Overall scheme design method and device for an open expansion cycle engine

Abstract

The present disclosure relates to a general design method and device for an open expander cycle engine, belonging to the technical field of general design of expander cycle engines. It includes: determining the engine design parameters, as well as the optimization ranges of the thrust chamber pressure, mixture ratio, and flow rate ratio; performing optimization within the optimization range with the engine specific impulse as the optimization objective, where the engine specific impulse = engine thrust / engine propellant flow rate, and the propellant flow rate is the sum of the coolant flow rate, thrust chamber fuel flow rate, and oxidizer flow rate. By transforming the general design of the open expander cycle engine into an optimization problem of three variables, namely the thrust chamber pressure, mixture ratio, and flow rate ratio, within a given range with the engine specific impulse as the optimization objective, on the one hand, the overall performance of the engine is optimized to the best; on the other hand, it is realistically achievable with the chamber pressure, mixture ratio, and flow rate ratio as the optimization variables; furthermore, the selection of the optimization objective and optimization variables is comprehensive, which can reduce the complexity of engine design.

Description

Technical Field

[0001] The present disclosure relates to the technical field of the overall scheme design of expander cycle engines in liquid rocket engines, and particularly relates to a method and device for the overall scheme design of an open expander cycle engine. Background Art

[0002] As one of the most important technical characteristics of liquid rocket engines, the cycle mode directly determines its performance level, applicable range and corresponding technical solutions. As one of the three typical cycles of liquid rocket engines, the expander cycle has certain advantages compared with the other two cycle modes (gas generator cycle and staged combustion cycle). Compared with the gas generator cycle, as a closed cycle, on the one hand, there are no complex thermal components such as gas generators, and on the other hand, there is no waste of unutilized gas, so the specific impulse performance is relatively high. Compared with the staged combustion cycle, there are no complex thermal components such as preburners, and the structure is simple.

[0003] Although the expander cycle mode has certain advantages, its defects are also relatively obvious. The literature (Research on the Scheme of a Parallel Electrothermal Synergistic Boosting Variable Thrust Rocket Engine. Manned Spaceflight, 2020, 26(6): 702-9.) points out that in this mode, the propellant absorbs heat from the cooling channel, then drives the turbine to do work, and finally enters the combustion chamber to burn. Compared with the high-temperature and high-pressure gas generated after combustion, the work capacity of the propellant after heat absorption is limited, and the turbine pressure ratio should not be too large. Therefore, the chamber pressure of the expander cycle engine is relatively low, the thrust is small, and it is mainly applied to the upper stage and cannot be used in the core stage or boosters of launch vehicles.

[0004] The open expander cycle scheme, as a new cycle mode, can effectively solve the problem of small thrust of the expander cycle engine by effectively increasing the turbine pressure ratio and further increasing the turbine work capacity. In this cycle mode, most of the propellant (liquid hydrogen) directly enters the thrust chamber after passing through the main valve, and a small part of the propellant passes through the cooling channel, absorbs heat and becomes high-temperature and high-pressure gas, and is directly discharged into the atmosphere after driving the turbine. For this cycle scheme, there is a lack of an overall design method that can optimize the engine performance. Summary of the Invention

[0005] The purpose of the present disclosure is to solve part or all of the above technical problems, and provide a method and device for the overall scheme design of an open expander cycle engine.

[0006] The purpose of the present disclosure is achieved through the following technical solutions.

[0007] In a first aspect, the present disclosure provides a method for the overall scheme design of an open expander cycle engine, including:

[0008] Obtaining the engine design parameters, as well as the optimization ranges of the thrust chamber chamber pressure, mixing and flow ratio.

[0009] Optimize within the optimization range with the engine specific impulse as the optimization goal. The engine specific impulse = engine thrust / engine propellant flow rate, and the propellant flow rate is the sum of the coolant flow rate, the thrust chamber fuel flow rate, and the oxidizer flow rate.

[0010] In a second aspect, the present disclosure provides an overall scheme design device for an open expansion cycle engine, including:

[0011] An input module for obtaining engine design parameters, as well as the optimization ranges of the thrust chamber chamber pressure, mixing ratio, and flow rate ratio.

[0012] An optimization module for optimizing within the optimization range with the engine specific impulse as the optimization goal. The engine specific impulse = engine thrust / engine propellant flow rate, and the propellant flow rate is the sum of the coolant flow rate, the thrust chamber fuel flow rate, and the oxidizer flow rate.

[0013] In a third aspect, the present disclosure provides an electronic device, including:

[0014] At least one processor; and,

[0015] A memory communicatively connected to the at least one processor; wherein, the memory stores instructions executable by the at least one processor, and when the instructions are executed by the at least one processor, the at least one processor is enabled to execute the method according to any one of the embodiments in the second aspect.

[0016] In a fourth aspect, the present disclosure provides a computer-readable storage medium, on which a computer program is stored, and when the program is executed by a processor, the processor is enabled to execute the method according to any one of the embodiments in the second aspect.

[0017] In a fifth aspect, the present disclosure provides a computer program product, including computer programs / instructions, and when the computer programs / instructions are executed by a processor, the processor is enabled to execute the method according to any one of the embodiments in the second aspect.

[0018] Beneficial effects

[0019] By transforming the overall scheme design of the open expansion cycle engine into an optimization problem of three variables, namely the thrust chamber chamber pressure, mixing ratio, and flow rate ratio, within a given range with the engine specific impulse as the optimization goal, the present disclosure reduces the complexity of the engine system design on the one hand, and on the other hand, it is realistically achievable to take the thrust chamber as the optimization object. Description of the drawings

[0020] Figure 1 It is a schematic diagram of a method for designing an overall scheme of an open expansion cycle engine provided by an embodiment of the present disclosure;

[0021] Figure 2Schematic diagram of an open expansion cycle engine provided by an embodiment of the present disclosure;

[0022] Figure 3 Schematic diagram of a method for estimating parameters of an open expansion cycle engine provided by an embodiment of the present disclosure;

[0023] Figure 4 Schematic diagram of a general design method for an open expansion cycle engine provided by an embodiment of the present disclosure;

[0024] Figure 5 Schematic diagram of the structure of an electronic device provided by an embodiment of the present disclosure. Detailed implementation manners

[0025] The present disclosure will be described in detail below in conjunction with the specific implementation manners shown in the accompanying drawings. However, these implementation manners are not limited to the present disclosure, and any structural, method, or functional transformation made by those of ordinary skill in the art based on these implementation manners is included in the protection scope of the present disclosure.

[0026] In the description of the present disclosure, it should be understood that the orientation or positional relationship indicated by the terms "center", "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing the present disclosure and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation to the present disclosure. In addition, the terms "first", "second", etc. are only used for descriptive purposes and cannot be construed as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, features defined with "first", "second", etc. may explicitly or implicitly include one or more of such features. In the description of the present disclosure, unless otherwise specified, the meaning of "a plurality" is two or more.

[0027] To illustrate the purpose, technical solutions, and advantages of the embodiments of the present disclosure, the technical solutions in the embodiments of the present disclosure will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present disclosure.

[0028] Figure 2An open-expansion cycle engine provided by the present disclosure. As shown in the figure, the engine includes a fuel turbine 2, a fuel pump 1, a fuel valve 3, a cooling channel 5, an injector 7, a combustion chamber 6, a nozzle 4, an oxidizer turbine 10, an oxidizer pump 9, and an oxidizer valve 8. Among them, the cooling channel 5, the injector 7, the combustion chamber 6, and the nozzle 4 form a thrust chamber. The fuel pump 1 is respectively connected to the fuel turbine 2 and the fuel valve 3, the oxidizer pump 9 is respectively connected to the oxidizer turbine 10 and the oxidizer valve 8, the cooling channel 5 is deployed around the thrust chamber to cool it, the outlet of the cooling channel 5 is connected to the fuel turbine 2, the fuel turbine 2 is connected to the oxidizer turbine 10, the fuel is divided into two paths at the outlet of the fuel valve 3, one path enters the cooling channel 5, and the other path enters the injector 7 together with the oxidizer at the outlet of the oxidizer valve 8. The injector 7 injects the fuel and the oxidizer into the combustion chamber 6, and the high-temperature and high-pressure gas generated by combustion is discharged by the nozzle 4.

[0029] The fuel is pressurized by the fuel pump 1 and passes through the fuel valve 3 and is divided into two paths. One path enters the cooling channel 5, absorbs heat from the combustion chamber 6, and then drives the fuel turbine 2 and the oxidizer turbine 10 to do work in sequence. The other path and the oxidizer pressurized by the oxidizer pump 9 and passing through the oxidizer valve 8 are injected into the combustion chamber 6 through the injector 7, burned, and then ejected by the nozzle 4 to push the rocket to fly; the fuel turbine 2 and the oxidizer turbine 10 respectively drive the fuel pump 1 and the oxidizer pump 9 to work.

[0030] Figure 1 A general design method for the open-expansion cycle engine provided by the present disclosure. For the Figure 2 engine shown, it includes the following contents:

[0031] Determine the engine design parameters, as well as the optimization ranges of the thrust chamber pressure, mixture ratio, and flow rate ratio.

[0032] Optimize within the optimization range with the engine specific impulse as the optimization goal. The engine specific impulse = engine thrust / engine propellant flow rate, and the propellant flow rate is the sum of the coolant flow rate, the fuel flow rate in the thrust chamber, and the oxidizer flow rate.

[0033] Figure 4 Another general design method for the open-expansion cycle engine provided by the present disclosure includes:

[0034] 1. Obtain the optimization ranges (upper and lower limits) of the thrust chamber pressure, mixture ratio, and flow rate ratio;

[0035] 2. Establish an optimization function with the engine specific impulse (thrust / (coolant flow rate + thrust chamber flow rate)) as the goal. Specifically, pack the calculation process of the off-design parameters of the open-expansion cycle engine into a function of the chamber pressure , mixture ratio and flow rate ratio . Expressed as:

[0036]

[0037] Among them, represents the function that packs the calculation process of off-design condition parameters; represents the specific impulse of the engine, represents the thrust of the engine, represents the fuel flow rate of the thrust chamber, represents the oxidizer flow rate of the thrust chamber, represents the coolant flow rate.

[0038] 3. Open the genetic algorithm toolbox in Matlab, substitute the optimization ranges of the three variables, call the optimization function of the engine specific impulse, and conduct the optimization. After the optimization is completed, the optimal chamber pressure, mixture ratio, and flow ratio can be determined.

[0039] By analyzing the engine shown in Figure 2 transform the overall scheme design of the open-expansion cycle engine into an optimization problem of finding the optimal values of three variables, namely the chamber pressure, mixture ratio, and flow ratio, within a given range with the engine specific impulse as the optimization goal. On the one hand, it makes the overall performance of the engine reach the optimal; on the other hand, it is realistically achievable to use the chamber pressure, mixture ratio, and flow ratio as the optimization variables. Moreover, the selection of the optimization goal and optimization variables is comprehensive, which can reduce the design complexity of the engine.

[0040] In a specific embodiment, the above-mentioned fuel and oxidizer are liquid hydrogen and liquid oxygen.

[0041] In a specific embodiment, for the given chamber pressure, mixture ratio, and flow ratio values in the above-mentioned optimization process, the coolant flow rate, fuel flow rate of the thrust chamber, and oxidizer flow rate are obtained through the off-design condition parameter estimation method of the open-expansion cycle engine.

[0042] In a specific embodiment, the off-design condition parameter estimation method of the open-expansion cycle engine includes based on the engine design parameters and the reference condition parameters: the chamber pressure of the thrust chamber p c0 、mixture ratio MR 0 、flow ratio 0 and the outlet temperature of the cooling channel T rc0 estimate the outlet temperature of the cooling channel T rc under the current condition; based on the engine design parameters and the current condition parameters, estimate the node state parameters by adjusting the turbine pressure ratio on the condition of turbine pump power matching.

[0043] Through the off-design parameter estimation method of an open-expansion cycle engine, the outlet temperature of the cooling channel under the current condition can be quickly obtained based on the existing conditions, and then the node state parameter estimation can be quickly carried out on the condition of turbine pump power matching, so as to realize the analysis of the variation law of the performance parameters of the open-expansion cycle engine; it is convenient for the overall scheme design and parameter optimization of the engine, so as to carry out the structural parameter design of the components of the open-expansion cycle engine (such as turbines, pumps, thrust chambers, etc.) subsequently.

[0044] Based on the engine design parameters and the current condition parameters, the node state parameters are estimated by adjusting the turbine pressure ratio on the condition of turbine pump power matching, such as Figure 3 shown, the process is as follows:

[0045] 1. Based on the chamber pressure of the thrust chamber of the engine p c 、the mixture ratio of the thrust chamber MR and the nozzle exit pressure p e calculate the specific impulse of the thrust chamber I spc .

[0046] I spc It can be obtained by the thermal calculation method, and the reference document can be (Liquid Rocket Engine Design published by Beihang University Press in 2011 by Cai Guobiao, Li Jiawen, Tian Aimei, Zhang Lihui, etc.); it can also be obtained by using software, such as the rocket engine performance analysis software. In this example, the rocket engine performance analysis software Rocket ProplusionAnalysis (RPA, www.propulsion-analysis.com) is used to obtain it.

[0047] 2. Based on the thrust of the engine F 、 MR 、the proportion of the thrust chamber flow rate of the engine and I spc calculate the oxidizer flow rate of the thrust chamber 、the fuel flow rate and the turbine working medium flow rate (i.e., the coolant flow rate) by the following formula:

[0048]

[0049] 3. Initialize the fuel turbine pressure ratio and the oxidizer turbine pressure ratio.

[0050] It can be initialized according to the preset value, or it can be an externally given value, that is, the input value. This value will be continuously adjusted in the subsequent steps to adapt to the relevant design parameters given in 1.

[0051] 4. Calculate the fuel pump power based on the outlet temperature of the cooling channel T rc Calculate the fuel turbine power, compare the fuel pump power and the fuel turbine power. If they do not match, adjust the fuel turbine pressure ratio and repeat the content of this step until the fuel pump power and the fuel turbine power match.

[0052] Specifically, the fuel pump power P pf can be calculated by the following formula:

[0053]

[0054] where is the fuel injection pressure drop, obtained by the formula ; is the fuel valve pressure drop, obtained by the formula ; and are constant coefficients; is the fuel pump inlet pressure, which is a preset constant; is the fuel density; is the fuel pump efficiency, which is a preset constant.

[0055] Specifically, the fuel turbine power P tf can be calculated by the following formula:

[0056]

[0057] where is the fuel turbine gas specific heat ratio, obtained based on the pressure and the outlet temperature of the cooling channel T rc ; is the cooling channel pressure drop, obtained by the formula ; is a constant coefficient; is the fuel turbine gas constant, obtained based on the pressure and T rc ; is the fuel turbine efficiency, which is a preset constant.

[0058] When P pf and P tf are not equal, that is, they do not match, then the fuel turbine pressure ratio π f needs to be adjusted and then recalculate P tfuntil they match. The adjustment method can be externally re-specified or adjusted according to a preset step size. Further, to improve the matching efficiency, the step size is set as a variable step size. The step size is calculated according to a preset ratio based on the difference between P pf and P tf .

[0059] The above gas specific heat ratio and gas constant can be obtained using query software. In this example, and use the thermophysical property query software REFPROP (www.boulder.nist.gov / div838 / theory / refprop / Frequently) to obtain according to the input and T rc .

[0060] 5. Calculate the power of the oxidizer pump and the oxidizer turbine and compare them. If they do not match, adjust the oxidizer turbine pressure ratio until the power of the oxidizer pump and the oxidizer turbine match.

[0061] Specifically, the power of the oxidizer pump P pox can be calculated by the following formula:

[0062]

[0063] where is the pressure drop of the oxidizer injection, obtained through the formula ; is the pressure drop of the oxidizer valve, obtained through the formula ; and are constant coefficients; is the inlet pressure of the oxidizer pump, which is a preset constant; is the oxidizer density; is the efficiency of the oxidizer pump, which is a preset constant.

[0064] Specifically, the power of the oxidizer turbine P tox can be calculated by the following formula:

[0065]

[0066] where is the gas specific heat ratio of the oxidizer turbine, obtained based on the pressure and the inlet temperature of the oxidizer turbine , obtained through formula calculation; is the gas constant of the oxidizer turbine, based on the pressure and obtain; is the oxidizer turbine efficiency and is a preset constant.

[0067] When P pox is not equal to P tox i.e., there is no match, the oxidizer turbine pressure ratio needs to be adjusted π ox and recalculated P tox until they match. The adjustment method can be externally re - specified or adjusted in a preset step. Similarly, to improve the matching efficiency, the step is set as a variable step. The step size is calculated according to P pox the difference between P tox in a preset ratio.

[0068] Similarly, in this example and are obtained by using the thermophysical property query software REFPROP according to the input and obtain.

[0069] After the above process, when the turbine pump powers of the fuel and the oxidizer are equal, the engine reaches the optimal state under the given parameter combination, and the state parameters of each key node can be obtained accordingly.

[0070] In the above process, for an engine design scheme, the distribution of node state parameters under a given working condition can be obtained, but the outlet temperature of the cooling channel must be given as a known quantity, and this parameter is closely related to the design of the open - cycle expansion engine (chamber pressure, mixture ratio, flow ratio, etc.), and needs to be obtained through a complex process based on the design parameters combined with rocket engine design knowledge. Due to the high complexity of obtaining this parameter, it hinders the efficiency of analyzing the influencing factors of variable parameters of this engine. To improve the estimation efficiency of the variable - working - condition state parameter distribution under a design scheme, the outlet temperature of the cooling channel under other working conditions can be quickly obtained based on one working condition through the following method:

[0071] ;

[0072] wherein, T rcin is the inlet temperature of the cooling channel, is the turbine working fluid flow rate under the reference working condition, is the propellant flow rate of the thrust chamber under the reference working condition, is the propellant flow rate of the thrust chamber under the current working condition, p c is the thrust chamber pressure under the current working condition, is the turbine working medium flow rate under the current working condition.

[0073] Among them, the propellant flow rate of the thrust chamber is the sum of the fuel flow rate and the oxidizer flow rate. The turbine working medium flow rate is equivalent to the coolant flow rate.

[0074] To sum up, for the reference working condition, the parameter distribution under the working condition can be obtained through Figure 3 the process shown. For other working conditions, the outlet temperature of the cooling channel under the working condition can be quickly obtained through the reference working condition parameters, and then continue to pass through Figure 3 the process shown to obtain the parameter distribution under the working condition. Combining Figure 1 , calculate the specific impulse of the engine under different working conditions, and find the optimal thrust chamber chamber pressure, mixture ratio and flow ratio through comparison to obtain the best overall scheme design.

[0075] In a specific embodiment, the above method further includes the step of outputting an optimized scheme. The output content includes: the specific impulse of the engine in the optimal state of the engine system, the thrust chamber chamber pressure, mixture ratio and flow ratio, the flow rate, temperature and pressure at each key node of the engine, the power of the turbopump, etc.

[0076] For example, the flow rate, temperature and pressure at each key node can be obtained through the following process:

[0077] For the flow rate:

[0078] The flow rates after the oxidizer valve, after the oxidizer pump, and before the oxidizer pump are all equal to the oxidizer flow rate of the thrust chamber ;

[0079] The combustion chamber flow rate ;

[0080] The flow rates before and after the fuel pump are the same, which is ;

[0081] The flow rates at the inlet of the cooling channel, the outlet of the cooling channel, after the fuel turbine, and after the oxidizer turbine are all equal to the turbine working medium flow rate ;

[0082] The flow rate after the fuel valve (before the injector) is equal to the fuel flow rate ;

[0083] For the pressure:

[0084] The pressure before the fuel pump is the above , and the pressure before the oxidizer pump is the above ;

[0085] The combustion chamber pressure is the above p c ;

[0086] The pressure after the fuel pump is ;

[0087] The pressures at the rear of the fuel valve (in front of the injector) and at the inlet of the cooling channel are both ;

[0088] The pressure at the outlet of the cooling channel is ;

[0089] The pressure at the rear of the oxidizer pump is ;

[0090] The pressure at the rear of the oxidizer valve is ;

[0091] The pressure at the rear of the fuel turbine is ;

[0092] The pressure at the rear of the oxidizer turbine is .

[0093] For temperature:

[0094] The combustion chamber temperature is based on p c , MR and p e calculated by the thermodynamic calculation method or software (such as RPA);

[0095] The temperature at the rear of the oxidizer turbine is ;

[0096] The temperature at the outlet of the cooling channel is the above-mentioned T rc ;

[0097] The temperature at the inlet of the cooling channel, the temperature at the rear of the fuel valve (in front of the injector), and the temperature at the rear of the fuel pump are all the same as the temperature before the fuel pump, which is a given value;

[0098] The temperature at the rear of the oxidizer valve and the temperature at the rear of the oxidizer pump are both the same as the temperature before the oxidizer pump, which is a given value;

[0099] The temperature at the rear of the fuel turbine is the above-mentioned .

[0100] The present disclosure also provides an overall design device for an open expansion cycle engine, including:

[0101] An input module for obtaining engine design parameters, as well as the chamber pressure of the thrust chamber, and the optimization ranges of mixing and flow ratios;

[0102] An optimization module for optimizing within the optimization range with the specific impulse of the engine as the optimization target, where the specific impulse of the engine = engine thrust / engine propellant flow rate, and the propellant flow rate is the sum of the coolant flow rate, the fuel flow rate in the thrust chamber, and the oxidizer flow rate.

[0103] Preferably, the optimization is completed by a genetic algorithm.

[0104] Preferably, for the given chamber pressure, mixture ratio, and flow rate ratio in the optimization process, the coolant flow rate, fuel flow rate in the thrust chamber, and oxidizer flow rate are obtained through the variable operating condition parameter estimation method of an open-expansion cycle engine.

[0105] Preferably, the variable operating condition parameter estimation method of the open-expansion cycle engine includes the following:

[0106] Based on the engine design parameters and reference operating condition parameters: the chamber pressure of the thrust chamber p c0 , mixture ratio MR 0 , flow rate ratio 0 and the coolant channel outlet temperature T rc0 estimate the coolant channel outlet temperature of the current operating condition T rc ;

[0107] Based on the engine design parameters and current operating condition parameters, estimate the node state parameters by adjusting the turbine pressure ratio on the condition of turbine pump power matching.

[0108] Preferably, the coolant channel outlet temperature of the current operating condition T rc is calculated by the following formula:

[0109] ;

[0110] where is the coolant channel inlet temperature, is the coolant channel outlet temperature of the reference operating condition, is the turbine working fluid flow rate of the reference operating condition, is the thrust chamber propellant flow rate of the reference operating condition, is the thrust chamber propellant flow rate of the current operating condition, p c is the thrust chamber pressure of the current operating condition, is the turbine working fluid flow rate of the current operating condition.

[0111] Preferably, the estimating the node state parameters by adjusting the turbine pressure ratio on the condition of turbine pump power matching based on the engine design parameters and current operating condition parameters includes:

[0112] Based on the chamber pressure p c of the thrust chamber of the engine, MR mixture ratio of the thrust chamber p eCalculating the specific impulse of the thrust chamber I spc ;

[0113] Based on the engine thrust F , MR , the proportion of the thrust chamber flow rate of the engine and I spc Calculate the oxidizer flow rate of the thrust chamber, the fuel flow rate , and the turbine working medium flow rate :

[0114]

[0115] Initialize the fuel turbine pressure ratio π f and the oxidizer turbine pressure ratio π ox ;

[0116] Calculate the fuel pump power, based on the outlet temperature of the cooling channel T rc Calculate the fuel turbine power, compare the fuel pump and fuel turbine powers. If they do not match, adjust the fuel turbine pressure ratio and repeat the content of this step until the fuel pump and fuel turbine powers match;

[0117] Calculate and compare the oxidizer pump and oxidizer turbine powers. If they do not match, adjust the oxidizer turbine pressure ratio until the oxidizer pump and oxidizer turbine powers match.

[0118] Preferably, the initialization of the fuel turbine pressure ratio and the oxidizer turbine pressure ratio is initialized according to a preset value or an input value.

[0119] Preferably, the adjustment is made according to a preset step size.

[0120] Preferably, it further includes the step of outputting optimized parameters.

[0121] For the device embodiment, since it is basically similar to the method embodiment, the description is relatively simple. For related parts, refer to the partial description of the method embodiment.

[0122] Figure 5 This is a schematic structural diagram of an electronic device provided by an embodiment of the present disclosure. The device can execute the processing flow provided by the above method embodiment. As Figure 5 shown, the electronic device 110 includes: a memory 111, a processor 112, a computer program, and a communication interface 113; wherein, the computer program is stored in the memory 111 and is configured to be executed by the processor 112 to perform the method as described above.

[0123] In addition, an embodiment of the present disclosure further provides a computer-readable storage medium, on which a computer program is stored, and the computer program is executed by a processor to implement the method described in the above embodiment.

[0124] An embodiment of the present disclosure further provides a computer program product, including a computer program / instructions, and when the computer program / instructions are executed by a processor, the processor is caused to execute the method described above.

[0125] Those of ordinary skill in the art can understand that all or part of the steps for implementing the above method embodiments can be completed by hardware related to program instructions. The foregoing program can be stored in a computer-readable storage medium. When the program is executed, it executes the steps including the above method embodiments; and the foregoing storage medium includes: various media such as ROM, RAM, magnetic disk, or optical disc that can store program codes.

[0126] To illustrate the content and implementation manner of the present disclosure, specific embodiments are given in this specification. The purpose of introducing details in the embodiments is not to limit the scope of the claims, but to help understand the content described in the present disclosure. Those skilled in the art should understand that although this specification is described according to the implementation manners, not every implementation manner only includes an independent technical solution. This narrative manner of the specification is only for clarity. Those skilled in the art should regard the specification as a whole, and the technical solutions in each implementation manner can also be appropriately combined to form other implementation manners that can be understood by those skilled in the art. And various modifications, changes, or substitutions of the steps of the best embodiment are possible without departing from the spirit and scope of the present disclosure and its appended claims. Therefore, the present disclosure should not be limited to the content disclosed in the best embodiment and the accompanying drawings.

Claims

1. A general design method for an open-expansion cycle engine, characterized in that: It includes: Obtaining the engine design parameters, as well as the optimization ranges of the thrust chamber chamber pressure, mixture ratio, and flow rate ratio; Optimizing within the optimization range with the engine specific impulse as the optimization target, where the engine specific impulse = engine thrust / engine propellant flow rate, and the propellant flow rate is the sum of the coolant flow rate, thrust chamber fuel flow rate, and oxidizer flow rate; For the given chamber pressure, mixture ratio, and flow rate ratio values in the optimization process, obtain the coolant flow rate, thrust chamber fuel flow rate, and oxidizer flow rate through the variable operating condition parameter estimation method of the open-expansion cycle engine; The variable operating condition parameter estimation method of the open-expansion cycle engine includes the following content: Based on the engine design parameters and the reference operating condition parameters: the chamber pressure p of the thrust chamber c0 , the mixture ratio MR 0 , the flow rate ratio 0 and the coolant channel outlet temperature T rc0 Estimate the coolant channel outlet temperature T of the current operating condition rc ; Based on the engine design parameters and current operating condition parameters, estimate the node state parameters by adjusting the turbine pressure ratio on the condition of turbine pump power matching; The estimating the node state parameters by adjusting the turbine pressure ratio based on the engine design parameters and current operating condition parameters on the condition of turbine pump power matching includes: Based on the chamber pressure p of the engine thrust chamber c , the mixture ratio MR of the thrust chamber, and the nozzle exit pressure p e calculate the specific impulse I of the thrust chamber spc ; Based on the engine thrust F, MR, and the proportion of the thrust chamber flow rate of the engine and I spc The oxidizer flow rate of the thrust chamber is calculated by the following formula , the fuel flow rate and the turbine working medium flow rate : ； Initialize the fuel turbine pressure ratio π f and the oxidizer turbine pressure ratio π ox ; Calculate the fuel pump power based on the outlet temperature T of the cooling channel rc Calculate the fuel turbine power, compare the fuel pump power and the fuel turbine power. If they do not match, adjust the fuel turbine pressure ratio, and repeat the content of this step until the fuel pump power and the fuel turbine power match; Calculating and comparing the power of the oxidizer pump and the oxidizer turbine. If they do not match, adjust the oxidizer turbine pressure ratio until the power of the oxidizer pump and the oxidizer turbine matches.

2. The method according to claim 1, characterized in that: The optimization is completed by a genetic algorithm.

3. The method according to claim 1, characterized in that: The outlet temperature T of the cooling channel under the current working condition rc is calculated by the following formula: ； Among them, T rcin is the inlet temperature of the cooling channel, is the working medium flow rate of the turbine under the reference condition, is the propellant flow rate of the thrust chamber under the reference condition, is the propellant flow rate of the thrust chamber under the current condition, p c is the thrust chamber pressure under the current condition, is the working medium flow rate of the turbine under the current condition.

4. The method according to claim 1, characterized in that: The initial fuel turbine pressure ratio and oxidizer turbine pressure ratio are initialized according to preset values or input values.

5. The method according to claim 1, characterized in that: The adjustment is made according to a preset step size.

6. The method according to claim 1, characterized in that: It further includes the step of outputting optimization parameters.

7. An overall design device for an open-expansion cycle engine, and this device is based on the method described in claim 1, characterized in that: It includes: An input module, used to obtain the engine design parameters, as well as the optimization ranges of the thrust chamber chamber pressure, mixture, and flow rate ratio; An optimization module, used to optimize within the optimization range with the engine specific impulse as the optimization target, where the engine specific impulse = engine thrust / engine propellant flow rate, and the propellant flow rate is the sum of the coolant flow rate, thrust chamber fuel flow rate, and oxidizer flow rate.

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