Simulation Determination of Centrifugal Pump-Pipeline Operating Characteristics of Liquid Rocket Engine under Variable Load Conditions: Methods, Systems, Equipment, and Media

Abstract

This application discloses a method, system, equipment, and medium for simulating and determining the operating characteristics of a centrifugal pump-pipeline in a liquid rocket engine under varying load conditions. It relates to the field of liquid rocket engine modeling and simulation technology. The method includes establishing a lumped parameter mathematical model of the propellant supply pipeline and a dynamic mathematical model of the centrifugal pump; building corresponding simulation models of the propellant supply pipeline and the centrifugal pump in Simulink based on these models; and inputting different load condition parameters into the simulation models to obtain the operating characteristics of the propellant supply pipeline and the centrifugal pump under different load condition parameters. This application improves the accuracy of the simulation results for the operating characteristics of the centrifugal pump-pipeline in a liquid rocket engine.

Description

Technical Field

[0001] This application relates to the field of liquid rocket engine modeling and simulation technology, and in particular to a method, system, equipment and medium for simulating and determining the operating characteristics of a centrifugal pump-pipeline of a liquid rocket engine under variable load conditions. Background Technology

[0002] In modern aerospace, liquid rocket engines, as the core of propulsion systems, have extremely high requirements for performance and reliability. Piping systems and centrifugal pumps are indispensable components of liquid rocket engines, working together to ensure the efficient and stable delivery of fuel and oxidizer to the combustion chamber. A liquid rocket engine is essentially a thermodynamic fluid network system connecting several typical components through piping; the fluid dynamics within the propellant supply piping is one of its key research areas. Meanwhile, centrifugal pumps, with their advantages of high efficiency, adaptability to high flow rates, and compact structure, are widely used in liquid rocket engines. As the complexity of space missions continues to increase, the performance stability and reliability requirements for centrifugal pumps and piping systems are also constantly rising. Through simulation modeling of centrifugal pumps and piping systems, the performance of the system under different operating conditions can be predicted and analyzed without actual manufacturing and testing, thereby guiding design optimization. This not only significantly reduces development costs but also allows for the early detection of potential design problems, ensuring the reliability and safety of the engine. However, the operating characteristics of centrifugal pumps and piping systems under varying load conditions still have some uncertainty. These systems must be able to adapt to the changing demands of different stages of liquid rocket engine startup, operation, and shutdown, maintaining efficient and stable output. Therefore, conducting in-depth research on the performance of these key components under different operating conditions and establishing accurate simulation models are of great significance for improving the overall performance and reliability of liquid rocket engines. Summary of the Invention

[0003] The purpose of this application is to provide a method, system, equipment, and medium for simulating and determining the operating characteristics of a centrifugal pump-pipeline in a liquid rocket engine under variable load conditions, thereby improving the accuracy of the simulation results.

[0004] To achieve the above objectives, this application provides the following solution:

[0005] Firstly, this application provides a simulation method for determining the operating characteristics of a centrifugal pump-pipeline in a liquid rocket engine under variable load conditions. The method includes:

[0006] A lumped parameter mathematical model of the propellant supply pipeline of a liquid rocket engine and a dynamic mathematical model of the centrifugal pump are established. The lumped parameter mathematical model of the propellant supply pipeline is based on the fluid motion characteristic equation considering fluid inertia and the fluid motion characteristic equation considering local fluid resistance. The dynamic mathematical model of the centrifugal pump includes: a mass flow rate transfer model of the centrifugal pump inlet face and diffuser outlet face, a model of the change in liquid pressure difference between the centrifugal pump inlet and outlet, and a model of the change in liquid temperature difference between the centrifugal pump inlet and outlet.

[0007] Based on the lumped parameter mathematical model of the propellant supply pipeline and the dynamic mathematical model of the centrifugal pump, respectively, the corresponding simulation models of the propellant supply pipeline and the centrifugal pump are built in Simulink.

[0008] Different load condition parameters are input into the simulation model of the propellant supply pipeline to obtain the operating characteristics of the propellant supply pipeline under different load condition parameters; the load condition parameters include: fluid pressure, mass flow rate and temperature conditions.

[0009] By inputting different load condition parameters into the centrifugal pump simulation model, the operating characteristics of the centrifugal pump under different load condition parameters can be obtained.

[0010] Optionally, the process of establishing the lumped parameter mathematical model of the propellant supply pipeline specifically includes:

[0011] Establish the characteristic equations of fluid motion that take into account fluid inertia;

[0012] Establish the fluid motion characteristic equations that take into account the local resistance factors of the fluid;

[0013] Based on the fluid motion characteristic equations considering fluid inertia and fluid local resistance, a set of fluid flow characteristic equations that simultaneously consider both fluid inertia and fluid local resistance is obtained.

[0014] By simultaneously solving the fluid motion characteristic equations in the fluid flow characteristic equation set that considers both fluid inertia and local fluid resistance, a lumped parameter mathematical model of the propellant supply pipeline is obtained.

[0015] Alternatively, the expression for the characteristic equation of fluid motion considering fluid inertia is:

[0016]

[0017] Where G is the mass flow rate of the liquid in the flow path; t is time; A is the minimum flow area at the local resistance; L is the length of the flow path segment; P1 is the inlet pressure of the flow path segment; and P2 is the outlet pressure of the flow path segment.

[0018] The expression for the characteristic equation of fluid motion considering local fluid resistance is as follows:

[0019]

[0020] in, μ is the flow resistance coefficient when the valve is fully open; μ is the flow coefficient. It is the product of μ and A when the valve is fully open.

[0021] Alternatively, the expression for the fluid flow characteristic equation, which simultaneously considers fluid inertia and local fluid resistance, is as follows:

[0022] P in -P1=R1·G 2 ;

[0023]

[0024]

[0025]

[0026] P4-P out =R3·G 2 ;

[0027] Among them, P in R1 is the fluid pressure before passing through the inlet local resistance; L1 is the first local resistance; L1 is the flow path segment length between the first fixed local resistance and the second adjustable local resistance; P3 is the fluid pressure after passing through the adjustable valve. P4 is the second local resistance when the valve is fully open; P2 is the fluid pressure before passing through the outlet local resistance; L2 is the flow path segment length between the second adjustable local resistance and the third fixed local resistance; P out R1 represents the fluid pressure after passing through the outlet local resistance; R2 represents the third local resistance.

[0028] Optionally, the expression for the lumped parameter mathematical model of the propellant supply pipeline is:

[0029]

[0030] Optionally, the process of establishing the centrifugal pump dynamic mathematical model specifically includes:

[0031] Based on the actual connection relationship between the rotor and the inducer during the operation of the centrifugal pump, the mass flow transfer model of the centrifugal pump inlet end face and the diffuser outlet end face is determined.

[0032] Based on the dynamic relationship of the supply fluid flowing through the centrifugal pump, a model for the change of liquid pressure difference between the inlet and outlet of the centrifugal pump is determined.

[0033] Based on the dynamic relationship of the supply liquid flowing through the centrifugal pump, a model for the change of liquid temperature difference at the inlet and outlet of the centrifugal pump is determined.

[0034] Optionally, the expression for the mass flow transfer model at the centrifugal pump inlet face and the diffuser outlet face is:

[0035]

[0036] in, The inlet mass flow rate of the inducer wheel; This refers to the mass flow rate at the diffuser outlet.

[0037] The expression for the model of the change in liquid pressure difference between the inlet and outlet of a centrifugal pump is as follows:

[0038] P l2 =P l1 +ΔP l ;

[0039]

[0040] Among them, P l2 P is the outlet pressure of the centrifugal pump. l1 ΔP is the inlet pressure of the centrifugal pump. l The dynamic head of the centrifugal pump; ΔP s A represents the steady-state head of the centrifugal pump. m A n This is a constant related to the centrifugal pump structure and propellant density; is the mass flow rate; n is the rotational speed of the centrifugal pump;

[0041] The expression for the model of the temperature difference between the inlet and outlet liquids of a centrifugal pump is as follows:

[0042]

[0043] Where T is the liquid temperature; t i ρ represents the coefficients to be fitted; p represents the liquid pressure; ρ represents the liquid density.

[0044] Secondly, this application provides a simulation and determination system for the operating characteristics of a centrifugal pump-pipeline of a liquid rocket engine under variable load conditions. This system is used to implement the aforementioned simulation and determination method for the operating characteristics of a centrifugal pump-pipeline of a liquid rocket engine under variable load conditions. The system includes:

[0045] The model building unit is used to establish a lumped parameter mathematical model of the propellant supply pipeline of a liquid rocket engine and a centrifugal pump dynamic mathematical model. The lumped parameter mathematical model of the propellant supply pipeline is based on the fluid motion characteristic equation considering fluid inertia and the fluid motion characteristic equation considering local fluid resistance. The centrifugal pump dynamic mathematical model includes: a mass flow rate transfer model of the centrifugal pump inlet end face and diffuser outlet end face, a model of the change in liquid pressure difference between the centrifugal pump inlet and outlet, and a model of the change in liquid temperature difference between the centrifugal pump inlet and outlet.

[0046] The model building unit is used to build corresponding simulation models of the propellant supply pipeline and centrifugal pump in Simulink based on the lumped parameter mathematical model of the propellant supply pipeline and the dynamic mathematical model of the centrifugal pump, respectively.

[0047] The propellant supply pipeline operating characteristic determination unit is used to input different load condition parameters into the propellant supply pipeline simulation model to obtain the operating characteristics of the propellant supply pipeline under different load condition parameters; the load condition parameters include: liquid circuit fluid pressure, mass flow rate and temperature conditions.

[0048] The centrifugal pump operating characteristic determination unit is used to input different load condition parameters into the centrifugal pump simulation model to obtain the operating characteristics of the centrifugal pump under different load condition parameters.

[0049] Thirdly, this application provides a computer device, including: a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the simulation determination method for the operating characteristics of a centrifugal pump-pipeline of a liquid rocket engine under variable load conditions as described in any of the above claims.

[0050] Fourthly, this application provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the simulation determination method for the operating characteristics of a centrifugal pump-pipeline of a liquid rocket engine under variable load conditions as described in any of the preceding claims.

[0051] According to the specific embodiments provided in this application, this application has the following technical effects:

[0052] This application discloses a method, system, equipment, and medium for simulating and determining the operating characteristics of a centrifugal pump-pipeline in a liquid rocket engine under variable load conditions. By establishing a lumped parameter mathematical model of the propellant supply pipeline of the liquid rocket engine and a dynamic mathematical model of the centrifugal pump, a hydrodynamic model of the centrifugal pump that is easy to connect with the finite element state variables of the distributed fluid pipeline is obtained. This model can more accurately describe the liquid flow characteristics in the supply pipeline and the centrifugal pump, thereby improving the accuracy of the simulation results of the operating characteristics of the centrifugal pump-pipeline in the liquid rocket engine. Attached Figure Description

[0053] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0054] Figure 1 A schematic flowchart of a simulation method for determining the operating characteristics of a centrifugal pump-pipeline of a liquid rocket engine under variable load conditions, provided in an embodiment of this application;

[0055] Figure 2 A schematic diagram considering fluid inertia and local resistance factors within the supply pipeline;

[0056] Figure 3 A schematic diagram of a centrifugal pump provided in one embodiment of this application;

[0057] Figure 4 A schematic diagram of the simulation model for calculating ΔP during the simulation of fluid pressure difference in the supply pipeline;

[0058] Figure 5 A schematic diagram of a simulation model for pressure changes at the inlet and outlet of fluid in a supply pipeline;

[0059] Figure 6 A schematic diagram of a simulation model for the temperature changes at the inlet and outlet of fluid in a supply pipeline;

[0060] Figure 7 Schematic diagram of the super component for the propellant supply pipeline module;

[0061] Figure 8 The simulation model diagram for calculating ΔP during the simulation of fluid pressure difference in a centrifugal pump;

[0062] Figure 9 A schematic diagram of a simulation model of pressure changes at the inlet and outlet of fluid in a centrifugal pump;

[0063] Figure 10 A schematic diagram of a simulation model of fluid inlet and outlet temperature changes in a centrifugal pump;

[0064] Figure 11 This is a schematic diagram of a super component for a centrifugal pump module.

[0065] Figure 12 A schematic diagram showing the change in speed of a centrifugal pump under load;

[0066] Figure 13 A schematic diagram showing the temperature change of liquid oxygen output from the turbopump;

[0067] Figure 14 This is a schematic diagram of the structure of a computer device provided in an embodiment of this application. Detailed Implementation

[0068] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0069] To make the above-mentioned objectives, features and advantages of this application more apparent and understandable, the application will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0070] In one exemplary embodiment, such as Figure 1 As shown, a simulation method for determining the operating characteristics of a centrifugal pump-pipeline in a liquid rocket engine under varying load conditions is provided, including the following steps S1 to S4. Wherein:

[0071] Step S1: Establish the lumped parameter mathematical model of the propellant supply pipeline of the liquid rocket engine and the dynamic mathematical model of the centrifugal pump. The lumped parameter mathematical model of the propellant supply pipeline is based on the fluid motion characteristic equation considering fluid inertia and the fluid motion characteristic equation considering local fluid resistance. The dynamic mathematical model of the centrifugal pump includes: a mass flow rate transfer model of the centrifugal pump inlet end face and diffuser outlet end face, a model of the change in liquid pressure difference between the centrifugal pump inlet and outlet, and a model of the change in liquid temperature difference between the centrifugal pump inlet and outlet.

[0072] As an optional implementation, step S1, the process of establishing the lumped parameter mathematical model of the propellant supply pipeline, specifically includes:

[0073] Step S111: Establish the fluid motion characteristic equation considering fluid inertia.

[0074] Specifically, the main influencing factors on the dynamic characteristics of the propellant supply pipeline are divided into fluid inertia factors and local resistance factors, which have roughly the same magnitude of influence, such as... Figure 2As shown; where, based on the assumption that the flow path segments are filled with inviscid, incompressible liquid, the characteristic equation of fluid motion considering fluid inertia is derived:

[0075]

[0076] Where A is the minimum flow area at the local resistance point; P1 is the inlet pressure of the flow path segment; P2 is the outlet pressure of the flow path segment; m is the mass of liquid in the flow path; u is the flow velocity of the liquid; t is the time; ρ is the density of the liquid; L is the length of the flow path segment; and G is the mass flow rate of the liquid in the flow path.

[0077] Therefore, the expression for the characteristic equation of fluid motion considering fluid inertia is obtained as follows:

[0078]

[0079] Step S112: Establish the fluid motion characteristic equation considering the local resistance factor of the fluid.

[0080] The local resistance pressure difference ΔP = P1 - P2 is proportional to the square of the liquid mass flow rate G in the flow path. Neglecting the inertia of the liquid, it can be expressed as:

[0081]

[0082]

[0083]

[0084] Therefore, the expression for the fluid motion characteristic equation considering local fluid resistance is obtained as follows:

[0085]

[0086] in, μ is the flow resistance coefficient when the valve is fully open; μ is the flow coefficient. R is the product of μ and A when the valve (adjustable local resistance) is fully open; R is the flow resistance coefficient.

[0087] Step S113: Based on the fluid motion characteristic equation considering fluid inertia and the fluid motion characteristic equation considering local fluid resistance, a set of fluid flow characteristic equations that simultaneously considers fluid inertia and local fluid resistance is obtained.

[0088] As an optional implementation, the fluid flow characteristic equations considering both fluid inertia and local resistance are expressed as follows (7)-(11), and the derivation process is as follows:

[0089] Specifically, considering the most general case, it is assumed that there is a fixed local resistance at both the inlet and outlet of the flow path, and an adjustable valve is installed in the middle of the flow path. The frictional loss (viscosity) of the fluid is equivalent to the local resistance at both ends.

[0090] For the first local resistance, we have:

[0091] P in -P1=R1·G 2 (7)

[0092] Where R1 is the first local resistance; P in This refers to the fluid pressure before passing through the local resistance at the inlet.

[0093] For the flow path segment (of length L1) between the first fixed local resistance and the second adjustable local resistance, we have:

[0094]

[0095] The second adjustable local resistance is:

[0096]

[0097] in, The flow resistance coefficient when the valve is fully open; P3 is the product of μ and A when the valve is fully open; P3 is the fluid pressure after passing through the adjustable valve.

[0098] For the flow path segment (of length L2) between the second adjustable local resistance and the third fixed local resistance, we have:

[0099]

[0100] Wherein, P4 is the fluid pressure before passing through the local resistance at the outlet;

[0101] For the third local resistance, we have:

[0102] P4-P out =R3·G 2 (11)

[0103] Among them, P out R1 represents the fluid pressure after passing through the outlet local resistance, and R2 represents the third local resistance.

[0104] Step S114: Solve the fluid motion characteristic equations in the fluid flow characteristic equation set that simultaneously considers fluid inertia factors and fluid local resistance factors to obtain the lumped parameter mathematical model of the propellant supply pipeline.

[0105] Specifically, by adding equations (7)-(11) together and rearranging them, we can obtain the following expression for the lumped parameter mathematical model of the propellant supply pipeline:

[0106]

[0107] As an optional implementation, step S1, the process of establishing the centrifugal pump dynamic mathematical model, specifically includes:

[0108] Step S121: Based on the actual connection relationship between the rotor and the inducer wheel during the operation of the centrifugal pump, determine the mass flow transfer model of the centrifugal pump inlet face and the diffuser outlet face.

[0109] like Figure 3 As shown, the volume between the centrifugal pump inlet face and the inducer inlet face is considered as a concentrated volume, and the relationship between the centrifugal pump inlet mass flow rate and the diffuser outlet mass flow rate is derived. To account for the volumetric effects of the inducer, impeller, and diffuser, the equivalent volume of this concentrated volume is: Where V1 is the volume of the flow channel between the inlet face of the centrifugal pump and the inlet face of the centrifugal pump inducer, V I V is the passage volume of the inducer wheel. W V is the impeller's passage volume. D Let this be the diffuser's passage volume. This allows us to assume the inlet mass flow rate of the inducer. Mass flow rate at diffuser outlet Since they are always equal, the expression for the mass flow transfer model at the inlet face of the centrifugal pump and the outlet face of the diffuser is obtained as follows:

[0110]

[0111] in, The inlet mass flow rate of the inducer wheel; This is the mass flow rate at the diffuser outlet.

[0112] Step S122: Based on the dynamic relationship of the supply liquid flowing through the centrifugal pump, determine the model of the change in liquid pressure difference between the inlet and outlet of the centrifugal pump.

[0113] Specifically, the fluid flow characteristic equation in a centrifugal pump is as follows:

[0114] Since the inlet pressure of the centrifugal pump is low, and the density change of the inlet propellant is not considered, the flow capacity equation for the lumped volume is as follows:

[0115]

[0116] Where, q in q1 and q1 represent the flow rates at the inlet face of the centrifugal pump and the inlet face of the centrifugal pump's inducer, respectively. C pumpThe equivalent flow capacity C of the inlet concentrated volume pump =V pump / (ρ in a 2 ), where a is the propellant wave velocity, and the inlet pressure P can be obtained by integration. in .

[0117] Centrifugal pump power and efficiency:

[0118] The power P of the centrifugal pump w Including steady-state power P sw and dynamic power P dw :

[0119]

[0120] Among them, T w This refers to the torque of the centrifugal pump.

[0121] Steady-state power P of centrifugal pump sw for:

[0122]

[0123] Among them, T s This is the steady-state torque of the centrifugal pump.

[0124] Dynamic power P of centrifugal pump dw for:

[0125]

[0126] Among them, J m J n It is a constant coefficient related to the propellant density.

[0127] The efficiency η of a centrifugal pump p for:

[0128]

[0129] Where, ΔP l The dynamic head of the centrifugal pump; is a correction factor related to cavitation volume; q is the propellant flow rate.

[0130] The expression for the model of the change in liquid pressure difference between the inlet and outlet of the centrifugal pump is as follows:

[0131] P l2 =P l1 +ΔP l (19)

[0132]

[0133] Among them, Pl2 P is the outlet pressure of the centrifugal pump. l1 ΔP is the inlet pressure of the centrifugal pump. l The dynamic head of the centrifugal pump; ΔP s A represents the steady-state head of the centrifugal pump. m A n This is a constant related to the centrifugal pump structure and propellant density; denoted as , where is the average mass flow rate of the centrifugal pump; and is the rotational speed of the centrifugal pump.

[0134] Specifically, during transient processes such as engine start-up and shutdown, the effects of the rate of change of mass flow rate and the rate of change of speed on the centrifugal pump head must be taken into account.

[0135]

[0136] The outlet pressure of the centrifugal pump is shown in equation (19).

[0137] Step S123: Based on the dynamic relationship of the supply liquid flowing through the centrifugal pump, determine the model of the temperature difference change between the inlet and outlet of the centrifugal pump.

[0138] The expression for the model of the temperature difference between the inlet and outlet liquids of the centrifugal pump is as follows:

[0139]

[0140] Where T is the temperature of the liquid to be calculated; t i (i = 0, 1, ..., 6) are the coefficients to be fitted, which can be obtained from the least squares fitting coefficient table derived from experimental data; p is the liquid pressure; ρ is the liquid density. Only ΔP needs to be... l Substituting these values ​​into the equation, we can obtain the propellant temperature at the centrifugal pump outlet.

[0141] Step S2: Based on the lumped parameter mathematical model of the propellant supply pipeline and the dynamic mathematical model of the centrifugal pump, respectively, build the corresponding simulation models of the propellant supply pipeline and the centrifugal pump in Simulink.

[0142] Specifically, the schematic diagram of the propellant supply pipeline simulation model is as follows: Figure 4 and Figure 5 As shown, the models for the pressure difference changes at the inlet and outlet of the flow path segments, the mass flow rate model inside the propellant supply pipeline, and the temperature changes at the inlet and outlet of the flow path segments are as follows: Figure 6 As shown, a fixed-length supply pipeline model is used as a super-element. Input and output parameters for the propellant supply pipeline super-element are set: input parameters include the liquid inlet pressure, temperature, and mass flow rate in the supply pipeline; output parameters include the liquid outlet pressure, temperature, and mass flow rate in the supply pipeline. A schematic diagram of the propellant supply pipeline super-element is shown below. Figure 7As shown.

[0143] Based on the actual connection between the rotor and the inducer during centrifugal pump operation, and the dynamic relationship of the supply liquid flowing through the centrifugal pump, a centrifugal pump model is established, such as... Figure 8 As shown; specifically including: mass flow transfer models at the inlet and outlet faces of the centrifugal pump, models of pressure difference changes between the inlet and outlet liquids of the centrifugal pump, and models of temperature difference changes between the inlet and outlet liquids of the centrifugal pump, such as... Figure 9 and Figure 10 As shown in the diagram, a single centrifugal pump model is encapsulated as a subsystem to form a super-component. The super-component interface is set up with input parameters including the rotor speed connected to the centrifugal pump, the inlet liquid pressure, temperature, and mass flow rate; and output parameters including the outlet liquid pressure, temperature, and mass flow rate. The resulting schematic diagram of the centrifugal pump super-component is shown in the diagram. Figure 11 As shown.

[0144] Step S3: Input different load condition parameters into the propellant supply pipeline simulation model to obtain the operating characteristics of the propellant supply pipeline under different load condition parameters; the load condition parameters include: fluid pressure, mass flow rate and temperature conditions.

[0145] Specifically, considering that liquid rocket engines commonly use liquid hydrogen and liquid oxygen as propellants, the corresponding liquid characteristic parameters are input into the propellant supply pipeline model: liquid hydrogen: inlet pressure 0.249MPa, inlet temperature 20.3K, mass flow rate 3.112kg / s; liquid oxygen: inlet pressure 0.283MPa, inlet temperature 89K, mass flow rate 15.991kg / s.

[0146] This allows us to obtain the liquid pressure, mass flow rate, and temperature characteristics of the propellant supply pipeline under different fluid pressure, mass flow rate, and temperature conditions.

[0147] Step S4: Input different load condition parameters into the centrifugal pump simulation model to obtain the operating characteristics of the centrifugal pump under different load condition parameters.

[0148] Specifically, the centrifugal pump input rotor speed is set to 14000 r / min, and the corresponding liquid characteristic parameters are input into the centrifugal pump model: liquid hydrogen: inlet pressure 0.255 MPa, inlet temperature 21.5 K, mass flow rate 3.112 kg / s, inlet density 69.58 kg / m3, efficiency 0.519; liquid oxygen: inlet pressure 0.294 MPa, inlet temperature 92 K, mass flow rate 15.991 kg / s, inlet density 1132.4 kg / m3, efficiency 0.692.

[0149] The centrifugal pump output fluid pressure, mass flow rate, and temperature characteristics under different input fluid pressure, mass flow rate, and temperature conditions are obtained with a given rotor speed.

[0150] Currently, the fluid flowing through turbopumps undergoes complex three-dimensional motion, typically described by the Navier-Stokes equations. However, these equations are overly complex for engine system analysis and control, necessitating simplification for practical application. Recent studies on the dynamic characteristics of engine systems have largely employed steady-state equations for centrifugal pumps. However, when connecting these equations to finite element state variable models of pipelines, boundary condition handling becomes cumbersome, making them unsuitable for modular partitioning of distributed parameter piping systems. This application establishes a turbopump fluid dynamics model by dividing the inlet and outlet pipes of the turbopump (i.e., centrifugal pump) into finite control volumes, facilitating connection with finite element state variables of distributed fluid pipelines. This model more accurately describes the liquid flow characteristics within the supply pipes and centrifugal pump.

[0151] Furthermore, after establishing simulation models for the propellant supply pipeline and centrifugal pump, it is necessary to test their operation under different loads. Figure 12 By observing the change in centrifugal pump speed after a load is applied, we can understand the impact of the load on the centrifugal pump speed. Figure 13 The temperature change of the liquid oxygen output from the turbine after the supply liquid passes through the pipeline-centrifugal pump is shown. Since the centrifugal pump is connected to the turbine, this temperature change also represents the temperature change of the liquid in the whole model to a certain extent, thus verifying the simulation results of the model's temperature fitting.

[0152] The beneficial technical effects of this application compared with related technologies are as follows:

[0153] 1. The simulation method for determining the operating characteristics of a centrifugal pump-pipeline of a liquid rocket engine under variable load conditions provided in this application establishes a simulation model of the propellant supply pipeline and a simulation model of the centrifugal pump based on the actual physical model, and can quantitatively analyze the liquid flow characteristics in the supply pipeline and the centrifugal pump.

[0154] 2. This application fully considers the influence of fluid inertia and local resistance in the supply pipeline and the flow relationship between the liquid at the inlet of the centrifugal pump inducer and the liquid at the outlet of the diffuser. The proposed simulation calculation method can more accurately describe the flow characteristics of the liquid in the supply pipeline and the centrifugal pump compared with other calculation methods.

[0155] Based on the same inventive concept, this application also provides a system for simulating and determining the operating characteristics of a centrifugal pump-pipeline under varying load conditions for a liquid rocket engine, used to implement the aforementioned method for simulating and determining the operating characteristics of a centrifugal pump-pipeline under varying load conditions. The solution provided by this system is similar to the solution described in the above method. Therefore, the specific limitations of one or more embodiments of the system for simulating and determining the operating characteristics of a centrifugal pump-pipeline under varying load conditions provided below can be found in the limitations of the method for simulating and determining the operating characteristics of a centrifugal pump-pipeline under varying load conditions described above, and will not be repeated here.

[0156] In one exemplary embodiment, a simulation and determination system for the operating characteristics of a centrifugal pump-pipeline of a liquid rocket engine under variable load conditions is provided, comprising:

[0157] The model building unit is used to establish a lumped parameter mathematical model of the propellant supply pipeline of a liquid rocket engine and a centrifugal pump dynamic mathematical model. The lumped parameter mathematical model of the propellant supply pipeline is based on the fluid motion characteristic equation considering fluid inertia and the fluid motion characteristic equation considering local fluid resistance. The centrifugal pump dynamic mathematical model includes: a mass flow rate transfer model of the centrifugal pump inlet face and diffuser outlet face, a model of the change in liquid pressure difference between the centrifugal pump inlet and outlet, and a model of the change in liquid temperature difference between the centrifugal pump inlet and outlet.

[0158] The model building unit is used to build corresponding simulation models of the propellant supply pipeline and centrifugal pump in Simulink based on the lumped parameter mathematical model of the propellant supply pipeline and the dynamic mathematical model of the centrifugal pump, respectively.

[0159] The propellant supply pipeline operating characteristic determination unit is used to input different load condition parameters into the propellant supply pipeline simulation model to obtain the operating characteristics of the propellant supply pipeline under different load condition parameters; the load condition parameters include: liquid circuit fluid pressure, mass flow rate and temperature conditions.

[0160] The centrifugal pump operating characteristic determination unit is used to input different load condition parameters into the centrifugal pump simulation model to obtain the operating characteristics of the centrifugal pump under different load condition parameters.

[0161] In one exemplary embodiment, a computer device is provided, including: a memory, a processor, and a computer program stored in the memory and executable on the processor. The processor executes the computer program to implement a method for simulating and determining the operating characteristics of a centrifugal pump-pipeline of a liquid rocket engine under variable load conditions.

[0162] In one exemplary embodiment, a computer-readable storage medium is provided having a computer program stored thereon that, when executed by a processor, implements a method for simulating and determining the operating characteristics of a centrifugal pump-pipeline of a liquid rocket engine under variable load conditions.

[0163] In one exemplary embodiment, a computer device is provided, which may be a server or a terminal, and its internal structure diagram may be as follows. Figure 14 As shown, this computer device includes a processor, memory, input / output (I / O) interfaces, and a communication interface. The processor, memory, and I / O interfaces are connected via a system bus, and the communication interface is also connected to the system bus via the I / O interfaces. The processor provides computational and control capabilities. The memory includes non-volatile storage media and internal memory. The non-volatile storage media stores the operating system, computer programs, and databases. The internal memory provides the environment for the operating system and computer programs stored in the non-volatile storage media. The I / O interfaces are used for exchanging information between the processor and external devices. The communication interface is used for communicating with external terminals via a network connection. When the computer program is executed by the processor, it implements a simulation method for determining the operating characteristics of a centrifugal pump-pipeline in a liquid rocket engine under varying load conditions.

[0164] Those skilled in the art will understand that Figure 14 The structure shown is merely a block diagram of a portion of the structure related to the present application and does not constitute a limitation on the computer device to which the present application is applied. Specific computer devices may include more or fewer components than those shown in the figure, or combine certain components, or have different component arrangements.

[0165] It should be noted that the user information (including but not limited to user device information, user personal information, etc.) and data (including but not limited to data used for analysis, data stored, data displayed, etc.) involved in this application are all information and data authorized by the user or fully authorized by all parties, and the collection, use and processing of the relevant data must comply with relevant regulations.

[0166] Those skilled in the art will understand that all or part of the processes in the above embodiments can be implemented by a computer program instructing related hardware. The computer program can be stored in a non-volatile computer-readable storage medium. When executed, the computer program can include the processes of the embodiments described above. Any references to memory, databases, or other media used in the embodiments provided in this application can include at least one of non-volatile and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetic random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory can include random access memory (RAM) or external cache memory, etc. By way of illustration and not limitation, RAM can take many forms, such as Static Random Access Memory (SRAM) or Dynamic Random Access Memory (DRAM).

[0167] The databases involved in the embodiments provided in this application may include at least one type of relational database and non-relational database. Non-relational databases may include, but are not limited to, blockchain-based distributed databases. The processors involved in the embodiments provided in this application may be general-purpose processors, central processing units, graphics processing units, digital signal processors, programmable logic devices, quantum computing-based data processing logic devices, etc., and are not limited to these.

[0168] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0169] This document uses specific examples to illustrate the principles and implementation methods of this application. The descriptions of the above embodiments are only for the purpose of helping to understand the methods and core ideas of this application. Furthermore, those skilled in the art will recognize that, based on the ideas of this application, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of this application.

Claims

1. A method for simulating and determining the operating characteristics of a centrifugal pump-pipeline in a liquid rocket engine under variable load conditions, characterized in that, The simulation method for determining the operating characteristics of the centrifugal pump-pipeline of a liquid rocket engine under variable load conditions includes: A lumped parameter mathematical model of the propellant supply pipeline of a liquid rocket engine and a dynamic mathematical model of the centrifugal pump are established. The lumped parameter mathematical model of the propellant supply pipeline is based on the fluid motion characteristic equation considering fluid inertia and the fluid motion characteristic equation considering local fluid resistance. The dynamic mathematical model of the centrifugal pump includes: a mass flow rate transfer model of the centrifugal pump inlet end face and diffuser outlet end face, a model of the change in liquid pressure difference between the centrifugal pump inlet and outlet, and a model of the change in liquid temperature difference between the centrifugal pump inlet and outlet. Based on the lumped parameter mathematical model of the propellant supply pipeline and the dynamic mathematical model of the centrifugal pump, respectively, the corresponding simulation models of the propellant supply pipeline and the centrifugal pump are built in Simulink. Different load condition parameters are input into the simulation model of the propellant supply pipeline to obtain the operating characteristics of the propellant supply pipeline under different load condition parameters; the load condition parameters include: fluid pressure, mass flow rate and temperature conditions. By inputting different load condition parameters into the centrifugal pump simulation model, the operating characteristics of the centrifugal pump under different load condition parameters can be obtained.

2. The method for simulating and determining the operating characteristics of a centrifugal pump-pipeline in a liquid rocket engine under variable load conditions according to claim 1, characterized in that, The process of establishing the lumped parameter mathematical model for the propellant supply pipeline specifically includes: Establish the characteristic equations of fluid motion that take into account fluid inertia; Establish the fluid motion characteristic equations that take into account the local resistance factors of the fluid; Based on the fluid motion characteristic equations considering fluid inertia and fluid local resistance, a set of fluid flow characteristic equations that simultaneously consider both fluid inertia and fluid local resistance is obtained. By simultaneously solving the fluid motion characteristic equations in the fluid flow characteristic equation set that considers both fluid inertia and local fluid resistance, a lumped parameter mathematical model of the propellant supply pipeline is obtained.

3. The method for simulating and determining the operating characteristics of a centrifugal pump-pipeline in a liquid rocket engine under variable load conditions according to claim 2, characterized in that, The expression for the characteristic equation of fluid motion considering fluid inertia is as follows: Where G is the mass flow rate of the liquid in the flow path; t is time; A is the minimum flow area at the local resistance; L is the length of the flow path segment; P1 is the inlet pressure of the flow path segment; and P2 is the outlet pressure of the flow path segment. The expression for the characteristic equation of fluid motion considering local fluid resistance is as follows: in, μ is the flow resistance coefficient when the valve is fully open; μ is the flow coefficient. It is the product of μ and A when the valve is fully open.

4. The method for simulating and determining the operating characteristics of a centrifugal pump-pipeline in a liquid rocket engine under variable load conditions according to claim 3, characterized in that, The fluid flow characteristic equations considering both fluid inertia and local fluid resistance are as follows: P in -P1=R1·G 2 ; P4-P out =R3·G 2 ; Among them, P in R1 is the fluid pressure before passing through the inlet local resistance; L1 is the first local resistance; L1 is the flow path segment length between the first fixed local resistance and the second adjustable local resistance; P3 is the fluid pressure after passing through the adjustable valve. P4 is the second local resistance when the valve is fully open; P2 is the fluid pressure before passing through the outlet local resistance; L2 is the flow path segment length between the second adjustable local resistance and the third fixed local resistance; P out R1 represents the fluid pressure after passing through the outlet local resistance; R2 represents the third local resistance.

5. The simulation method for determining the operating characteristics of a centrifugal pump-pipeline of a liquid rocket engine under variable load conditions according to claim 4, characterized in that, The mathematical model expression for the lumped parameters of the propellant supply pipeline is as follows:

6. The method for simulating and determining the operating characteristics of a centrifugal pump-pipeline in a liquid rocket engine under variable load conditions according to claim 1, characterized in that, The process of establishing the centrifugal pump dynamic mathematical model specifically includes: Based on the actual connection relationship between the rotor and the inducer during the operation of the centrifugal pump, the mass flow transfer model of the centrifugal pump inlet end face and the diffuser outlet end face is determined. Based on the dynamic relationship of the supply fluid flowing through the centrifugal pump, a model for the change of liquid pressure difference between the inlet and outlet of the centrifugal pump is determined. Based on the dynamic relationship of the supply liquid flowing through the centrifugal pump, a model for the change of liquid temperature difference at the inlet and outlet of the centrifugal pump is determined.

7. The simulation method for determining the operating characteristics of a centrifugal pump-pipeline of a liquid rocket engine under variable load conditions according to claim 6, characterized in that, The expression for the mass flow transfer model between the inlet face of the centrifugal pump and the outlet face of the diffuser is as follows: in, Mass flow rate at the inlet of the inducer wheel; This refers to the mass flow rate at the diffuser outlet. The expression for the model of the change in liquid pressure difference between the inlet and outlet of a centrifugal pump is as follows: P l2 =P l1 +ΔP l ; Among them, P l2 P is the outlet pressure of the centrifugal pump. l1 ΔP is the inlet pressure of the centrifugal pump. l The dynamic head of the centrifugal pump; ΔP s A represents the steady-state head of the centrifugal pump. m A n This is a constant related to the centrifugal pump structure and propellant density; t is the liquid mass flow rate; n is the centrifugal pump speed; t is time. The expression for the model of the temperature difference between the inlet and outlet liquids of a centrifugal pump is as follows: Where T is the liquid temperature; t i ρ is the coefficient to be fitted, i∈[0,6]; p is the liquid pressure; ρ is the liquid density.

8. A simulation and determination system for the operating characteristics of a centrifugal pump-pipeline in a liquid rocket engine under variable load conditions, characterized in that, The simulation and determination system for the operating characteristics of a centrifugal pump-pipeline of a liquid rocket engine under variable load conditions is used to implement the simulation and determination method for the operating characteristics of a centrifugal pump-pipeline of a liquid rocket engine under variable load conditions as described in claims 1-7. The simulation and determination system for the operating characteristics of a centrifugal pump-pipeline of a liquid rocket engine under variable load conditions includes: The model building unit is used to establish a lumped parameter mathematical model of the propellant supply pipeline of a liquid rocket engine and a centrifugal pump dynamic mathematical model. The lumped parameter mathematical model of the propellant supply pipeline is based on the fluid motion characteristic equation considering fluid inertia and the fluid motion characteristic equation considering local fluid resistance. The centrifugal pump dynamic mathematical model includes: a mass flow rate transfer model of the centrifugal pump inlet end face and diffuser outlet end face, a model of the change in liquid pressure difference between the centrifugal pump inlet and outlet, and a model of the change in liquid temperature difference between the centrifugal pump inlet and outlet. The model building unit is used to build corresponding simulation models of the propellant supply pipeline and centrifugal pump in Simulink based on the lumped parameter mathematical model of the propellant supply pipeline and the dynamic mathematical model of the centrifugal pump, respectively. The propellant supply pipeline operating characteristic determination unit is used to input different load condition parameters into the propellant supply pipeline simulation model to obtain the operating characteristics of the propellant supply pipeline under different load condition parameters; the load condition parameters include: liquid circuit fluid pressure, mass flow rate and temperature conditions. The centrifugal pump operating characteristic determination unit is used to input different load condition parameters into the centrifugal pump simulation model to obtain the operating characteristics of the centrifugal pump under different load condition parameters.

9. A computer device, comprising: A memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that the processor executes the computer program to implement the simulation determination method for the operating characteristics of a centrifugal pump-pipeline of a liquid rocket engine under variable load conditions as described in any one of claims 1-7.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that, When executed by a processor, the computer program implements the simulation determination method for the operating characteristics of a centrifugal pump-pipeline of a liquid rocket engine under variable load conditions as described in any one of claims 1-7.

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