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

Abstract

The invention provides a combustion assembly stability identification test system and method based on high-frequency adjustable hydraulic excitation. The system and method are used for solving the technical problem that the stability response of a combustion assembly to excitation when corresponding combustion instability occurs cannot be accurately obtained in an existing mode of directly applying pulse gun excitation to a combustion chamber. According to the combustion assembly stability identification test system based on high-frequency adjustable hydraulic excitation, the hydraulic exciter is arranged on the oxidant pipeline, frequency adjustment of pressure pulsation is achieved by controlling excitation frequencies of the hydraulic exciter at different moments, amplitude adjustment of the pressure pulsation is achieved by adjusting the adjusting valve on the throttling throat structure, and the stability of the combustion assembly is identified. Meanwhile, a multi-measuring-point scheme is adopted, pulsating pressure of an oxidizing agent head cavity inlet pipeline serves as input, pulsating pressure in a combustion chamber and vibration acceleration of the combustion assembly serve as target control quantities, a response function of vibration of the combustion assembly to inlet hydraulic excitation is analyzed, and quantitative analysis of the stability of the combustion assembly can be achieved.

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] The problem of combustion instability is a major challenge for liquid rocket engines. At present, researchers have given many valuable guiding engineering improvement or design ideas through a large number of studies. However, the stability of the improved engine still needs to be verified through tests. Due to the randomness of the occurrence of combustion instability, it is difficult to judge whether the engine stability meets the requirements based on the results of a single engine test run, whether it is a combustion component test or a whole engine test run. Currently, the engine stability identification method still mainly relies on the statistical analysis of the results of multiple sub-sample test runs. However, the test runs of liquid rocket engines, especially large-thrust liquid rocket engines, often consume a large amount of propellant, with extremely high single-test-run costs, and high operation difficulty and risks.

[0003] In order to increase the probability of the occurrence of combustion instability, currently, most often, holes are opened at the head or body of the combustion chamber, and during the operation of the combustion component, a pulse gun excitation is directly applied to the combustion chamber to identify the stability of the combustion component, and then the stability result of the engine is obtained. The pulse gun excitation generally uses the impact during the ignition of high-energy solid gunpowder to achieve. This excitation method has a very short excitation time, usually in the order of 0.001 - 0.1 s. Its excitation frequency is the superposition of broadband excitation, with relatively low divided-frequency energy, and the excitation time and excitation frequency are uncontrollable. When medium and high-frequency combustion instability occurs, the combustion component often exhibits a certain characteristic frequency, and the excitation frequency will greatly affect the probability of the occurrence of combustion instability. In addition, the excitation time and the level of energy also have a greater impact on the probability of the occurrence of combustion instability. Therefore, 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. 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] To achieve the above purpose, the technical solution provided by the present invention is as follows: A combustion component stability identification test system based on high-frequency adjustable hydraulic excitation. The combustion component includes a combustion chamber, an oxidant head cavity and a fuel head cavity that are respectively communicated with the combustion chamber. The special feature is that it includes an oxidant pipeline, a fuel pipeline, a gas work component, two pressure sensors, an acceleration sensor, an exciter control system and a test bench control system; The inlet of the oxidant pipeline is used to receive external oxidant, and the outlet is communicated with the oxidant head cavity. Along the oxidant flow direction, a hydraulic exciter and an oxidant control valve are sequentially arranged on it. The position of the oxidant pipeline corresponding to the outlet of the hydraulic exciter is set as a throttling throat structure, and a regulating valve is arranged on the throttling throat structure. The inlet of the fuel pipeline is used to receive external fuel, and the outlet is communicated with the fuel head cavity. A fuel control valve is arranged on it; The gas work component is arranged at the nozzle of the combustion chamber to simulate the chamber pressure and acoustic cavity environment of the combustion component; The two pressure sensors are respectively installed on the inlet pipeline of the oxidant 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 oxidant head cavity or the fuel head cavity to measure the vibration acceleration of the combustion component; The test bench control system 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 oxidant head cavity and the combustion chamber in real time, as well as the vibration acceleration of the combustion component. Taking the pulsating pressure of the inlet pipeline of the oxidant head cavity as the input, and the pulsating pressure in the combustion chamber and the vibration acceleration of the combustion component as the target control quantities, analyze the response function of the vibration of the combustion component to the inlet pulsating pressure, and then quantitatively analyze the combustion stability of the combustion component; The test bench control system is communicatively connected to the exciter control system and is used to send the excitation initial moment to the exciter control system. The exciter control system is electrically connected to the hydraulic exciter and is used to control the excitation start moment and the excitation frequency at different moments of the hydraulic exciter.

[0006] Further, the hydraulic exciter includes an exciter housing, a grid impeller, a magnetic coupling mechanism and a drive motor; The grid impeller is arranged 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 circumferentially distributed on its side wall. The plurality of wedge-shaped grooves are radial through grooves, and their small-diameter ends are all located on the outer side wall of the impeller housing, so that the outer side wall of the impeller housing forms a grid structure; The side wall of the exciter housing is provided with an inlet and an outlet, and it is connected to the oxidant pipeline through the inlet and the outlet; The magnetic coupling mechanism is located outside the exciter housing, and the output end is fixedly connected to the central rotating shaft and is used to drive the grid impeller to rotate; 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; The actuator control system is electrically connected to the driving motor.

[0007] Further, the actuator control system includes an actuator control unit and an actuator controller; The actuator control unit is configured to convert the excitation initial moment sent by the test bench control system into an initial trigger signal, and send the initial trigger signal, the excitation mode, frequency and duration stored internally to the actuator controller; The actuator controller is communicatively connected to the actuator control unit through a network cable, and is configured 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 moment of the hydraulic actuator and the excitation frequency at different moments.

[0008] Further, the actuator controller adopts a high-speed negative feedback control system, the negative feedback operation period is set to 10 ms, and it is internally provided with a memory, a timer, an f-n conversion module, a differentiator and a driving unit; The input end of the memory is connected to the first output end of the actuator control unit, 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 actuator control unit, and is used to receive the initial trigger signal and start timing at the received moment; The input end of the f-n 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 motor speed; The first input end of the differentiator is connected to the output end of the f-n conversion module, and the second input end is connected to the actual motor speed output port of the hydraulic actuator, and is used to perform differential operation on the target motor speed and the actual motor 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 according to the differential operation result.

[0009] Further, pressure sensors are respectively arranged at the outlet position of the hydraulic actuator, the oxidizer head cavity and the fuel head cavity, which are used to assist in monitoring the working state of the combustion assembly and further analyze the combustion stability of the combustion assembly.

[0010] Further, pressure sensors are respectively arranged on the inlet pipeline of the oxidizer pipeline and the inlet pipeline of the fuel pipeline, which are used to accurately control the inlet flow rates of the fuel and the oxidizer through the inlet pressures of the fuel and the oxidizer respectively.

[0011] Further, a first cavitation tube is provided at a position in the oxidant pipeline near the inlet of the hydraulic actuator. A second cavitation tube is provided at a position 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 oxidant and fuel flow rates.

[0012] Further, two solenoid valves are further included; the two solenoid valves are respectively used to control the opening and closing of the oxidant control valve and the fuel control valve. The test bench control system is respectively communicatively connected to the two solenoid valves and is used to send working instructions to the solenoid valves.

[0013] In addition, the present invention also provides a method for identifying the stability of a combustion assembly based on high-frequency adjustable hydraulic excitation, which is characterized in that it includes the following steps: Step 1, build the above-mentioned test system for identifying the stability of a combustion assembly based on high-frequency adjustable hydraulic excitation. Step 2, the fuel sequentially enters the combustion chamber through the fuel pipeline and the fuel head cavity, and the oxidant sequentially enters the combustion chamber through the oxidant pipeline and the oxidant head cavity to be mixed with the fuel and burned, and the generated high-temperature and high-pressure gas drives the gas power component to do work. Step 3, the test bench control system sends the excitation initial moment to the actuator control system, and the actuator control system controls the hydraulic actuator to start excitation, so that the constant-flow oxidant impacts the hydraulic actuator on the oxidant pipeline, generating pressure pulsation. Step 4, control the excitation frequency of the hydraulic actuator at different moments through the actuator control system to realize the frequency adjustment of the pressure pulsation; change the flow area of the throttle throat structure by adjusting the regulating valve on the throttle throat structure to realize the amplitude adjustment of the pressure pulsation. Step 5, the test bench control system takes the pulsating pressure collected from the inlet pipeline of the oxidant head cavity as the input, and the pulsating pressure in the combustion chamber and the vibration acceleration of the combustion assembly as the target control quantities, analyzes the response function of the vibration of the combustion assembly to the inlet hydraulic excitation, and further quantitatively analyzes the stability of the combustion assembly.

[0014] Further, in step 4, it also includes: controlling the excitation duration through the actuator control system. In step 5, it also includes: assisting in monitoring the working state of the combustion assembly according to the real-time pressures at the inlet pipeline of the oxidant pipeline, the inlet pipeline of the fuel pipeline, the outlet position of the hydraulic actuator, inside the oxidant head cavity, and inside the fuel head cavity, and further analyzing the combustion stability of the combustion assembly.

[0015] The beneficial effects of the present invention compared with the prior art are as follows: 1. A combustion component stability identification test system based on high-frequency adjustable hydraulic excitation provided by the present invention sets a hydraulic exciter on the oxidizer pipeline, so that the pressure pulsation generated by it generates an input disturbance in the inlet pipeline of the oxidizer head cavity and acts on the combustion component to apply excitation with a specific frequency to the atomization and combustion processes, facilitating the observation of the coupling response process of the combustion component to the input excitation, and then identifying the stability of the combustion component. Compared with the full-engine test run, this test method only targets the test run of the combustion component, greatly reducing the consumption of fuel and oxidizer flow rate, making the test operation simpler, and having the ability to work multiple times, greatly reducing the cost of the stability identification test, improving the test efficiency of the stability identification, and greatly promoting the engine development process.

[0016] 2. The present invention controls the excitation frequency of the hydraulic exciter at different times through the exciter control system to achieve the frequency adjustment of the pressure pulsation, and changes the flow area of the throttle throat structure by adjusting the regulating valve on the throttle throat structure to achieve the amplitude adjustment of the 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, and the input and output parameters are measurable and adjustable, and the response characteristics of the combustion component can be accurately measured.

[0017] 3. The combustion component stability identification test system of the present invention adopts a multi-measurement point scheme, taking the pulsating pressure of the inlet pipeline of the oxidizer head cavity as the input, and the pulsating pressure in the combustion chamber and the vibration acceleration of the combustion component as the target control quantities, and analyzing the response function of the vibration of the combustion component to the inlet hydraulic excitation, so as to realize the quantitative analysis of the stability of the combustion component.

[0018] 3. The present invention adopts a dual control system layout of a lower computer and an upper computer, that is, the exciter control system is set as a structure including an exciter control unit (upper computer) and an exciter controller (lower computer), and the two use a network cable communication method with a longer transmission distance and stronger shielding function to achieve long-distance communication from the test bench to the control room. Before the test run, 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 run, and ensuring the safety of the experiment.

[0019] 4. The hydraulic exciter of the present invention is designed as a grid structure. As the grid impeller rotates, a periodic flow resistance is generated at the nozzle, and then pressure pulsation is generated. The layout of the grid structure of the present invention makes the liquid flow direction almost all point to the center of the circle, which can ensure the force balance of the grid impeller, avoid the shaft deflection moment caused by the impact of the liquid flow at large flow rates, and then improve the flow capacity and service life of the exciter.

[0020] 5. The multi-measurement point solution of the present invention combines the outlet position of the hydraulic actuator, the pressure in the oxidizer head cavity, and the pressure in the fuel head cavity, which can assist in monitoring the working state of the combustion assembly and further analyze the combustion stability of the combustion assembly.

[0021] 6. In the present invention, the drive unit of the actuator controller controls the servo motor of the hydraulic actuator through a high-speed negative feedback control system, and the negative feedback operation period is set to 10 ms, effectively avoiding the problems of servo motor skipping and losing steps, realizing precise control of the motor speed, and greatly improving the continuity and control accuracy of the pressure pulsation frequency adjustment.

[0022] 7. In the present invention, a first cavitation tube is arranged at a position in the oxidizer pipeline close to the inlet of the hydraulic actuator, and a second cavitation tube is arranged at a position in the fuel pipeline corresponding to the position 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 oxidizer and fuel flow rates, and realize 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 to the pipeline system of the test bench under high-frequency pressure pulsation. Description of the Drawings

[0023] Figure 1 is a schematic structural diagram of an embodiment of a combustion assembly stability identification test system based on a high-frequency adjustable hydraulic actuator of the present invention; Figure 2 is a schematic structural diagram of the hydraulic actuator in the embodiment of the present invention; Figure 3 is a schematic diagram of the control principle of the hydraulic actuator in the embodiment of the present invention; Figure 4 is a schematic diagram of the axial vibration response of the combustion assembly obtained before and after applying hydraulic excitation for 5 s and removing hydraulic excitation for 10 s in the embodiment of the present invention; Figure 5 is a schematic diagram of the vibration response of each combustion assembly when controlling the combustion stability of four different combustion assemblies under the same input disturbance conditions in the embodiment of the present invention, where (a), (b), (c), and (d) are schematic diagrams of the vibration responses of the combustion assemblies corresponding to four different combustion stability control schemes respectively; Figure 6 is a signal diagram of the pulsating pressure of the inlet pipeline of the oxidizer head cavity under three different excitation modes in the embodiment of the present invention, where (a), (b), and (c) are signal diagrams of the pulsating pressure of the inlet pipeline of the oxidizer head cavity under sweep excitation, fixed-frequency excitation, and timed excitation respectively.

[0024] The specific reference numerals are as follows: 1 - Oxidizer pipeline; 2 - First cavitation tube; 3 - Hydraulic actuator, 31 - Actuator housing, 32 - Grille impeller, 321 - Central rotating shaft, 322 - Impeller housing, 323 - Wedge-shaped groove, 33 - Magnetic coupling mechanism, 331 - Inner magnetic steel, 332 - Isolation sleeve, 333 - Outer magnetic steel, 34 - Driving motor; 4 - Oxidizer control valve; 5 - Combustion assembly, 51 - Combustion chamber, 52 - Oxidizer head cavity, 53 - Fuel head cavity; 6 - Gas work component; 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. Specific implementation manner

[0025] To make the advantages and features of the present invention clearer, the following further elaborates on the present invention in detail with reference to the accompanying drawings and specific embodiments.

[0026] As Figure 1 shown, a combustion assembly stability identification test system based on high-frequency adjustable hydraulic excitation includes an oxidizer pipeline 1, a fuel pipeline 9, a gas work component 6, an actuator control system, and a test bench control system 12.

[0027] The combustion assembly 5 includes a combustion chamber 51 and an oxidizer head cavity 52 and a fuel head cavity 53 that are respectively communicated with the combustion chamber 51. The inlet of the oxidizer pipeline 1 is used to receive external oxidizer, and the outlet is communicated with the oxidizer head cavity 52. A hydraulic actuator 3 and an oxidizer control valve 4 are sequentially arranged along the oxidizer flow direction in the middle of the oxidizer pipeline 1. The inlet of the fuel pipeline 9 is used to receive external fuel, and the outlet is communicated with the fuel head cavity. A fuel control valve 8 is arranged in the middle of the fuel pipeline 9. The fuel enters through the inlet of the fuel pipeline 9 (see Figure 1 the position ② in), and sequentially enters the combustion chamber 51 through the fuel pipeline 9 and the fuel head cavity 53. The oxidizer enters through the inlet of the oxidizer pipeline 1 (see Figure 1 the position ① in), and sequentially enters the combustion chamber 51 through the oxidizer pipeline 1 and the oxidizer head cavity 52, so that the fuel and the oxidizer are mixed and burned in the combustion chamber 51. The gas work component 6 is arranged at the outlet of the combustion chamber 51, and is used to simulate the chamber pressure and acoustic cavity environment of the combustion assembly, and the generated high-temperature and high-pressure gas drives the gas work component 6 to achieve simulated work. In this embodiment, pressure sensors are respectively arranged on the inlet pipeline of the oxidizer pipeline 1 and the inlet pipeline of the fuel pipeline 9, and are used to accurately control the inlet flow rates of the fuel and the oxidizer through the fuel inlet pressure Pif and the oxidizer inlet pressure Pio, and further control the working flow rate and mixing ratio of the combustion assembly 5.

[0028] The hydraulic actuator 3 is used to generate pressure pulsation of the oxidizer in the oxidizer pipeline 1. In this embodiment, the hydraulic actuator 3 is designed as a grille structure, as Figure 2As shown in the figure, it includes an exciter housing 31, a grid impeller 32, a magnetic coupling mechanism 33, and a drive motor 34. The grid impeller 32 is arranged inside the exciter housing 31, and it includes a central rotating shaft 321 and an impeller housing 322 connected to the central rotating shaft. The impeller housing 322 is of a cylindrical structure, and a plurality of axially extending wedge-shaped grooves 323 are circumferentially and evenly distributed on its side wall; 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 exciter housing 31, and it is connected to the oxidant pipeline 1 through the inlet and the outlet. During operation, the oxidant with a constant flow rate impacts the hydraulic exciter 3 and enters from the inlet of the exciter housing 31, and then enters the inside of the impeller housing 322 through the small-diameter ends of the plurality of wedge-shaped grooves 323 (i.e., each grid of the grid structure). As the grid impeller 32 rotates, the outer side wall of the grid impeller 32 and the small-diameter ends of the wedge-shaped grooves 323 will periodically block and release the outlet, resulting in a periodic change in the minimum fluid area at the outlet of the hydraulic exciter 3, generating a periodic flow resistance, and further generating pressure pulsations. The oxidant with pressure pulsations acts on the inlet of the oxidant head cavity 52 after passing through the downstream oxidant pipeline 1, and the pulsating pressure here can be regarded as the input disturbance of the combustion assembly 5. Under this input disturbance, through the coupling action of the oxidant head cavity 52 and the combustion chamber 51, a periodic pulsating injection pressure drop is generated, which further affects the atomization and combustion processes. Since the duration of the hydraulic excitation method is adjustable and the application time of the hydraulic excitation is controllable, the combustion oscillation has enough time to match the phase with the input disturbance. Finally, under the action of combustion damping, a dynamically coupled combustion effect to a certain extent is generated. In the hydraulic exciter 3 with a grid structure in this embodiment, since the liquid flow direction points to the center of the circle, the force on the grid impeller 32 is balanced, avoiding the shaft deflection moment caused by the impact of the liquid flow during large flow rates, and further improving the flow capacity and service life of the hydraulic exciter 3.

[0029] A first cavitation tube 2 is arranged at a position near the inlet of the hydraulic exciter 3 in the oxidant pipeline 1, and a second cavitation tube 7 is arranged at a position between the fuel head cavity and the fuel control valve 8 in the fuel pipeline 9, which can effectively shield the influence of the pressure pulsations generated by the hydraulic exciter 3 on the oxidant and fuel flow rates, and only by adjusting the system inlet pressure, the precise control of the oxidant and fuel flow rates can be achieved.

[0030] In addition, the position of the oxidant pipeline 1 corresponding to the outlet of the hydraulic exciter 3 is set as a throttle throat structure, and a regulating valve 14 is arranged on the throttle throat structure. By changing the rotation speed of the grid impeller 32 through the drive motor 34, the excitation frequency can be controlled to realize the frequency adjustment of the pressure pulsations; by adjusting the regulating valve 14 on the throttle throat structure to change the flow area of the throttle throat structure, the amplitude adjustment of the pressure pulsations can be realized, and the smaller the flow area of the throttle throat structure, the greater the amplitude change of the pressure difference at both ends of the hydraulic exciter 3.

[0031] The magnetic coupling mechanism 33 is located outside the exciter housing 31 and includes an inner magnetic steel 331, an isolation sleeve 332, and an outer magnetic steel 333 coaxially sleeved from the inside to the outside in sequence. The main bodies of the inner magnetic steel 331 and the outer magnetic steel 333 are preferably made of permanent magnet materials. The two are arranged coaxially, and a strong magnetic field interaction is adopted between the inner magnetic steel 331 and the outer magnetic steel 333. The driving end of the driving motor 34 is connected to the outer magnetic steel 333 and is used to drive the outer magnetic steel to rotate, so that its magnetic field changes, and then drive the inner magnetic steel 331 to rotate. The inner magnetic steel 331 is fixedly connected to the central rotating shaft 321 of the grid impeller 32 and is used to drive the grid impeller 32 to rotate. The isolation sleeve 332 is arranged between the inner magnetic steel 331 and the outer magnetic steel 333 and is fixed on the exciter housing 31. It is formed by 3D printing with titanium alloy material. On the one hand, because the titanium alloy material has excellent magnetic conductivity and high strength, the wall thickness is greatly reduced when using high-pressure static sealing, avoiding the decrease of magnetic transmission efficiency. On the other hand, a complex spiral water-cooling channel is designed inside the isolation sleeve 332, which can take away the heat generated by the movement of cutting magnetic induction lines and ensure the safety of the experimental device. The present invention adopts a magnetic coupling mechanism, and through magnetic rotation technology, the motor torque is transmitted to the inner magnetic steel 331 through the stationary isolation sleeve 332, skillfully avoiding the problem of high-speed rotating shaft high-pressure dynamic sealing, and effectively preventing the leakage of high-pressure toxic propellants, greatly improving the safety of the test.

[0032] The oxidizer control valve 4 and the fuel control valve 8 are respectively used to realize the supply and shutdown of the oxidizer and the fuel. Preferably, in this embodiment, two solenoid valves 10 are respectively used to control the opening and closing of the oxidizer control valve 4 and the fuel control valve 8. The two solenoid valves 10 are both controlled by air pressure. The air source for forming the air pressure is divided into two paths for the two solenoid valves 10 to use after being input through the same inlet (see the position ③ in Figure 1 ). The test bench control system 12 is respectively communicatively connected to the two solenoid valves 10 and is used to send working instructions to the solenoid valves 10.

[0033] A pressure sensor is installed on the side wall of the inlet pipeline of the oxidizer head cavity 52 to measure the pulsating pressure dPhi of the inlet pipeline of the oxidizer head cavity 52; a pressure sensor is installed on the side wall of the combustion chamber 51 to measure the pulsating pressure dPc in the combustion chamber 51; an acceleration sensor is provided on the side wall of the fuel head cavity 53 to measure the vibration acceleration Agg of the combustion assembly 5. In other embodiments of the present invention, the acceleration sensor can also be provided on the side wall of the oxidizer head cavity 52 or the combustion chamber 51. The test bench control system 12 is electrically connected to the pressure sensor and the acceleration sensor respectively, and is used to collect in real time the pulsating pressure dPhi of the inlet pipeline of the oxidizer head cavity 52, the pulsating pressure dPc in the combustion chamber 51, and the vibration acceleration Agg of the combustion assembly 5. The sampling frequency can be as high as 50000 Hz. Then, taking the pulsating pressure dPhi of the inlet pipeline of the oxidizer head cavity 52 as the input, and the pulsating pressure dPc in the combustion chamber 51 and the vibration acceleration Agg of the combustion assembly 5 as the target control quantities (outputs), the response function of the vibration of the combustion assembly 5 to the inlet hydraulic excitation is analyzed, and further the combustion stability of the combustion assembly 5 is quantitatively analyzed. The weaker the response, the better the combustion stability of the combustion assembly 5.

[0034] Preferably, in this embodiment, pressure sensors are respectively provided at the outlet position of the hydraulic actuator 3, the oxidizer head cavity 52, and the fuel head cavity 53 to measure the pulsating pressure dPjlh at the outlet position 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, so as to assist in monitoring the working state of the combustion assembly 5 and further analyze the combustion stability of the combustion assembly 5.

[0035] In order to improve the test efficiency, the hydraulic actuator 3 is designed with functions of sweep frequency excitation, fixed frequency excitation, and timing excitation, so as to analyze the sensitive frequency, response degree, and attenuation strength of the combustion assembly 5. However, due to the large environmental interference and safety risks during the ignition test process, the hydraulic actuator 3 must be controlled in an explosion-proof control room far away from the test bench. Therefore, there will be attenuation problems of signal transmission under long-distance, complex sound, electricity, and magnetic signals. To solve this problem, the present invention adopts a dual control system layout of a lower computer and an upper computer, and a network cable communication method with a longer transmission distance and stronger shielding function is used between the two, completely avoiding the attenuation problem of data transmission during the ignition test process. As Figure 3As shown in the figure, the actuator control system includes an actuator control unit 13 (host computer) and an actuator controller 11 (slave computer). The actuator 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, the excitation mode, frequency and duration stored internally to the actuator controller 11. The actuator controller 11 is provided with a memory, a timer, an f-n conversion module, a differentiator and a drive unit; the input end of the memory is communicatively connected to the first output end of the actuator control unit 13 through 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 end of the timer is connected to the second output end of the actuator control unit 13, and is used to receive the initial trigger signal and start timing at the receiving moment; the input end of the f-n 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 current time information, and convert the target excitation frequency into the target speed of the motor; the actual speed of the drive motor 34 is collected by a sensor, the first input end of the differentiator is connected to the output end of the f-n conversion module, and the second input end is connected to the output end of the sensor that collects the actual speed of the drive motor 34, and is used to perform a differential operation on the target speed of the motor and the actual speed of the motor; the input end of the drive unit is connected to the output end of the differentiator, and is used to control the speed of the drive motor 34 according to the differential operation result, and further control the excitation start moment and the excitation frequency at different moments of the hydraulic actuator 3. The specific working process is as follows: the operator inputs the excitation mode, frequency and duration through the operation software pre-installed in the actuator control unit 13, sends them to the actuator controller 11 and converts them into a time-frequency sequence (t, f) for storage. The start moment (t = 0) of the hydraulic actuator 3 sends a rising edge trigger signal to the actuator controller 11 through the test bench control system 12. The actuator controller 11 then starts timing and obtains the target excitation frequency fi at time ti, converts it into the target speed ni of the motor, and then performs a differential operation on the target speed ni of the motor and the actual speed ne of the motor to control the speed of the drive motor 34, and further control the excitation start moment and the excitation frequency at different moments. When the timer time is greater than the excitation duration, the actuator controller 11 sends a drive motor stop command to achieve the control of the excitation duration.

[0036] Preferably, the drive motor 34 is a servo motor. The drive unit of the actuator controller 11 is electrically connected to the servo motor. Through a high-speed negative feedback control system, that is, by using high-speed acquisition and communication protocols, the problems of servo motor step skipping and step loss are effectively avoided, the precise control of the motor speed can be achieved, and the continuity and control accuracy of the pressure pulsation frequency regulation are greatly improved. In this embodiment, the negative feedback operation period is set to 10 ms.

[0037] The present invention also provides a method for identifying the stability of a combustion assembly based on high-frequency adjustable hydraulic excitation, which specifically includes the following steps: Step 1: Build the above-mentioned test system for identifying the stability of a combustion assembly based on high-frequency adjustable hydraulic excitation.

[0038] Step 2: Fuel sequentially passes through the fuel pipeline 9 and the fuel head cavity and enters the combustion chamber. The oxidant sequentially passes through the oxidant pipeline 1 and the oxidant head cavity and enters the combustion chamber to mix and burn with the fuel. The generated high-temperature and high-pressure gas drives the gas work component 6 to do work.

[0039] Step 3: The test bench control system 12 sends the excitation initial moment to the exciter control unit 13. The exciter control unit 13 converts the excitation initial 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 oxidant with a constant flow rate impacts the hydraulic exciter 3 on the oxidant pipeline 1, pressure pulsation is generated.

[0040] Step 4: At the same time, send the excitation mode, frequency, and duration stored inside the exciter control unit 13 to the exciter controller 11, and control the excitation mode, excitation frequency, and excitation duration of the hydraulic exciter 3 at different moments through the drive motor 34 to realize the frequency adjustment of the pressure pulsation.

[0041] By adjusting the regulating valve 14 on the throttling throat structure, change the flow area of the throttling throat structure to realize the amplitude adjustment of the pressure pulsation.

[0042] Step 5: The test bench control system 12 takes the pulsating pressure of the inlet pipeline of the oxidant head cavity 52 collected as the input, and the pulsating pressure in the combustion chamber 51 and the vibration acceleration of the combustion assembly 5 as the target control quantities, analyzes the response function of the vibration of the combustion assembly 5 to the inlet hydraulic excitation, and further quantitatively analyzes the stability of the combustion assembly 5.

[0043] At the same time, according to the real-time pressures at the inlet pipeline of the oxidant pipeline 1, the inlet pipeline of the fuel pipeline 9, the outlet position of the hydraulic exciter 3, inside the oxidant head cavity, and inside the fuel head cavity, assist in monitoring the working state of the combustion assembly 5, and further analyze the combustion stability of the combustion assembly 5.

[0044] To further prove the effect of the present invention, the change in the axial vibration response of the combustion assembly 5 obtained before and after applying hydraulic excitation for 5 s and removing hydraulic excitation for 10 s is as Figure 4 shown. It can be seen that the hydraulic excitation has an obvious effect on stimulating the vibration combustion of the combustion assembly 5. Under the same input disturbance conditions, the combustion stability of four different combustion assemblies is controlled to form different combustion stability control schemes, and the vibration response schematic diagrams of the corresponding four combustion assemblies are asFigure 5 As shown in (a), (b), (c), and (d) in , after applying hydraulic excitation, the vibrations of the four combustion components all have obvious responses, and different coupling response amplitudes are shown, which proves the feasibility of the combustion component stability identification test system and method based on high-frequency adjustable hydraulic excitation.

[0045] In addition, analyze the pulsating pressure signals of the inlet pipeline of the oxidizer head cavity 52 under three excitation methods: sweep-frequency excitation, fixed-frequency excitation, and fixed-time excitation, as shown in Figure 6 (a), (b), and (c) in . It can be seen that the combustion component stability identification 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 fixed-time excitation during the test within a small range. The sweep-frequency excitation has good continuity, the fixed-frequency excitation maintains stability, the fixed-time excitation is applied and removed quickly, and the parameter control effect is good.

[0046] As described above, it is only used to illustrate the technical solution of the present invention, rather than to limit it. For those of ordinary skill in the art, the specific technical solution recorded in the above embodiments can be modified, or some technical features can be equivalently replaced. These modifications or replacements do not make the essence of the corresponding technical solution 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 arranged on the oxidant pipeline in sequence along the oxidant flow direction; the position of the oxidant pipeline (1) corresponding to the outlet of the hydraulic actuator (3) is arranged as a throttling throat structure, and a regulating valve (14) is arranged on the throttling 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) to simulate the chamber pressure and acoustic cavity environment of the combustion component; The two pressure sensors are respectively mounted on the inlet pipeline of the oxidant head cavity (52) and the side wall of the combustion chamber (51); the acceleration sensor is mounted 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 connection 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 of the hydraulic exciter (3) and the excitation frequency at different times.

2. The combustion component stability identification test system based on high-frequency adjustable hydraulic excitation according to claim 1 is characterized in that: The hydraulic exciter (3) comprises an exciter housing (31), a grid impeller (32), a magnetic coupling mechanism (33) and a drive motor (34); The grille impeller (32) is arranged in the exciter housing (31), and comprises 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 evenly 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 grille 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) and is used to drive 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).

3. The combustion component stability identification test system based on high-frequency adjustable hydraulic excitation according to claim 1 or 2 is characterized in that: The exciter control system comprises an exciter control unit (13) and an exciter controller (11); 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 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 it, and to control the excitation start time of the hydraulic exciter (3) and the excitation frequency at different times according to the received initial trigger signal and the time-frequency sequence.

4. The combustion component stability identification test system based on high-frequency adjustable hydraulic excitation according to claim 3 is characterized in that: The exciter controller (11) adopts a high-speed negative feedback control system, the negative feedback operation cycle is set to 10ms, and is provided 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 exciter (3), and is used to perform a differential operation between 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.

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

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

7. The combustion component stability identification test system based on high-frequency adjustable hydraulic excitation according to claim 6 is characterized in that: A first cavitation tube (2) is arranged 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).

8. The combustion component stability identification test system based on high-frequency adjustable hydraulic excitation according to claim 1 is characterized by: 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 respectively connected to the two solenoid valves (10) for communication, and is used to send working instructions to the solenoid valves (10).

9. A combustion component stability identification test method based on high-frequency adjustable hydraulic excitation, characterized in that: The following steps are involved: Step 1, constructing a combustion component stability identification test system based on high-frequency adjustable hydraulic excitation as described in any one of claims 1 to 8; Step 2, the fuel enters the combustion chamber (51) through the fuel pipeline (9) and the fuel head cavity (53) in sequence, and the oxidant enters the combustion chamber (51) through the oxidant pipeline (1) and the oxidant head cavity (52) in sequence to mix with the fuel and burn, and the generated high-temperature and high-pressure gas drives the fuel gas working component (6) to 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 exciter (3) at different times through the exciter control system to achieve frequency regulation of the pressure pulsation; and changing the flow area of ​​the throttling throat structure by adjusting the regulating valve (14) on the throttling throat structure to achieve amplitude regulation of the pressure pulsation; Step 5, the test bench control system (12) takes the collected pulsating pressure of the inlet pipeline of the oxidizer head chamber (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).

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

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