A test apparatus and method for simulating two-phase flow in a solid propellant engine

Abstract

The application provides a test device and method for simulating two-phase flow in a solid engine. The test device for simulating two-phase flow in the solid engine is characterized in that: a gaseous oxidant is provided by an oxidant storage tank, particles are provided by a particle storage cylinder, a gas-particle two-phase flow is formed in a gas-particle mixing chamber, and the two-phase flow in the solid engine is simulated. The particles are directly sent into the gas-particle mixing chamber by a motor-driven piston, pure particle input is realized, a pneumatic conveying mode is not used, no fluidizing gas is attached, and a high-temperature gas main flow is not disturbed.

Description

Technical Field

[0001] This invention belongs to the field of solid propellant propulsion technology and relates to a test apparatus and method for simulating two-phase flow inside a solid propellant engine. Background Technology

[0002] In solid rocket motors or solid ramjet engines, solid propellants typically contain metal particles. These metal particles burn to form oxide particles, which melt under high temperatures, forming condensed particles. Intense collisions and agglomeration occur between these condensed particles, altering their size and distribution. Condensed particles can cause two-phase flow losses, accelerated ablation of the nozzle throat liner insulation, and slag deposition, all of which degrade engine performance. Experimental research on condensed particles and gas / particle two-phase flow is crucial for addressing these problems.

[0003] Currently, common two-phase flow tests for solid rocket motors include nozzle two-phase flow tests, solid-fuel mixture combustion tests, nozzle insulation layer ablation tests, and particle deposition tests. Current experimental research methods include real engine testing, propellant combustion experiments, and cold two-phase flow experiments. However, due to the high temperature, high pressure, and high speed environment of real engine testing, as well as the presence of a large number of particles in the plume, existing experimental methods struggle to measure specific particle parameters, such as particle size distribution, particle concentration, particle velocity, and particle temperature. Furthermore, once a solid rocket motor is ignited, it is difficult to control, and gas flow rate and particle distribution are completely uncontrollable. In nozzle efficiency evaluation and profile design, the particle phase parameters at the nozzle inlet are crucial. However, these parameters are difficult to measure during real engine testing, thus hindering the achievement of experimental objectives.

[0004] Propellant combustion experiments are frequently used in insulation ablation experiments: solid propellant containing metal particles combusts to form a high-temperature gas-solid two-phase flow, which then passes through a nozzle to form a high-speed two-phase jet. Insulation material is placed in the direction of the jet, and the ablation behavior is tested to study the ablation mechanism and material properties. In this type of experiment, once the solid propellant is ignited, it is difficult to control, making it difficult to control the initial parameters of the two-phase flow, including the particle size and particle size distribution formed after combustion. Therefore, it is difficult to study the influence of parameters such as particle size on ablation.

[0005] Cold two-phase flow experiments are commonly used for nozzle two-phase flow studies. In these experiments, parameters such as particle size distribution, particle concentration, and gas flow rate are controllable, and the flow is easy to observe. However, the gas phase is at room temperature, and many physical processes differ significantly from the two-phase flow in a real engine.

[0006] Currently, there are two-phase flow simulation devices for solid rocket motors. These typically involve burning liquid or gaseous fuel and oxidizer to produce high-temperature combustion gas, which is then injected into the high-temperature combustion gas via pneumatic conveying. This method requires separate adjustment and control of the fuel and oxidizer flow rates. Furthermore, in pneumatic conveying-based particle supply systems, the flow rates of the fluidizing gas and particles need to be adjusted to maintain optimal fluidization, making the process complex. Additionally, during the mixing of the particle phase with the high-temperature combustion gas, the fluidizing gas is also mixed in, interfering with the state of the high-temperature gas flow and leading to inaccurate results. Summary of the Invention

[0007] The purpose of this invention is to provide an experimental device and method for simulating two-phase flow inside a solid rocket motor, which can realize controllable and measurable high-temperature and high-speed two-phase flow, and provide relevant means and methods for insulation layer ablation experiments, nozzle two-phase flow experiments, etc.

[0008] This invention is achieved through the following technical solution:

[0009] A test apparatus for simulating two-phase flow in a solid fuel engine includes an oxidizer tank, solid fuel, a gas-solid mixing chamber, a pellet storage cylinder, and an electric motor; the solid fuel has a cylindrical structure.

[0010] The oxidant storage tank is connected to one end of the solid fuel via an oxidant supply pipeline, and the other end of the solid fuel is connected to a gas inlet on the gas-solid mixing chamber; or, the oxidant storage tank is connected to the gas inlet of the gas-solid mixing chamber via an oxidant supply pipeline, and the outlet of the gas-solid mixing chamber is connected to one end of the solid fuel.

[0011] The gas-solid mixing chamber has a particle inlet on its side, and the particle outlet of the particle storage cylinder is connected to the particle inlet of the gas-solid mixing chamber. The particle storage cylinder includes a cylinder body, and a piston is provided inside the cylinder body. The space between the piston and the particle outlet is used to fill particles, and the output shaft of the motor is connected to the piston.

[0012] Preferably, the oxidant storage tank is connected to one end of the solid fuel via an oxidant supply pipeline, and the other end of the solid fuel is connected to a gas inlet on the gas-solid mixing chamber; a nozzle is connected to the downstream outlet of the gas-solid mixing chamber.

[0013] Furthermore, an insulation layer is provided on the inner wall of the nozzle.

[0014] Preferably, the oxidant storage tank is connected to one end of the solid fuel via an oxidant supply pipeline, and the other end of the solid fuel is connected to a gas inlet on the gas-solid mixing chamber; a visible combustion chamber is connected to the downstream outlet of the gas-solid mixing chamber.

[0015] Preferably, the gas-solid mixing chamber is equipped with a pressure sensor and a temperature sensor.

[0016] Preferably, a flange is connected to each end of the solid fuel, and the two flanges are fixed together by a screw. The solid fuel is fixedly connected to the gas-solid mixing chamber through one of the flanges.

[0017] Preferably, the gas-solid mixing chamber and the particle storage cylinder are connected by threads.

[0018] Preferably, a flow controller and a flow meter are installed on the oxidant supply pipeline.

[0019] Preferably, the gaseous oxidant stored in the oxidant storage tank is air or other gaseous oxidants.

[0020] A test method for simulating two-phase flow in a solid fuel engine, based on the test device, involves introducing gaseous oxidant into the cavity inside the solid fuel through an oxidant storage tank, igniting the solid fuel to burn, turning on the motor, and causing the piston to push the particles in the cylinder into the gas-solid mixing chamber to form a gas-solid two-phase flow.

[0021] Alternatively, gaseous oxidant can be introduced into the gas-solid mixing chamber through an oxidant storage tank. The motor is then turned on, causing the piston to push the particles in the cylinder into the gas-solid mixing chamber. The particles mix with the gaseous oxidant to form a gas-solid two-phase flow, which then enters the cavity of the solid fuel and burns after ignition, producing high-temperature fuel gas.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] The experimental apparatus for simulating two-phase flow in a solid rocket motor, as described in this invention, uses a gaseous oxidizer supplied through an oxidizer tank and particles supplied through a particle storage cylinder. A gas-solid two-phase flow is formed in the gas-solid mixing chamber, simulating the two-phase flow within a solid rocket motor. The key feature of this invention is that the particles are directly fed into the gas-solid mixing chamber by a piston driven by a motor, enabling pure particle input without pneumatic conveying, fluidizing gas, or interference with the high-temperature gas flow path. By adjusting the particle size or motor speed, input particle parameters (such as particle size distribution and flow rate) can be adjusted to study the influence of particle parameters on the two-phase flow. This experimental apparatus employs a mixed propellant mode of gaseous oxidizer and solid fuel to generate high-temperature combustion gas. The temperature and pressure parameters of the high-temperature combustion gas are adjusted by regulating the gaseous oxidizer flow rate. It combines the structural simplicity of a solid rocket motor with the ease of adjustment of a liquid rocket motor, requiring no additional temperature control system, and is simple in structure and easy to operate and control.

[0024] Furthermore, by setting up a nozzle, the experimental device for simulating two-phase flow inside a solid rocket motor described in this invention can realize two-phase flow or plume experiments inside the nozzle.

[0025] Furthermore, an insulation layer is provided on the inner wall of the nozzle, which can enable high-temperature two-phase flow ablation experiments of the insulation layer.

[0026] Furthermore, by setting up a visual combustion chamber, two-phase flow experiments can be conducted within the combustion chamber. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the experimental apparatus for simulating two-phase flow inside a solid rocket motor as described in this invention;

[0028] Figure 2 This is an example structure of the solid fuel, gas-solid mixing chamber, and nozzle in the experimental device of the present invention;

[0029] Figure 3 This is an example structure of the gas-solid mixing chamber and nozzle in the experimental apparatus of the present invention. Detailed Implementation

[0030] To further understand the present invention, the present invention will be described below with reference to embodiments. These descriptions are only for further explaining the features and advantages of the present invention and are not intended to limit the claims of the present invention.

[0031] Reference Figure 1 The experimental apparatus for simulating two-phase flow in a solid rocket motor according to the present invention includes an oxidant storage tank 1, a solid fuel 2, a gas-solid mixing chamber 3, a particle storage cylinder 5, and an electric motor 6.

[0032] The solid fuel 2 has a cylindrical structure, similar to the shape of solid propellant in a solid rocket motor, and its length and diameter are determined by the required experimental parameters. The oxidizer storage tank 1 is connected to one end of the solid fuel 2 via an oxidizer supply pipeline, and the other end of the solid fuel 2 is connected to the gas inlet of the gas-solid mixing chamber 3; alternatively, the oxidizer storage tank 1 is connected to the gas inlet of the gas-solid mixing chamber 3 via an oxidizer supply pipeline, and the outlet of the gas-solid mixing chamber 3 is connected to one end of the solid fuel 2. A particle inlet is provided on the side of the gas-solid mixing chamber 3, and the particle outlet of the particle storage cylinder 5 is connected to the particle inlet of the gas-solid mixing chamber 3.

[0033] The particle storage cylinder 5 includes a cylinder body 51, within which a piston 52 is disposed. The space between the piston 52 and the particle outlet is used for filling particles. The output shaft of the motor 6 is connected to the piston 52. The cylinder body 51 is a slender straight cylinder structure or a conical barrel structure to ensure that the particles can smoothly enter the gas-solid mixing chamber 3. The motor speed is adjustable, thereby achieving adjustable particle flow rate.

[0034] The gaseous oxidant in the oxidant storage tank 1 is introduced into the cylindrical cavity in the middle of the solid fuel 2, where it contacts the inner surface of the solid fuel 2 and burns after ignition, producing high-temperature gas. By adjusting the gaseous oxidant flow rate, parameters such as the temperature of the high-temperature gas and the pressure of the combustion chamber can be controlled. Subsequently, the high-temperature gas enters the gas-solid mixing chamber 3. Driven by the piston 52, particles enter the gas-solid mixing chamber 3, where they are heated (or burned). The particles and the high-temperature gas mix within the gas-solid mixing chamber 3 to form a high-temperature gas-solid two-phase flow. Alternatively, the gaseous oxidant in the oxidant storage tank 1 is introduced into the gas-solid mixing chamber 3. Driven by the piston 52, particles enter the gas-solid mixing chamber 3, where they mix with the gaseous oxidant to form a high-temperature gas-solid two-phase flow, which then enters the cavity of the solid fuel 2. The gaseous oxidant contacts the inner surface of the solid fuel 2 and burns after ignition, producing high-temperature gas. The particles are heated (or burned) within the cavity of the solid fuel 2.

[0035] By changing the particle size, gas-solid two-phase flow under different particle sizes can be studied. By adjusting the speed of motor 6 to control the propulsion speed of piston 52, gas-solid two-phase flow under different particle mass fractions can be studied.

[0036] In one specific embodiment of the present invention, a pressure sensor and a temperature sensor are installed in the gas-solid mixing chamber 3 to measure the pressure and temperature of the high-temperature gas-solid two-phase flow.

[0037] In one specific embodiment of the present invention, the gas-solid mixing chamber 3 and the particle storage cylinder 5 are connected by threads.

[0038] In one specific embodiment of the present invention, a flange is connected to each end of the solid fuel 2, and the two flanges are fixed together by bolts. The solid fuel 2 is fixedly connected to the gas-solid mixing chamber 3 through one of the flanges. This facilitates replacement of the solid fuel 2 after it has been completely burned.

[0039] In one specific embodiment of the present invention, reference is made to Figure 2 and Figure 3 The oxidant storage tank 1 is connected to one end of the solid fuel 2 via an oxidant supply pipeline, and the other end of the solid fuel 2 is connected to the gas inlet of the gas-solid mixing chamber 3. To form a high-speed jet, a nozzle 4 is connected to the downstream outlet of the gas-solid mixing chamber 3. The high-temperature gas-solid two-phase flow forms a high-speed jet after passing through the nozzle 4. By changing different nozzles 4, two-phase flows at different velocities can be studied. To prevent erosion by the high-temperature gas, the lining materials of the gas-solid mixing chamber 3 and the nozzle 4 are selected from high-temperature resistant composite materials. The purpose of setting the nozzle 4 is to study the gas-solid two-phase flow or plume of the nozzle 4. If the relevant high-speed flow is not being studied, the nozzle 4 can be omitted.

[0040] In one specific embodiment of the present invention, an insulating layer is provided on the inner wall of the nozzle 4 for conducting a two-phase flow ablation experiment of the insulating layer.

[0041] In one specific embodiment of the present invention, the oxidant storage tank 1 is connected to one end of the solid fuel 2 through an oxidant supply pipeline, the other end of the solid fuel 2 is connected to the gas inlet of the gas-solid mixing chamber 3, and the downstream outlet of the gas-solid mixing chamber 3 is connected to a visualization combustion chamber for conducting two-phase flow experiments in the combustion chamber.

[0042] In one specific embodiment of the present invention, the solid fuel 2 has a length of 20cm, an outer diameter of 4cm, and an inner diameter of 2cm.

[0043] In one specific embodiment of the present invention, the gaseous oxidant stored in the oxidant storage tank 1 is air. The solid fuel is polymer fuel.

[0044] In one specific embodiment of the present invention, a flow controller and a flow meter are provided on the oxidant supply pipeline to control and regulate the flow rate of the gaseous oxidant.

[0045] The present invention provides an experimental method for simulating two-phase flow within a solid rocket motor, the process of which is as follows:

[0046] 1. Open valve 11 on the oxidant supply pipeline, and gaseous oxidant is introduced into the cavity of solid fuel 2. Ignite the solid fuel 2 to burn. Adjust the gaseous oxidant flow rate so that the pressure and temperature of the gas-solid mixing chamber 3 reach the predetermined values. Turn on motor 6, and piston 52 pushes particles into gas-solid mixing chamber 3 at a certain rate to form a gas-solid two-phase flow.

[0047] 2. Set up corresponding devices according to different experimental purposes: 1) When conducting nozzle two-phase flow or plume experiments, set up nozzle 4 downstream of gas-solid mixing chamber 3 to form a high-temperature, high-speed two-phase flow. Observe the high-temperature, high-speed two-phase flow using a series of measuring instruments (such as high-speed photography, PIV, LDV, laser particle size analyzer, etc.). 2) When conducting combustion chamber two-phase flow experiments, set up a visualization combustion chamber (e.g., through a quartz glass observation window) downstream of gas-solid mixing chamber 3. Observe the high-temperature gas-solid two-phase flow in the combustion chamber using measuring instruments. 3) When conducting insulation layer two-phase flow ablation experiments, set up a nozzle of a specific shape (such as a converging nozzle) downstream of gas-solid mixing chamber 3 to make the two-phase flow reach a predetermined velocity. Then, set up the insulation layer sample to be studied along the path of the airflow so that the high-temperature two-phase flow scours the insulation layer. Observe the ablation and scour process using optical instruments and other means; alternatively, a nozzle of a specific shape can be directly processed and connected downstream of gas-solid mixing chamber 3 to observe the scour and ablation of the nozzle by the high-temperature two-phase flow.

[0048] This invention can simulate high-temperature two-phase flow in a solid rocket motor. When mixing particles into the high-temperature gas flow, it does not carry fluidizing gas and avoids interference with the high-temperature gas flow. At the same time, it can adjust the particle size, particle concentration and gas flow rate. It can be used for mechanism experiments such as two-phase flow experiments in combustion chambers, two-phase flow experiments in nozzles, high-temperature two-phase flow ablation experiments in insulation layers, and engine plume experiments to study the two-phase flow mechanism in engines.

Claims

1. A test apparatus for simulating two-phase flow inside a solid rocket motor, characterized in that, It includes an oxidant storage tank (1), solid fuel (2), a gas-solid mixing chamber (3), a pellet storage cylinder (5), and a motor (6); the solid fuel (2) has a cylindrical structure; The oxidant storage tank (1) is connected to one end of the solid fuel (2) through an oxidant supply pipeline, and the other end of the solid fuel (2) is connected to the gas inlet opened on the gas-solid mixing chamber (3); or, the oxidant storage tank (1) is connected to the gas inlet of the gas-solid mixing chamber (3) through an oxidant supply pipeline, and the outlet of the gas-solid mixing chamber (3) is connected to one end of the solid fuel (2); The gas-solid mixing chamber (3) has a particle inlet on its side. The particle outlet of the particle storage cylinder (5) is connected to the particle inlet of the gas-solid mixing chamber (3). The particle storage cylinder (5) includes a cylinder body (51). A piston (52) is provided inside the cylinder body (51). The space between the piston (52) and the particle outlet is used to fill particles. The output shaft of the motor (6) is connected to the piston (52). The motor directly pushes the piston to send the particles into the gas-solid mixing chamber, realizing pure particle input without fluidizing gas.

2. The experimental apparatus for simulating two-phase flow inside a solid rocket motor according to claim 1, characterized in that, The oxidant storage tank (1) is connected to one end of the solid fuel (2) through an oxidant supply pipeline, and the other end of the solid fuel (2) is connected to the gas inlet opened on the gas-solid mixing chamber (3); the downstream outlet of the gas-solid mixing chamber (3) is connected to a nozzle (4).

3. The experimental apparatus for simulating two-phase flow inside a solid rocket motor according to claim 2, characterized in that, The inner wall of the nozzle (4) is provided with a heat insulation layer.

4. The experimental apparatus for simulating two-phase flow inside a solid rocket motor according to claim 1, characterized in that, The oxidant storage tank (1) is connected to one end of the solid fuel (2) through an oxidant supply pipeline, and the other end of the solid fuel (2) is connected to the gas inlet opened on the gas-solid mixing chamber (3); the downstream outlet of the gas-solid mixing chamber (3) is connected to a visual combustion chamber.

5. The experimental apparatus for simulating two-phase flow inside a solid rocket motor according to claim 1, characterized in that, The gas-solid mixing chamber (3) is equipped with a pressure sensor and a temperature sensor.

6. The experimental apparatus for simulating two-phase flow inside a solid rocket motor according to claim 1, characterized in that, The solid fuel (2) is connected to a flange at each end, and the two flanges are fixed together by a screw. The solid fuel (2) is fixedly connected to the gas-solid mixing chamber (3) through one of the flanges.

7. The experimental apparatus for simulating two-phase flow inside a solid rocket motor according to claim 1, characterized in that, The gas-solid mixing chamber (3) is connected to the particle storage cylinder (5) by a thread.

8. The experimental apparatus for simulating two-phase flow inside a solid rocket motor according to claim 1, characterized in that, A flow controller and a flow meter are installed on the oxidant supply pipeline.

9. The experimental apparatus for simulating two-phase flow inside a solid rocket motor according to claim 1, characterized in that, The gaseous oxidant stored in the oxidant storage tank (1) is air or other gaseous oxidants.

10. A test method for simulating two-phase flow inside a solid rocket motor, characterized in that, Based on the test apparatus according to any one of claims 1-9, gaseous oxidant is introduced into the cavity of solid fuel (2) through oxidant storage tank (1), and solid fuel (2) is ignited to burn. Motor (6) is turned on, and piston (52) pushes the particles in cylinder (51) into gas-solid mixing chamber (3) to form gas-solid two-phase flow. Alternatively, gaseous oxidant can be introduced into the gas-solid mixing chamber (3) through the oxidant storage tank (1), and the motor (6) can be turned on to make the piston (52) push the particles in the cylinder (51) into the gas-solid mixing chamber (3). The particles mix with the gaseous oxidant to form a gas-solid two-phase flow, and enter the cavity of the solid fuel (2). After ignition, it burns to produce high-temperature gas.

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