An experimental apparatus for measuring the condensed phase distribution inside a single-sided expansion nozzle in rocket mode.

Abstract

This invention belongs to the field of rocket-based combined cycle engine testing technology. It discloses an experimental device for measuring the condensed phase distribution within a single-sided expansion nozzle under rocket mode. The device includes a two-phase flow gas generator connected to an ignition system. The two-phase flow gas generator simulates the rocket operating mode of a rocket-based combined cycle engine and generates high-pressure, high-temperature gas containing condensed phases. A single-sided expansion nozzle has its inlet end connected to the outlet end of the two-phase flow gas generator to receive the high-pressure, high-temperature gas containing condensed phases output by the two-phase flow gas generator. An optical measurement system is provided, with transparent windows on both the two-phase flow gas generator and the single-sided expansion nozzle. The optical measurement system performs non-contact measurement of the condensed phase particles inside the two-phase flow gas generator and the single-sided expansion nozzle through these transparent windows. This invention achieves visualized, non-contact measurement of the condensed phase particle distribution and particle size within the single-sided expansion nozzle, providing experimental data support for engine design and optimization.

Description

Technical Field

[0001] This invention belongs to the field of rocket-based combined cycle engine testing technology, and particularly relates to an experimental device for measuring the condensation distribution inside a single-sided expansion nozzle in rocket mode. Background Technology

[0002] As an asymmetric structure, the single-sided expansion nozzle, due to its shape, can directly utilize the rear body structure of the aircraft as an extension, effectively utilizing the lift of the rear body and significantly reducing the bottom drag and structural weight of the aircraft. It has become a key component for solving the high-efficiency exhaust requirements of rocket-based combined cycle engines under wide speed range and large airspace flight conditions.

[0003] When the core rocket of a rocket-based combined cycle engine is a solid rocket, the condensed particles generated by the combustion of metal additives in the solid propellant form a gas-solid two-phase mixture with the high-temperature, high-pressure combustion gas within the single-sided expansion nozzle. During engine operation, the hysteresis effect of the condensed particles on the combustion gas and the ablation effect on the nozzle wall directly affect the engine's thrust performance.

[0004] Accurately simulating rocket modes of rocket-based combined cycle engines and simultaneously observing the distribution and flow state of condensed particles within a single-sided expansion nozzle is crucial for engine design and optimization. However, traditional engine hot-fire tests often use nozzles with closed metal structures that lack effective optical observation windows. Experiments also typically employ contact-based measurement methods such as pressure sensors, force balances, or thermocouples, which can only acquire wall or overall performance parameters, failing to directly capture the internal flow field structure.

[0005] Therefore, there is an urgent need for an experimental device to measure the condensation distribution inside a single-sided expansion nozzle in rocket mode to solve the above problems. Summary of the Invention

[0006] The purpose of this invention is to provide an experimental apparatus for measuring the condensation distribution inside a single-sided expansion nozzle in rocket mode, so as to solve the problems existing in the prior art.

[0007] To achieve the above objectives, the present invention provides the following solution: The present invention provides an experimental apparatus for measuring the condensation distribution within a unilateral expansion nozzle in rocket mode, comprising: A two-phase flow gas generator is connected to an ignition system. The two-phase flow gas generator is used to simulate the rocket working mode of a rocket-based combined cycle engine and generate high-pressure, high-temperature gas containing condensation. A single-sided expansion nozzle, with its inlet end connected to the outlet end of the two-phase flow gas generator, is used to receive the high-pressure, high-temperature gas containing condensate output from the two-phase flow gas generator. The optical measurement system has transparent windows on both the two-phase flow gas generator and the single-sided expansion nozzle. The optical measurement system performs non-contact measurement of the condensed particles inside the two-phase flow gas generator and the single-sided expansion nozzle through the transparent windows.

[0008] According to the present invention, an experimental apparatus for measuring the condensed phase distribution inside a single-sided expansion nozzle in rocket mode is provided. The two-phase flow gas generator includes a generator outer shell, with end caps connected to both ends of the generator outer shell. Both ends of the generator outer shell are provided with a propellant chamber, which is connected by a chamber connecting column. Solid propellant is provided in the propellant chamber. The generator outer shell is connected to the single-sided expansion nozzle through a round-to-square connecting section. A pressure relief valve and a pressure measuring and drainage hole are installed on the generator outer shell, and a test tube seat is installed on the pressure measuring and drainage hole.

[0009] According to the present invention, an experimental apparatus for measuring the condensation distribution in a single-sided expansion nozzle in rocket mode is provided. The single-sided expansion nozzle includes a nozzle body, and side cover plates are fixedly connected to both sides of the nozzle body. The inlet end of the nozzle body is fixedly connected to the outlet flange on the round-to-square connecting section through an inlet flange. A single-sided expansion channel is provided inside the nozzle body.

[0010] According to the present invention, an experimental device for measuring the condensation distribution inside a single-sided expansion nozzle in rocket mode is provided, wherein a circular viewing window is provided on the outer shell of the generator. Both sides of the nozzle body are provided with side square viewing window grooves. A transparent side viewing window is installed in the side square viewing window groove. An inner sealing gasket of the side square viewing window is provided between the transparent side viewing window and the side square viewing window groove. An outer sealing gasket of the side viewing window is provided between the transparent side viewing window and the side cover plate. Multiple side bolt holes are provided around the side square viewing window groove. The side cover plate is connected to the side bolt holes by bolts.

[0011] According to the present invention, an experimental apparatus for measuring the condensed phase distribution inside a single-sided expansion nozzle in rocket mode is provided. The optical measurement system includes a high-speed camera system, a Malvern laser particle size analysis system, a pressure acquisition system, and a synchronous measurement and control computer. The high-speed camera system, the Malvern laser particle size analysis system, and the pressure acquisition system are electrically connected to the synchronous measurement and control computer.

[0012] According to the present invention, an experimental apparatus for measuring the condensation distribution inside a single-sided expansion nozzle in rocket mode is provided. The high-speed camera system includes a first high-speed camera and a second high-speed camera. The first high-speed camera's field of view corresponds to the circular window, and the second high-speed camera's field of view corresponds to the transparent side window.

[0013] According to the present invention, an experimental apparatus for measuring the condensed phase distribution inside a single-sided expansion nozzle in rocket mode is provided. The Malvern laser particle size analysis system includes a Malvern laser particle size analyzer signal transmitter and a Malvern laser particle size analyzer signal receiver. The Malvern laser particle size analyzer signal transmitter and the Malvern laser particle size analyzer signal receiver are respectively placed on both sides of the single-sided expansion nozzle via guide rails. The Malvern laser particle size analyzer signal transmitter is used to emit laser signals into the single-sided expansion nozzle, and the Malvern laser particle size analyzer signal receiver is used to receive the laser signals.

[0014] According to the present invention, an experimental apparatus for measuring the condensation distribution inside a single-sided expansion nozzle in rocket mode is provided. The pressure acquisition system includes a pressure sensor and a pressure signal acquisition instrument. The pressure sensor is installed on the generator housing and is sealed to the generator housing by a sealing gasket. The pressure sensor is electrically connected to the pressure signal acquisition instrument and the pressure signal acquisition instrument is electrically connected to a synchronous measurement and control computer.

[0015] According to the present invention, an experimental apparatus for measuring the condensed phase distribution inside a single-sided expansion nozzle in rocket mode is provided. The ignition system includes an ignition charge, an ignition wire, an igniter, and an ignition power supply. The ignition charge is disposed on the surface of the solid propellant charge. The igniter is connected to the ignition power supply through the ignition wire. The ignition power supply is electrically connected to the synchronous measurement and control computer.

[0016] According to the present invention, an experimental apparatus for measuring the condensation distribution inside a single-sided expansion nozzle in rocket mode is provided, wherein the circular viewing window and the transparent side viewing window are both made of quartz glass.

[0017] Compared with the prior art, the present invention has the following advantages and technical effects: This invention provides an experimental apparatus for measuring the condensed phase distribution within a single-sided expansion nozzle in rocket mode. By combining a two-phase flow gas generator and a single-sided expansion nozzle, it realistically simulates the operating state of a rocket-based combined cycle engine in solid rocket mode. Transparent windows are installed at two key locations, combined with an optical measurement system, enabling full-process, non-contact visualization of condensed phase particles inside the gas generator and nozzle. This provides a hardware foundation for studying the generation, transport, and distribution of condensed phase particles. This invention achieves visualized, non-contact measurement of the distribution and particle size of condensed phase particles within a single-sided expansion nozzle in rocket mode, providing crucial experimental data support for engine design and optimization. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a schematic diagram showing the connection state between the two-phase flow gas generator and the single-sided expansion nozzle of the present invention; Figure 2 This is a schematic diagram of the internal structure of the two-phase flow gas generator and the single-sided expansion nozzle of the present invention; Figure 3 This is an exploded view of the internal structure of the two-phase flow gas generator and the single-sided expansion nozzle of the present invention. Figure 4 This is a schematic diagram showing the location of the high-speed camera system of the present invention; Figure 5 This is a schematic diagram showing the location of the Malvern laser particle size analysis system of the present invention; The components include: 1. Two-phase flow gas generator; 1-01. Round-to-square connecting section; 1-02. Generator outer shell; 1-03. End cap; 1-04. Insulation sleeve; 1-05. Charge chamber; 1-06. Chamber connecting column section; 1-07. Solid propellant charge; 1-08. Pressure relief valve; 1-09. Pressure testing and drainage hole; 1-10. Pressure test tube seat; 1-11. Sealing gasket; 1-12. Circular viewing window; 1-13. Outlet flange; 2. Single-sided expansion nozzle; 2-01. Nozzle body; 2-02. Transparent side viewing window; 2-03. Side cover plate; 2-04. Inlet flange; 2-05. Single-sided expansion channel; 2-06. Side square viewing window groove; 2-07. Side viewing window inner sealing gasket; 2-08. 1. Side window outer sealing gasket; 2-09. Side bolt holes; 3. Ignition system; 3-01. Ignition charge; 3-02. Ignition wire; 3-03. Ignition device; 3-04. Ignition power supply; 4. High-speed camera system; 4-01. First high-speed camera; 402. Field of view of the first high-speed camera; 4-03. Second high-speed camera; 404. Field of view of the second high-speed camera; 5. Malvern laser particle size analysis system; 5-01. Malvern laser particle size analyzer signal transmitter; 5-02. Malvern laser particle size analyzer signal receiver; 5-03. Malvern laser particle size analyzer laser signal; 5-04. Guide rail; 6. Pressure acquisition system; 6-01. Pressure sensor; 6-02. Pressure signal acquisition instrument; 7. Synchronous measurement and control computer. Detailed Implementation

[0020] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0021] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0022] Reference Figures 1-5 This invention provides an experimental apparatus for measuring the condensation distribution within a single-sided expansion nozzle in rocket mode, comprising: Two-phase flow gas generator 1 is connected to ignition system 3. Two-phase flow gas generator 1 is used to simulate the rocket working mode of rocket-based combined cycle engine and generate high-pressure and high-temperature gas containing condensation phase. The single-sided expansion nozzle 2 has its inlet end connected to the outlet end of the two-phase flow gas generator 1, and is used to receive the high-pressure, high-temperature gas containing condensate output from the two-phase flow gas generator 1. The optical measurement system has transparent windows on both the two-phase flow gas generator 1 and the single-sided expansion nozzle 2. The optical measurement system performs non-contact measurement of the condensed particles inside the two-phase flow gas generator 1 and the single-sided expansion nozzle 2 through the transparent windows.

[0023] In one embodiment of the present invention, by setting up a combined structure of a two-phase flow gas generator and a single-sided expansion nozzle, the working state of a rocket-based combined cycle engine in solid rocket mode can be realistically simulated; transparent windows are set at two key locations, and combined with an optical measurement system, the entire process of non-contact visualization observation of condensed particles inside the gas generator and nozzle is realized, providing a hardware foundation for studying the generation, transport and distribution laws of condensed particles.

[0024] As an optional implementation, the two-phase flow gas generator 1 includes a generator housing 1-02, with end caps 1-03 connected to both ends of the generator housing 1-02. Both ends of the generator housing 1-02 are provided with charging chambers 1-05, which are connected by a chamber connecting column 1-06. Solid propellant charges 1-07 are provided inside the charging chambers 1-05. The generator housing 1-02 is connected to a single-sided expansion nozzle 2 via a round-to-square connecting section 1-01. A pressure relief valve 1-08 and a pressure measuring and guiding hole 1-09 are installed on the generator housing 1-02, and a test tube seat 1-10 is installed on the pressure measuring and guiding hole 1-09.

[0025] In one embodiment of the present invention, the main body of the two-phase flow gas generator 1 is a generator housing 1-02, which is connected to an end cap 1-03 by bolts and nuts. The end cap 1-03 has an annular boss on the engine housing side, with threaded holes along its circumferential edge to mate with an annular groove on the head of the generator housing. An O-ring is added to the gap during mating for sealing. An insulating sleeve 1-04 is installed inside the generator housing 1-02 to provide thermal protection for the metal housing and improve the generator's high-temperature resistance during experiments. The two-phase flow gas generator contains two propellant charging chambers 1-05 (left and right), connected by a chamber connecting column 1-06. Each charging chamber contains a solid propellant charge 1-07. A pressure relief valve 1-08 is installed on the generator housing 1-02 for pressure relief protection in case of engine malfunction. The generator housing 1-02 is equipped with a pressure testing and drainage hole 1-09, and a pressure test tube seat 1-10 is connected to the pressure testing and drainage hole by thread.

[0026] As an optional implementation, the single-sided expansion nozzle 2 includes a nozzle body 2-01, with side cover plates 2-03 fixedly connected to both sides of the nozzle body 2-01. The inlet end of the nozzle body 2-01 is fixedly connected to the outlet flange 1-13 on the round-to-square connecting section 1-01 through the inlet flange 2-04. A single-sided expansion channel 2-05 is provided inside the nozzle body 2-01.

[0027] In one embodiment of the present invention, the nozzle body 2-01 contains a single-sided expansion channel 2-05 with a semi-bell-shaped surface of a "convergence-expansion" structure. The high-pressure, high-temperature gas containing condensate generated by the two-phase flow gas generator 1 enters the single-sided expansion channel 2-05 through the inlet flange 2-04 and is accelerated, achieving the experimental effect of condensate distribution in the single-sided expansion nozzle in the simulated solid rocket mode.

[0028] As an optional implementation, a circular viewing window 1-12 is provided on the generator housing 1-02; Both sides of the nozzle body 2-01 are provided with side square viewing window grooves 2-06. A transparent side viewing window 2-02 is installed in the side square viewing window grooves 2-06. An inner sealing gasket 2-07 of the side square viewing window is provided between the transparent side viewing window 2-02 and the side square viewing window grooves 2-06. An outer sealing gasket 2-08 of the side viewing window is provided between the transparent side viewing window 2-02 and the side cover plate 2-03. Multiple side bolt holes 2-09 are provided around the side square viewing window grooves 2-06. The side cover plate 2-03 is connected to the side bolt holes 2-09 by bolts.

[0029] In one embodiment of the present invention, a circular viewing window 1-12 is installed on the chamber connecting column section 1-06 of the two-phase flow gas generator. A square viewing window groove 2-06 is located on each side of the single-sided expansion channel 2-05. A transparent side viewing window 2-02, containing a single-sided expansion nozzle profile step, is embedded in the square viewing window groove 2-06 and is positioned and sealed by an inner sealing gasket 2-07, and positioned and sealed to the side cover plate 2-03 by an outer sealing gasket 2-08. Several side bolt holes 2-09 are arranged around the square viewing window groove 2-06 along the nozzle profile, connecting it to the side cover plate 2-03 by bolts. Simultaneously, the compression gasket enhances the sealing effect.

[0030] As an optional implementation, the optical measurement system includes a high-speed camera system 4, a Malvern laser particle size analysis system 5, a pressure acquisition system 6, and a synchronous measurement and control computer 7, wherein the high-speed camera system 4, the Malvern laser particle size analysis system 5, and the pressure acquisition system 6 are electrically connected to the synchronous measurement and control computer 7.

[0031] In one embodiment of the present invention, a synchronous measurement and control computer is used to realize the collaborative work of multiple systems, ensuring that the measurement data are strictly synchronized in time, thus providing a data foundation for subsequent analysis of the intrinsic relationship between condensed particle distribution and flow characteristics.

[0032] As an optional implementation, the high-speed camera system 4 includes a first high-speed camera 4-01 and a second high-speed camera 4-03. The first high-speed camera field of view 4-02 of the first high-speed camera 4-01 corresponds to the circular window 1-12, and the second high-speed camera field of view 4-04 of the second high-speed camera 4-03 corresponds to the transparent side window 2-02.

[0033] In one embodiment of the present invention, during the experiment, a first high-speed camera 4-01 is placed to the side of the circular viewing window 1-12 of the two-phase flow gas generator, at a distance of 0.5 meters from the two-phase flow gas generator 1. The field of view 4-02 of the first high-speed camera covers the entire area of ​​the circular viewing window 1-12, and is used to observe the distribution of condensed phase in the two-phase flow gas generator during the experiment. A second high-speed camera 4-03 is placed to the side of the transparent side viewing window 2-02 of the single-sided expansion nozzle, at a distance of 0.5 meters from the single-sided expansion nozzle 2. The field of view 4-04 of the second high-speed camera covers the entire area of ​​the transparent side viewing window 2-02, and is used to observe the distribution of condensed phase in the single-sided expansion nozzle during the experiment. During the experiment, the high-speed camera captures images of the condensed phase in the flow field in real time, and the image data is input to the synchronous measurement and control computer 7 through a signal transmission line. The analysis software in the synchronous measurement and control computer 7 further analyzes the particle distribution and particle size.

[0034] As an optional implementation, the Malvern laser particle size analysis system 5 includes a Malvern laser particle size analyzer signal transmitter 5-01 and a Malvern laser particle size analyzer signal receiver 5-02. The Malvern laser particle size analyzer signal transmitter 5-01 and the Malvern laser particle size analyzer signal receiver 5-02 are respectively placed on both sides of the single-sided expansion nozzle 2 via guide rails 5-04. The Malvern laser particle size analyzer signal transmitter 5-01 is used to emit laser signals 5-03 into the single-sided expansion nozzle 2, and the Malvern laser particle size analyzer signal receiver 5-02 is used to receive laser signals 5-03.

[0035] In one embodiment of the present invention, the laser signal 5-03 emitted by the signal transmitter 5-01 of the Malvern laser particle size analyzer is diffracted on the surface of the condensed particles in the single-sided expansion channel 2-05 and then enters the signal receiver 5-02 of the Malvern laser particle size analyzer. The receiver tracks and records the angle change of the diffracted light when the laser passes through the condensed particles, and the analysis software in the synchronous measurement and control computer 7 further analyzes the particle size.

[0036] As an optional implementation, the pressure acquisition system 6 includes a pressure sensor 6-01 and a pressure signal acquisition device 6-02. The pressure sensor 6-01 is mounted on the generator housing 1-02, and the pressure sensor 6-01 and the generator housing 1-02 are sealed by a sealing gasket 1-11. The pressure sensor 6-01 is electrically connected to the pressure signal acquisition device 6-02, and the pressure signal acquisition device 6-02 is electrically connected to the synchronous measurement and control computer 7.

[0037] In one embodiment of the present invention, the internal ballistic characteristics of the engine during operation can be obtained by real-time monitoring of the internal pressure of the gas generator by pressure sensor 6-01.

[0038] As an optional implementation, the ignition system 3 includes an ignition charge 3-01, an ignition wire 3-02, an igniter 3-03, and an ignition power supply 3-04. The ignition charge 3-01 is disposed on the surface of the solid propellant charge 1-07. The igniter 3-03 is connected to the ignition power supply 3-04 via the ignition wire 3-02. The ignition power supply 3-04 is electrically connected to the synchronous measurement and control computer 7.

[0039] In one embodiment of the present invention, the ignition system 3 is connected to the synchronous measurement and control computer 7, which can realize remote automatic ignition and improve the safety of experimental operations.

[0040] As an optional implementation, both the circular viewing window 1-12 and the transparent side viewing window 2-02 are made of quartz glass.

[0041] In one embodiment of the present invention, the quartz glass has good high temperature resistance and optical transmittance, and can maintain structural integrity and optical clarity in a high temperature and high pressure gas environment, ensuring that the optical measurement system can obtain high-quality image and signal data.

[0042] In one embodiment of the present invention, the specific experimental method for conducting experiments on the experimental device using a high-speed camera system is as follows: Step 1: After assembling the experimental apparatus, build the ignition system according to the connection relationship of the ignition system, build the high-speed camera system according to the connection relationship of the high-speed camera system, and build the pressure acquisition system according to the connection relationship of the pressure acquisition system.

[0043] Step 2: Run the synchronous measurement and control computer; debug the high-speed camera system, set the camera resolution and exposure time according to the specific experimental conditions, adjust the aperture, focus, image correction, and image white balance of the high-speed camera, and calibrate the size of the shooting field of view; debug the pressure acquisition system and balance and zero the pressure signal value.

[0044] Step 3: After verifying that the above-mentioned data acquisition equipment is connected correctly, connect the ignition wire between the ignition charge and the ignition power supply; debug the synchronous measurement and control software to ensure that the ignition system, high-speed camera system and pressure acquisition system are in a synchronous external trigger state.

[0045] Step 4: Start the experiment by turning on the ignition power supply to ignite the solid propellant in the two-phase flow gas generator, simulating the solid rocket mode of a rocket-based combined cycle engine; simultaneously acquire images from the high-speed camera system and acquire ballistic pressure in the two-phase flow gas generator through the synchronous measurement and control computer.

[0046] Step 5: Once the solid propellant in the two-phase flow gas generator has burned out, the experiment is complete. Disconnect the ignition power supply and, through the synchronous measurement and control computer, stop the image acquisition of the high-speed camera system and the ballistic pressure acquisition of the two-phase flow gas generator in the pressure acquisition system.

[0047] Step Six: Operate the built-in software of the high-speed camera system to output image data of the sampling area; operate the built-in software of the pressure acquisition system to output internal ballistic pressure data; save the image data results and internal ballistic pressure data results.

[0048] Step 7: Disassemble the experimental setup, clean the solid propellant charge residue inside the two-phase flow gas generator, and replace the insulation sleeve, O-ring, and circular viewing window of the two-phase flow gas generator; clean the solid propellant charge residue inside the single-sided expansion nozzle, and replace the transparent side viewing window, the inner sealing gasket of the side viewing window, and the outer sealing gasket of the side viewing window.

[0049] Step 8: Remove the pressure sensor from the generator housing and recalibrate it; wipe the lenses of high-speed camera one and high-speed camera two; replace the solid propellant charge, repeat the test, and analyze the experimental results.

[0050] In one embodiment of the present invention, the specific experimental method for conducting experiments on the experimental apparatus using a Malvern laser particle size analysis system is as follows: Step 1: After assembling the experimental apparatus, build the ignition system according to the connection relationship of the ignition system, build the Malvern laser particle size analysis system according to the connection relationship of the Malvern laser particle size analysis system, and build the pressure acquisition system according to the connection relationship of the pressure acquisition system.

[0051] Step 2: Run the synchronous measurement and control computer; debug the lenses of the laser emitter and laser receiver of the Malvern laser particle size analysis system until the lenses of the laser emitter and laser receiver are at the same horizontal position and angle, and at the same time make the laser beam path perpendicular to the flow channel of the single-sided expansion nozzle, and control the particle size analysis software to zero-calibrate the floating dust in the environment; debug the pressure acquisition system and balance and zero the pressure signal value.

[0052] Step 3: After verifying that the above-mentioned data acquisition equipment is connected correctly, connect the ignition wire between the ignition charge and the ignition power supply; debug the synchronous measurement and control software to ensure that the ignition system, Malvern laser particle size analysis system and pressure acquisition system are in a synchronous external trigger state.

[0053] Step 4: Start the experiment by turning on the ignition power supply to ignite the solid propellant in the two-phase flow gas generator, simulating the solid rocket mode of a rocket-based combined cycle engine; simultaneously collect condensed particle size data from the Malvern laser particle size analysis system and ballistic pressure data from the two-phase flow gas generator using the pressure acquisition system through the synchronous measurement and control computer.

[0054] Step 5: After the solid propellant in the two-phase flow gas generator has burned out, the experiment ends. Disconnect the ignition power supply and stop the condensation particle size acquisition of the Malvern laser particle size analysis system and the ballistic pressure acquisition in the two-phase flow gas generator of the pressure acquisition system through the synchronous measurement and control computer.

[0055] Step 6: Operate the built-in software of the Malvern laser particle size analysis system to output the condensed particle size data at the measurement point; operate the built-in software of the pressure acquisition system to output the internal ballistic pressure data; save the condensed particle size data results and the internal ballistic pressure data results.

[0056] Step 7: Disassemble the experimental setup, clean the solid propellant charge residue inside the two-phase flow gas generator, and replace the insulation sleeve, O-ring, and circular viewing window of the two-phase flow gas generator; clean the solid propellant charge residue inside the single-sided expansion nozzle, and replace the transparent side viewing window, the inner sealing gasket of the side viewing window, and the outer sealing gasket of the side viewing window.

[0057] Step 8: Remove the pressure sensor from the generator housing and recalibrate it; wipe the lenses of the laser emitter and receiver of the Malvern laser particle size analyzer system; replace the solid propellant charge; adjust the position of the laser emitter and receiver of the Malvern laser particle size analyzer system, repeat the experiment, obtain the particle size of the condensed phase in different regions of the nozzle, and analyze the experimental results.

[0058] In one embodiment of the present invention, particle classification and particle size calculation are performed on flow field image data at a specific moment during the experiment. The specific operation method is as follows: Step 1: Calculate the average background of the image and subtract the background from the current image to eliminate the fixed interference of wall reflections or window stains from the single-sided expansion nozzle and extract the core area of ​​the flow field.

[0059] Step 2: Locate potential condensed particle centers within the core region. Use the local maximum algorithm to scan the image, set a low global grayscale threshold, treat all connected bright pixels as a spot, and preliminarily determine the grayscale weighted centroid of each spot.

[0060] Step 3: For each detected spot, extract the grayscale value of the center pixel and analyze the rate of change of the difference between the center pixel and its surrounding neighboring pixels. Classify and label the spots: spots with a saturated center pixel and surrounding pixels exhibiting Gaussian decay are defined as Type 1; spots with an unsaturated center pixel but significantly higher than the background noise level and a clear grayscale gradient, and surrounding pixels exhibiting a point spread function pattern are defined as Type 2; spots with no clear grayscale gradient, chaotic or diffuse pixel distribution, and unable to form a focal point are defined as Type 3.

[0061] Step 4: Perform binary segmentation on condensed particles according to different spot types. For saturated particles that meet the characteristics of type 1, use the maximum gradient-based thresholding method. Calculate the first derivative of each pixel in the single particle image to find the position with the maximum gradient value, and view the original gray value corresponding to that position as the threshold. For unsaturated particles that meet the characteristics of type 2, use the 50% peak value thresholding method, i.e., take half of the particle's peak gray value as the threshold. For similar noise particles that meet the characteristics of type 3, set a lower threshold and directly remove spots below this value, excluding them from the calculation.

[0062] Step 5: Based on the threshold segmentation results, and using the equivalent diameter of the circle area, calculate the particle size of the condensed particles within the core region. Compare the particle size calculations obtained from the high-speed camera system and the Malvern laser particle size analysis system for verification.

[0063] In the description of this invention, it should be understood that the terms "longitudinal", "lateral", "up", "down", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this invention, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention.

[0064] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. An experimental apparatus for measuring the condensed phase distribution within a unilateral expansion nozzle in rocket mode, characterized in that, include: A two-phase flow gas generator (1) is connected to an ignition system (3). The two-phase flow gas generator (1) is used to simulate the rocket working mode of a rocket-based combined cycle engine and generate high-pressure, high-temperature gas containing condensation. The single-sided expansion nozzle (2) is connected at its inlet end to the outlet end of the two-phase flow gas generator (1) and is used to receive the high-pressure, high-temperature gas containing condensate output from the two-phase flow gas generator (1). The optical measurement system is provided with transparent windows on both the two-phase flow gas generator (1) and the single-sided expansion nozzle (2). The optical measurement system performs non-contact measurement of the condensed particles inside the two-phase flow gas generator (1) and the single-sided expansion nozzle (2) through the transparent windows.

2. The experimental apparatus for measuring the condensed phase distribution inside a single-sided expansion nozzle in rocket mode according to claim 1, characterized in that: The two-phase flow gas generator (1) includes a generator housing (1-02), with end caps (1-03) connected to both ends of the generator housing (1-02). Both ends of the generator housing (1-02) are provided with a charging chamber (1-05), and the two charging chambers (1-05) are connected by a chamber connecting column section (1-06). Solid propellant charges (1-07) are provided in the charging chambers (1-05). The generator housing (1-02) is connected to the single-sided expansion nozzle (2) through a round-to-square connecting section (1-01). A pressure relief valve (1-08) and a pressure measuring and drainage hole (1-09) are installed on the generator housing (1-02), and a pressure test tube seat (1-10) is installed on the pressure measuring and drainage hole (1-09).

3. The experimental apparatus for measuring the condensation distribution within a single-sided expansion nozzle in rocket mode according to claim 2, characterized in that: The single-sided expansion nozzle (2) includes a nozzle body (2-01), and side cover plates (2-03) are fixedly connected to both sides of the nozzle body (2-01). The inlet end of the nozzle body (2-01) is fixedly connected to the outlet flange (1-13) on the round-to-square connecting section (1-01) through the inlet flange (2-04). A single-sided expansion channel (2-05) is provided inside the nozzle body (2-01).

4. The experimental apparatus for measuring the condensation distribution within a single-sided expansion nozzle in rocket mode according to claim 3, characterized in that: A circular viewing window (1-12) is provided on the outer casing (1-02) of the generator. The nozzle body (2-01) has square side window grooves (2-06) on both sides. A transparent side window (2-02) is installed in the square side window groove (2-06). An inner sealing gasket (2-07) is provided between the transparent side window (2-02) and the square side window groove (2-06). An outer sealing gasket (2-08) is provided between the transparent side window (2-02) and the side cover plate (2-03). Multiple side bolt holes (2-09) are provided around the square side window groove (2-06). The side cover plate (2-03) is connected to the side bolt holes (2-09) by bolts.

5. The experimental apparatus for measuring the condensed phase distribution inside a single-sided expansion nozzle in rocket mode according to claim 4, characterized in that: The optical measurement system includes a high-speed camera system (4), a Malvern laser particle size analysis system (5), a pressure acquisition system (6), and a synchronous measurement and control computer (7). The high-speed camera system (4), the Malvern laser particle size analysis system (5), and the pressure acquisition system (6) are electrically connected to the synchronous measurement and control computer (7).

6. The experimental apparatus for measuring the condensed phase distribution inside a single-sided expansion nozzle in rocket mode according to claim 5, characterized in that: The high-speed camera system (4) includes a first high-speed camera (4-01) and a second high-speed camera (4-03). The first high-speed camera field of view (4-02) of the first high-speed camera (4-01) corresponds to the circular window (1-12), and the second high-speed camera field of view (4-04) of the second high-speed camera (4-03) corresponds to the transparent side window (2-02).

7. The experimental apparatus for measuring the condensation distribution within a single-sided expansion nozzle in rocket mode according to claim 5, characterized in that: The Malvern laser particle size analysis system (5) includes a Malvern laser particle size analyzer signal transmitter (5-01) and a Malvern laser particle size analyzer signal receiver (5-02). The Malvern laser particle size analyzer signal transmitter (5-01) and the Malvern laser particle size analyzer signal receiver (5-02) are respectively placed on both sides of the single-sided expansion nozzle (2) via guide rails (5-04). The Malvern laser particle size analyzer signal transmitter (5-01) is used to emit laser signals (5-03) to the single-sided expansion nozzle (2), and the Malvern laser particle size analyzer signal receiver (5-02) is used to receive the laser signals (5-03).

8. The experimental apparatus for measuring the condensed phase distribution inside a single-sided expansion nozzle in rocket mode according to claim 5, characterized in that: The pressure acquisition system (6) includes a pressure sensor (6-01) and a pressure signal acquisition instrument (6-02). The pressure sensor (6-01) is installed on the generator housing (1-02), and the pressure sensor (6-01) and the generator housing (1-02) are sealed by a sealing gasket (1-11). The pressure sensor (6-01) is electrically connected to the pressure signal acquisition instrument (6-02), and the pressure signal acquisition instrument (6-02) is electrically connected to the synchronous measurement and control computer (7).

9. The experimental apparatus for measuring the condensed phase distribution inside a single-sided expansion nozzle in rocket mode according to claim 5, characterized in that: The ignition system (3) includes an ignition charge (3-01), an ignition wire (3-02), an igniter (3-03), and an ignition power supply (3-04). The ignition charge (3-01) is disposed on the surface of the solid propellant charge (1-07). The igniter (3-03) is connected to the ignition power supply (3-04) through the ignition wire (3-02). The ignition power supply (3-04) is electrically connected to the synchronous measurement and control computer (7).

10. The experimental apparatus for measuring the condensed phase distribution inside a single-sided expansion nozzle in rocket mode according to claim 4, characterized in that: Both the circular viewing window (1-12) and the transparent side viewing window (2-02) are made of quartz glass.

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