Equivalent calculation method for the high dynamic load test device of rocket engine combustion chamber and nozzle

Abstract

The invention discloses an equivalent calculation method for a rocket engine combustion chamber and a nozzle strong dynamic load test device, which directly converts an energetic medium into a high-temperature and high-pressure air mass according to the energy released in the reaction process of the energetic medium in the initial state of the flow field of the strong dynamic load test device; the mass and mole number of the high-temperature and high-pressure air mass are calculated according to the initial mass of the energetic medium and the product form, and the thermodynamic state of the high-temperature and high-pressure air mass is determined according to the initial mass and calorific value of the energetic medium, and the temperature and air pressure of the high-temperature and high-pressure air mass are equivalently calculated; the high-temperature and high-pressure air mass with equivalently calculated mass, mole number, temperature and pressure is taken as an analysis object, the high-temperature and high-pressure air mass is equivalently placed at a designated position of the initial state of the flow field of the strong dynamic load test device, and a numerical simulation calculation is performed on the strong dynamic load process generated by the high-temperature and high-pressure air mass; the invention reduces the difficulty of boundary condition processing, improves the calculation efficiency of simulation, and can obtain simulation results in a shorter time.

Description

Technical Field

[0001] The invention relates to the technical field of rocket engines, and in particular to an equivalent calculation method for a rocket engine combustion chamber and a nozzle strong dynamic load test device. Background Art

[0002] The performance verification of the rocket engine combustion chamber and nozzle is crucial. The strong dynamic load test is one of the key links in the technology research and development process. The strong dynamic load environment is extremely complex and has a strong energy impact. There are usually strong energy release processes such as detonation, explosion, high-speed impact, and rapid flight, which instantly produce extremely high pressure, temperature or speed changes.

[0003] The high dynamic load test device for the rocket engine combustion chamber and nozzle is driven jointly by high-pressure air and energetic medium. The high-pressure air provides the initial power, and the energy is further released through the combustion or explosion of the energetic medium. The collaborative work can accurately simulate the high dynamic load environment faced by the rocket engine during startup and actual operation, including extremely complex pressure, temperature, speed, etc.

[0004] The strong dynamic load test device of the rocket engine combustion chamber and nozzle is driven by high-pressure air and energetic medium, which is a typical way to generate a strong dynamic load environment. However, the traditional strong dynamic load environment calculation and simulation implementation method mainly considers the detailed processes such as complex chemical reactions and multiphase flows of energetic media, and then simulates and calculates the impact of shock waves after complex chemical reactions and multiphase flows of energetic media on the strong dynamic load test device. The defects of this method are: the existing model considering the reaction process of energetic media is seriously restricted by multiple factors such as multiphase flow problems, chemical reaction coupling phenomena, complexity of boundary conditions, high pressure and high temperature characteristics, and limitations of numerical calculation methods. The ability to quickly and accurately simulate the strong dynamic load environment is severely restricted. Summary of the invention

[0005] The purpose of the present invention is to provide an equivalent calculation method for a rocket engine combustion chamber and nozzle high dynamic load test device, so as to solve the technical problems in the prior art that are seriously restricted in the ability to quickly and accurately simulate high dynamic load environments due to various factors such as multiphase flow problems, chemical reaction coupling phenomena, complexity of boundary conditions, high pressure and high temperature characteristics and limitations of numerical calculation methods.

[0006] In order to solve the above technical problems, the present invention specifically provides the following technical solutions:

[0007] The equivalent calculation method of the rocket engine combustion chamber and nozzle strong dynamic load test device includes the following steps:

[0008] The energetic medium is directly converted into a high-temperature and high-pressure gas mass according to the energy released in the reaction process of the energetic medium in the initial state of the flow field of the strong dynamic load test device;

[0009] Calculating the mass and mole number of the high-temperature and high-pressure air mass according to the initial mass of the energetic medium and the product form, and determining the thermodynamic state of the high-temperature and high-pressure air mass according to the initial mass and calorific value of the energetic medium, and equivalently calculating the temperature and pressure of the high-temperature and high-pressure air mass;

[0010] A high-temperature and high-pressure air mass with equivalently calculated mass, molar number, temperature and pressure is taken as the analysis object, and the high-temperature and high-pressure air mass is equivalently placed at a specified position of the initial state of the flow field of a strong dynamic load test device, and a numerical simulation calculation is performed on the strong dynamic load process generated by the high-temperature and high-pressure air mass.

[0011] As a preferred solution of the present invention, the method for equivalently converting the energetic medium into a high-temperature and high-pressure gas mass is as follows:

[0012] Determine the chemical energy that can be released by the energetic medium during the reaction process;

[0013] The chemical energy released by the energetic medium during the reaction process is completely converted into the internal energy of the same mass of high-temperature and high-pressure gas;

[0014] The pressure and temperature of the high-temperature and high-pressure air mass are determined according to the internal energy of the high-temperature and high-pressure air mass.

[0015] As a preferred solution of the present invention, the mass of the high-temperature and high-pressure gas mass is calculated based on the principle of the chemical reaction equation of the given mass of the energetic medium;

[0016] The calculation method of the mole number of the high temperature and high pressure air mass is:

[0017] The number of moles of high-temperature and high-pressure gas mass = the mass of the energetic medium ÷ the molar mass of the energetic medium, where the molar mass of the energetic medium is 0.029 kg / mol.

[0018] As a preferred solution of the present invention, based on the law of conservation of energy, the chemical energy released by the energetic medium during the reaction process = the internal energy of the high-temperature and high-pressure gas mass = the mass m of the energetic medium × the calorific value Q of the energetic medium;

[0019] Among them, the mass m of the energetic medium is given in advance according to the test conditions;

[0020] The calorific value Q of the energetic medium is the heat release per unit mass of the energetic medium, which can be directly obtained by querying the medium type.

[0021] As a preferred solution of the present invention, the thermodynamic state of the high-temperature and high-pressure air mass is determined according to the initial mass and calorific value of the energetic medium, and the pressure of the high-temperature and high-pressure air mass is equivalently calculated as follows:

[0022] The formula for calculating the chemical energy released by the energetic medium during the reaction process is m*Q=p / (γ-1)+ρu 2 / 2;

[0023] Where u=0, ρ is the density of the energetic medium, P is the pressure of the energetic medium; γ is the specific heat ratio;

[0024] The pressure of the energetic medium is obtained as P=(γ-1)*m*Q.

[0025] As a preferred solution of the present invention, the thermodynamic state of the high-temperature and high-pressure air mass is determined according to the initial mass and calorific value of the energetic medium, and the temperature of the high-temperature and high-pressure air mass is equivalently calculated as follows:

[0026] The temperature of the high-temperature and high-pressure air mass is T=p / (ρR);

[0027] Wherein, ρ is the density of the energetic medium, ρ=m / V, V is the initial volume of the high-temperature and high-pressure air mass, which is determined according to the resident volume of the strong dynamic load test device, and m is the mass of the energetic medium;

[0028] P is the pressure of the energetic medium;

[0029] R is the gas constant.

[0030] Compared with the prior art, the present invention has the following beneficial effects:

[0031] The equivalent method of the energetic medium reaction process in the strong dynamic load test of the present invention greatly simplifies the model structure, and effectively breaks through the limitations of multiple factors such as complex physical models, multiphase flow, chemical reaction coupling, boundary conditions, high pressure and high temperature characteristics, and numerical calculation methods for rapid simulation. By equating the energetic medium to an air mass, it avoids directly dealing with complex chemical processes and multiphase flow problems, which greatly reduces the amount of calculation, and also reduces the difficulty of boundary condition processing, improves the calculation efficiency of the simulation, and can obtain simulation results in a shorter time. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the implementation methods of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for the implementation methods or the description of the prior art. Obviously, the drawings in the following description are only exemplary, and for ordinary technicians in this field, other implementation drawings can be derived from the provided drawings without creative work.

[0033] Figure 1 Schematic diagram of the flow of the equivalent calculation simulation method according to an embodiment of the present invention. DETAILED DESCRIPTION

[0034] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0035] like Figure 1 As shown, the present invention provides an equivalent calculation method for a rocket engine combustion chamber and nozzle strong dynamic load test device, comprising the following steps:

[0036] The energetic medium is equivalently converted into a high-temperature and high-pressure air mass directly according to the energy released in the reaction process of the energetic medium in the initial state of the flow field of the strong dynamic load test device.

[0037] The mass and molar number of the high-temperature and high-pressure air mass are calculated based on the initial mass of the energetic medium and the product form, and the thermodynamic state of the high-temperature and high-pressure air mass is determined based on the initial mass and calorific value of the energetic medium, and the temperature and pressure of the high-temperature and high-pressure air mass are equivalently calculated.

[0038] The high-temperature and high-pressure air mass with equivalently calculated mass, molar number, temperature and pressure is taken as the analysis object, and the high-temperature and high-pressure air mass is equivalently placed at the specified position of the initial state of the flow field of the strong dynamic load test device, and the strong dynamic load process generated by the high-temperature and high-pressure air mass is numerically simulated.

[0039] It should be noted that the strong dynamic load test device for the rocket engine combustion chamber and nozzle includes a high-pressure energetic medium reaction chamber, and a connecting section, a combustion chamber and a nozzle connected in sequence to the high-pressure energetic medium reaction chamber. The high-pressure energetic medium reaction chamber is driven jointly by high-pressure air and energetic medium, with initial power provided by high-pressure air, and further releases energy through the combustion or explosion of the energetic medium to form a shock wave. The shock wave moves along the connecting section, combustion chamber and nozzle in sequence, and works together to accurately simulate the strong dynamic load environment faced by the rocket engine during startup and actual operation.

[0040] The equivalent calculation simulation method in this embodiment is specifically as follows: the energetic medium reaction process is omitted, and based on the energy change generated by the energetic medium reaction process, the energetic medium is directly converted into a high-temperature and high-pressure air mass according to the energy released by its reaction process, and the high-temperature and high-pressure air mass is used as the subsequent initial condition to replace the chemical reaction process itself. This equivalent and simplified process will greatly reduce the calculation simulation process of the rocket engine combustion chamber and nozzle high-dynamic load test device, improve the simulation efficiency, and make it more concise and efficient to determine the test conditions and states of the device.

[0041] The chemical energy driven by the joint high-pressure air and energetic medium is released instantly, causing the surrounding medium to produce a high temperature and high pressure state. The basis of this treatment method is that, from a macroscopic point of view, the joint driving of high-pressure air and energetic medium and the products after driving are similar to the effect of a high-temperature and high-pressure air mass with corresponding energy.

[0042] The energy released by the energetic medium during the reaction process is mainly in the form of high-temperature, high-pressure gas to do external work and produce dynamic load effects such as impact. As a widely existing medium with relatively simple and clear properties, air can be equivalent to high-temperature, high-pressure air masses, which can greatly simplify the subsequent calculation and simulation process.

[0043] This computational simulation process method may have large deviations near the detonation point of the high-pressure energetic medium reaction chamber, but the states obtained in the right connecting section, combustion chamber and nozzle of the device are not much different from the complex computational simulation. It can be directly compared with the test through the propagation speed of the shock wave, etc., with good results, and the deviation generally does not exceed 10%.

[0044] Furthermore, the method for converting the energetic medium into high-temperature and high-pressure air masses is as follows:

[0045] (1) Determine the chemical energy that can be released by the energetic medium during the reaction process;

[0046] (2) The chemical energy released by the energetic medium during the reaction process is completely converted into the internal energy of the same mass of high-temperature and high-pressure air;

[0047] (3) Determine the pressure and temperature of the high-temperature and high-pressure air mass based on its internal energy.

[0048] Among them, in order to determine the internal energy of high-temperature and high-pressure air masses of the same mass, it is necessary to determine the mass of the energetic medium and the product form of the energetic medium. The mass of the energetic medium directly determines the total amount of energy it contains, while the product form determines the amount of energy after the energy is converted into high-temperature and high-pressure air masses.

[0049] For example, for a specific energetic medium, after complete reaction, the type and quantity of generated gas products can be determined according to the chemical reaction equation. Combined with relevant theories such as the ideal gas state equation, the mass and molar number of the equivalent high-temperature and high-pressure air mass can be calculated. Taking the explosion of the common energetic material TNT as an example, based on the chemical composition of TNT and the explosion reaction equation, the amount of gas products produced by the explosion can be accurately calculated, and then the relevant parameters of the equivalent high-temperature and high-pressure air mass can be determined.

[0050] Specifically, the mass of the high-temperature and high-pressure air mass is calculated based on the principle of the chemical reaction equation of a given mass of energetic medium;

[0051] The calculation method of the molar number of high temperature and high pressure air mass is:

[0052] The number of moles of high-temperature and high-pressure gas mass = the mass of the energetic medium ÷ the molar mass of the energetic medium, where the molar mass of the energetic medium is 0.029 kg / mol.

[0053] The thermodynamic state of the high-temperature and high-pressure air mass is determined based on the initial mass and calorific value of the energetic medium, which is used to calculate the temperature, pressure and other parameters of the high-temperature and high-pressure air mass. The initial mass of the energetic medium determines its total energy reserve, while the calorific value is a key indicator for measuring the energy release capacity of the unit mass of the energetic medium. Through these two parameters, the total energy released by the complete reaction of the energetic medium can be calculated. According to the law of conservation of energy, this energy will be converted into the internal energy of the equivalent high-temperature and high-pressure air mass, and combined with the thermodynamic properties such as the specific heat of air, the temperature of the high-temperature and high-pressure air mass can be calculated.

[0054] For the calculation of the pressure of high-temperature and high-pressure air masses, it is necessary to further consider factors such as the volume of the high-temperature and high-pressure air masses. For example, for the reaction of an energetic medium in a closed space, the pressure of the equivalent high-temperature and high-pressure air mass can be calculated using the modified formula of the ideal gas state equation based on the volume of the space and the energy release of the energetic medium.

[0055] Based on the law of conservation of energy, the chemical energy released by the energetic medium during the reaction process = the internal energy of the high-temperature and high-pressure gas mass = the mass m of the energetic medium × the calorific value Q of the energetic medium;

[0056] Among them, the mass m of the energetic medium is given in advance according to the test conditions;

[0057] The calorific value Q of the energetic medium is the heat release per unit mass of the energetic medium, which can be directly obtained by querying the medium type.

[0058] The thermodynamic state of the high-temperature and high-pressure air mass is determined according to the initial mass and calorific value of the energetic medium, and the pressure of the high-temperature and high-pressure air mass is equivalently calculated as follows:

[0059] The formula for calculating the chemical energy released by the energetic medium during the reaction process is m*Q=p / (γ-1)+ρu 2 / 2;

[0060] Where u=0, ρ is the density of the energetic medium, P is the pressure of the energetic medium; γ is the specific heat ratio;

[0061] The pressure of the energetic medium is obtained as P=(γ-1)*m*Q.

[0062] The thermodynamic state of the high-temperature and high-pressure air mass is determined according to the initial mass and calorific value of the energetic medium. The temperature of the high-temperature and high-pressure air mass is equivalently calculated as follows:

[0063] The temperature of the high-temperature and high-pressure air mass is T=p / (ρR);

[0064] Wherein, ρ is the density of the energetic medium, ρ=m / V, V is the initial volume of the high-temperature and high-pressure air mass, which is determined according to the resident volume of the strong dynamic load test device, and m is the mass of the energetic medium;

[0065] P is the pressure of the energetic medium;

[0066] R is the gas constant.

[0067] After the above equivalent calculation, the mass, molar number, temperature and pressure of the high-temperature and high-pressure air mass formed in the high-pressure energetic medium reaction chamber after the energetic medium reacts can be obtained, that is, the initial state of the high-temperature and high-pressure air mass at the initial position of the flow field of the strong dynamic load test device can be obtained. The movement of the high-temperature and high-pressure air mass in the strong dynamic load test device and the effect on the connecting section, combustion chamber and nozzle can be directly used by computational fluid dynamics and other related technologies, with the high-temperature and high-pressure air mass as the simulation medium, and the existing mature aerodynamic calculation models and algorithms can be fully utilized. Placing the high-temperature and high-pressure air mass with determined mass, molar number, temperature and pressure parameters at the specified position of the initial state of the flow field is equivalent to introducing an equivalent energetic medium energy source in the simulation environment. Subsequently, by solving the fluid mechanics equations, the air flow, pressure wave propagation, energy transfer and other processes under the strong dynamic load environment can be simulated.

[0068] For example, when simulating the propagation of shock waves generated by an explosion in the air, this equivalent method can accurately simulate key characteristics of the shock wave such as propagation speed and intensity changes, providing data support for further analysis of the impact of strong dynamic loads on surrounding structures or objects.

[0069] Compared with the traditional model that considers the detailed processes such as complex chemical reactions and multiphase flow of energetic media, the equivalent method of the energetic medium reaction process in the strong dynamic load test of the present invention greatly simplifies the model structure, and effectively breaks through the limitations of multiple factors such as complex physical models, multiphase flow, chemical reaction coupling, boundary conditions, high pressure and high temperature characteristics, and numerical calculation methods for rapid simulation. By equating the energetic medium to an air mass, it avoids directly dealing with complex chemical processes and multiphase flow problems, which greatly reduces the amount of calculation, and also reduces the difficulty of boundary condition processing, improves the calculation efficiency of the simulation, and can obtain simulation results in a shorter time.

[0070] In addition, the equivalent calculation method for the energetic medium reaction process of this embodiment has strong versatility and can be applied to various types of energetic media and different strong dynamic load environment simulation scenarios. Whether it is conventional explosive explosion or energy release simulation of some new energetic materials, this equivalent method can be used.

[0071] The above embodiments are only exemplary embodiments of the present application and are not intended to limit the present application. The protection scope of the present application is defined by the claims. Those skilled in the art may make various modifications or equivalent substitutions to the present application within the essence and protection scope of the present application, and such modifications or equivalent substitutions shall also be deemed to fall within the protection scope of the present application.

Claims

1. The equivalent calculation method of the rocket engine combustion chamber and nozzle strong dynamic load test device is characterized by: The following steps are involved: The energetic medium is directly converted into a high-temperature and high-pressure gas mass according to the energy released in the reaction process of the energetic medium in the initial state of the flow field of the strong dynamic load test device; The above equivalent conversion into high temperature and high pressure air masses is achieved by: Determine the chemical energy that can be released by the energetic medium during the reaction process; The chemical energy released by the energetic medium during the reaction process is completely converted into the internal energy of the same mass of high-temperature and high-pressure gas; Determine the pressure and temperature of the high-temperature and high-pressure air mass according to the internal energy of the high-temperature and high-pressure air mass; Calculate the mass and mole number of the high-temperature and high-pressure air mass according to the mass of the energetic medium and the product form, determine the thermodynamic state of the high-temperature and high-pressure air mass according to the mass and calorific value of the energetic medium, and equivalently calculate the temperature and pressure of the high-temperature and high-pressure air mass; The equivalent calculation method for calculating the pressure of the high temperature and high pressure air mass is: Formula for calculating the chemical energy released by an energetic medium during a reaction ; Get the pressure of the energetic medium ; The temperature of the high-temperature and high-pressure air mass is equivalently calculated as follows: The temperature of the high-temperature and high-pressure air mass is T=P / (ρR); In the above formula, u=0, γ is the specific heat ratio, and the calorific value Q of the energetic medium is the heat release per unit mass of the energetic medium, which can be directly obtained by querying the medium type; ρ is the density of the energetic medium, and ρ=m / V, V is the initial volume of the high-temperature and high-pressure air mass, which is determined according to the resident volume of the strong dynamic load test device, and m is the mass of the energetic medium; P is the pressure of the energetic medium; R is the gas constant; A high-temperature and high-pressure air mass with equivalently calculated mass, molar number, temperature and pressure is taken as the analysis object, and the high-temperature and high-pressure air mass is equivalently placed at a specified position of the initial state of the flow field of a strong dynamic load test device, and a numerical simulation calculation is performed on the strong dynamic load process generated by the high-temperature and high-pressure air mass.

2. The equivalent calculation method for the rocket engine combustion chamber and nozzle strong dynamic load test device according to claim 1 is characterized in that: The mass of the high-temperature and high-pressure gas mass is calculated based on the chemical reaction equation principle of the given mass of the energetic medium; The calculation method of the mole number of the high temperature and high pressure air mass is: The number of moles of high-temperature and high-pressure gas mass = the mass of the energetic medium ÷ the molar mass of the energetic medium, where the molar mass of the energetic medium is 0.029 kg / mol.

3. The equivalent calculation method for the rocket engine combustion chamber and nozzle strong dynamic load test device according to claim 1 is characterized in that: Based on the law of conservation of energy, the chemical energy released by the energetic medium during the reaction process = the internal energy of the high-temperature and high-pressure gas mass = the mass m of the energetic medium × the calorific value Q of the energetic medium; The mass m of the energetic medium is given in advance according to the test conditions.

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