Combustion component stability identification test system and method based on high-frequency adjustable hydraulic excitation

Abstract

The present invention provides a combustion component stability identification test system and method based on high-frequency adjustable hydraulic excitation, which is used to solve the technical problem that the existing method of directly applying pulse gun excitation to the combustion chamber cannot accurately obtain the stability response of the combustion component to the excitation when the corresponding combustion instability occurs. The present invention provides a combustion component stability identification test system based on high-frequency adjustable hydraulic excitation, and sets a hydraulic exciter on the oxidizer pipeline. The frequency of the pressure pulsation is adjusted by controlling the excitation frequency of the hydraulic exciter at different times, and the amplitude of the pressure pulsation is adjusted by adjusting the regulating valve on the throttle throat structure. At the same time, a multi-measurement point scheme is adopted to take the pulsating pressure of the oxidizer head cavity inlet pipeline as input, the pulsating pressure in the combustion chamber and the vibration acceleration of the combustion component as target control quantities, and analyze the response function of the combustion component vibration to the inlet hydraulic excitation, so as to achieve quantitative analysis of the stability of the combustion component.

Description

Technical Field

[0001] The present invention relates to a combustion component stability identification test system and method, and in particular to a combustion component stability identification test system and method based on high-frequency adjustable hydraulic excitation. Background Art

[0002] Combustion instability is a major problem plaguing liquid rocket engines. While extensive research has yielded valuable guidance for engineering improvements or design ideas, the stability of these improvements still requires testing. However, due to the random nature of combustion instability, it's difficult to determine whether engine stability meets requirements based on the results of a single engine test, whether it's a combustion component or a complete engine test. Currently, engine stability assessment methods still primarily rely on statistical analysis of multiple test results. However, testing liquid rocket engines, especially high-thrust liquid rocket engines, often requires significant propellant consumption, making individual tests extremely costly and challenging to conduct.

[0003] To increase the probability of combustion instability, current methods often involve opening holes in the combustion chamber head or body and directly applying pulse gun excitation to the combustion chamber during operation. This method then assesses the stability of the combustion component and provides engine stability results. Pulse gun excitation is generally achieved using the impact of igniting high-energy solid propellant. This method has a very short excitation time, typically on the order of 0.001 to 0.1 seconds. Its excitation frequency is a superposition of broadband excitations, resulting in low frequency division energy, and the excitation time and frequency are uncontrollable. When medium- and high-frequency combustion instabilities occur, the combustion component often exhibits a characteristic frequency, and the excitation frequency significantly influences the probability of combustion instability. Furthermore, the excitation time and energy also significantly influence the probability of combustion instability. Therefore, the existing method of directly applying pulse gun excitation to the combustion chamber cannot accurately determine the stability response of the combustion component to excitation when combustion instability occurs. Summary of the Invention

[0004] The purpose of the present invention is to solve the technical problem that the existing method of directly applying pulse gun excitation to the combustion chamber cannot accurately obtain the stability response of the combustion component to the excitation when the corresponding combustion instability occurs, and to provide a combustion component stability identification test system and method based on high-frequency adjustable hydraulic excitation.

[0005] In order to achieve the above object, the technical solution provided by the present invention is as follows:

[0006] A combustion assembly stability evaluation test system based on high-frequency adjustable hydraulic excitation, comprising a combustion chamber, an oxidizer head chamber, and a fuel head chamber, each connected to the combustion chamber. The combustion assembly is characterized in that it includes an oxidizer line, a fuel line, a gas working assembly, two pressure sensors, an acceleration sensor, an actuator control system, and a test bench control system.

[0007] The inlet of the oxidizer pipeline is used to receive external oxidizer, and the outlet is connected to the oxidizer head cavity. A hydraulic actuator and an oxidizer control valve are sequentially arranged on the pipeline along the oxidizer flow direction; the position of the oxidizer pipeline corresponding to the outlet of the hydraulic actuator is provided with a throttle throat structure, and a regulating valve is provided on the throttle throat structure; the inlet of the fuel pipeline is used to receive external fuel, and the outlet is connected to the fuel head cavity. A fuel control valve is provided on the pipeline;

[0008] The gas working component is arranged at the nozzle of the combustion chamber to simulate the combustion component chamber pressure and acoustic cavity environment;

[0009] The two pressure sensors are respectively installed on the inlet pipe of the oxidizer head cavity and the side wall of the combustion chamber; the acceleration sensor is installed on the side wall of the combustion chamber or the oxidizer head cavity or the fuel head cavity to measure the vibration acceleration of the combustion assembly;

[0010] The test bench control system is electrically connected to a pressure sensor and an acceleration sensor, respectively, and is used to collect the pulsating pressure in the oxidizer head cavity inlet pipeline and the combustion chamber, as well as the vibration acceleration of the combustion assembly in real time. The pulsating pressure in the oxidizer head cavity inlet pipeline is used as input, and the pulsating pressure in the combustion chamber and the vibration acceleration of the combustion assembly are used as target control quantities. The response function of the vibration of the combustion assembly to the inlet pulsating pressure is analyzed, and the combustion stability of the combustion assembly is quantitatively analyzed.

[0011] The test bench control system is communicatively connected to the exciter control system for sending the initial excitation time to the exciter control system; the exciter control system is electrically connected to the hydraulic exciter for controlling the excitation start time and the excitation frequency of the hydraulic exciter at different times.

[0012] Furthermore, the hydraulic exciter includes an exciter housing, a grid impeller, a magnetic coupling mechanism, and a drive motor;

[0013] The grid impeller is disposed in the exciter housing and includes a central rotating shaft and an impeller housing connected to the central rotating shaft. The impeller housing is a cylindrical structure, and a plurality of axially extending wedge-shaped grooves are uniformly distributed on its sidewall in the circumferential direction. The plurality of wedge-shaped grooves are radial through grooves, and their smaller diameter ends are all located on the outer sidewall of the impeller housing, so that the outer sidewall of the impeller housing forms a grid structure.

[0014] An inlet and an outlet are provided on the side wall of the actuator housing, and the actuator is connected to the oxidant pipeline through the inlet and the outlet;

[0015] The magnetic coupling mechanism is located outside the exciter housing, and the output end is fixedly connected to the central shaft, and is used to drive the grille impeller to rotate;

[0016] The driving end of the driving motor is connected to the input end of the magnetic coupling mechanism for controlling the operation of the magnetic coupling mechanism;

[0017] The exciter control system is electrically connected to the drive motor.

[0018] Furthermore, the exciter control system includes an exciter control unit and an exciter controller;

[0019] The exciter control unit is used to convert the initial excitation moment sent by the test bench control system into an initial trigger signal, and send the initial trigger signal and the internally stored excitation mode, frequency and duration to the exciter controller;

[0020] The exciter controller is connected to the exciter control unit via a network cable, and is used to convert the received excitation mode, frequency, and duration into a time-frequency sequence and store it. According to the received initial trigger signal and time-frequency sequence, it controls the excitation start time of the hydraulic exciter and the excitation frequency at different times.

[0021] Furthermore, the actuator controller adopts a high-speed negative feedback control system, and the negative feedback operation cycle is set to 10ms, which is equipped with a memory, a timer, an fn conversion module, a differentiator and a driving unit;

[0022] The input end of the memory is connected to the first output end of the exciter control unit, and is used to receive the excitation mode, frequency, and duration, and convert them into a time-frequency sequence for storage;

[0023] The input end of the timer is connected to the second output end of the exciter control unit, and is used to receive the initial trigger signal and start timing at the moment of receiving;

[0024] The input end of the fn conversion module is connected to the output end of the memory and the output end of the timer, and is used to obtain the target excitation frequency from the time-frequency sequence of the memory according to the time information of the timer, and convert the target excitation frequency into the target speed of the motor;

[0025] The first input end of the differentiator is connected to the output end of the fn conversion module, and the second input end is connected to the motor actual speed output port of the hydraulic actuator, and is used to perform a differential operation between the motor target speed and the motor actual speed;

[0026] The input end of the driving unit is connected to the output end of the differentiator, and is used to control the motor speed of the hydraulic actuator according to the differential operation result.

[0027] Furthermore, pressure sensors are respectively provided at the outlet position of the hydraulic actuator, the oxidant head cavity and the fuel head cavity to assist in monitoring the working state of the combustion component and further analyze the combustion stability of the combustion component.

[0028] Furthermore, pressure sensors are respectively provided on the inlet pipeline of the oxidant pipeline and the inlet pipeline of the fuel pipeline, for accurately controlling the inlet flow rates of the fuel and the oxidant respectively according to the inlet pressures of the fuel and the oxidant.

[0029] Furthermore, a first cavitation tube is provided in the oxidant pipeline near the inlet of the hydraulic actuator.

[0030] A second cavitation tube is provided in the fuel pipeline between the fuel head cavity and the fuel control valve, which can effectively shield the influence of the pressure pulsation generated by the hydraulic actuator on the flow of oxidant and fuel.

[0031] Furthermore, it also includes two solenoid valves; the two solenoid valves are used to control the opening and closing of the oxidant control valve and the fuel control valve respectively;

[0032] The test bench control system is communicatively connected to the two solenoid valves respectively, and is used to send working instructions to the solenoid valves.

[0033] In addition, the present invention also provides a combustion component stability identification test method based on high-frequency adjustable hydraulic excitation, which is special in that it includes the following steps:

[0034] Step 1: Build the combustion component stability evaluation test system based on high-frequency adjustable hydraulic excitation.

[0035] Step 2: The fuel enters the combustion chamber through the fuel line and the fuel header cavity in sequence. The oxidant enters the combustion chamber through the oxidant line and the oxidant header cavity in sequence, mixes with the fuel, and burns. The high-temperature and high-pressure gas generated drives the gas-powered working component to perform work.

[0036] Step 3: The test bench control system sends the initial excitation time to the exciter control system. The exciter control system controls the hydraulic exciter to start excitation, so that the constant flow of oxidant impacts the hydraulic exciter on the oxidant pipeline, generating pressure pulsation.

[0037] Step 4: The excitation frequency of the hydraulic actuator at different times is controlled by the actuator control system to achieve frequency regulation of the pressure pulsation; the amplitude of the pressure pulsation is adjusted by adjusting the regulating valve on the throttle throat structure to change the flow area of the throttle throat structure;

[0038] In step 5, the test bench control system uses the collected pulsating pressure of the oxidizer head cavity inlet pipeline as input, the pulsating pressure in the combustion chamber and the vibration acceleration of the combustion component as target control quantities, analyzes the response function of the combustion component vibration to the inlet hydraulic excitation, and then quantitatively analyzes the stability of the combustion component.

[0039] Furthermore, step 4 also includes: controlling the excitation duration through an exciter control system;

[0040] Step 5 also includes: assisting in monitoring the working status of the combustion component based on the real-time pressures of the oxidizer line inlet line, the fuel line inlet line, the hydraulic actuator outlet position, the oxidizer head cavity, and the fuel head cavity, and further analyzing the combustion stability of the combustion component.

[0041] The beneficial effects of the present invention compared to the prior art are as follows:

[0042] 1. The present invention provides a combustion component stability identification test system based on high-frequency adjustable hydraulic excitation. A hydraulic exciter is arranged on the oxidizer pipeline so that the pressure pulsation generated by the hydraulic exciter generates an input disturbance in the inlet pipeline of the oxidizer head cavity, which acts on the combustion component to apply an excitation of a specific frequency to the atomization and combustion process, thereby facilitating the observation of the coupled response process of the combustion component to the input excitation, and further identifying the stability of the combustion component. Compared with the whole-machine test run, this test method is only for the test run mode of the combustion component, and the fuel consumption and oxidizer flow rate are greatly reduced, the test operation is simpler, and it has the ability to work multiple times, which greatly reduces the cost of the stability identification test, improves the test efficiency of the stability identification, and greatly promotes the engine development process.

[0043] 2. The present invention controls the excitation frequency of the hydraulic exciter at different times through the exciter control system to achieve frequency regulation of pressure pulsation, and changes the flow area of the throttle throat structure by adjusting the regulating valve on the throttle throat structure to achieve amplitude regulation of pressure pulsation. Compared with the existing method of directly applying pulse gun excitation to the combustion chamber, the excitation frequency, amplitude and time of the present invention are controllable, the input and output parameters are measurable and adjustable, and the response characteristics of the combustion component can be accurately measured.

[0044] 3. The combustion component stability identification test system of the present invention adopts a multi-measurement point scheme to take the pulsating pressure of the oxidizer head cavity inlet pipeline as input, the pulsating pressure in the combustion chamber and the vibration acceleration of the combustion component as target control quantities, and analyzes the response function of the combustion component vibration to the inlet hydraulic excitation, which can realize the quantitative analysis of the stability of the combustion component.

[0045] 3. The present invention adopts a dual control system layout of a lower computer and a host computer, that is, the exciter control system is set to a structure including an exciter control unit (host computer) and an exciter controller (lower computer), and a network cable communication method with a longer transmission distance and stronger shielding function is adopted between the two, thereby realizing long-distance communication between the test bench and the control room. Before the test, the time-frequency sequence can be transmitted through the network cable and stored in the exciter controller, avoiding the signal attenuation problem caused by long distance or strong electromagnetic environment interference during the test process, and ensuring the safety of the experiment.

[0046] 4. The hydraulic exciter of the present invention is designed as a grid structure. As the grid impeller rotates, periodic flow resistance is generated at the nozzle, thereby generating pressure pulsation. The layout of the grid structure of the present invention makes the liquid flow almost point to the center of the circle, which can ensure the force balance of the grid impeller and avoid the shaft deflection torque caused by the impact of the liquid flow at large flow rates, thereby improving the flow capacity and service life of the exciter.

[0047] 5. The multi-measurement point solution of the present invention, combined with the outlet position of the hydraulic actuator, the pressure of the oxidizer head cavity and the fuel head cavity, can assist in monitoring the working status of the combustion component and further analyze the combustion stability of the combustion component.

[0048] 6. The driving unit of the exciter controller in the present invention controls the servo motor of the hydraulic exciter through a high-speed negative feedback control system, and the negative feedback operation cycle is set to 10ms, which effectively avoids the step skipping and step dropping problems of the servo motor, and can realize precise control of the motor speed, greatly improving the continuity and control accuracy of the pressure pulsation frequency regulation.

[0049] 7. The present invention sets a first cavitation tube at a position near the inlet of the hydraulic actuator in the oxidizer pipeline, and sets a second cavitation tube at a position corresponding to the fuel head cavity and the fuel control valve in the fuel pipeline. This can effectively shield the influence of the pressure pulsation generated by the hydraulic actuator on the oxidizer and fuel flow rates, and achieve precise control of the oxidizer and fuel flow rates only by adjusting the system inlet pressure. On the one hand, it ensures the quantitative control of the external parameters of the test system, and on the other hand, it avoids the risk of fatigue damage of the test bench pipeline system under high-frequency pressure pulsation. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] Figure 1 This is a structural schematic diagram of an embodiment of a combustion component stability evaluation test system based on high-frequency adjustable hydraulic excitation according to the present invention;

[0051] Figure 2 Schematic diagram of the structure of a hydraulic actuator in an embodiment of the present invention;

[0052] Figure 3 Schematic diagram of the control principle of the hydraulic actuator in an embodiment of the present invention;

[0053] Figure 4 Schematic diagram of the axial vibration response of the combustion assembly obtained before and after applying hydraulic excitation for 5 seconds and removing the hydraulic excitation for 10 seconds in an embodiment of the present invention;

[0054] Figure 5 Schematic diagrams of the vibration responses of four different combustion assemblies when combustion stability control is performed on them under the same input disturbance conditions according to an embodiment of the present invention, where (a), (b), (c), and (d) are schematic diagrams of the vibration responses of the combustion assemblies corresponding to the four different combustion stability control schemes, respectively;

[0055] Figure 6 Schematic diagrams of the pulsating pressure signals of the oxidizer head cavity inlet pipeline under three different excitation modes according to an embodiment of the present invention, wherein (a), (b), and (c) are schematic diagrams of the pulsating pressure signals of the oxidizer head cavity inlet pipeline under swept frequency excitation, fixed frequency excitation, and timed excitation, respectively.

[0056] The specific reference numerals are as follows:

[0057] 1-Oxidant pipeline; 2-First cavitation tube; 3-Hydraulic actuator, 31-Actuator housing, 32-Grid impeller, 321-Center shaft, 322-Impeller housing, 323-Wedge groove, 33-Magnetic coupling mechanism, 331-Inner magnet, 332-Isolation sleeve, 333-Outer magnet, 34-Drive motor; 4-Oxidant control valve; 5-Combustion assembly, 51-Combustion chamber, 52-Oxidant head cavity, 53-Fuel head cavity; 6-Gas working assembly; 7-Second cavitation tube; 8-Fuel control valve; 9-Fuel pipeline; 10-Solenoid valve; 11-Actuator controller; 12-Test bench control system; 13-Actuator control unit; 14-Regulating valve. DETAILED DESCRIPTION

[0058] In order to make the advantages and features of the present invention more clear, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0059] like Figure 1 As shown, a combustion component stability identification test system based on high-frequency adjustable hydraulic excitation includes an oxidizer pipeline 1, a fuel pipeline 9, a gas working component 6, an exciter control system and a test bench control system 12.

[0060] The combustion assembly 5 includes a combustion chamber 51 and an oxidizer head chamber 52 and a fuel head chamber 53, respectively connected to the combustion chamber 51. The inlet of the oxidizer line 1 is used to receive external oxidizer, and the outlet is connected to the oxidizer head chamber 52. A hydraulic actuator 3 and an oxidizer control valve 4 are arranged in the middle of the oxidizer line 1 along the oxidizer flow direction. The inlet of the fuel line 9 is used to receive external fuel, and the outlet is connected to the fuel head chamber. A fuel control valve 8 is arranged in the middle of the fuel line 9. Fuel enters through the inlet of the fuel line 9 (see Figure 1 Position ② in the middle), enters the combustion chamber 51 through the fuel pipeline 9 and the fuel head cavity 53 in sequence, and the oxidant enters through the inlet of the oxidant pipeline 1 (see Figure 1 Position ① in the figure), enters the combustion chamber 51 through the oxidant pipeline 1 and the oxidant head chamber 52 in sequence, causing the fuel and oxidant to mix and burn in the combustion chamber 51. The gas working component 6 is arranged at the outlet of the combustion chamber 51 to simulate the combustion component chamber pressure and acoustic cavity environment. The high-temperature and high-pressure gas generated drives the gas working component 6 to achieve simulated work. In this embodiment, pressure sensors are respectively provided on the inlet pipeline of the oxidant pipeline 1 and the inlet pipeline of the fuel pipeline 9 to accurately control the inlet flow rate of the fuel and oxidant according to the fuel inlet pressure Pif and the oxidant inlet pressure Pio, thereby controlling the working flow rate and mixing ratio of the combustion component 5.

[0061] The hydraulic actuator 3 is used to generate pressure pulsation in the oxidant in the oxidant pipeline 1. In this embodiment, the hydraulic actuator 3 is designed as a grid structure, such as Figure 2As shown, the exciter housing 31 includes a grille impeller 32, a magnetic coupling mechanism 33, and a drive motor 34. The grille impeller 32 is disposed within the exciter housing 31 and includes a central shaft 321 and an impeller housing 322 connected to the central shaft. The impeller housing 322 is a cylindrical structure with a plurality of axially extending wedge-shaped grooves 323 uniformly distributed circumferentially on its sidewall. The plurality of wedge-shaped grooves 323 are radial through-slots, with their smaller diameter ends located on the outer sidewall of the impeller housing 322, forming a grille structure on the outer sidewall of the impeller housing 322. The sidewall of the actuator housing 31 is provided with an inlet and an outlet, which are connected to the oxidizer pipeline 1 through the inlet and outlet. During operation, a constant flow of oxidizer impacts the hydraulic actuator 3 and enters through the inlet of the actuator housing 31. It then passes through the smaller diameter ends of the multiple wedge-shaped slots 323 (i.e., the individual grids of the grid structure) and enters the interior of the impeller housing 322. As the grid impeller 32 rotates, the outer wall of the grid impeller 32 and the smaller diameter ends of the wedge-shaped slots 323 periodically block and open the outlet, causing periodic changes in the minimum flow area at the outlet of the hydraulic actuator 3, resulting in periodic flow resistance and, in turn, pressure pulsation. The oxidizer with pressure pulsation passes through the downstream oxidizer pipeline 1 and acts on the inlet of the oxidizer header chamber 52. The fluctuating pressure at this point can be considered an input disturbance to the combustion assembly 5. This input disturbance, coupled with the oxidizer header chamber 52 and the combustion chamber 51, produces a periodic pulsating injection pressure drop, which in turn affects the atomization and combustion processes. Because the hydraulic excitation mode has adjustable duration and controllable application timing, combustion oscillations have ample time to phase-match the input disturbance. Ultimately, combustion damping produces a dynamic combustion effect with a certain degree of coupling. In this embodiment, the grid-structured hydraulic exciter 3, with its liquid flow directed toward the center of the circle, ensures balanced forces on the grid impeller 32, preventing shaft deflection torque caused by liquid impact at high flow rates. This improves the flow capacity and service life of the hydraulic exciter 3.

[0062] A first cavitation tube 2 is provided in the oxidant pipeline 1 near the inlet of the hydraulic actuator 3, and a second cavitation tube 7 is provided in the fuel pipeline 9 between the fuel head cavity and the fuel control valve 8. These can effectively shield the influence of the pressure pulsation generated by the hydraulic actuator 3 on the oxidant and fuel flow rates, and achieve precise control of the oxidant and fuel flow rates by only adjusting the system inlet pressure.

[0063] In addition, the oxidant pipeline 1 is configured as a throttle throat structure at the outlet of the hydraulic actuator 3, and a regulating valve 14 is installed on the throttle throat structure. By driving the motor 34 to change the speed of the grid impeller 32, the excitation frequency can be controlled, thereby adjusting the frequency of the pressure pulsation. By adjusting the regulating valve 14 on the throttle throat structure to change the flow area of the throttle throat structure, the amplitude of the pressure pulsation can be adjusted. The smaller the flow area of the throttle throat structure, the greater the amplitude of the pressure difference across the hydraulic actuator 3.

[0064] The magnetic coupling mechanism 33 is located outside the exciter housing 31 and comprises an inner magnet 331, an isolation sleeve 332, and an outer magnet 333, which are coaxially arranged from the inside out. The inner and outer magnets 331, 333 are preferably made of permanent magnet material and are coaxially arranged. Strong magnetic field interaction is achieved between the inner and outer magnets 331, 333. The drive end of the drive motor 34 is connected to the outer magnet 333 to drive the outer magnet to rotate, thereby changing its magnetic field and, in turn, driving the inner magnet 331 to rotate. The inner magnet 331 is fixedly connected to the central shaft 321 of the grille impeller 32 to drive the grille impeller 32 to rotate. Isolation sleeve 332 is positioned between inner magnet 331 and outer magnet 333 and fixed to exciter housing 31. It is 3D-printed from titanium alloy. Due to the excellent magnetic conductivity and high strength of titanium alloy, the wall thickness can be significantly reduced when using high-pressure static sealing, thus avoiding a decrease in magnetic transmission efficiency. Furthermore, complex spiral water-cooling channels are designed within isolation sleeve 332 to remove heat generated by cutting magnetic flux lines, ensuring the safety of the experimental device. The present invention utilizes a magnetic coupling mechanism, using magnetic rotation technology to transmit motor torque to inner magnet 331 through stationary isolation sleeve 332. This cleverly circumvents the problem of high-pressure dynamic sealing of high-speed rotating shafts, effectively preventing leakage of high-pressure toxic propellants and significantly improving the safety of the experiment.

[0065] The oxidant control valve 4 and the fuel control valve 8 are used to realize the supply and shutoff of the oxidant and fuel respectively. Preferably, in this embodiment, the opening and closing of the oxidant control valve 4 and the fuel control valve 8 are controlled by two solenoid valves 10 respectively. Both solenoid valves 10 are controlled by air pressure, and the air source for forming the air pressure passes through the same inlet (see Figure 1 After the position ③) is input, it is divided into two paths for use by the two solenoid valves 10. The test bench control system 12 is connected to the two solenoid valves 10 for sending working instructions to the solenoid valves 10.

[0066] A pressure sensor is mounted on the sidewall of the inlet pipe of the oxidizer head chamber 52 to measure the pulsating pressure dPhi at the inlet pipe of the oxidizer head chamber 52. A pressure sensor is mounted on the sidewall of the combustion chamber 51 to measure the pulsating pressure dPc within the combustion chamber 51. An acceleration sensor is mounted on the sidewall of the fuel head chamber 53 to measure the vibration acceleration Agg of the combustion assembly 5. In other embodiments of the present invention, the acceleration sensor may also be mounted on the sidewall of the oxidizer head chamber 52 or the combustion chamber 51. The test bench control system 12 is electrically connected to the pressure sensor and the acceleration sensor, respectively, to collect real-time data on the pulsating pressure dPhi at the inlet pipe of the oxidizer head chamber 52, the pulsating pressure dPc within the combustion chamber 51, and the vibration acceleration Agg of the combustion assembly 5. The sampling frequency can be as high as 50,000 Hz. Then, the pulsating pressure dPhi of the inlet pipeline of the oxidizer head cavity 52 is taken as input, the pulsating pressure dPc in the combustion chamber 51 and the vibration acceleration Agg of the combustion component 5 are taken as target control quantities (outputs), and the response function of the vibration of the combustion component 5 to the inlet hydraulic excitation is analyzed, and then the combustion stability of the combustion component 5 is quantitatively analyzed. The weaker the response, the better the combustion stability of the combustion component 5.

[0067] Preferably, this embodiment further provides pressure sensors at the outlet of the hydraulic actuator 3, the oxidizer head cavity 52, and the fuel head cavity 53, respectively, for measuring the pulsating pressure dPjlh at the outlet of the hydraulic actuator 3, the pulsating pressure dPho in the oxidizer head cavity 52, and the pulsating pressure dPhf in the fuel head cavity 53, respectively, to assist in monitoring the working state of the combustion component 5 and further analyze the combustion stability of the combustion component 5.

[0068] In order to improve the test efficiency, the hydraulic exciter 3 is designed with sweep frequency excitation, fixed frequency excitation and timing excitation functions, and then analyzes the sensitive frequency, response degree and attenuation strength of the combustion component 5. However, due to the large environmental interference and safety risks in the ignition test process, the hydraulic exciter 3 must be controlled in an explosion-proof control room far away from the test bench, so there will be attenuation problems in signal transmission under long distances and complex acoustic, electrical and magnetic signals. To address this problem, the present invention adopts a dual control system layout of a lower computer and an upper computer, and uses a network cable communication method with a longer transmission distance and stronger shielding function between the two, which completely avoids the problem of data transmission attenuation during the ignition test. Figure 3As shown, the exciter control system includes an exciter control unit 13 (host computer) and an exciter controller 11 (slave computer). The exciter control unit 13 is used to convert the initial excitation moment sent by the test bench control system 12 into an initial trigger signal, and then send the initial trigger signal and the internally stored excitation mode, frequency, and duration to the exciter controller 11. The exciter controller 11 is provided with a memory, a timer, an Fn conversion module, a differentiator, and a drive unit. The input of the memory is communicatively connected to the first output of the exciter control unit 13 via a network cable, and is used to receive the excitation mode, frequency, and duration, and convert them into a time-frequency sequence for storage. The input of the timer is connected to the second output of the exciter control unit 13, and is used to receive the initial trigger signal and start timing at the moment of receipt. The input of the Fn conversion module is connected to the output of the memory and the output of the timer, and is used to obtain the target excitation frequency from the time-frequency sequence in the memory based on the current time information and convert the target excitation frequency into the target motor speed. The actual speed of the drive motor 34 is collected by a sensor. The first input of the differentiator is connected to the output of the Fn conversion module, and the second input is connected to the output of the sensor that collects the actual speed of the drive motor 34. The differentiator is used to perform a differential operation between the target motor speed and the actual motor speed. The input of the drive unit is connected to the output of the differentiator, and is used to control the speed of the drive motor 34 based on the differential operation result, thereby controlling the excitation start time and the excitation frequency at different times of the hydraulic exciter 3. The specific operating process is as follows: The operator inputs the excitation mode, frequency, and duration through the pre-installed operating software in the exciter control unit 13. This is sent to the exciter controller 11, which converts it into a time-frequency sequence (t, f) and stores it. At the start-up time (t=0) of the hydraulic exciter 3, the test bench control system 12 sends a rising edge trigger signal to the exciter controller 11. The exciter controller 11 then begins counting and obtains the target excitation frequency fi at time ti. After converting this to the motor target speed ni, it performs a differential operation between the motor target speed ni and the actual motor speed ne to control the speed of the drive motor 34, thereby controlling the excitation start time and the excitation frequency at different times. If the timer time exceeds the excitation duration, the exciter controller 11 sends a stop command to the drive motor, thus controlling the excitation duration.

[0069] Preferably, the drive motor 34 is a servo motor, and the drive unit of the actuator controller 11 is electrically connected to the servo motor. A high-speed negative feedback control system, i.e., utilizing high-speed data acquisition and communication protocols, effectively avoids step skipping and step loss problems of the servo motor, enabling precise control of the motor speed, greatly improving the continuity and control accuracy of the pressure pulsation frequency regulation. In this embodiment, the negative feedback operation period is set to 10ms.

[0070] The present invention also provides a combustion component stability identification test method based on high-frequency adjustable hydraulic excitation, which specifically includes the following steps:

[0071] Step 1: Build the above-mentioned combustion component stability identification test system based on high-frequency adjustable hydraulic excitation.

[0072] In step 2, the fuel enters the combustion chamber through the fuel pipeline 9 and the fuel head cavity in turn, and the oxidizer enters the combustion chamber through the oxidizer pipeline 1 and the oxidizer head cavity in turn to mix with the fuel and burn. The high-temperature and high-pressure gas generated drives the gas working component 6 to do work.

[0073] In step 3, the test bench control system 12 sends the initial excitation moment to the exciter control unit 13. The exciter control unit 13 converts the initial excitation moment sent by the test bench control system 12 into an initial trigger signal, and sends the converted initial trigger signal to the exciter controller 11 to control the hydraulic exciter 3 to start excitation. After the constant flow of oxidant impacts the hydraulic exciter 3 on the oxidant pipeline 1, pressure pulsation is generated.

[0074] In step 4, the excitation mode, frequency and duration stored in the exciter control unit 13 are sent to the exciter controller 11, and the excitation mode, excitation frequency and excitation duration of the hydraulic exciter 3 at different times are controlled by the driving motor 34 to achieve frequency regulation of pressure pulsation.

[0075] By adjusting the regulating valve 14 on the throttle throat structure, the flow area of the throttle throat structure is changed, thereby achieving amplitude adjustment of the pressure pulsation.

[0076] In step 5, the test bench control system 12 takes the collected pulsating pressure of the inlet pipeline of the oxidizer head cavity 52 as input, the pulsating pressure in the combustion chamber 51 and the vibration acceleration of the combustion component 5 as target control quantities, analyzes the response function of the vibration of the combustion component 5 to the inlet hydraulic excitation, and then quantitatively analyzes the stability of the combustion component 5.

[0077] At the same time, according to the real-time pressures at the inlet of the oxidizer line 1, the inlet of the fuel line 9, the outlet position of the hydraulic actuator 3, the inside of the oxidizer head cavity and the inside of the fuel head cavity, the working status of the combustion component 5 is assisted in monitoring, and the combustion stability of the combustion component 5 is further analyzed.

[0078] In order to further demonstrate the effect of the present invention, the axial vibration response changes of the combustion component 5 are obtained before and after the hydraulic excitation is applied for 5 seconds and the hydraulic excitation is removed for 10 seconds, as shown in FIG. Figure 4As shown in Figure 1, it can be seen that hydraulic excitation has a significant effect on stimulating the vibration combustion of the combustion component 5. Under the same input disturbance conditions, combustion stability control is performed on four different combustion components to form different combustion stability control schemes. The corresponding vibration response diagrams of the four combustion components are shown in Figure 1. Figure 5 As shown in (a), (b), (c), and (d), after hydraulic excitation is applied, the vibrations of the four combustion components all respond significantly and exhibit different coupling response amplitudes, proving the feasibility of the combustion component stability identification test system and method based on high-frequency adjustable hydraulic excitation.

[0079] In addition, the pulsating pressure signals of the inlet pipe of the oxidizer head cavity 52 under three excitation modes, namely, sweep frequency excitation, fixed frequency excitation and timing excitation, are analyzed as follows: Figure 6 As shown in (a), (b), and (c) of Figure 1, the combustion component stability evaluation test system based on high-frequency adjustable hydraulic excitation of the present invention realizes the functions of continuous sweep frequency excitation, fixed frequency excitation, and timed excitation within a small range. The sweep frequency excitation has good continuity, the fixed frequency excitation is stable, the timed excitation is applied and removed quickly, and the parameter control effect is good.

[0080] The above description is only used to illustrate the technical solution of the present invention, rather than to limit it. For ordinary professional and technical personnel in this field, the specific technical solutions recorded in the above embodiments can be modified, or some of the technical features therein can be replaced by equivalents. These modifications or replacements do not cause the essence of the corresponding technical solution to deviate from the scope of the technical solution protected by the present invention.

Claims

1. A combustion assembly stability evaluation test system based on high-frequency adjustable hydraulic excitation, wherein the combustion assembly (5) comprises a combustion chamber (51), and an oxidant head chamber (52) and a fuel head chamber (53) respectively connected to the combustion chamber (51); characterized in that: The invention comprises an oxidant pipeline (1), a fuel pipeline (9), a gas working component (6), two pressure sensors, an acceleration sensor, an actuator control system and a test bench control system (12); the inlet of the oxidant pipeline (1) is used to receive external oxidant, the outlet is communicated with the oxidant head cavity (52), and a hydraulic actuator (3) and an oxidant control valve (4) are sequentially arranged on the oxidant pipeline along the oxidant flow direction; the position of the oxidant pipeline (1) corresponding to the outlet of the hydraulic actuator (3) is set as a throttle throat structure, and a regulating valve (14) is arranged on the throttle throat structure; the inlet of the fuel pipeline (9) is used to receive external fuel, the outlet is communicated with the fuel head cavity (53), and a fuel control valve (8) is arranged on the fuel pipeline; The gas working component (6) is arranged at the nozzle of the combustion chamber (51) and is used to simulate the combustion component chamber pressure and the acoustic cavity environment; The two pressure sensors are respectively installed on the inlet pipe of the oxidant head cavity (52) and the side wall of the combustion chamber (51); the acceleration sensor is installed on the side wall of the combustion chamber (51) or the oxidant head cavity (52) or the fuel head cavity (53) to measure the vibration acceleration of the combustion assembly (5); The test bench control system (12) is electrically connected to the pressure sensor and the acceleration sensor respectively, and is used to collect the pulsating pressure in the inlet pipeline of the oxidizer head cavity (52) and the combustion chamber (51), as well as the vibration acceleration of the combustion component (5) in real time, and uses the pulsating pressure of the inlet pipeline of the oxidizer head cavity (52) as input, the pulsating pressure in the combustion chamber (51) and the vibration acceleration of the combustion component (5) as target control quantities, analyzes the response function of the vibration of the combustion component (5) to the inlet pulsating pressure, and further quantitatively analyzes the combustion stability of the combustion component (5); The test bench control system (12) is in communication with the exciter control system and is used to send the excitation initial time to the exciter control system; The exciter control system is electrically connected to the hydraulic exciter (3) and is used to control the excitation start time and the excitation frequency at different times of the hydraulic exciter (3); The hydraulic exciter (3) comprises an exciter housing (31), a grid impeller (32), a magnetic coupling mechanism (33) and a drive motor (34); The grid impeller (32) is arranged in the exciter housing (31), and includes a central rotating shaft (321) and an impeller housing (322) connected to the central rotating shaft. The impeller housing (322) is a cylindrical structure, and a plurality of axially extending wedge-shaped grooves (323) are uniformly distributed on its side wall in the circumferential direction. The plurality of wedge-shaped grooves (323) are radial through grooves, and their small-diameter ends are all located on the outer side wall of the impeller housing (322), so that the outer side wall of the impeller housing (322) forms a grid structure. An inlet and an outlet are provided on the side wall of the actuator housing (31), and the actuator housing (31) is connected to the oxidant pipeline (1) through the inlet and the outlet; The magnetic coupling mechanism (33) is located outside the exciter housing (31), and the output end is fixedly connected to the central rotating shaft (321) for driving the grille impeller (32) to rotate; The driving end of the driving motor (34) is connected to the input end of the magnetic coupling mechanism (33) and is used to control the operation of the magnetic coupling mechanism (33); The actuator control system is electrically connected to the drive motor (34).

2. The combustion component stability evaluation test system based on high-frequency adjustable hydraulic excitation according to claim 1 is characterized in that: The exciter control system includes an exciter control unit (13) and an exciter controller (11); The exciter control unit (13) is used to convert the excitation initial moment sent by the test bench control system (12) into an initial trigger signal, and send the initial trigger signal and the internally stored excitation mode, frequency and duration to the exciter controller (11); The exciter controller (11) is connected to the exciter control unit (13) via a network cable for communication, and is used to convert the received excitation mode, frequency, and duration into a time-frequency sequence and store the converted data, and to control the excitation start time and the excitation frequency of the hydraulic exciter (3) at different times according to the received initial trigger signal and the time-frequency sequence.

3. The combustion component stability evaluation test system based on high-frequency adjustable hydraulic excitation according to claim 2 is characterized in that: The actuator controller (11) adopts a high-speed negative feedback control system, and the negative feedback operation cycle is set to 10ms. It is equipped with a memory, a timer, an fn conversion module, a differentiator and a driving unit; The input end of the memory is connected to the first output end of the exciter control unit (13), and is used to receive the excitation mode, frequency, and duration, and convert them into a time-frequency sequence for storage; The input end of the timer is connected to the second output end of the exciter control unit (13) and is used to receive an initial trigger signal and start timing at the moment of receiving the signal; The input end of the fn conversion module is connected to the output end of the memory and the output end of the timer, and is used to obtain the target excitation frequency from the time-frequency sequence of the memory according to the time information of the timer, and convert the target excitation frequency into the target speed of the motor; The first input end of the differentiator is connected to the output end of the fn conversion module, and the second input end is connected to the motor actual speed output port of the hydraulic actuator (3), and is used to perform a differential operation on the motor target speed and the motor actual speed; The input end of the driving unit is connected to the output end of the differentiator and is used to control the motor speed of the hydraulic actuator (3) according to the differential operation result.

4. The combustion component stability evaluation test system based on high-frequency adjustable hydraulic excitation according to claim 3 is characterized by: Pressure sensors are respectively provided at the outlet position of the hydraulic actuator (3), the oxidant head cavity (52) and the fuel head cavity (53).

5. The combustion component stability evaluation test system based on high-frequency adjustable hydraulic excitation according to claim 4 is characterized in that: Pressure sensors are respectively provided on the inlet pipeline of the oxidant pipeline (1) and the inlet pipeline of the fuel pipeline (9).

6. The combustion component stability evaluation test system based on high-frequency adjustable hydraulic excitation according to claim 5 is characterized by: A first cavitation tube (2) is provided in the oxidant pipeline (1) at a position close to the inlet of the hydraulic actuator (3); A second cavitation tube (7) is provided in the fuel pipeline (9) at a position between the fuel head cavity (53) and the fuel control valve (8).

7. The combustion component stability evaluation test system based on high-frequency adjustable hydraulic excitation according to claim 1 is characterized in that: Also includes two solenoid valves (10); The two solenoid valves (10) are used to control the opening and closing of the oxidant control valve (4) and the fuel control valve (8) respectively; The test bench control system (12) is communicatively connected to the two solenoid valves (10) respectively, and is used to send working instructions to the solenoid valves (10).

8. A combustion component stability evaluation test method based on high-frequency adjustable hydraulic excitation, characterized in that: The following steps are involved: Step 1: constructing a combustion component stability evaluation test system based on high-frequency adjustable hydraulic excitation according to any one of claims 1 to 7; Step 2: The fuel enters the combustion chamber (51) through the fuel pipeline (9) and the fuel header cavity (53) in sequence, and the oxidant enters the combustion chamber (51) through the oxidant pipeline (1) and the oxidant header cavity (52) in sequence, mixes with the fuel, and burns. The generated high-temperature and high-pressure gas drives the gas working component (6) to perform work; Step 3: The test bench control system (12) sends the initial excitation time to the exciter control system, and the exciter control system controls the hydraulic exciter (3) to start excitation, so that the constant flow of oxidant impacts the hydraulic exciter (3) on the oxidant pipeline (1), generating pressure pulsation; Step 4, controlling the excitation frequency of the hydraulic actuator (3) at different times through the actuator control system to achieve frequency regulation of the pressure pulsation; and changing the flow area of the throttle throat structure by adjusting the regulating valve (14) on the throttle throat structure to achieve amplitude regulation of the pressure pulsation; In step 5, the test bench control system (12) takes the collected pulsating pressure of the inlet pipeline of the oxidizer head cavity (52) as input, the pulsating pressure in the combustion chamber (51) and the vibration acceleration of the combustion component (5) as target control quantities, analyzes the response function of the vibration of the combustion component (5) to the inlet hydraulic excitation, and then quantitatively analyzes the stability of the combustion component (5).

9. The combustion assembly stability evaluation test method based on high-frequency adjustable hydraulic excitation according to claim 8 is characterized in that: Step 4 also includes: controlling the excitation duration through the exciter control system; Step 5 also includes: assisting in monitoring the working state of the combustion component (5) based on the real-time pressures at the inlet of the oxidizer line (1), the inlet of the fuel line (9), the outlet position of the hydraulic actuator (3), the inside of the oxidizer head cavity, and the inside of the fuel head cavity, and further analyzing the combustion stability of the combustion component (5).

Images