Modularized solid-liquid mixed propulsion fuel combustion testing device and method

Abstract

The invention belongs to the field of propellant combustion testing, and discloses a modularized solid-liquid mixed propulsion fuel combustion testing device and method. The high-pressure combustion chamber cavity comprises a movable cavity and a fixed cavity which are communicated with each other; the moving cavity comprises an oxygen inlet transparent window, a transparent window cover plate, a vortex injector, a moving cavity cover plate, an electric ignition device and a modularized sample table; the oxygen inlet transparent window is fixed at the front end of the vortex injector, the transparent window cover plate is arranged at the front end of the transparent window, the high-speed camera is arranged on one side of the transparent window cover plate, the vortex injector is connected with the modularized sample table, and the movable cavity cover plate with a hole is arranged between the vortex injector and the modularized sample table; and an electric ignition device is arranged on the outer side of the vortex injector. The device is not influenced by the structure of the grain, is suitable for testing various complex grain shapes, can measure the instantaneous thickness of the grain and calculate the instantaneous retreat rate of microsecond or above, is not influenced by any external factors during data processing, is convenient and simple to process, and is accurate in result.

Description

Technical Field

[0001] The present invention belongs to the technical field of solid-liquid hybrid propellant combustion testing, and relates to a combustion testing device, and specifically to a modular solid-liquid hybrid propellant combustion testing device and method, which is suitable for testing and analyzing the combustion recession rate and flame structure of solid-liquid hybrid propellant under a certain pressure. Background Art

[0002] Solid-liquid hybrid propellants have the advantages of high specific impulse, good safety, easy thrust adjustment, multiple start-stop, good grain stability, low temperature sensitivity, good environmental protection and good economy, which are in line with the technical requirements of the next generation of aerospace platforms for green and environmentally friendly propulsion systems, intelligent control, rapid response and recyclability. However, the low heat transfer and low fuel degradation rate caused by solid-liquid hybrid propulsion and oxidant diffusion combustion have seriously restricted the development and application of solid-liquid hybrid propulsion. The thermal decomposition process of the fuel is the fuel combustion control step.

[0003] The fuel recession rate of solid-liquid hybrid propulsion presents a power exponential relationship with the oxidizer mass density flow. The turbulent boundary layer structure of its diffusion combustion is complex, and it is difficult to directly observe and test. The main test methods for fuel recession rate are: average recession rate method in the engine, ultrasonic pulse echo measurement, X-ray imaging measurement, microwave measurement, embedded resistance measurement, high-speed photogrammetry, plasma capacitance measurement, numerical iterative calculation of internal ballistic parameters, Helmholtz oscillation frequency calculation method, etc. Several methods for testing the instantaneous recession rate are difficult to handle for complex-type grains, and the functions of the combustion chamber are limited; at the same time, ultrasonic pulse echo measurement needs to correct the influence of temperature, pressure and engine geometry on the ultrasonic sound velocity; the equipment for X-ray imaging measurement is expensive and the data processing is complicated, and the X-rays used are harmful to the human body; microwave measurement calculates the fuel recession rate by the rate of change of the phase shift between the incident signal and the reflected signal, but it is affected by the grain structure, and the system is complex and costly; embedded resistance measurement embeds the resistance recession sensor into the fuel, and calculates the instantaneous thickness and recession rate of the fuel by the change of resistance during the fuel recession process, but the embedded resistor affects the fuel decomposition and recession process; high-speed photography records the recession process of the fuel end face, and processes it to obtain the real-time recession rate of the fuel, but most combustion chambers do not have a nozzle structure, and the instantaneous combustion of the grain fluctuates greatly. Data processing is mostly manual to find feature points, which is time-consuming and labor-intensive, with large human errors, and it is difficult to process data for heterogeneous fuel grains. Summary of the invention

[0004] The present invention aims to solve the problems of limited versatility and difficult data processing of existing combustion chambers, and aims to provide a modular solid-liquid hybrid propellant combustion test device and method, which can significantly improve the solid-liquid hybrid propellant test efficiency and reduce costs.

[0005] To achieve the above purpose, the technical solution adopted by the present invention is as follows:

[0006] A modular solid-liquid hybrid propellant combustion test device comprises a high-pressure combustion chamber cavity; the high-pressure combustion chamber cavity comprises a mobile cavity and a fixed cavity connected to each other;

[0007] The movable chamber includes a transparent window cover, an oxygen inlet transparent window, a vortex injector, a movable chamber cover, an electric ignition device and a modular sample stage;

[0008] The oxygen inlet window is fixed at the front end of the vortex injector, a window cover is arranged at the front end of the oxygen inlet window, a high-speed camera is arranged on one side of the window cover, the vortex injector is connected to the modular sample stage, a movable cavity cover with an opening is arranged between the vortex injector and the modular sample stage; an electric ignition device is arranged on the outside of the vortex injector.

[0009] A further improvement of the present invention is that a first flange joint and a second flange structure are arranged between the vortex injector and the modular sample table, and the electric ignition device includes a nickel-chromium wire, one end of the nickel-chromium wire extends into the center position between the second flange joint and the modular sample table, and the other end is located above the vortex injector.

[0010] A further improvement of the present invention is that the hollow spaces at the axial centers of the movable cavity and the fixed cavity form an axial oxygen channel.

[0011] A further improvement of the present invention is that a disc with threads for connecting the fixed cavity and the movable cavity is arranged between the vortex injector and the movable cavity cover plate.

[0012] A further improvement of the present invention is that the vortex injector comprises a one-to-four joint, the oxygen intake pipeline is connected to the one-to-four joint, the oxygen intake pipeline is four pipelines perpendicular to each other, and the oxygen intake pipeline is arranged tangent to the internal channel of the vortex injector.

[0013] A further improvement of the present invention is that the oxygen intake pipeline is connected in sequence via an oxygen shut-off valve, an oxygen mass flow meter, an oxygen filter, and a one-way valve, and the one-way valve and the nitrogen intake valve are both connected to the vortex injector.

[0014] A further improvement of the present invention is that the fixed cavity includes a combustion chamber cavity, an air inlet hole is arranged at the top of the combustion chamber cavity, a sealing cover plate is arranged at one end of the combustion chamber cavity, an exhaust pipe is arranged on the sealing cover plate, the exhaust pipe is connected to a water cooling module, and a solenoid valve is arranged on one side of the exhaust pipe; a gas outlet visual window is arranged on one side of the sealing cover plate, and a perspective window cover plate is arranged on the gas outlet visual window.

[0015] A further improvement of the present invention is that it also includes a nitrogen intake pipeline, the outlet of the nitrogen intake pipeline is connected to the nitrogen shut-off valve, the nitrogen shut-off valve is divided into three paths, one path is connected to the vortex injector through the nitrogen intake valve, another path is connected to the combustion chamber cavity, and the third path is connected to the air intake valve, and the air intake valve is connected to the air compressor;

[0016] A pressure gauge, a PID pressure control device and a safety valve are installed on the combustion chamber cavity; and visual window holes are opened on both sides of the combustion chamber cavity.

[0017] A further improvement of the present invention is that the modular sample stage comprises a center hole drug column sample stage for mounting a drug column having an outer diameter ranging from 10 to 35 mm; or

[0018] The modular sample stage comprises a cantilever beam medicine column sample stage, and the cantilever beam medicine column sample stage comprises a quartz glass tube for suspending a medicine column with an inner and outer diameter ranging from 10 to 30 mm.

[0019] A modular solid-liquid mixed combustion test method comprises the following steps:

[0020] Ignite the propellant column on the modular sample stage through an electric ignition device to obtain the flame turbulence boundary layer combustion video of the propellant column;

[0021] For the flame turbulence boundary layer combustion video of the propellant column, the flame brightness of the combustion boundary layer is identified through a video processing algorithm to automatically identify the combustion equivalent radius. Based on the combustion equivalent radius, the curve of the combustion equivalent radius changing with time and the curve of the recession rate changing with time are obtained to realize the combustion test.

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

[0023] The present invention provides a mobile cavity and a fixed cavity, so that the operation is simple and convenient, the replaceable sample table can realize different combustion tests with the same sample, and the vortex injector can make the sample fully contact with oxygen and other advantages. The present invention provides a mobile cavity and a fixed cavity, and the mobile cavity is coupled with a replaceable vortex injector, an electric ignition device, a modular sample table and an oxygen inlet window. The mobile cavity improves the convenience and airtightness of charging, and also facilitates the maintenance of gas circuits and parts. The present invention is not affected by the structure of the drug column, and is suitable for testing various complex drug column shapes. It can measure the instantaneous thickness of the drug column and calculate the instantaneous recession rate of microseconds and above. The processed data is not affected by any external factors, and the processing is convenient and simple, and the results are accurate.

[0024] Furthermore, the fixed cavity is coupled with an oxygen inlet gas path, an oxygen shut-off valve, an oxygen mass flowmeter, a filter, a one-way valve, a nitrogen inlet gas path, a nitrogen inlet valve, a nitrogen shut-off valve, an air inlet hole, a PID pressure control device, a safety valve, and an exhaust pressure relief pipeline. The PID pressure control device provides a certain stable combustion chamber pressure for the grain combustion. The installation of a transparent window in the axial radial direction is conducive to high-speed photography of the grain combustion process, and is convenient for cleaning the combustion chamber after the grain combustion. The device adopts a modular sample table, which is simple to operate, fast and accurate in testing, highly safe, and low in cost. It can quickly obtain a large amount of combustion data and accelerate the screening of solid-liquid mixed propellant high-degradation rate fuels.

[0025] Furthermore, the oxygen inlet transparent window and the gas outlet visual window are combined with the center hole charge sample stand to observe the combustion process of the front and rear end faces of the charge through high-speed photography, and to determine the burning rate difference and the charge dispersion process; the visual window hole is combined with the arm beam sample stand to observe the flame combustion boundary layer structure, thereby realizing the diversification of charge combustion and observation methods, facilitating the shooting and installation of high-speed photography, and increasing the diversity of combustion methods.

[0026] Furthermore, in the present invention, a PID pressure control device is provided to control the solenoid valve to open and close rapidly according to the internal pressure of the combustion chamber cavity, so that the internal pressure of the combustion chamber cavity fluctuates slightly above and below the set value, thereby improving the stability of combustion measurement.

[0027] Furthermore, the vortex injector is divided into four intake pipes which are perpendicular to each other and tangent to the central pipe by one oxygen pipe, and it is an oxygen vortex intake, which increases the oxygen turbulence degree and the residence time in the central hole of the grain, compresses the thickness of the turbulent boundary layer of the grain, and significantly improves the withdrawal rate of the grain.

[0028] Furthermore, when terminating combustion, the oxygen supply valve and the fixed cavity pressurized nitrogen pipeline valve are closed, and the nitrogen branch valve is opened, so that nitrogen quickly enters the mobile cavity oxygen pipeline, causing the grain to quickly stop burning, significantly reducing the slow decomposition of the grain under oxygen deficiency, retaining the completeness of the combustion surface, and facilitating the characterization of the grain combustion surface.

[0029] Furthermore, when a center hole charge column sample stand is used, oxygen flows in from the center hole of the charge column, and two high-speed cameras can axially collect the inner hole radial combustion end face recession process of the front and rear end faces of the charge column; when a cantilever beam charge column sample stand is used, oxygen flows in from the annular gap between the charge column and the quartz glass tube, and the high-speed camera collects the flame structure and particle combustion and scattering effects laterally. The present invention adopts a simple electric ignition, and the replaceable vortex injector intake can increase the oxygen turbulence degree and the residence time of contact with the charge column. Terminating the combustion gas path significantly reduces the slow decomposition of the charge column under hypoxia, retains the completeness of the combustion surface, and is conducive to the characterization of the charge column combustion surface. The equivalent diameter-t curve and the recession rate-t curve are directly obtained by directly processing the captured combustion video using a video processing algorithm. This method is not affected by the charge column structure and is suitable for various complex charge column shape tests. The instantaneous thickness of the charge column can be measured and the instantaneous recession rate of microseconds and above can be calculated. The processed data is not affected by any external factors, and the processing is convenient and simple, and the results are accurate. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is a side split cross-sectional view of the modular solid-liquid hybrid propulsion fuel combustion test device of the present invention;

[0031] Figure 2 It is a side split cross-sectional view of the moving chamber of the modular solid-liquid hybrid propellant combustion test device of the present invention;

[0032] Figure 3 It is a side split cross-sectional view of the fixed cavity of the modular solid-liquid hybrid propellant fuel combustion test device of the present invention;

[0033] Figure 4 Schematic diagram of the structure of the cantilever beam column sample stage, where (a) is the main view and (b) is the top view;

[0034] Figure 5 Schematic diagram of the structure of the center hole medicine column sample stage, where (a) is the main view and (b) is the top view;

[0035] Figure 6 Schematic diagram of the vortex injector structure, wherein (a) is an overall side view, and (b) is a cross-sectional view at the air inlet;

[0036] Figure 7 It is a top view of the installation of the modular solid-liquid hybrid propellant combustion test device of the present invention;

[0037] Figure 8 The figure is a diagram of the oxygen vortex intake effect of the HTPB material; (a), (b) and (c) are diagrams of the vortex intake effect of the HTPB material at different times that change with time;

[0038] Fig. 9 This is the effect diagram of the cantilever beam combustion test;

[0039] Fig.10 The following are the combustion effect diagrams of the sample axial non-swirl intake; (a) is the initial combustion effect diagram, (b) is the initial combustion effect diagram, (c) is the mid-combustion effect diagram, and (d) is the final combustion effect diagram;

[0040] Fig.11 Dt distribution diagram obtained by video processing method;

[0041] Fig.12 It is a data processing curve diagram of average burning rate;

[0042] Fig.13 It is the flow fluctuation state curve diagram of oxygen intake;

[0043] Fig.14 These are sample diagrams of pure HTPB and HTPB after the termination of combustion by the termination gas path with the combustion rate adjustment added; wherein, (a) is a sample diagram of HTPB after the termination of combustion by the termination gas path with the combustion rate adjustment added; (b) is a sample diagram of pure HTPB after the termination of combustion by the termination gas path;

[0044] Fig.15 Processing images of the burning video data of heterogeneous hole samples;

[0045] In the figure, 1-transparent window cover, 2-oxygen inlet transparent window, 3-vortex injector, 4-movable chamber cover, 5-disc, 6-electric ignition device, 7-first flange joint, 8-second flange joint, 9-modular sample table, 10-combustion chamber cavity, 11-air inlet, 12-PID pressure control device, 13-safety valve, 14-pressure gauge, 15-sealing cover, 16-visible window hole, 17-gas outlet visual window, 18-transparent window cover, 19-oxygen inlet pipeline, 20-nitrogen inlet pipeline, 21-oxygen stop valve, 22-exhaust pressure relief pipeline, 23-oxygen mass flow meter, 24-nitrogen inlet valve, 25-nitrogen stop valve, 26-air inlet valve, 27-air compressor, 28-high-speed camera, 29-solenoid valve, 30-oxygen filter, 31-check valve. DETAILED DESCRIPTION

[0046] In order to facilitate the understanding of the present invention, the present invention will be described more fully below with reference to the relevant drawings. The preferred embodiments of the present invention are given in the drawings. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present invention more thoroughly and comprehensively understood.

[0047] In addition, when an element in the present invention is referred to as being "fixed to" or "disposed on" another element, it may be directly on the other element or there may be a central element. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be a central element at the same time. The terms "vertical", "horizontal", "left", "right" and similar expressions used herein are for illustrative purposes only and are not intended to be the only embodiment.

[0048] In order to overcome the problems in the prior art of obtaining the regression rate of the grain through a radial combustion chamber and the flame structure through an axial combustion chamber, using manual search for combustion images to obtain characteristic diameters, time-consuming and labor-intensive data processing, large human errors, and being limited to observing the combustion flame conditions and being unable to observe and calculate the regression rate of special-shaped holes, the present invention provides a modular solid-liquid hybrid propellant fuel combustion test device with a visualized and replaceable sample table under high temperature and high pressure conditions, which can further study the combustion performance of solid-liquid hybrid propellants.

[0049] like Figure 1-Figure 6 As shown, a modular solid-liquid hybrid propellant combustion test device of the present invention includes a high-pressure combustion chamber cavity and a PID pressure control device 12.

[0050] The high pressure combustion chamber cavity comprises a moving cavity and a fixed cavity.

[0051] Among them, Figure 2 As shown, the mobile chamber includes a transparent window cover plate 1, an oxygen inlet transparent window 2, a vortex injector 3, a mobile chamber cover plate 4, an electric ignition device 6, a first flange joint 7, a second flange joint 8 and a modular sample stage 9. The oxygen inlet transparent window 2 is fixed at the front end of the vortex injector 3, and a transparent window cover plate 1 is arranged at the front end of the oxygen inlet transparent window 2. A high-speed camera 28 is arranged on one side of the transparent window cover plate 1. The high-speed camera 28 is horizontally aligned with the axial and lateral visual window structure to record the combustion flame image of the combustion process. That is, the oxygen inlet transparent window 2 is arranged between the transparent window cover plate 1 and the vortex injector 3. The mobile chamber cover plate 4 is arranged at the rear end of the vortex injector 3, and an opening is arranged on the mobile chamber cover plate 4. The vortex injector 3 is connected to the first flange joint 7, the first flange joint 7 is connected to the second flange joint 8, and the second flange joint 8 is connected to the modular sample stage 9. The vortex injector 3 is used to generate a vortex airflow when oxygen is inhaled, so that the oxygen in the combustion chamber cavity contacts the sample in a vortex state, and the sample contacts the oxygen fully, so that the combustion of the sample is more complete.

[0052] The end face of the moving cavity is provided with two NPT1 / 4 triangular cone-shaped center holes, each center hole is filled with a plug, and a conical copper electrode is used to seal the center hole and the plug.

[0053] The electric ignition device 6 includes a nickel-chromium wire, one end of which extends into the center between the second flange joint 8 and the modular sample stage 9, and the other end is located above the vortex injector 3. The nickel-chromium wire passes through the plug, and a conical copper electrode is installed in the center hole and sealed. The nickel-chromium wire made of phenolic resin is insulated from the outside world, and the nickel-chromium wire is used to ignite steel wool for fuel ignition, which not only avoids the danger of ignition by laser, but also improves the ignition stability, and makes the sample ignition simple, easy to operate, and easy to control.

[0054] The hollow space at the axial center of the moving cavity and the fixed cavity forms an axial oxygen passage 33 .

[0055] A disc 5 with a tightening thread is arranged between the vortex injector 3 and the movable chamber cover plate 4, for connecting the fixed chamber and the movable chamber. The vortex injector 3 comprises a one-to-four joint, and the oxygen inlet pipeline 19 is connected to the one-to-four joint. There are four oxygen inlet pipelines 19, which are perpendicular to each other. Figure 6 As shown in (a) and (b), the oxygen intake pipe 19 is tangent to the internal channel of the vortex injector 3, so that the oxygen forms a vortex intake state. The vortex oxygen passes through the internal flow channels of the vortex injector 3, the first flange joint 7, and the second flange joint 8 and contacts the sample fixed on the modular sample table 9, thereby increasing the oxygen residence time and the fuel withdrawal rate.

[0056] The oxygen intake pipeline 19 is connected in sequence through the oxygen stop valve 21, the oxygen mass flowmeter 23, the oxygen filter 30, and the one-way valve 31. The one-way valve 31 and the nitrogen intake valve 24 are both connected to the vortex injector 3. The oxygen mass flowmeter 23 is arranged at the front end of the vortex injector 3. The oxygen mass flowmeter 23 is connected to a computer, which can monitor the oxygen flow in real time to achieve a stable oxygen intake flow. Specifically, the oxygen intake pipeline 19 is supplied by the oxygen filter 30, and the oxygen filter 30 is transported into four internal flow channels of the vortex injector 3 that are perpendicular to each other and distributed in the tangent direction of the pipeline through a one-to-four joint after passing through the one-way valve 31.

[0057] like Figure 3 As shown, the fixed cavity includes a combustion chamber cavity 10, an air inlet hole 11 is provided at the top of the combustion chamber cavity 10, a sealing cover plate 15 is provided at one end of the combustion chamber cavity 10, a through hole is opened on the sealing cover plate 15, a gas outlet visual window 17 is provided on one side of the sealing cover plate 15, and a perspective window cover plate 18 is provided on the gas outlet visual window 17. The interior of the combustion chamber cavity 10 is quickly pressurized through the air inlet hole 11. A pipeline connected to the combustion chamber cavity 10 is provided at one end of the combustion chamber cavity 10, and a solenoid valve 29 is provided on the pipeline.

[0058] The combustion chamber cavity 10 is a closed combustion chamber resistant to high pressure and high temperature, which can test the combustion performance of solid-liquid mixed propellant under high temperature and high pressure. The combustion chamber cavity 10 is a cylindrical shell with three holes on the top, which are used to install a pressure gauge 14, a PID pressure control device 12 and a safety valve 13 respectively.

[0059] The PID pressure control device 12 includes a connected pressure sensor and a PID pressure controller. The PID pressure sensor is fixed on the upper part of the combustion chamber cavity 10. The pressure of the combustion chamber cavity is maintained by continuously inputting nitrogen. When the signal of the pressure sensor is input to the PID pressure controller, the set data is compared after the PID algorithm. When the PID calculated value is greater than the set pressure value, the solid-state relay is powered off and the solenoid valve 29 is opened to release air. When the PID calculated value is less than or equal to the set value, the solid-state relay is powered on and the solenoid valve 29 is opened to release air. The switching frequency of the solenoid valve 29 is 10 times / s, which ensures the stability of the pressure in the combustion chamber cavity. The PID pressure control device 12 is used to maintain the pressure inside the combustion chamber cavity at a constant value. The pressure gauge 14 is used to observe the pressure inside the combustion chamber cavity. A pressure sensor is arranged on the upper part of the combustion chamber cavity 10. The pressure sensor is connected to a memory-type PID regulator to perform real-time pressure inspection and control. When the internal pressure of the combustion chamber cavity 10 reaches the set pressure value, the memory-type PID regulator starts to work and realizes the stability of the pressure in the combustion chamber by controlling the opening and closing of the solenoid valve 29.

[0060] A visual window hole 16 is provided on both sides of the combustion chamber cavity 10, and the visual window hole 16 is screwed and fixed to the side of the combustion chamber cavity 10 through a sealing gasket and a threaded disc, which is used for the conditions of combustion conditions and flame structure. Two fixing devices are provided at the lower end of the combustion chamber cavity 10 to enhance the stability of the combustion chamber cavity 10.

[0061] The movable chamber cover plate 4 is a detachable cover plate used to replace the combustion chamber to achieve different combustion functions. The disc 5 is completely fitted to the combustion chamber cavity 10 through a spiral connection, which can not only achieve good air tightness but also achieve the convenience of installation and removal. Two exhaust pressure relief pipes 22 are provided at the rear end to maintain the pressure stability and pressure relief of the combustion chamber cavity 10. The combustion chamber cavity 10 is cooled by water cooling.

[0062] See also Figure 7 The outlet of the nitrogen intake pipeline 20 is connected to the nitrogen shut-off valve 25. The nitrogen shut-off valve 25 is divided into three paths. One path is connected to the vortex injector 3 through the nitrogen intake valve 24, another path is connected to the intake port 11 on the combustion chamber cavity 10, and the third path is connected to the air intake valve 26. The air intake valve 26 is connected to the air compressor 27. The air compressor 27 is used to realize the pressurization in the combustion chamber cavity. The intake part is arranged at the upper part of the combustion chamber cavity. This device greatly reduces the cost and improves the economy of the experiment.

[0063] The combustion is terminated by the oxygen inlet valve 21, the nitrogen inlet valve 24 and the nitrogen stop valve 25. When the combustion is terminated, the oxygen inlet valve 21 is quickly closed to stop the oxygen supply. The nitrogen stop valve 25 is quickly closed, and the nitrogen inlet valve 24 is quickly opened. The nitrogen quickly changes the flow channel and enters the vortex injector 3. At this time, the surface of the burning sample is quickly covered by nitrogen. At this time, the combustion conditions of the sample are not sufficient, so that the combustion of the sample is terminated.

[0064] An exhaust pipeline 22 is arranged on the sealing cover plate 15, and the exhaust pipeline 22 is connected to a water cooling module. A solenoid valve 29 is arranged on one side of the exhaust pipeline 22, and the solenoid valve 29 is used to control the opening and closing of the exhaust pipeline 22. The exhaust pressure relief pipeline 22 is used for exhaust and pressure relief required to maintain a constant pressure inside the combustion chamber cavity 10. Among them, the water cooling module includes a circulating cooling part and an immersion cooling part. The circulating cooling part is installed in the combustion chamber and its output gas path through an aluminum cooling water plate for cooling. The water circulation is circulated through a DC micro water pump, and the water source of the circulating water is the water in the cooling water tank. The immersion cooling part is that the output gas path is immersed in the circulating water tank for cooling. Through the cooling of the two parts, the space occupancy rate is reduced and the cooling effect is greatly improved.

[0065] The oxygen inlet transparent window 2 and the gas outlet visual window 17 are installed in the axial direction of the moving cavity, and are sealed by sealing gaskets and fixed to the front and rear ends of the combustion chamber axially with a threaded metal shell, respectively, for observing and photographing the fuel combustion conditions and the turbulent boundary layer structure of the combustion flame.

[0066] The modular sample stage 9 includes a center hole charge sample stage, which can be used to install charges with an outer diameter range of 10-35 mm. The inner hole of the charge can have complex combustion surface structures such as vortex type, honeycomb type and wheel type. Oxygen flows into the charge from the center hole, and the recession process of the combustion at the end face of the inner hole of the charge is observed axially. The recession rate is obtained by processing, and the combustion difference at the front and rear ends of the charge can be observed simultaneously.

[0067] Alternatively, the modular sample stage 9 includes a cantilever beam charge sample stage, the charge is cantilevered in a quartz glass tube, the outer diameter of the charge is in the range of 10-30 mm, an M6 thread is embedded in the center of the charge for cantilevering on a hollow flange, a polytetrafluoroethylene gasket is used for sealing, oxygen flows in from the gap between the charge and the quartz glass tube, a high-speed camera records the flame structure and the axial retreat process, and the retreat rate is obtained through processing.

[0068] In the following description, in order to clearly explain the structure of this experiment and its working method, many directional words will be used to describe it, but these directional words are for convenience and should not be understood as restrictive words.

[0069] This embodiment provides a solid-liquid mixed propellant combustion test method for a modular sample stage, comprising the following steps:

[0070] 1) After installing a 16mm-35mm powder column on the replaceable sample table, the ignition wire is brought into contact with the ignited part of the solid-liquid mixed propellant sample, and the ignition wire is led out through a pressure plate and then connected to an ignition power supply; then the combustion chamber 9 and the combustion chamber cavity 10 are fixed into one body by a pressure plate and sealed with an O-ring.

[0071] Align the high-speed camera 28 horizontally with the axial or lateral visual window hole 16, and then adjust the focus and aperture brightness of the high-speed camera;

[0072] 2) Open the air compressor and the nitrogen inlet valve 24 to pressurize the combustion chamber cavity 10. Then, the pressure in the combustion chamber cavity 10 is kept stable through the combined action of the PID pressure control device 12 and the solenoid valve 29. At this time, open the oxygen stop valve 21 and set the oxygen intake flow rate through the oxygen mass flow meter 23;

[0073] 3) Ignition is performed by the electric ignition device 6, and the high-speed camera 28 records the combustion of the flame turbulence boundary layer, thereby completing the combustion test of the solid-liquid mixed propellant;

[0074] 4) When the combustion is terminated, the oxygen inlet valve 21 is quickly closed to stop the oxygen supply. The nitrogen stop valve 25 is quickly closed, and the nitrogen inlet valve 24 is quickly opened. The nitrogen quickly changes the flow path and enters the oxygen vortex injector 3. At this time, the surface of the burning sample is quickly covered by nitrogen. At this time, the combustion conditions of the sample are not sufficient, so that the combustion of the sample is terminated.

[0075] 5) Data processing: After the combustion is terminated, the video processing software is opened, the center position of the circle is manually selected, the image and the actual scale are input according to the actual shooting situation, the number of frames is shot, and the data processing begins. The video automatically identifies the combustion equivalent radius by identifying the flame brightness of the combustion boundary layer. The processing process is as follows: Fig. 9 As shown in the green circle, it can be seen that the sample combustion equivalent radius gradually increases and is a stable diffusion combustion. The processed data automatically screens out points with large deviations, and after identifying the combustion equivalent radius, a scatter plot of the combustion equivalent radius over time and the Dt distribution diagram is obtained, and the diameter change D(t)-D(t 0 ) and time tt 0 The relationship satisfies the power function:

[0076]

[0077] Where D(t) is the diameter at time t, D(t 0 ) is t 0 Moment diameter, a Dis the first constant, t is the combustion time, t 0 is the initial time, n D is an exponential constant.

[0078] The curve of combustion equivalent radius changing with time is fitted by formula (1), as follows: Fig.11 As shown by the red line in the middle; the fuel retreat end diameter change is differentiated with respect to time to obtain the fuel retreat rate r f for:

[0079]

[0080] According to the diameter at time t, the mass density flow G of the oxidant is obtained ox (t):

[0081]

[0082] In the formula, m ox is the oxygen flow rate, and D(t) is the diameter at time t.

[0083] The fuel's retreat rate and the oxidant's mass density flow are expressed as a power function:

[0084]

[0085] In the formula, r f (t) is the mass density flow, a r is the second constant, n r is an exponential constant.

[0086] Through program control, the formula is fitted into a curve such as Fig.11 , Fig.12 As shown, from Fig.11 , Fig.12 It can be seen that the sample combustion process and data are stable without large fluctuations. The irregular sample combustion video processing diagram is as follows Fig.15 As shown, it can be seen that the invention can process the combustion regression rate of regular samples as well as the combustion data of irregular samples. The sample diagram after the combustion is terminated is shown in FIG. Fig.14 As shown, it can be seen that the combustion process is a stable and uniform diffusion combustion, and the termination combustion effect is excellent, with little or no complete combustion products covering the sample surface.

[0087] In this test, the replaceable sample table and the air intake connector must be tightly connected and fit together to prevent oxygen from entering the combustion chamber through the gap and causing errors.

[0088] In this test, the contact portion between the ignition wire and the grain should be set in the middle area on the axial inside, which also ensures that the combustion surface of the solid-liquid mixed propellant grain diffuses from the inside to the outside, preventing errors caused by local ignition of the grain burning surface.

[0089] The combustion rate of the solid-liquid mixed propellant in this device is only determined by the internal pressure of the combustion chamber cavity and the oxygen flow rate, and is not affected by the structure of the combustion chamber cavity. It has the advantages of few interference factors and diversified tests.

[0090] During the combustion test of the device, there was no pressure relief, no air leakage, local temperature was too high, and fire problems occurred. The experimental process was normal, and the fitting curve after the test was stable without abnormal fluctuations.

[0091] Figure 8 (a), (b) and (c) are images of the axially observed combustion flame structure. Figure 8 It can be seen from (a), (b) and (c) that due to the effect of vortex injection, the flame structure presents a clear counterclockwise vortex effect. The flame swirls around the outer surface of the grain, greatly enhancing the contact time and contact efficiency between oxygen and the grain, which can achieve the effect of sufficient and uniform combustion of the sample from the inside to the outside.

[0092] See also Fig. 9 The image of the flame structure is observed from the side. It can be seen that due to the effect of vortex injection, the flame structure presents a clear counterclockwise vortex effect. The flame swirls around the outer surface of the grain, greatly enhancing the contact time and contact efficiency between oxygen and the grain, which can achieve the effect of sufficient and uniform combustion of the sample from the outside to the inside.

[0093] Fig.10 (a) and (b) are images of the flame combustion structure without swirl intake. Fig.10 It can be seen from (a), (b), (c), and (d) that the flame does not show a swirl effect as it passes through the grain, and the combustion efficiency of the grain from the inside to the outside is lower than that of using a swirl nozzle.

[0094] See also Fig.11 , it can be seen that the radius changes relatively evenly over time without any point with large deviation.

[0095] See also Fig.12 ,It can be seen that the error analysis can draw a conclusion that the error fluctuation is small.

[0096] See also Fig.13 , it can be seen that the oxygen flow and pressure of the device are relatively stable.

[0097] See also Fig.14 In (a) and (b), it can be seen that the combustion diffuses outward evenly and only a small amount of impurities cover the surface when the combustion is terminated.

[0098] See also Fig.15 ,It can be seen that the device can process images of irregular samples with radius changing over time.

[0099] The present invention provides a movable chamber and a fixed chamber, so that the operation is simple and convenient. The replaceable sample table can realize different combustion tests for the same sample. The multiple windows are conducive to observing the combustion conditions in different directions. The PID pressure control device monitors the combustion chamber pressure in real time, and the exhaust pressure relief is achieved through the solenoid valve to maintain the internal pressure of the combustion chamber stable, thereby ensuring the stability of the pressure. The flame of the sample burning under stable pressure can be observed through transparent visual windows at multiple angles, and the vortex injector can make the sample fully contact with oxygen, etc.

[0100] Furthermore, in the present invention, a mobile cavity and a fixed cavity are provided, and a replaceable vortex injector, an electric ignition device, a modular sample table and an oxygen inlet transparent window are coupled to the mobile cavity. The mobile cavity improves the convenience and airtightness of charging, and also facilitates the maintenance of the gas path and parts; the fixed cavity is coupled with an oxygen inlet gas path, an oxygen shut-off valve, an oxygen mass flow meter, an oxygen filter, a one-way valve, a nitrogen inlet gas path, a nitrogen inlet valve, a nitrogen shut-off valve, an air inlet hole, a PID pressure control device, a safety valve and an exhaust pressure relief pipeline. The PID pressure control device provides a certain stable combustion chamber pressure for the combustion of the grain. The installation of the transparent windows in the axial and radial directions is conducive to high-speed photography of the combustion process of the grain, and is convenient for cleaning the combustion chamber after the combustion of the grain.

[0101] The end face of the moving cavity is provided with two NPT1 / 4 triangular cone-shaped center hole plugs, the center hole is sealed with a conical copper electrode, insulated with phenolic resin, and nickel-chromium wire is used to ignite steel wool for fuel ignition, which not only avoids the danger of laser ignition, but also improves the ignition stability.

[0102] Visual window and replaceable modular sample stage: The oxygen upper and gas outlet windows cooperate with the center hole equidistant sample stage to observe the combustion process of the front and rear end faces of the grain through high-speed photography, determine the burning rate difference and the grain dispersion process; the side window cooperates with the arm beam sample stage to observe the flame combustion boundary layer structure, realize the diversification of grain combustion and observation methods, facilitate the shooting and installation of high-speed photography, and increase the diversity of combustion methods.

[0103] In the present invention, a PID pressure control device is provided to control the electromagnetic valve to switch on and off quickly according to the internal pressure of the combustion chamber cavity, so that the internal pressure of the combustion chamber cavity fluctuates slightly above and below the set value, thereby improving the stability of combustion measurement;

[0104] The replaceable vortex injector is divided into four intake pipes which are perpendicular to each other and tangent to the central pipe through one oxygen pipe. It is an oxygen vortex intake, which increases the oxygen turbulence degree and the residence time in the central hole of the grain, compresses the thickness of the turbulent boundary layer of the grain, and significantly improves the withdrawal rate of the grain.

[0105] The combustion termination gas circuit is composed of multiple oxygen and nitrogen valves. The oxygen supply, fixed cavity pressurized nitrogen pipeline and nitrogen branch valve are controlled by an electronic switch. When the combustion is terminated, the electronic switch is turned off. At this time, the oxygen supply valve and the fixed cavity pressurized nitrogen pipeline valve are closed, and the nitrogen branch valve is opened. Nitrogen quickly enters the mobile cavity oxygen pipeline, causing the grain to stop burning quickly, significantly reducing the slow decomposition of the grain under hypoxia, retaining the completeness of the combustion surface, and facilitating the characterization of the grain combustion surface.

[0106] This method is not affected by the structure of the drug column and is suitable for testing various complex drug column shapes. It can measure the instantaneous thickness of the drug column and calculate the instantaneous recession rate of microseconds and above. The processed data is not affected by any external factors, and the processing is convenient and simple, and the results are accurate.

[0107] Four windows are set in the axial and radial directions. The combustion process of the front and rear end faces of the charge can be observed by testing the center hole charge, and the difference in burning rate and the dispersion process of the charge can be determined. The cantilever beam charge obtains its turbulent boundary layer flame structure. Simple electric ignition is used. The intake of the replaceable vortex nozzle increases the degree of oxygen turbulence and the retention time of contact with the charge. Terminating the combustion gas path significantly reduces the slow decomposition of the charge under hypoxia, retains the completeness of the combustion surface, and is conducive to the characterization of the combustion surface of the charge. The video processing algorithm is used to directly process the combustion video taken by high-speed photography to directly obtain the equivalent diameter-t curve and the recession rate-t curve. This method is not affected by the charge structure and is suitable for various complex charge shape tests. The instantaneous thickness of the charge can be measured and the instantaneous recession rate of microseconds and above can be calculated. The processed data is not affected by any external factors, and the processing is convenient and simple, and the results are accurate.

[0108] The above description is only for the best embodiment of the present invention, but it should not be understood as limiting the claims. The present invention is not limited to the above embodiments, and its specific structure is allowed to be changed. However, all changes made within the protection scope of the independent claims of the present invention are within the protection scope of the present invention.

[0109] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more related listed items.

Claims

1. A modular solid-liquid hybrid propellant combustion test device, characterized in that: It includes a high-pressure combustion chamber cavity; the high-pressure combustion chamber cavity includes a movable cavity and a fixed cavity that are connected; The movable chamber comprises a transparent window cover plate (1), an oxygen inlet transparent window (2), a vortex injector (3), a movable chamber cover plate (4), an electric ignition device (6) and a modular sample stage (9); An oxygen inlet window (2) is fixed at the front end of the vortex injector (3); a window cover plate (1) is arranged at the front end of the oxygen inlet window (2); a high-speed camera (28) is arranged on one side of the window cover plate (1); the vortex injector (3) is connected to a modular sample stage (9); a movable cavity cover plate (4) with an opening is arranged between the vortex injector (3) and the modular sample stage (9); and an electric ignition device (6) is arranged on the outside of the vortex injector (3).

2. The modular solid-liquid hybrid propellant combustion test device according to claim 1, characterized in that: A first flange joint (7) and a second flange structure (8) are provided between the vortex injector (3) and the modular sample platform (9), and the electric ignition device (6) comprises a nickel-chromium wire, one end of which extends into the center position between the second flange joint (8) and the modular sample platform (9), and the other end is located above the vortex injector (3).

3. The modular solid-liquid hybrid propellant combustion test device according to claim 1, characterized in that: The hollow space at the axial center of the moving cavity and the fixed cavity forms an axial oxygen passage (33).

4. The modular solid-liquid hybrid propellant combustion test device according to claim 1, characterized in that: A circular disc (5) with threads for connecting the fixed cavity and the movable cavity is arranged between the vortex injector (3) and the movable cavity cover plate (4).

5. The modular solid-liquid hybrid propellant combustion test device according to claim 1, characterized in that: The vortex injector (3) comprises a one-to-four joint, an oxygen intake pipeline (19) is connected to the one-to-four joint, there are (4) oxygen intake pipelines (19) which are perpendicular to each other, and the oxygen intake pipelines (19) are arranged tangentially to the internal channel of the vortex injector (3).

6. The modular solid-liquid hybrid propellant combustion test device according to claim 1, characterized in that: The oxygen intake pipeline (19) is connected in sequence via an oxygen stop valve (21), an oxygen mass flow meter (23), an oxygen filter (30), and a one-way valve (31); the one-way valve (31) and the nitrogen intake valve (24) are both connected to the vortex injector (3).

7. The modular solid-liquid hybrid propellant combustion test device according to claim 1, characterized in that: The fixed cavity comprises a combustion chamber cavity (10), an air inlet hole (11) is arranged at the top of the combustion chamber cavity (10), a sealing cover plate (15) is arranged at one end of the combustion chamber cavity (10), an exhaust pipeline (22) is arranged on the sealing cover plate (15), the exhaust pipeline (22) is connected to a water cooling module, and a solenoid valve (29) is arranged on one side of the exhaust pipeline (22); a gas outlet visual window (17) is arranged on one side of the sealing cover plate (15), and a perspective window cover plate (18) is arranged on the gas outlet visual window (17).

8. The modular solid-liquid hybrid propellant combustion test device according to claim 1, characterized in that: It also includes a nitrogen intake pipeline (20), the outlet of the nitrogen intake pipeline (20) is connected to a nitrogen shut-off valve (25), the nitrogen shut-off valve (25) is divided into three paths, one path is connected to the vortex injector (3) via the nitrogen intake valve (24), another path is connected to the combustion chamber cavity (10), and the third path is connected to the air intake valve (26), and the air intake valve (26) is connected to the air compressor (27); A pressure gauge (14), a PID pressure control device (12) and a safety valve (13) are installed on the combustion chamber cavity (10); and visual window holes (16) are provided on both sides of the combustion chamber cavity (10).

9. The modular solid-liquid hybrid propellant combustion test device according to claim 1, characterized in that: The modular sample stage (9) comprises a central hole drug sample stage for mounting drug with an outer diameter ranging from 10 to 35 mm; or The modular sample stage (9) comprises a cantilever beam drug column sample stage, and the cantilever beam drug column sample stage comprises a quartz glass tube for suspending a drug column with an inner and outer diameter ranging from 10 to 30 mm.

10. A modular solid-liquid mixed combustion test method, characterized in that: The following steps are involved: Ignite the propellant column on the modular sample stage through an electric ignition device to obtain the flame turbulence boundary layer combustion video of the propellant column; For the flame turbulence boundary layer combustion video of the propellant column, the video processing algorithm is used to identify the flame brightness of the combustion boundary layer and automatically calculate the combustion equivalent radius. Based on the combustion equivalent radius, the curve of the combustion equivalent radius changing with time and the curve of the recession rate changing with time are obtained to realize the combustion test.

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