Surface structure of inner wall of liquid film cooling combustion chamber of liquid rocket engine

Abstract

According to the inner wall surface structure of the liquid film cooling combustion chamber of the liquid rocket engine, the inner wall surface, receiving jet flow impact, of the combustion chamber spreads jet flow to form a liquid film, and the liquid film makes contact with fuel gas; wherein the surface roughness of the inner wall is smaller than or equal to 12.5 microns so as to cool the combustion chamber. According to the method, the roughness of the wall surface where the liquid film is spread after the jet flow impacts the wall surface is optimized, the liquid film spread on the wall surface is in direct contact with the high-temperature fuel gas, and the effect of a liquid film cold area is enhanced by optimizing the roughness of the wall surface, so that the cooling effect on the wall surface of the combustion chamber is improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of liquid rocket engines, and more particularly relates to a liquid rocket engine liquid film cooling combustion chamber inner wall surface structure, and more particularly to a liquid rocket engine high-efficiency liquid film cooling combustion chamber inner wall surface structure and a liquid rocket engine thereof. Background Art

[0002] With the rapid development of my country's aerospace technology, the launch missions of spacecraft have increased rapidly, which has put forward higher requirements on the life and reliability of their power devices.

[0003] Liquid rocket engines are key products of its power unit, and their on-orbit reliability directly affects the on-orbit service life of the spacecraft and the success or failure of the spacecraft's orbit change mission.

[0004] Engine reliability and service life are closely related to the combustion chamber temperature. Lowering the combustion chamber temperature increases the service life margin and improves reliability. For radiantly cooled liquid rocket engines, the liquid film cooling effect directly affects the combustion chamber temperature.

[0005] The engine combustion chamber is a critical, heat-resistant component. Its inner walls are directly exposed to high-temperature, high-pressure combustion gases. The side holes in the head allow coolant to be sprayed directly onto the inner surfaces of the combustion chamber, forming a liquid film to protect the walls. Differences in the surface condition of the combustion chamber's inner walls can affect the effectiveness of the liquid film cooling, and thus the combustion chamber temperature.

[0006] In existing technologies, the liquid film cooling effect is optimized primarily by optimizing design parameters related to the side holes, such as the number, arrangement, angle, diameter, and flow rate ratio of the side holes. However, there is a lack of design methods and structures for optimizing liquid film cooling effects related to the combustion chamber's inner wall structure. Therefore, a highly efficient liquid film cooling combustion chamber surface structure for liquid rocket engines is urgently needed to achieve temperature reduction and temperature consistency in space liquid rocket engines within existing technology systems, thereby improving the engine's long-life operational reliability.

[0007] Patent document CN114165362A discloses a composite forming method for a liquid rocket engine combustion chamber, which includes inner layer forming, cooling groove filling, nickel electroplating, outer layer laser deposition forming, outer layer machining, and cooling groove cleaning. Laser melting (SLM), nickel electroplating, and laser deposition (LENS) forming are used to create a complex composite structure of a dissimilar combustion chamber. The resulting cooling channels have low roughness, low flow resistance during the cooling process, and high heat transfer efficiency. The overall dissimilar metal interface strength of the combustion chamber is high, and the processing efficiency is high.

[0008] Patent document CN211202146U discloses an integrated liquid film cooling structure of a thrust chamber, which comprises a guide pipe, a baffle, an injection hole, an upper liquid collecting chamber and a lower liquid collecting chamber. The baffle is arranged between the upper liquid collecting chamber and the lower liquid collecting chamber. The guide pipe, the baffle, the injection hole, the upper liquid collecting chamber and the lower liquid collecting chamber are integrally formed by 3D printing. The baffle divides the liquid collecting chamber into an upper chamber and a lower chamber. The coolant enters the lower liquid collecting chamber after being uniformly distributed in the upper liquid collecting chamber, and is uniformly sprayed from the injection hole, thereby improving the cooling efficiency of the liquid film. Meanwhile, the 3D printing technology is used to integrate the parts of the liquid film structure, thereby reducing the number of parts and eliminating the welding seams.

[0009] Although the two prior patents CN114165362A and CN211202146U both mention optimizing the roughness of the inner wall of the combustion chamber, the purpose of optimizing the roughness in the two prior patents is only to improve the flow characteristics of the propellant in the flow channel and to optimize the injection jet flow.

[0010] However, one of the purposes of optimizing the roughness of the wall surface in the present application is to optimize the roughness of the wall surface on which the liquid film spreads after the jet impact for some engine combustion chambers. The liquid film spread on the wall surface directly contacts the high-temperature gas. By optimizing the roughness of the wall surface, the liquid film cooling effect on the combustion chamber wall surface is improved.

[0011] In addition, the second purpose of optimizing the roughness of the wall surface in the present application is to strengthen the combustion by splashing atomized liquid droplets from the jet impact on the wall surface for other engine combustion chambers. SUMMARY

[0012] In view of the defects in the prior art, the purpose of the present application is to provide a liquid rocket engine liquid film cooling combustion chamber inner wall surface structure.

[0013] According to the liquid rocket engine liquid film cooling combustion chamber inner wall surface structure provided by the present application, the inner wall surface of the combustion chamber receives the jet impact, the jet spreads to form a liquid film, and the liquid film contacts the gas.

[0014] Preferably, the inner wall surface roughness is greater than or equal to 3.0 μm and less than or equal to 12.5 μm.

[0015] Preferably, the inner wall surface roughness is less than 1.6 μm.

[0016] Preferably, the liquid rocket engine is a radiative cooling type liquid rocket engine, and the liquid film contacts the gas.

[0017] Preferably, the liquid rocket engine is a radiative cooling type liquid rocket engine, and the liquid film contacts the gas.

[0018] Preferably, the inner wall surface of the combustion chamber is a coating.

[0019] Preferably, the inner wall surface of the combustion chamber is a metal surface.

[0020] Preferably, the roughness of the metal surface is 1.6 to 12.5 microns, or below 1.6 microns.

[0021] According to the present application, a liquid rocket engine liquid film cooling combustion chamber inner wall surface structure is provided, the inner wall surface of the combustion chamber receives jet impact, the jet splashes to form atomized droplets, and the atomized droplets contact the combustion gas.

[0022] The inner wall surface of the combustion chamber is prepared by casting or 3D printing, and the roughness of the inner wall surface of the combustion chamber is not less than 12.5 microns to strengthen combustion.

[0023] According to the present application, an engine is provided, comprising the combustion chamber structure with the liquid rocket engine liquid film cooling combustion chamber inner wall surface structure.

[0024] According to the present application, a rocket is provided, comprising the engine.

[0025] Compared with the prior art, the present application has the following beneficial effects:

[0026] 1. For some engine combustion chambers, the present application optimizes the roughness of the wall surface on which the liquid film spreads after jet impact, the liquid film spread on the wall directly contacts the high-temperature combustion gas, and the roughness of the wall is optimized to strengthen the liquid film cooling effect, thereby improving the cooling effect of the combustion chamber wall.

[0027] 2. For some engine combustion chambers, the present application optimizes the roughness of the inner wall surface of the combustion chamber to achieve consistent cooling effect control, improve the temperature margin of the space liquid rocket engine combustion chamber under the existing design state, and control the temperature consistency of the combustion chamber, thereby improving the reliability of the engine.

[0028] 3. For some other engine combustion chambers, the present application strengthens combustion by splashing atomized liquid droplets from the jet impact on the wall. BRIEF DESCRIPTION OF DRAWINGS

[0029] Other features, objects and advantages of the present application will become more apparent from the following detailed description of non-limiting embodiments, made with reference to the accompanying drawings:

[0030] Figure 1 The present application provides a liquid rocket engine high-efficiency liquid film cooling combustion chamber.

[0031] Figure 2This is a partial schematic diagram of the high-efficiency liquid film cooling combustion chamber and surface structure described in the present invention.

[0032] The figure shows:

[0033] DETAILED DESCRIPTION

[0034] The present invention will be described in detail below with reference to specific embodiments. The following examples will help those skilled in the art to further understand the present invention, but are not intended to limit the present invention in any form. It should be noted that, for those skilled in the art, several changes and improvements can be made without departing from the scope of the present invention. These all fall within the scope of protection of the present invention.

[0035] The present invention relates to a high-efficiency liquid film-cooled combustion chamber surface structure for a liquid rocket engine, specifically a structure for the inner wall of a radiation-cooled liquid rocket engine combustion chamber. This high-efficiency liquid film-cooled combustion chamber surface structure for a space liquid rocket engine is located within a combustion chamber. The combustion chamber comprises a combustion chamber surface coating and a head portion with cooling edge holes that match the combustion chamber. Fuel enters the combustion chamber through the head edge holes, impacts the combustion chamber inner wall surface, and spreads to form a liquid film, cooling the combustion chamber. By optimizing the surface structure of the combustion inner wall, the present invention improves the liquid film cooling effect and achieves consistent control of the cooling effect. It also increases the temperature margin and controls the temperature consistency of the combustion chamber of a space liquid rocket engine under existing design conditions, thereby improving engine reliability.

[0036] like Figure 1 and Figure 2 As shown, an embodiment of the present invention provides a liquid film cooling combustion chamber structure of a liquid rocket engine, comprising a combustion chamber and a head with cooling edge area holes matching the combustion chamber.

[0037] The surface structure of the inner wall of the combustion chamber is described in detail below.

[0038] For combustion chambers with inner wall coatings, the combustion chamber inner wall surface structure includes the inner wall coating. While maintaining the existing design dimensions of the head and body of the liquid rocket engine, the 750N engine combustion chamber inner wall coating was optimized and replaced with a coating with improved roughness. This reduced the surface roughness of the combustion chamber inner wall coating to below 1.6μm, achieving more efficient liquid film cooling and significantly reducing the maximum combustion chamber temperature. Please see the summary table of combustion chamber inner wall roughness and throat temperature test results.

[0039] Summary of combustion chamber inner wall roughness and throat temperature test results

[0040] Serial No. Product Combustion chamber inner wall roughness Throat temperature / °C 1 Engine A 3.0-12.5 μm 1438 2 Engine A 3.0-12.5 μm 1425 3 Engine A 3.0-12.5 μm 1449 4 Engine A <1.6 μm 1365 5 Engine A <1.6 μm 1345 6 Engine A <1.6 μm 1345

[0041] In one variation, for the combustion chamber with inner wall coating, for the coating with surface roughness of 1.6 μm to 12.5 μm, which is applied to the liquid rocket engine, the liquid film cooling effect can be controlled by controlling the fluctuation range of the surface roughness in the range of ± 2 μm, the combustion temperature dispersion control is realized, and the product consistency is improved. Please see the test result summary table of the combustion chamber inner wall roughness and throat temperature.

[0042] According to the test result summary table of the combustion chamber inner wall roughness and throat temperature, for the radiant cooling type liquid rocket engine, the engine is not damaged under the high temperature gas erosion, the coating is prepared on the inner wall of the combustion chamber, for a certain type of engine, the inner wall roughness after coating is in the range of 3.0-12.5 μm, the throat temperature of three products is not less than 1425℃, and the inner wall coating surface structure can be realized by optimizing the process (which can be realized by those skilled in the art in combination with the prior art, which is not described here), so that the roughness is less than 1.6 μm, three times of test are carried out, the throat temperature of the product is not more than 1365℃, the liquid film cooling effect of the liquid rocket engine is directly represented by the throat temperature measured by the test, the throat temperature is low, and the cooling effect is good. The test results show that improving the inner wall roughness to less than 1.6 μm can significantly improve the liquid film cooling effect.

[0043] In another variation, for the regenerative cooling combustion chamber without coating and with edge cooling, the inner wall surface metal roughness of the combustion chamber is directly controlled by mechanical processing, chemical pickling and other methods to realize the purpose of reducing and controlling the temperature of the combustion chamber. For example, the inner wall surface metal roughness of the combustion chamber is reduced to less than 1.6 μm, or is controlled in the range of 1.6 μm to 12.5 μm.

[0044] In more variations, for the combustion chamber of the direct-flow cold-wall engine, the combustion chamber can be prepared by casting and 3D printing, and the inner wall surface roughness of the combustion chamber is controlled to be not less than 12.5 μm, the combustion is strengthened, and the combustion efficiency is improved.

[0045] In the description of the present application, it should be understood that the terms "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application.

[0046] The specific embodiments of the present application are described above. It needs to be understood that the present application is not limited to the specific embodiments described above, and various changes or modifications can be made by those skilled in the art within the scope of the claims, which does not affect the essential content of the present application. The embodiments of the present application and the features in the embodiments can be combined with each other at will without conflict.

Claims

1. A liquid film cooling combustion chamber inner wall surface structure of a liquid rocket engine, characterized in that: The inner wall surface of the combustion chamber receives the impact of the jet, and the jet spreads to form a liquid film, which contacts the combustion gas; Wherein, the surface roughness of the inner wall is less than or equal to 12.5 μm to cool the combustion chamber.

2. The liquid film cooling combustion chamber inner wall surface structure of a liquid rocket engine according to claim 1, characterized in that: The inner wall surface roughness is greater than or equal to 3.0 μm and less than or equal to 12.5 μm.

3. The liquid film cooling combustion chamber inner wall surface structure of a liquid rocket engine according to claim 1, characterized in that: The inner wall surface roughness is less than 1.6 μm.

4. The liquid film cooling combustion chamber inner wall surface structure of a liquid rocket engine according to any one of claims 1 to 3, characterized in that: The liquid rocket engine is a radiation-cooled liquid rocket engine, and the liquid film is in contact with the combustion gas.

5. The liquid film cooling combustion chamber inner wall surface structure of a liquid rocket engine according to any one of claims 1 to 3, characterized in that: The inner wall surface of the combustion chamber is a coating.

6. The liquid film cooling combustion chamber inner wall surface structure of a liquid rocket engine according to claim 1, characterized in that: The inner wall surface of the combustion chamber is a metal surface.

7. The liquid film cooling combustion chamber inner wall surface structure of a liquid rocket engine according to claim 6, characterized in that: The roughness of the metal surface is 1.6 μm to 12.5 μm, or less than 1.6 μm.

8. A liquid film cooling combustion chamber inner wall surface structure of a liquid rocket engine, characterized in that: The inner wall surface of the combustion chamber receives the impact of the jet, and the jet is splashed to form atomized droplets, and the atomized droplets come into contact with the combustion gas; The inner wall surface of the combustion chamber is prepared by casting or 3D printing, and the roughness of the inner wall surface of the combustion chamber is not less than 12.5 μm to enhance combustion.

9. An engine, characterized in that: It comprises a combustion chamber structure having a liquid film cooling combustion chamber inner wall surface structure of a liquid rocket engine according to any one of claims 1 to 8.

10. A rocket, characterized in that: Including the engine described in claim 9.

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