CN-122021409-A - Flame surface simulation method suitable for turbulent combustion of liquid rocket engine

CN122021409ACN 122021409 ACN122021409 ACN 122021409ACN-122021409-A

Abstract

The application relates to the technical field of rocket engine combustion, in particular to a flame surface simulation method and electronic equipment suitable for turbulent combustion of a liquid rocket engine, wherein the method comprises the steps of obtaining propellant composition parameters of the liquid rocket engine; the method comprises the steps of determining a proper real fluid state equation and a thermal physical property and transport property correction method according to propellant composition parameters, calculating real fluid one-dimensional opposite-flushing diffusion flame according to the real fluid correction method and a two-ignition flame control method, constructing a laminar diffusion flame surface database according to the real fluid correction method and the two-ignition flame control method, expanding the laminar diffusion flame surface database into a real fluid diffusion flame surface database considering turbulence fluctuation, constructing a turbulence combustion model suitable for a liquid rocket engine according to the real fluid diffusion flame surface database, and simulating combustion behaviors of the liquid rocket engine by using the turbulence combustion model. Therefore, the problems that in the related art, a turbulent combustion model is simulated and distorted under the ultrahigh pressure working condition of the liquid rocket engine, the actual combustion behavior is separated and the like are solved.

Inventors

WANG XINGJIAN
Zuo Ruiye
CHU XU
Zhang Lanfei

Assignees

清华大学

Dates

Publication Date: 20260512
Application Date: 20260107

Claims (10)

1. The flame surface simulation method suitable for turbulent combustion of the liquid rocket engine is characterized by comprising the following steps of: acquiring propellant composition parameters of a liquid rocket engine; determining a real fluid state equation according to the propellant composition parameters, and a thermophysical property and transport property correction method; calculating a real fluid pair-wise diffusion flame according to a real fluid correction method and a two-ignition flame control method, constructing a laminar diffusion flame surface database according to the real fluid pair-wise diffusion flame, and expanding the laminar diffusion flame surface database into a real fluid diffusion flame surface database considering turbulence fluctuation; and constructing a turbulent combustion model suitable for the liquid rocket engine according to the real fluid diffusion flame surface database, and simulating the combustion behavior of the liquid rocket engine by using the turbulent combustion model.
2. The flame front simulation method suitable for turbulent combustion of a liquid rocket engine according to claim 1, wherein the true fluid state equation is: Wherein, the The pressure of the fluid is indicated and, Indicating the density of the fluid and, The general gas constant is indicated as such, Indicating the thermodynamic temperature of the fluid, Represents the molar mass of the mixture, And The parameter of the physical characteristic is represented by, The thermodynamic properties are expressed as: Wherein, the Indicating the internal energy of the fluid, Represents the internal energy of the ideal gas, subscript 0 represents the ideal state at low pressure, Representing the partial derivative of pressure with temperature at equal density, Indicating the enthalpy of the fluid, Indicating the enthalpy of the ideal gas, Indicating the specific heat capacity of the fluid, Represents the specific heat capacity of the ideal gas, Representing the second partial derivative of pressure with temperature at equal density, Representing the partial derivative of the density with respect to pressure at isothermal, The expression of thermal conductivity is: Wherein, the Represents the thermal conductivity of the material, A gas phase contribution to thermal conductivity is represented, Representing the remaining contribution to the thermal conductivity, The viscosity is expressed as: Wherein, the The viscosity is indicated as a function of the viscosity, A gas phase contribution term representing the viscosity, Representing the remaining contribution of viscosity.
3. The flame front simulation method for turbulent combustion of a liquid rocket engine according to claim 1, wherein the calculating a pair of spread flames of a real fluid according to a real fluid correction method and a two-ignition flame control method comprises: Constructing a control equation of the real fluid pair to diffuse flame, and setting inlet boundary conditions of a fuel inlet and an oxidant inlet of the liquid rocket engine; Solving corresponding physical quantities in the control equation according to thermodynamic properties and transport property correction methods; Solving the control equation based on a two-ignition flame control method to obtain a series of real fluid one-dimensional opposite-flushing spread flames along an S curve.
4. A flame front simulation method suitable for turbulent combustion of a liquid rocket engine as recited in claim 3, wherein the control equation is: Wherein, the , , , The density is indicated by the term "density", The viscosity is indicated as a function of the viscosity, The temperature is indicated as a function of the temperature, Represents the thermal conductivity of the material, And The axial and radial components of the velocity respectively, Representing the mass fraction of component k, Represents the molar mass of component k, Indicating the specific enthalpy of component k, Indicating the diffusion rate of component k, Indicating the chemical formation rate of component k, Indicating the total number of components involved in the chemical reaction mechanism, The inlet boundary conditions of the fuel inlet are: Wherein, the Represents the fuel-side axial flux, Indicating that the fuel inlet radial flux is 0, Indicating the temperature of the fuel inlet and, Representing the mass fraction of each component of the fuel inlet, Inlet boundary conditions of the oxidant inlet: Wherein, the Indicating the measured axial flux of the oxidizing agent, Indicating that the oxidant inlet radial flux is 0, Indicating the temperature of the oxidant inlet(s), Indicating the mass fraction of each component of the oxidant inlet.
5. A flame face simulation method suitable for turbulent combustion of a liquid rocket engine as recited in claim 3, wherein said two-ignition flame control method comprises: Solving the control equation under a preset low strain rate to obtain an initial flame solution; On the basis of the initial flame solution, two control points are selected at two sides of the peak temperature, a temperature change smaller than zero is applied to the two control points, a new flame solution is obtained by solving, the highest flame temperature is reduced along with the increase of the fuel inlet speed and the strain rate, and the highest flame temperature is continuously reduced; when the flameout critical point is reached, the temperatures of the two control points are further reduced near the flameout critical point, so that the highest temperature of the flame is monotonically reduced, and a series of real fluid pair-wise spread flames along the S-curve are obtained.
6. The flame face simulation method suitable for turbulent combustion of a liquid rocket engine according to claim 1, wherein the constructing a laminar diffusion flame face database from the real fluid pair-wise diffusion flame comprises: setting a mixing fraction and a reaction progress variable; and constructing a laminar diffusion flame surface database by linear interpolation according to the real fluid pair-wise diffusion flame.
7. The flame face simulation method suitable for turbulent combustion of a liquid rocket engine according to claim 1, wherein the expanding the laminar flow diffusion flame face database into a real fluid diffusion flame face database considering turbulence fluctuations comprises: determining a piecewise linear function between the mixing score and grid points in a reaction progress variable space; solving coefficients of the piecewise linear function, and approximating the full-range integral of the piecewise linear function to the sum of the small-segment integral; Determining from the sum of the coefficients of the piecewise linear function and the integrals of the segments PDF integration; The mixing fraction and the reaction progress variable are subjected to a PWSA integration method PDF integration, building a database of real fluid diffusion flame faces taking into account turbulence fluctuations.
8. The flame front simulation method suitable for turbulent combustion of a liquid rocket engine according to claim 1, wherein the constructing a turbulent combustion model of the liquid rocket engine according to the real fluid diffusion flame front database comprises: solving a transport equation of the mass, momentum, mixing fraction and reaction progress variables to obtain flow field parameters; updating physical properties and chemical reaction source items in the real fluid diffusion flame surface database through table lookup interpolation according to the mixing fraction and reaction progress variable corresponding to each grid point of the flow field, and table lookup to obtain temperature and components; and repeatedly executing the solving action and the updating action until the flow field parameters are converged.
9. The flame front simulation method suitable for turbulent combustion of a liquid rocket engine according to claim 8, wherein the transport equation is: Wherein, the The average fluid density is indicated as being the average fluid density, The time is represented by the time period of the day, The velocity component in the j-direction is indicated, The velocity component in the i-direction is indicated, Representing the spatial coordinate component of the j-direction, Representing the spatial coordinate component of the i-direction, The average fluid pressure is indicated as being the average fluid pressure, The effective stress tensor is represented by a graph, The blending score is represented as a function of the blending score, , Representing the mass diffusion coefficient of the turbulent flow, A variable representing the progress of the reaction, And the variable source item represents the reaction progress.
10. An electronic device comprising a memory, a processor and a computer program stored on the memory and executable on the processor, the processor executing the program to implement the flame front simulation method of any of claims 1-9 suitable for turbulent combustion of a liquid rocket engine.

Description

Flame surface simulation method suitable for turbulent combustion of liquid rocket engine Technical Field The application relates to the technical field of rocket engine combustion, in particular to a flame surface simulation method and electronic equipment suitable for turbulent combustion of a liquid rocket engine. Background With the rapid development of reusable launch vehicles and the rise of the commercial aerospace industry, liquid rocket engines are being propelled toward high performance, high reliability, reusability, and lower cost. The liquid rocket engine works under the conditions of high pressure, high temperature and strong turbulence, the turbulent combustion process is very complex, and the liquid rocket engine has obvious nonlinearity and coupling characteristics. The turbulent structure intensifies the mixing process of fuel and oxidant, thus affecting the average chemical reaction rate, and simultaneously, the heat release of chemical reaction affects turbulent combustion. Therefore, high-fidelity numerical simulation of the combustion chamber of the liquid rocket engine is always a technical difficulty in the fields of computational fluid mechanics and combustion, and the key is the selection of a turbulent combustion model. However, the liquid rocket engine in the related art operates at an ultra-high pressure, and its combustion is subjected to a trans/supercritical state. In this state, the fluid shows remarkable real fluid effect, the thermophysical parameters of the fluid change with the pressure and the temperature, and the traditional turbulent combustion model has the problems of simulation distortion, separation from actual combustion behavior and the like under the ultrahigh pressure working condition of the liquid rocket engine. Disclosure of Invention The application provides a flame surface simulation method and electronic equipment suitable for turbulent combustion of a liquid rocket engine, which are used for solving the problems that a turbulent combustion model in the related art is simulated and distorted under the ultrahigh pressure working condition of the liquid rocket engine, and is separated from actual combustion behavior. The embodiment of the first aspect of the application provides a flame face simulation method suitable for turbulent combustion of a liquid rocket engine, which comprises the following steps of obtaining propellant composition parameters of the liquid rocket engine, determining a real fluid state equation and a thermophysical property and transportation property correction method according to the propellant composition parameters, calculating real fluid one-dimensional opposite-spread flame according to the real fluid correction method and the two-ignition flame control method, constructing a laminar flow diffusion flame face database according to the real fluid one-dimensional opposite-spread flame, expanding the laminar flow diffusion flame face database into a real fluid diffusion flame face database considering turbulent fluctuation, constructing a turbulent combustion model suitable for the liquid rocket engine according to the real fluid diffusion flame face database, and simulating combustion behavior of the liquid rocket engine by using the turbulent combustion model. According to one embodiment of the application, the true fluid state equation is: Wherein, the The pressure of the fluid is indicated and,Indicating the density of the fluid and,The general gas constant is indicated as such,Indicating the thermodynamic temperature of the fluid,Represents the molar mass of the mixture,AndThe parameter of the physical characteristic is represented by, The thermodynamic properties are expressed as: Wherein, the Indicating the internal energy of the fluid,Represents the internal energy of the ideal gas, subscript 0 represents the ideal state at low pressure,Representing the partial derivative of pressure with temperature at equal density,Indicating the enthalpy of the fluid,Indicating the enthalpy of the ideal gas,Indicating the specific heat capacity of the fluid,Represents the specific heat capacity of the ideal gas,Representing the second partial derivative of pressure with temperature at equal density,Representing the partial derivative of the density with respect to pressure at isothermal, The expression of thermal conductivity is: Wherein, the Represents the thermal conductivity of the material,A gas phase contribution to thermal conductivity is represented,Representing the remaining contribution to the thermal conductivity, The viscosity is expressed as: Wherein, the The viscosity is indicated as a function of the viscosity,A gas phase contribution term representing the viscosity,Representing the remaining contribution of viscosity. According to one embodiment of the application, the calculation of the real fluid pair-wise diffusion flame according to the real fluid correction method and the two-ignition flame control method compri