Method for analyzing and evaluating heat transfer performance of turbine pump of liquid rocket engine

Abstract

The invention discloses a liquid rocket engine turbine pump heat transfer performance analysis and evaluation method, and relates to the technical field of liquid rocket engine turbine pump design. The method comprises the following steps: establishing a pre-cooling and work simplification time sequence of the liquid rocket engine; constructing a simplified three-dimensional model of the turbine pump shell; determining a heat flow boundary and a convective heat transfer coefficient of the three-dimensional model of the target turbopump shell; acquiring a heat transfer coefficient of each heat flow boundary; on the basis of the pre-cooling and working simplified time sequence, the working medium property, the heat flow boundary and the heat transfer coefficient, turbine pump shell heat transfer finite element simulation is conducted on the pre-cooling and working process of the liquid rocket engine, and a simulation result is obtained; and the heat transfer performance of the turbopump shell is evaluated based on the simulation result, so that whether the heat transfer performance of the turbopump shell meets the requirement or not can be accurately known, and the risk of forward research and development design of a liquid rocket engine turbopump is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of liquid rocket engine turbo pump design, and in particular to a method for analyzing and evaluating the heat transfer performance of a liquid rocket engine turbo pump. Background Art

[0002] For liquid oxygen-kerosene engines, the turbopump works simultaneously in three temperature spans: cryogenic liquid oxygen, normal temperature kerosene, and high temperature gas; for liquid oxygen-methane / liquid hydrogen-liquid oxygen engines, the turbopump works simultaneously in three temperature spans: cryogenic liquid oxygen, cryogenic liquid methane / liquid hydrogen, and high temperature gas. The heat transfer performance of the turbopump is crucial to rocket engine design, affecting whether the engine can operate safely and reliably in a complex temperature environment. At present, there is still a lack of standardized heat transfer performance evaluation methods for cryogenic turbopumps, which brings risks to the forward research and development design of liquid rocket engine turbopumps. Summary of the invention

[0003] An embodiment of the present invention provides a method for analyzing and evaluating the heat transfer performance of a liquid rocket engine turbopump, aiming to solve the problem that the prior art lacks a standardized method for evaluating the heat transfer performance of a cryogenic turbopump, which brings risks to the forward research and development design of a liquid rocket engine turbopump.

[0004] In a first aspect, an embodiment of the present invention provides a method for analyzing and evaluating the heat transfer performance of a liquid rocket engine turbopump, which comprises:

[0005] According to the duration of the working medium introduced, the precooling and work simplification sequence of the liquid rocket engine is established;

[0006] Constructing a simplified three-dimensional model of a turbine pump housing to obtain a target three-dimensional model of a turbine pump housing, wherein the target three-dimensional model of the turbine pump housing includes an oxygen pump, a fuel pump, and a turbine;

[0007] Determining a heat flow boundary of the target turbopump housing three-dimensional model and a convective heat transfer coefficient of the heat flow boundary;

[0008] Based on the precooling and work simplification timing, the heat flow boundary and the convective heat transfer coefficient of the heat flow boundary, the heat transfer coefficient of each heat flow boundary at different time nodes is obtained;

[0009] Based on the simplified precooling and working sequence, the heat flow boundary, the convection heat transfer coefficient and the heat transfer coefficient, a finite element simulation of the heat transfer of the turbine pump casing is performed on the precooling and working process of the liquid rocket engine to obtain a simulation result;

[0010] The heat transfer performance of the turbine pump housing is evaluated based on the simulation results.

[0011] A further technical solution is that, according to the duration of the working medium introduced, the precooling and work simplification timing of the liquid rocket engine is:

[0012] The total duration of the precooling phase is set to 3400-3800 seconds, of which the first 1600-2000 seconds are for liquid oxygen and the remaining Remaining time Liquid oxygen and kerosene are passed; after precooling, the ignition stage begins, and the ignition time is 280-320s, during which liquid oxygen, kerosene and gas are passed simultaneously.

[0013] A further technical solution is that during the precooling stage, the flow rates of liquid oxygen and kerosene are set to 3-8%, preferably 5%, of the normal operating flow rate of the engine.

[0014] A further technical solution is that the construction of a simplified three-dimensional model of the turbine pump housing includes:

[0015] Simplifying target geometric features in the three-dimensional model of the turbine pump housing, wherein the target geometric features include fillets, chamfers, bosses, and gaps;

[0016] The target area in the three-dimensional model of the turbine pump housing is meshed, wherein the characteristic size C of the target area is j Smaller than the characteristic size threshold C jL .

[0017] A further technical solution is that the target area after mesh encryption satisfies Gm <k·C j , where Gm is the minimum grid size, k is the grid refinement factor, and C j is the characteristic size.

[0018] A further technical solution is to further include performing multiple smoothing processes on all meshes in the three-dimensional model of the turbine pump housing.

[0019] A further technical solution is that determining the heat flow boundary of the target turbine pump housing three-dimensional model and the convective heat transfer coefficient of the heat flow boundary includes:

[0020] Based on the three-dimensional model of the target turbopump housing, heat flow boundaries are defined for the outer wall surface and the inner wall surface of the target turbopump housing respectively; wherein,

[0021] For the outer wall surface of the target turbopump housing, the convective heat transfer coefficient of the outer wall surface is set to be the natural convection coefficient of air;

[0022] For the inner wall surface of the target turbo pump housing, the distribution of the working medium temperature and the working medium flow rate when the engine is working normally is used to define the convection heat transfer surface, and the convection heat transfer coefficient of each convection heat transfer surface is calculated according to the formula: Nu = 0.023Re 0.8Pr n ; In the formula, Re is the Reynolds number of the working medium; when heating the fluid, n = 0.4; when cooling the fluid, n = 0.3; the use of the correlation formula is limited to fluid Pr>0.6.

[0023] A further technical solution is that based on the precooling and work simplification timing, the heat flow boundary and the convective heat transfer coefficient of the heat flow boundary, the heat transfer coefficient of each heat flow boundary at different time nodes is obtained, including:

[0024] The convective heat transfer coefficient h of each heat transfer surface at different time nodes is obtained according to the formula Nu = hL / λ; where Nu is the convective heat transfer coefficient, L is the characteristic length of each heat transfer surface, and λ is the thermal conductivity of the working medium.

[0025] A further technical solution is that the precooling and working simplified timing, the heat flow boundary and the heat transfer coefficient are used to perform a finite element simulation of the turbine pump casing of the liquid rocket engine during precooling and working, including:

[0026] Based on the precooling and simplified working sequence, the temperature, flow velocity and flow rate of the working medium in different time periods, and the convective heat transfer coefficient h of each heat transfer surface, a convective heat transfer finite element simulation is performed on the outer wall and inner wall of the turbine pump housing.

[0027] A further technical solution is to also perform a thermal conduction finite element simulation of the interior of the turbine pump housing based on the precooling and simplified working sequence, the temperature, flow velocity and flow rate of the working medium in different time periods.

[0028] A further technical solution is that the heat transfer performance of the turbine pump housing is evaluated based on the simulation results, including:

[0029] Determining whether the heat transfer performance of the turbine pump housing meets a preset setting condition based on the simulation result;

[0030] If the heat transfer performance of the turbine pump housing meets a preset setting condition, it is determined that the heat transfer performance of the turbine pump housing is qualified.

[0031] A further technical solution is that the setting conditions include: (1):

[0033] For oxygen pumps, |T O -T OD |≤σ O ; Among them, T O Temperature of any point on the oxygen pump housing, T OD Liquid oxygen temperature, σ O The allowable temperature deviation range of the oxygen pump housing;

[0034] For the fuel pump, |TF -T FD |≤σ F ; Among them, T F Temperature of any point on the fuel pump housing, T FD Liquid kerosene temperature, σ F The allowable temperature deviation range of the fuel pump housing;

[0035] For turbine, T Wmin ≤T W ≤T Wmax ; Among them, T W The temperature of any point on the turbine casing, T Wmin The lowest permissible temperature of the turbine housing, T Wmax The maximum permissible temperature of the turbine housing;

[0036] (2):T F >T FJ , T O <T OQ , where T FJ is the crystallization temperature of kerosene, T OQ is the liquid oxygen vaporization temperature;

[0037] (3): After the working medium is introduced for a period of time Δt, the condition in (1) is always met.

[0038] The embodiment of the present invention provides a method for analyzing and evaluating the heat transfer performance of a liquid rocket engine turbine pump. The method includes: establishing a precooling and simplified working sequence of a liquid rocket engine according to the duration of the working medium introduced; constructing a simplified three-dimensional model of the turbine pump housing to obtain a target three-dimensional model of the turbine pump housing; determining the heat flow boundary of the target three-dimensional model of the turbine pump housing and the convective heat transfer coefficient of the heat flow boundary; obtaining the heat transfer coefficient of each heat flow boundary at different time nodes based on the precooling and simplified working sequence, the heat flow boundary and the convective heat transfer coefficient of the heat flow boundary; performing a finite element simulation of the heat transfer of the turbine pump housing during the precooling and working process of the liquid rocket engine based on the precooling and simplified working sequence, the heat flow boundary, the convective heat transfer coefficient and the heat transfer coefficient to obtain a simulation result; and evaluating the heat transfer performance of the turbine pump housing based on the simulation result. By applying the technical solution of the embodiment of the present invention, a finite element simulation of the heat transfer of the turbine pump casing is performed on the pre-cooling and working process of the liquid rocket engine. Based on the simulation results, the heat transfer performance of the turbine pump casing can be accurately evaluated, so that it is possible to accurately know whether the heat transfer performance of the turbine pump casing meets the requirements, thereby reducing the risk of forward research and development design of the liquid rocket engine turbine pump. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying any creative work.

[0040] Figure 1 A schematic flow chart of a method for analyzing and evaluating the heat transfer performance of a liquid rocket engine turbopump provided by an embodiment of the present invention;

[0041] Figure 2 A simplified timing diagram of precooling and operation of a liquid rocket engine provided by an embodiment of the present invention;

[0042] Figure 3 It is a schematic diagram of the three-dimensional structure modeling of the turbine pump housing;

[0043] Figure 4 A schematic diagram of the finite element sectioning of a turbine pump housing provided in an embodiment of the present invention;

[0044] Figure 5 A schematic diagram of a thermal flow boundary of a turbine pump casing provided by an embodiment of the present invention;

[0045] Figure 6 is a schematic diagram of the temperature distribution of the turbine pump housing in the precooling stage provided by an embodiment of the present invention;

[0046] Figure 7 It is a schematic diagram of the temperature distribution of the turbine pump casing during the working stage provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0047] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0048] It should be understood that when used in this specification and the appended claims, the terms "include" and "comprises" indicate the presence of described features, integers, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or combinations thereof.

[0049] It should also be understood that the terms used in this specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. As used in the specification of the present invention and the appended claims, unless the context clearly indicates otherwise, the singular forms "a", "an" and "the" are intended to include plural forms.

[0050] It should be further understood that the term "and / or" used in the present description and the appended claims refers to and includes any and all possible combinations of one or more of the associated listed items.

[0051] As used in this specification and the appended claims, the term "if" may be interpreted as "when" or "upon" or "in response to determining" or "in response to detecting," depending on the context. Similarly, the phrases "if it is determined" or "if [described condition or event] is detected" may be interpreted as meaning "upon determination" or "in response to determining" or "upon detection of [described condition or event]" or "in response to detecting [described condition or event]," depending on the context.

[0052] See also Figure 1 , Figure 1 FIG. 1 is a flow chart of a method for analyzing and evaluating the heat transfer performance of a liquid rocket engine turbo pump provided by an embodiment of the present invention. Figure 1 As shown, the method includes the following steps S1-S6.

[0053] S1, establish the pre-cooling and work simplification sequence of the liquid rocket engine according to the length of time the working medium is introduced.

[0054] In a specific implementation, the operation of a liquid rocket engine includes a precooling stage and a working stage. In the present invention, in order to reduce the amount of calculation, firstly, a simplified timing of precooling and working of the liquid rocket engine is established according to the duration of the working medium introduced. By simplifying the timing of the liquid rocket engine in the precooling stage and the working stage, the amount of calculation can be effectively reduced.

[0055] In the specific implementation, the total duration of the precooling stage is set to 3400-3800 seconds, of which the first 1600-2000 seconds are liquid oxygen, and the remaining Remaining time Liquid oxygen and kerosene are passed; after precooling, the ignition stage begins, and the ignition time is 280-320s, during which liquid oxygen, kerosene and gas are passed simultaneously.

[0056] In a specific implementation, during the precooling stage, the flow rate of liquid oxygen and kerosene is set to 3-8% of the normal working flow rate of the engine.

[0057] For example, see Figure 2In one embodiment, the precooling and simplified working sequence of the liquid rocket engine is as follows: 3600s precooling, of which 1800s is liquid oxygen, and 1800s is liquid oxygen and kerosene; 300s ignition, of which liquid oxygen, kerosene and fuel gas are simultaneously passed during ignition. During the precooling stage, the flow rates of liquid oxygen and kerosene are set to 5% of the normal working flow rate of the engine.

[0058] S2, build a simplified three-dimensional model of the turbine pump casing.

[0059] In a specific implementation, a three-dimensional model of the turbine pump casing is constructed by three-dimensional modeling software, including an oxygen pump, a fuel pump and a turbine.

[0060] For example, in one embodiment, see Figure 3 , Figure 3 It is a schematic diagram of the three-dimensional structural modeling of the turbopump housing. The turbopump is a single-axis layout, and the oxygen pump 10, the fuel pump 20, and the turbine 30 are distributed in sequence according to the temperature step change.

[0061] S3, simplifying and performing finite element segmentation on the three-dimensional model of the turbine pump housing to obtain a target three-dimensional model of the turbine pump housing.

[0062] For specific implementation, see Figure 4 In order to reduce the amount of calculation and ensure the accuracy of the simulation, the three-dimensional model of the turbine pump housing is simplified and finite element segmented to obtain a target three-dimensional model of the turbine pump housing.

[0063] For example, in one embodiment, the above step S3 includes:

[0064] The target geometric features in the three-dimensional model of the turbine pump housing are simplified, wherein the target geometric features include fillets, chamfers, bosses, and gaps. By simplifying (i.e., deleting) the target geometric features such as fillets, chamfers, bosses, and gaps that sharply increase the number of grids while not affecting the simulation restoration, the amount of calculation can be effectively reduced.

[0065] Furthermore, mesh encryption is performed on the target area in the three-dimensional model of the turbine pump housing, wherein the characteristic size C of the target area is j Smaller than the characteristic size threshold C jL The target area is the area where the shell temperature changes drastically and the structure is complex. By performing mesh encryption in the area where the shell temperature changes drastically and the structure is complex, the accuracy of the simulation can be effectively improved.

[0066] In a specific implementation, the target area after mesh encryption satisfies Gm <k·C j , where Gm is the minimum grid size, k is the grid refinement factor, and C j is the characteristic size.

[0067] Furthermore, all meshes in the three-dimensional model of the turbine pump housing are smoothed for multiple times, for example, three times, which can be determined by those skilled in the art according to actual processing conditions. By smoothing all meshes for multiple times, the mesh quality can be improved.

[0068] S4, determining the heat flow boundary of the target turbine pump housing three-dimensional model and the convective heat transfer coefficient of the heat flow boundary.

[0069] In a specific implementation, determining the heat flow boundary of the target turbine pump housing three-dimensional model, that is, determining the convection heat transfer surface of the target turbine pump housing three-dimensional model, includes: based on the target turbine pump housing three-dimensional model, defining the heat flow boundaries of the outer wall surface and the inner wall surface of the target turbine pump housing respectively.

[0070] Specifically, in one embodiment, the convection heat transfer surface of the target turbine pump housing three-dimensional model is defined based on the convection heat transfer coefficient and the medium temperature of the boundary of the target turbine pump housing three-dimensional model. Figure 5 The turbine pump housing includes an oxygen pump low-pressure housing 21, an oxygen pump shoulder seal 22, an oxygen pump high-pressure housing 23, a fuel pump seal 24, a fuel pump housing 25, a turbine housing 26, a guide vane 27, and a turbine outlet pipe 28. In this embodiment, the convection heat transfer surface of the main housing of the target turbine pump housing three-dimensional model is divided into 0-9. Specifically, the entire outer shell of the turbine pump is coated with an insulation layer, and natural convection heat transfer is carried out with the ambient air; the inner wall of the turbine pump housing is subjected to forced convection heat transfer with low-temperature liquid oxygen, room-temperature kerosene, and high-temperature fuel gas respectively; and heat conduction heat transfer is carried out inside the turbine pump housing, inside the oxygen pump shoulder seal, and inside the fuel pump shoulder. Compared with the medium flow rate in the oxygen pump and the fuel pump, the medium flow rate in the turbine pump isolation cavity and the turbine end face seal is significantly reduced, and it is considered that the inner wall surface here is insulated. Compared with forced convection heat transfer, the turbine radiation heat level is small and can be ignored. The outer surface of the turbine pump housing is coated with an insulation layer, and natural convection heat transfer is carried out with the ambient air. In the precooling stage, the inner wall of the turbine and the air in the inner cavity are subjected to natural convection. The range of air natural convection coefficient is 1-10W·m -2 ·K -1 The inner wall of the turbine pump housing and the medium undergo forced convection. The intensity of convection heat transfer is related to factors such as fluid flow state, fluid physical properties, heat exchange surface geometry, and flow origin. The convection heat transfer coefficient is calculated based on the Dittus-Boelter heat transfer correlation formula for turbulent forced convection in heat transfer: Nu = 0.023Re 0.8 Pr n Where Re is the Reynolds number of the working medium. When heating the fluid, n = 0.4; when cooling the fluid, n = 0.3. The use of the correlation formula is limited to fluid Pr> 0.6.

[0071] Furthermore, in this embodiment, the convective heat transfer surface is divided into convective heat transfer surfaces 0-9 mainly based on the convective heat transfer coefficient of the heat transfer surface of the target turbine pump housing three-dimensional model and the medium temperature. The convective heat transfer coefficient of the convective heat transfer surface is mainly related to the flow rate and thermal properties of the working medium.

[0072] Specifically, the outer wall surface of the turbine pump housing mainly undergoes natural convection with the air, and the heat transfer coefficient and the medium temperature are constant. Therefore, the outer wall surface is defined as the convection heat transfer surface 0, and the convection heat transfer coefficient is the natural convection coefficient of the air.

[0073] For the inner wall surface of the turbine pump housing, when the engine is working normally, the distribution of the working medium temperature and the working medium flow rate when the engine is working normally is used to define the convection heat transfer surface. For the oxygen pump, when the engine is working, the medium is liquid oxygen, and the temperature is about -180°C, but the liquid oxygen velocity at different positions is different. In this embodiment, the heat flow boundary of the oxygen pump is divided into convection heat transfer surfaces 1 and 2 according to the characteristics of the liquid oxygen velocity distribution. For the fuel pump, when the engine is working, the medium is kerosene, and the temperature is about 15°C, but the kerosene velocity at different positions is different. In this embodiment, the heat flow boundary of the fuel pump is divided into convection heat transfer surfaces 3, 4, and 5 according to the characteristics of the kerosene velocity distribution. For the turbine, when the engine is working, the medium is fuel gas, and the temperature is about 300-750°C. In this embodiment, the heat flow boundary of the turbine is divided into convection heat transfer surfaces 6, 7, 8, and 9 according to the different fuel gas temperature and velocity distribution at different positions.

[0074] The convective heat transfer coefficient of the above convective heat transfer surfaces 1-9 is calculated according to the formula: Nu = 0.023Re 0.8 Pr n ; In the formula, Re is the Reynolds number of the working medium; when heating the fluid, n = 0.4; when cooling the fluid, n = 0.3; the use of the correlation formula is limited to fluid Pr>0.6.

[0075] S5, based on the pre-cooling and work simplification timing, the heat flow boundary and the convective heat transfer coefficient of the heat flow boundary, obtaining the heat transfer coefficient of each heat flow boundary at different time nodes.

[0076] After the convective heat transfer coefficient Nu of the convective heat transfer surfaces 0-9 is obtained in the above step S4, the convective heat transfer coefficient h of each heat transfer surface at different time nodes is obtained according to the formula Nu=hL / λ; wherein Nu is the convective heat transfer coefficient, L is the characteristic length of each heat transfer surface, and λ is the thermal conductivity of the working medium.

[0077] S6. Based on the simplified precooling and working sequence, the target turbine pump housing three-dimensional model and the heat flow boundary, a finite element simulation of the heat transfer of the turbine pump housing is performed on the precooling and working process of the liquid rocket engine to obtain a simulation result.

[0078] In the specific implementation, finite element simulation is performed through simulation software, and the simplified pre-cooling and working timing, the heat flow boundary of the target turbine pump housing three-dimensional model and the heat transfer coefficient are used as input parameters. According to the characteristics of the working medium passing through different time periods of the timing, the convective heat transfer coefficient h and the corresponding medium temperature of each heat transfer surface are given in this time period. In the simulation software, the convective heat transfer finite element simulation of the outer wall and inner wall of the turbine pump housing of the liquid rocket engine pre-cooling and working process is carried out to obtain the simulation results.

[0079] In a specific embodiment, since the interior of the turbine pump housing, the interior of the oxygen pump shoulder seal, and the interior of the fuel pump shoulder are heat conductive, the finite element simulation of the heat transfer of the turbine pump housing also includes: based on the pre-cooling and simplified working sequence, the temperature, flow rate and flow rate of the working medium at different time periods, a thermal conductive finite element simulation of the interior of the turbine pump housing is performed.

[0080] For example, in one embodiment, the simulation results are shown in Figure 6-Figure 7 , Figure 6 This is a schematic diagram of the temperature distribution of the turbine pump casing during the precooling stage. Figure 7 It is a schematic diagram of the temperature distribution of the turbine pump casing during the working stage.

[0081] S6, evaluating the heat transfer performance of the turbine pump casing based on the simulation results.

[0082] In a specific implementation, the simulation results include the temperature distribution of the turbine pump housing during each working stage of the liquid rocket engine, and the heat transfer performance of the turbine pump housing is evaluated based on the temperature distribution of the turbine pump housing.

[0083] For example, in one embodiment, it is determined whether the heat transfer performance of the turbine pump housing meets the preset setting conditions based on the simulation results; if the heat transfer performance of the turbine pump housing meets the preset setting conditions, it is determined that the heat transfer performance of the turbine pump housing is qualified. If the heat transfer performance of the turbine pump housing does not meet the preset setting conditions, it is determined that the heat transfer performance of the turbine pump housing is qualified.

[0084] Specifically, the setting conditions include: (1):

[0086] For oxygen pumps, |T O -T OD |≤σ O ; Among them, T O Temperature of any point on the oxygen pump housing, T OD Liquid oxygen temperature, σ O The allowable temperature deviation range of the oxygen pump housing;

[0087] For the fuel pump, |T F -T FD |≤σF ; Among them, T F Temperature of any point on the fuel pump housing, T FD Liquid kerosene temperature, σ F The allowable temperature deviation range of the fuel pump housing;

[0088] For turbine, T Wmin ≤T W ≤T Wmax ; Among them, T W The temperature of any point on the turbine casing, T Wmin The lowest permissible temperature of the turbine housing, T Wmax The maximum permissible temperature of the turbine housing;

[0089] (2):T F >T FJ , T O <T OQ , where T FJ is the crystallization temperature of kerosene, T OQ is the liquid oxygen vaporization temperature;

[0090] (3): After the working medium is introduced for a period of time Δt, the condition in (1) is always met.

[0091] The above three setting conditions can ensure:

[0092] 1. During the working stage of the turbine pump housing, the oxygen pump, fuel pump and turbine all work in their respective temperature ranges, and no obvious temperature erosion occurs;

[0093] 2. The kerosene in the fuel pump does not freeze, and the liquid oxygen in the oxygen pump does not vaporize;

[0094] 3. After the working medium is introduced, the temperatures of the oxygen pump, fuel pump and turbine casing quickly balance to a range close to the corresponding working medium temperature.

[0095] In the present invention, Δt can be set by those skilled in the art and is not specifically limited in the present invention.

[0096] The embodiment of the present invention provides a method for analyzing and evaluating the heat transfer performance of a liquid rocket engine turbine pump. The method includes: establishing a simplified precooling and working sequence of a liquid rocket engine; constructing a three-dimensional model of a turbine pump housing; simplifying and finite element segmenting the three-dimensional model of the turbine pump housing to obtain a target three-dimensional model of the turbine pump housing; determining the heat flow boundary of the target three-dimensional model of the turbine pump housing; based on the simplified precooling and working sequence, the target three-dimensional model of the turbine pump housing and the heat flow boundary, performing a finite element simulation of the heat transfer of the turbine pump housing during the precooling and working process of the liquid rocket engine to obtain a simulation result; and evaluating the heat transfer performance of the turbine pump housing based on the simulation result. By applying the technical solution of the embodiment of the present invention, a finite element simulation of the heat transfer of the turbine pump housing is performed during the precooling and working process of the liquid rocket engine. Based on the simulation result, the heat transfer performance of the turbine pump housing can be accurately evaluated, so that it is possible to accurately know whether the heat transfer performance of the turbine pump housing meets the requirements, thereby reducing the risk of forward research and development design of the liquid rocket engine turbine pump.

[0097] In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0098] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

[0099] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can easily think of various equivalent modifications or replacements within the technical scope disclosed by the present invention, and these modifications or replacements should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention shall be based on the protection scope of the claims.

Claims

1. A method for analyzing and evaluating the heat transfer performance of a liquid rocket engine turbopump, characterized in that: include: According to the duration of the working medium introduced, the precooling and work simplification sequence of the liquid rocket engine is established; Constructing a simplified three-dimensional model of a turbine pump housing to obtain a target three-dimensional model of a turbine pump housing, wherein the target three-dimensional model of the turbine pump housing includes an oxygen pump, a fuel pump, and a turbine; Determining a heat flow boundary of the target turbopump housing three-dimensional model and a convective heat transfer coefficient of the heat flow boundary; Based on the precooling and work simplification timing, the heat flow boundary and the convective heat transfer coefficient of the heat flow boundary, the heat transfer coefficient of each heat flow boundary at different time nodes is obtained; Based on the simplified precooling and working sequence, the heat flow boundary, the convection heat transfer coefficient and the heat transfer coefficient, a finite element simulation of the heat transfer of the turbine pump casing is performed on the precooling and working process of the liquid rocket engine to obtain a simulation result; The heat transfer performance of the turbine pump housing is evaluated based on the simulation results.

2. The method for analyzing and evaluating heat transfer performance of a liquid rocket engine turbopump according to claim 1, characterized in that: According to the duration of the working medium introduced, the precooling and simplified working sequence of the liquid rocket engine is as follows: The total duration of the precooling phase is set to 3400-3800 seconds, of which the first 1600-2000 seconds are for liquid oxygen and the remaining Remaining time Liquid oxygen and kerosene are passed; after precooling, the ignition stage begins, and the ignition time is 280-320s, during which liquid oxygen, kerosene and gas are passed simultaneously.

3. The method for analyzing and evaluating heat transfer performance of a liquid rocket engine turbopump according to claim 2, characterized in that: During the precooling stage, the flow rate of liquid oxygen and kerosene is set to 3-8% of the normal operating flow rate of the engine.

4. The method for analyzing and evaluating heat transfer performance of a liquid rocket engine turbopump according to claim 1, characterized in that: The simplified three-dimensional model of the turbine pump housing is constructed, comprising: Simplifying target geometric features in the three-dimensional model of the turbine pump housing, wherein the target geometric features include fillets, chamfers, bosses, and gaps; The target area in the three-dimensional model of the turbine pump housing is meshed, wherein the characteristic size C of the target area is j Smaller than the characteristic size threshold C jL .

5. The method for analyzing and evaluating heat transfer performance of a liquid rocket engine turbopump according to claim 4, characterized in that: Also includes: The target area after mesh encryption satisfies Gm <k·C j , where Gm is the minimum grid size, k is the grid refinement factor, and C j is the characteristic size.

6. The method for analyzing and evaluating heat transfer performance of a liquid rocket engine turbopump according to claim 1, characterized in that: The step of determining the heat flow boundary of the target turbine pump housing three-dimensional model and the convective heat transfer coefficient of the heat flow boundary includes: Based on the three-dimensional model of the target turbopump housing, heat flow boundaries are defined for the outer wall surface and the inner wall surface of the target turbopump housing respectively; wherein, For the outer wall surface of the target turbopump housing, the convective heat transfer coefficient of the outer wall surface is set to be the natural convection coefficient of air; For the inner wall surface of the target turbo pump housing, the distribution of the working medium temperature and the working medium flow rate when the engine is working normally is used to define the convection heat transfer surface, and the convection heat transfer coefficient of each convection heat transfer surface is calculated according to the formula: Nu = 0.023Re 0.8 Pr n ; In the formula, Re is the Reynolds number of the working medium; when heating the fluid, n = 0.4; when cooling the fluid, n = 0.3; the use of the correlation formula is limited to fluid Pr>0.

6.

7. The method for analyzing and evaluating heat transfer performance of a liquid rocket engine turbopump according to claim 6, characterized in that: The obtaining of the heat transfer coefficient of each heat flow boundary at different time nodes based on the precooling and work simplification timing, the heat flow boundary and the convective heat transfer coefficient of the heat flow boundary includes: The convective heat transfer coefficient h of each heat transfer surface at different time nodes is obtained according to the formula Nu = hL / λ; where Nu is the convective heat transfer coefficient, L is the characteristic length of each heat transfer surface, and λ is the thermal conductivity of the working medium.

8. The method for analyzing and evaluating heat transfer performance of a liquid rocket engine turbo pump according to claim 7, characterized in that: The method of performing a finite element simulation of a turbine pump casing on a precooling and working process of a liquid rocket engine based on the precooling and simplified working sequence, the heat flow boundary and the heat transfer coefficient includes: Based on the precooling and simplified working sequence, the temperature, flow velocity and flow rate of the working medium in different time periods, and the convective heat transfer coefficient h of each heat transfer surface, a convective heat transfer finite element simulation is performed on the outer wall and inner wall of the turbine pump housing.

9. The method for analyzing and evaluating heat transfer performance of a liquid rocket engine turbopump according to claim 8, characterized in that: It also includes, based on the pre-cooling and simplified working sequence, the temperature, flow velocity and flow rate of the working medium in different time periods, performing a thermal conduction finite element simulation on the interior of the turbine pump housing.

10. The method for analyzing and evaluating heat transfer performance of a liquid rocket engine turbopump according to claim 9, characterized in that: The evaluating the heat transfer performance of the turbine pump housing based on the simulation results includes: Determining whether the heat transfer performance of the turbine pump housing meets a preset setting condition based on the simulation result; If the heat transfer performance of the turbine pump housing meets the preset setting conditions, it is determined that the heat transfer performance of the turbine pump housing is qualified; The setting conditions include: (1): For oxygen pump, |T O -T OD |≤σ O ; Among them, T O Temperature of any point on the oxygen pump housing, T OD Liquid oxygen temperature, σ O The allowable temperature deviation range of the oxygen pump housing; For the fuel pump, |T F -T FD |≤σ F ; Among them, T F Temperature of any point on the fuel pump housing, T FD Liquid kerosene temperature, σ F The allowable temperature deviation range of the fuel pump housing; For turbine, T Wmin ≤T W ≤T Wmax ; Among them, T W The temperature of any point on the turbine casing, T Wmin The lowest permissible temperature of the turbine housing, T Wmax The maximum permissible temperature of the turbine housing; (2):T F >T FJ , T O <T OQ , where T FJ is the crystallization temperature of kerosene, T OQ is the liquid oxygen vaporization temperature; (3): After the working medium is introduced for a period of time Δt, the condition in (1) is always met.

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