate cooling blind spots, significantly improve the cooling effect, and improve the overall structural strength and quality stability, thereby greatly improving the service life and service reliability of the combustion chamber. Attached Figure Description

[0031] To more clearly illustrate the technical solutions in the specific embodiments of this application or the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0032] Figure 1This is a 1 / 4 cross-sectional view of the combustion chamber sidewall in the prior art;

[0033] Figure 2 This is a 1 / 4 cross-sectional view of the combustion chamber sidewall in Example 1;

[0034] Figure 3 This is a schematic cross-sectional view of the combustion chamber sidewall in Example 1;

[0035] Figure 4 This is a 1 / 4 cross-sectional view of the combustion chamber sidewall in Example 2;

[0036] Figure 5 This is a schematic cross-sectional view of the combustion chamber sidewall in Example 2;

[0037] Figure 6 This is a temperature field distribution diagram of the combustion chamber sidewall in the prior art;

[0038] Figure 7 This is a temperature field distribution diagram of the combustion chamber sidewall in Example 2;

[0039] Figure 8 This is a diagram showing the cooling water pressure distribution on the sidewall of the combustion chamber in existing technology;

[0040] Figure 9 This is a diagram showing the cooling water pressure distribution on the side wall of the combustion chamber in Example 2. Detailed Implementation

[0041] refer to Figure 1 As shown, in the prior art, the top of the manifold 1A within the sidewall of the combustion chamber needs to be designed as a pointed structure to achieve integrated additive manufacturing and supportless forming. Due to the presence of this pointed structure, a cooling blind zone 1b is formed in the area corresponding to the pointed structure at the gas inlet end of the combustion chamber, meaning that the coolant cannot reach this area.

[0042] To address the contradiction between additive manufacturing and cooling blind spots caused by the pointed structure, this invention provides a combustion chamber cooling structure that eliminates the pointed structure and guides the coolant to the gas inlet end by changing the structure of the manifold (liquid inlet chamber), while also meeting the requirements for unsupported forming.

[0043] Example 1

[0044] This embodiment provides a detailed description of the combustion chamber cooling structure.

[0045] refer to Figure 2 As shown, a combustion chamber cooling structure includes:

[0046] The liquid inlet and liquid outlet are located in the first flow channel 103 within the side wall 1 of the combustion chamber;

[0047] The liquid inlet end includes a liquid inlet hole 101 and a first liquid inlet chamber 102 arranged sequentially along the liquid inlet direction;

[0048] The first liquid inlet chamber 102 extends obliquely along the liquid inlet direction to the combustion chamber side wall area corresponding to the gas inlet end, and the angle α between the top wall of the first liquid inlet chamber 102 and the horizontal plane is not less than 45°.

[0049] The first liquid inlet chamber 102 is connected to the liquid inlet hole 101 and the first flow channel 103 at both ends, respectively; the first flow channel 103 is connected to the liquid outlet end.

[0050] This embodiment eliminates the pointed top structure of the first liquid inlet chamber 102 and designs it as an obliquely extending structure so that the coolant can be guided along the first liquid inlet chamber 102 to the combustion chamber sidewall area corresponding to the gas inlet end, thereby eliminating the cooling blind zone. Furthermore, the angle between the top wall of the first liquid inlet chamber 102 and the horizontal plane is not less than 45°, ensuring that the first liquid inlet chamber 102 can be formed without support during additive manufacturing.

[0051] refer to Figure 3 In this embodiment, a plurality of liquid inlet holes 101 are distributed circumferentially along the side wall 1 of the combustion chamber; the first liquid inlet chamber 102 is an annular cavity surrounding the combustion chamber.

[0052] In addition, the first liquid inlet chamber can also be several independent chambers distributed circumferentially along the side wall of the combustion chamber. In this case, the smaller the interval between each independent chamber, the better the cooling effect on the side wall area of ​​the combustion chamber corresponding to the gas inlet end.

[0053] Multiple inlet holes 101 can increase the flow rate of coolant. The first inlet chamber 102 is an annular cavity so that the inlet holes 101 can share the first inlet chamber 102 and communicate with the first flow channel 103 for sharing, which simplifies the structure and can also ensure that the combustion chamber side wall area corresponding to the gas inlet end is cooled in the circumferential direction.

[0054] In this embodiment, the first flow channel 103 extends along the axial direction of the combustion chamber. This allows for axial cooling of the combustion chamber sidewall 1 through the first flow channel 103.

[0055] In this embodiment, a plurality of first flow channels 103 are distributed circumferentially along the sidewall 1 of the combustion chamber. This allows for circumferential cooling of the sidewall 1 of the combustion chamber, resulting in a more uniform cooling effect.

[0056] In this embodiment, the liquid outlet end includes a liquid outlet manifold chamber 104 and a liquid outlet hole 105 arranged sequentially along the liquid outlet direction; the liquid outlet manifold chamber has a pointed structure, and the included angle γ of the pointed structure is not less than 45°; the first flow channel 103 extends along the axial direction of the combustion chamber to the liquid outlet manifold chamber, and is connected to the liquid outlet hole 105 through the liquid outlet manifold chamber 104.

[0057] Each primary flow channel shares a common outlet manifold, which simplifies the structure and facilitates manufacturing. The pointed structure of the outlet manifold 104 ensures supportless forming during additive manufacturing.

[0058] Example 2

[0059] This embodiment provides a detailed description of another combustion chamber cooling structure.

[0060] refer to Figure 4 As shown, a combustion chamber cooling structure includes:

[0061] The liquid inlet and liquid outlet are located in the first flow channel 103 within the side wall 1 of the combustion chamber;

[0062] The liquid inlet end includes a liquid inlet hole 101 and a first liquid inlet chamber 102 arranged sequentially along the liquid inlet direction;

[0063] The first liquid inlet chamber 102 extends obliquely along the liquid inlet direction to the combustion chamber side wall area corresponding to the gas inlet end, and the angle between the top wall of the first liquid inlet chamber 102 and the horizontal plane is not less than 45°.

[0064] The first liquid inlet chamber 102 is connected to the liquid inlet hole 101 and the first flow channel 103 at both ends, respectively; the first flow channel 103 is connected to the liquid outlet end.

[0065] It also includes a second liquid inlet chamber 106 and a second flow channel 107 arranged sequentially along the liquid inlet direction;

[0066] The second flow channel 107 is located outside the first flow channel 103; the two ends of the second liquid inlet chamber 106 are respectively connected to the liquid inlet hole 101 and the second flow channel 107; the second flow channel 107 is connected to the liquid outlet end;

[0067] The second liquid inlet chamber 106 extends obliquely to the second flow channel 107 along the liquid inlet direction, and the angle β between the top wall of the second liquid inlet chamber 106 and the horizontal plane is not less than 45°.

[0068] Adding a second liquid inlet chamber 106 and a second flow channel 107 enables differential cooling of the combustion chamber sidewall 1: the first flow channel 103 is close to the inner side of the combustion chamber sidewall 1, and the coolant flowing through the first flow channel 103 carries away a large amount of heat, resulting in a relatively high coolant temperature; the second flow channel 107 is located outside the first flow channel 103 and is relatively far from the inner side of the combustion chamber sidewall 1, so the coolant flowing through the second flow channel 107 has a relatively low temperature and can carry away the heat from the outside of the first flow channel 103, thereby improving the overall cooling and heat dissipation effect.

[0069] Adding a second liquid inlet chamber and a second flow channel 107 can also reduce the pressure drop between the liquid inlet and the liquid outlet: the first liquid inlet chamber 102, the first flow channel 103 and the second liquid inlet chamber 106 and the second flow channel 107 form a double-chamber double-row cooling structure. Compared with a single-row cooling structure, the total cross-sectional area of ​​the inner flow channel is increased, which can reduce the flow resistance of the inner flow channel, so that the coolant can be discharged from the liquid inlet chamber more timely.

[0070] In this embodiment, a plurality of liquid inlet holes 101 are distributed circumferentially along the side wall 1 of the combustion chamber; the second liquid inlet chamber 106 is an annular cavity surrounding the combustion chamber 1. By providing a plurality of liquid inlet holes 101, the liquid inlet flow rate is increased, and the second liquid inlet chamber 106 is an annular cavity for sharing, simplifying the structure and facilitating processing and manufacturing.

[0071] refer to Figure 5 As shown, in this embodiment, the first flow channel 103 and the second flow channel 107 are staggered along the circumference of the combustion chamber sidewall 1. This makes the wall thickness of the combustion chamber sidewall 1 more uniform and ensures the strength of the combustion chamber sidewall 1.

[0072] In this embodiment, the liquid outlet end includes a liquid outlet manifold 104 and a liquid outlet hole 105 arranged sequentially along the liquid outlet direction; the liquid outlet manifold has a pointed structure with an included angle of not less than 45°; the first flow channel 103 and the second flow channel 107 both extend to the liquid outlet manifold along the axial direction of the combustion chamber and are connected to the liquid outlet hole 105 through the liquid outlet manifold 104.

[0073] The first flow channel 103 and the second flow channel 107 share a liquid outlet manifold, simplifying the structure; the pointed structure of the liquid outlet manifold ensures supportless forming during additive manufacturing.

[0074] Example 3

[0075] This embodiment also provides a combustion heater, including the combustion chamber cooling structure of embodiment 1 or 2.

[0076] This embodiment also provides an additive manufacturing method for a combustion heater, wherein the combustion heater is formed by stacking layers vertically upwards, and the lower liquid outlet end is formed first, followed by the upper liquid inlet end.

[0077] The liquid outlet is formed first, followed by the liquid inlet, to ensure that the angle between the top wall of the liquid inlet chamber and the horizontal plane, as well as the angle of the pointed structure, can meet the process requirements of additive manufacturing without support.

[0078] In this embodiment, laser selective melting technology is used for integrated additive manufacturing. The forming direction is with the liquid inlet end at the top and the liquid outlet end at the bottom, stacking layers vertically upwards. The inclination angles of the first and second liquid inlet chambers to the horizontal plane are both designed to be 45°, achieving supportless printing. After post-processing steps such as vibration powder removal, stress-relief annealing, and wire cutting, a combustion heater with a novel dual-chamber, dual-row differential temperature cooling structure is obtained.

[0079] The additive manufacturing method of this embodiment achieves high-efficiency, high-quality, and low-cost integrated manufacturing. The combustion heater processed by the additive manufacturing method of this embodiment can eliminate cooling blind spots, significantly improve the cooling effect, and enhance the overall structural strength and quality stability, thereby greatly improving the service life and reliability of the combustion heater.

[0080] Example 4

[0081] This embodiment uses finite element simulation to compare and verify the cooling effect of the combustion heater.

[0082] First, a fluid-structure interaction finite element model (hereinafter referred to as the finite element model) of water cooling in the combustion chamber's internal flow channel and high-temperature, high-pressure gas heat transfer on the wall was established. The model material was GH3625 nickel-based alloy, and the key finite element model parameters are shown in Table 1. Under the condition that the cooling water inlet flow rate was set to 60 kg / s, the SST k-Omega governing equations were used for solving. Based on equations (1), (2), and (3), the finite element model was calculated, thereby deriving the required cooling water inlet pressure and obtaining the combustion chamber temperature field and the cooling water pressure distribution in the flow channel.

[0083] Table 1 Model Parameters

[0084]

[0085]

[0086] In the formula: P k It is a turbulent production term; β * These are turbulence model parameters; σ k It is the Prandtl number for turbulence; u t These are the turbulent viscosity coefficients (based on turbulent shear stress); α, β, σ ω These are the parameters of the turbulence model; R TThis is the turbulence interaction term. The SST model combines the advantages of the k-ω model and the k-∈ model to better predict turbulence separation and boundary layer characteristics, and achieves a combination of the two models. Finally, a correction term for turbulent shear stress is introduced to improve the prediction results.

[0087] Based on the established finite element model, the existing technology was simulated under the working condition of a water inlet flow rate of 60 kg / s in the combustion chamber. Figure 1 The temperature field distribution of the combustion heater in Example 2 is similar to that of the combustion heater containing the combustion chamber cooling structure in Example 2. Figure 6 , Figure 7 As shown; and respectively simulating existing technologies ( Figure 1 The water pressure distribution of the combustion heater in Example 2 is similar to that of the combustion heater containing the combustion chamber cooling structure in Example 2. Figure 8 , Figure 9 As shown. Finally, the cooling effect under the operating condition of a water inlet flow rate of 60 kg / s in the combustion chamber was obtained:

[0088] Table 1 Comparison of Cooling Effects

[0089]

[0090]

[0091] The combustion chamber in the prior art (original model) has the following characteristics: inlet cooling water pressure of 3.05 MPa, outlet pressure of 0.38 MPa, pressure drop of 2.27 MPa, maximum combustion heating wall temperature of 638.2 K, and average temperature of 455.4 K.

[0092] The combustion chamber (dual chamber, dual exhaust) corresponding to Embodiment 2 has the following characteristics: the inlet cooling water pressure is 1.64 MPa, the cooling water inlet pressure is reduced to 53.8% of the original structure, the outlet pressure is 0.44 MPa, and the pressure drop is 1.05 MPa; the highest temperature of the combustion heating wall is 440.8 K, which is reduced to 69.1% of the original structure; the average wall temperature is 367.3 K, which is reduced to 80.7% of the original structure.

[0093] This invention eliminates cooling blind spots by improving the structure of the liquid inlet chamber, resulting in a more uniform cooling effect. It also reduces flow resistance and pressure drop through dual-row flow channels, promoting rapid flow of coolant and thus significantly improving the cooling effect.

[0094] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this application.

Claims

1. A combustion chamber cooling structure, characterized in that, include: The liquid inlet, liquid outlet, and first flow channel are located inside the side wall of the combustion chamber; The liquid inlet end includes a liquid inlet hole and a first liquid inlet chamber arranged sequentially along the liquid inlet direction; The first liquid inlet chamber has no pointed top structure, and its top wall is a single sloping wall; The first liquid inlet chamber extends obliquely along the liquid inlet direction to the combustion chamber sidewall area corresponding to the gas inlet end, and the angle between the top wall of the first liquid inlet chamber and the horizontal plane is not less than 45°. The first liquid inlet chamber is connected to the liquid inlet hole and the first flow channel at both ends, respectively; the first flow channel is connected to the liquid outlet.

2. The combustion chamber cooling structure according to claim 1, characterized in that, The first liquid inlet chamber is an annular cavity surrounding the combustion chamber.

3. The combustion chamber cooling structure according to claim 1, characterized in that, The first flow channel extends along the axial direction of the combustion chamber.

4. The combustion chamber cooling structure according to claim 1, characterized in that, Several first flow channels are distributed circumferentially along the side wall of the combustion chamber.

5. The combustion chamber cooling structure according to claim 1, characterized in that, It also includes a second liquid inlet chamber and a second flow channel arranged sequentially along the liquid inlet direction; The second flow channel is located outside the first flow channel; the two ends of the second liquid inlet chamber are respectively connected to the liquid inlet hole and the second flow channel; the second flow channel is connected to the liquid outlet; the diameter of the first liquid inlet chamber gradually decreases along the liquid inlet direction; The second liquid inlet chamber has no pointed top structure, and its top wall is a single sloping wall; The second liquid inlet chamber extends obliquely to the second flow channel along the liquid inlet direction, and the angle between the top wall of the second liquid inlet chamber and the horizontal plane is not less than 45°; the diameter of the second liquid inlet chamber gradually increases along the liquid inlet direction.

6. The combustion chamber cooling structure according to claim 5, characterized in that, The first flow channel and the second flow channel are staggered along the circumferential sidewall of the combustion chamber.

7. The combustion chamber cooling structure according to any one of claims 5 to 6, characterized in that, Several liquid inlet holes are distributed circumferentially along the side wall of the combustion chamber; the second liquid inlet chamber is an annular cavity surrounding the combustion chamber.

8. The combustion chamber cooling structure according to claim 7, characterized in that, The liquid outlet end includes a liquid outlet manifold and a liquid outlet hole arranged sequentially along the liquid outlet direction; the liquid outlet manifold has a pointed structure with an included angle of not less than 45°; the first flow channel and the second flow channel both extend to the liquid outlet manifold along the axial direction of the combustion chamber and are connected to the liquid outlet hole through the liquid outlet manifold.

9. A combustion heater, characterized in that, Includes the combustion chamber cooling structure as described in any one of claims 1 to 8.

10. An additive manufacturing method for a combustion heater, characterized in that, The combustion heater as described in claim 9 is formed by stacking layers vertically upwards, with the lower liquid outlet end formed first, followed by the upper liquid inlet end.

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