High frequency pulse trigger for solid rocket engine combustion stability evaluation

Abstract

The high-frequency pulse trigger for solid rocket engine combustion stability evaluation disclosed by the application belongs to the field of solid rocket unstable combustion. The application comprises a pulse trigger, an oscillating pressure data processing module, a pulse generator performance prediction and structure selection module. The pulse trigger is customized with a membrane breaking piece, and the trigger customized membrane breaking piece can break the membrane at a specified pressure. The pulse trigger outputs high-frequency signals, and the pulse trigger is installed outside the engine acoustic cavity. Only when the pulse generator inputs high-frequency pressure oscillation high enough, the inherent oscillation of the solid rocket engine acoustic cavity below the frequency can be excited as much as possible. The pressure oscillation signal analysis module obtains the attenuation coefficient and the resonance frequency two key parameters through data processing after obtaining the pressure oscillation signal, and carries out the solid rocket engine unstable combustion evaluation. The application has the advantages of simple structure, reusability and low cost.

Description

Technical Field

[0001] This invention relates to a high-frequency pulse trigger for stability assessment of solid rocket motors, belonging to the field of combustion instability in solid rocket motors. Background Technology

[0002] Unstable combustion in solid rocket motors generally refers to the periodic oscillations of pressure within the combustion chamber, which can lead to engine failure or even explosion. With the increasing demand for high maneuverability and high thrust, current solid rocket motors are mostly characterized by large aspect ratios and high fill ratios. The complex geometries and high-energy propellants used in unstable combustion have brought this issue back into focus. Nonlinear axial modal instability in solid rocket motors is typically caused by random, finite amplitude vibrations, such as those caused by the ejection of igniter and insulating debris from the nozzle; this is a triggered instability. Solid rocket motors often withstand harsh environments such as high overloads, and the mechanism of unstable combustion is highly complex, requiring experimental verification. Methods such as rocket skid tests, flight overload tests, and overload ignition tests on overload test benches are extremely costly; therefore, a simple and reliable method for assessing engine stability is urgently needed. This method should satisfy the stability assessment requirements of the engine structure during the design phase while saving on machine, manpower, and financial resources. Summary of the Invention

[0003] The main objective of this invention is to provide a high-frequency pulse trigger for evaluating the combustion stability of solid rocket engines. The pulse trigger has adjustable injection flow rate and trigger pressure, enabling stability prediction experiments of solid rocket engines under different trigger excitation intensities. A custom-designed diaphragm ruptures under a specified pressure, ensuring that the trigger ruptures at the designated pressure, preventing spontaneous rupture during engine operation and making the triggering timing controllable during hot testing. The pulse trigger outputs a high-frequency signal and is installed outside the engine acoustic cavity. Only when the pulser receives a sufficiently high high-frequency pressure oscillation can it excite as many of the inherent oscillations below that frequency in the solid rocket engine acoustic cavity as possible. After acquiring the pressure oscillation signal, the pressure oscillation signal analysis method obtains two key parameters—attenuation coefficient and resonant frequency—through data processing. Unstable combustion evaluation of the solid rocket engine is then performed based on these two parameters. The selection of the pulse trigger's throttling orifice diameter, diaphragm thickness, channel length, and chamber size is based on indicators such as excitation oscillation frequency, amplitude, average pressure rise, and flow rate. Furthermore, all structural components of the pulse trigger, except for the diaphragm and seals, are reusable.

[0004] The objective of this invention is achieved through the following technical solution.

[0005] The present invention discloses a high-frequency pressure pulse trigger for evaluating the combustion stability of rocket engines, comprising a pulse trigger, a data processing module for oscillating pressure, and a pulser performance prediction and structure selection module.

[0006] The high-frequency pressure pulse trigger is used to generate an oscillating pressure signal exceeding 6kHz, thereby exciting a lower intrinsic mode frequency within the engine combustion chamber and causing pressure oscillations within the engine combustion chamber. The pulse trigger includes a propellant holder, an ignition cartridge, a main housing, an end cap, a throttle ring, a transition channel, and a custom diaphragm.

[0007] The individual gunpowder box holder is used to hold black powder boxes and has internal threads reserved for installing finished ignition components.

[0008] The throttling ring is a short cylindrical axial sealing groove with a small central hole. The central hole plays a throttling role, and different orifice diameters are selected according to the actual flow rate.

[0009] The main housing can withstand pressures exceeding 100 MPa and includes the main housing body, the internal thread of the head that mates with the medicine box holder, and the external thread that mates with the end cap; the external thread of the main housing has a hole reserved for placing a throttling ring.

[0010] The end cap has a groove slightly larger than the outer diameter of the throttling ring on its inner side for placing a custom-made diaphragm.

[0011] The adapter channel is used to allow the gas box diaphragm to pass through the adapter channel. The adapter channel has a pre-drilled threaded hole for installing a pressure sensor, and an external thread is left on the outside of the channel to install the pulse generator on the outside of the engine.

[0012] Preferably, a platform is milled and threaded holes are tapped on the side of the main housing, and sensors are installed through the milled platform and tapped holes. The sensors include pressure sensors and thermocouples.

[0013] Preferably, the head of the main housing has an annular shallow groove for placing the sealing copper. When the medicine box holder is tightened, the copper is pressed together to complete the seal. The groove prevents the copper gasket from becoming misaligned because the diameter of the medicine box holder's relief groove is smaller than that of the copper, thus causing the seal to fail.

[0014] Preferably, the space in the main housing for accommodating the throttling ring should have a shallow groove, which is used to accommodate and limit the copper gasket to achieve end face sealing under high pressure.

[0015] Preferably, the throttling ring is equipped with an O-ring to add a circumferential seal.

[0016] As a preferred option, the rupture pressure of the customized diaphragm was determined through multiple black powder rupture experiments.

[0017] Preferably, the end cap has a shallow groove at the front end for placing copper to achieve a seal with the adapter.

[0018] Preferably, the pulse trigger housing is milled with steps around its perimeter to facilitate the use of installation tools.

[0019] The high-frequency pressure pulse trigger can generate an oscillating pressure signal exceeding 6kHz, thereby exciting a lower intrinsic mode frequency in the engine combustion chamber and causing pressure oscillations in the engine combustion chamber.

[0020] The oscillation pressure data analysis module determines the pressure oscillation frequency within the pulse generator and the tested object through spectrum analysis, determines the rise in average pressure of the tested object through low-pass filtering, obtains the oscillation pressure of each order of the tested object through band-pass filtering, and obtains the attenuation coefficient of the oscillation pressure through least-squares fitting. Engine stability is then assessed based on the attenuation coefficient. A larger attenuation coefficient amplitude indicates a more stable acoustic cavity structure, while a smaller attenuation coefficient amplitude indicates less damping in the acoustic cavity structure and insufficient stability of the engine acoustic cavity structure.

[0021] Re(p'(x,t))=p m 'exp(αt)cos(ω n t-kx) (1)

[0022]

[0023] α is the acoustic cavity attenuation coefficient, and |α| is used to evaluate the stability of the engine acoustic cavity. Equation (1) is the analytical expression of pressure oscillation in the engine acoustic cavity obtained based on the linear stability theory. Based on this, the calculation formula (2) for the attenuation coefficient is derived.

[0024] The high-frequency pressure pulser exhibits nonlinear characteristics in the early stage of the pressure oscillation excited within the acoustic cavity, which is used to trigger nonlinear oscillations within the combustion chamber of a solid rocket motor.

[0025] The pulse trigger pulse generator performance prediction and structure selection module, based on the internal ballistic prediction model of the pulse trigger and measured basic data, realizes parameter selection, including throttling orifice diameter, chamber size, channel diameter, and channel length.

[0026] The high-frequency pressure pulse trigger for rocket engine combustion stability assessment disclosed in this invention comprises the following steps:

[0027] Step 1: Apply a small amount of red glue to the glass tube and screw it into the main housing, aligning the small hole on the glass tube with the sensor hole on the main housing. The small amount of red glue refers to enough to lubricate and bond the glass tube into the main housing while preventing it from being difficult to remove after use.

[0028] Step 2: Place a copper sheet at the hole at the front end of the main housing, and then insert the throttling ring horizontally.

[0029] Preferably, a sealing ring is placed around the throttling ring to assist in sealing, and then the throttling hole is inserted. Silicone grease is applied to the throttling ring for lubrication and sealing.

[0030] The copper gasket measures 28x20x1mm.

[0031] Step 3: Place the copper foil sheet in the center of the throttling orifice, aligning it, and apply silicone grease to secure it. Tighten the end cap, and use a vise and pipe wrench to press the main housing and front end cap firmly, leaving indentations on the copper at the throttling orifice to create a seal.

[0032] Step 4: Insert the copper fitting into the adapter channel, tighten the main housing end cap, screw the adapter on in the throttling orifice test, and check whether the exploding copper piece can fly out smoothly from the throttling orifice through the adapter.

[0033] Preferably, the copper pad has dimensions of 30x24x2mm. The throttling orifice is 6mm.

[0034] Step 5: The medicine box frame is sealed with copper. After the black powder is bonded, the copper is put on and the medicine box frame is tightened to the main shell. The medicine box frame is reprocessed and tightened with a wrench.

[0035] Step Six: Screw the standard ignition element into the medicine box holder and tighten it until the copper threads deform to form a seal.

[0036] Step 7: Install the sensor and its adapter onto the pulse generator.

[0037] Step 8: A custom-designed diaphragm rupture plate is used to trigger the pulse. This diaphragm ensures that the pulse trigger ruptures under a specified pressure, preventing spontaneous rupture during engine operation and making the triggering time controllable during hot testing. The pulse trigger outputs a high-frequency signal and is installed outside the engine acoustic cavity. Only when the pulser receives a sufficiently high high-frequency pressure oscillation can it excite as many of the natural oscillations below that frequency in the solid rocket engine's acoustic cavity as possible. After acquiring the pressure oscillation signal, the pressure oscillation signal analysis module processes the data to obtain two key parameters: the attenuation coefficient and the resonant frequency. Based on these two key parameters, an unstable combustion assessment of the solid rocket engine is performed.

[0038] Beneficial effects:

[0039] 1. The present invention discloses a high-frequency pressure pulse trigger and its working method for evaluating the combustion stability of solid rocket engines. The pulser can input a high-frequency oscillating pressure signal into the engine cavity, thereby exciting the engine acoustic cavity to undergo forced oscillation, thereby obtaining information such as the resonance frequency and attenuation coefficient of the acoustic cavity for evaluating the stability of its acoustic cavity structure. The larger the amplitude of the attenuation coefficient, the more stable the system. The resonance frequency is used to analyze the type of unstable combustion in complex acoustic cavity structures. The present invention has superior reliability and stability performance.

[0040] 2. The high-frequency pressure pulse trigger and its working method disclosed in this invention for evaluating the combustion stability of solid rocket engines, wherein a customized diaphragm ruptures at a specified pressure, which is highly efficient and controllable, and can be used for triggering and excitation experiments under the hot test conditions of solid rocket engines, forming pulse excitation at any time.

[0041] 3. The high-frequency pressure pulse trigger and its working method disclosed in this invention for evaluating the combustion stability of solid rocket engines inject mass flow rate and gas flow velocity through a control pulser with parameters such as throttling ring and channel area, and the parameters can be adjusted over a wide range.

[0042] 4. The high-frequency pressure pulse trigger and its working method for evaluating the combustion stability of solid rocket engines disclosed in this invention, based on the beneficial effects 1, 2, and 3, allow for adjustable injection flow rate and trigger pressure of the pulse trigger, enabling stability prediction experiments of solid rocket engines under different trigger excitation intensities.

[0043] 5. The high-frequency pressure pulse trigger and its working method for evaluating the combustion stability of solid rocket engines disclosed in this invention directly provide the attenuation coefficient and resonance frequency corresponding to the experimental data through the integration of data processing methods.

[0044] 6. The high-frequency pressure pulse trigger and its working method for evaluating the combustion stability of solid rocket engines disclosed in this invention adjust the high-frequency pressure oscillation frequency of the input engine by adjusting the length of the transition channel. Attached Figure Description

[0045] Figure 1 This is an assembly diagram of a pulse trigger.

[0046] Figure 2 This is a diagram of the medicine box shelf structure.

[0047] Figure 3 It is the main shell

[0048] Figure 4 It is a glass column tube

[0049] Figure 5 It is an end cap

[0050] Figure 6 It is a throttling ring

[0051] Figure 7 It is a constant pressure rupture membrane.

[0052] Figure 8 It is a transfer channel

[0053] Figure 9 This is a picture of the pulse generator assembly.

[0054] Figure 10 Measured data of pressure in the pulse generator and channel 1

[0055] Figure 11 This is a pressure oscillation and spectrum diagram of a certain engine.

[0056] The components are: 1—Powder box holder, 2—Main housing, 3—Glass cylinder tube, 4—End cap, 5—Throttle ring, 6—Custom diaphragm, 7—Adapter channel. 1.1—Connecting thread for ignition components, 1.2—Bonded part of the black powder box, 1.3—Glass cylinder tube sleeve, 2.1—Sealing copper, 2.2—Internal thread for head to mate with powder box holder, 2.3—Internal thread for mate with sensor, 2.4—Pre-drilled hole for throttle ring, 4.1—Pre-drilled hole for throttle ring, 4.2—Connecting thread for adapter, 5.1—Throttle hole, 5.2—Throttle ring sealing groove, 7.1—Engine connecting thread, 7.2—Pulse trigger connecting thread, 7.3—Sensor connecting thread. Detailed Implementation

[0057] To better illustrate the purpose and advantages of the present invention, the invention will be further described below in conjunction with the accompanying drawings and examples.

[0058] Example 1:

[0059] like Figure 1 The high-frequency pressure pulse trigger disclosed in this embodiment for evaluating the combustion stability of a solid rocket engine includes a cartridge holder 1, a main shell 2, a glass column tube 3, an end cap 4, a throttling ring 5, a custom diaphragm 6, and a transfer channel 7.

[0060] like Figure 2 The main features of the shown gunpowder box holder include: 1.1 connecting threads for the ignition components, 1.2 the bonding area for the black powder box, and 1.3 the glass tube sleeve. 1.1 The connecting threads for the ignition components mate with standard sintered copper ignition components to achieve a seal. 1.3 The glass tube sleeve is inserted into the glass tube 4 to limit its movement. 1.2 The bonding area for the black powder box is secured with AB glue.

[0061] like Figure 3 The main features of the main housing 2 shown include: sealing copper 2.1, medicine box holder connecting thread 2.2, sensor connecting thread 2.3, and throttle ring mating hole 2.4.

[0062] 2.1 The sealing copper is used for safety and limiting within the groove. 2.2 The medicine box holder 1 is screwed into the threaded hole to tighten the copper. 2.1 This achieves a seal.

[0063] A 1mm thick copper gasket needs to be placed between the throttling ring mating hole 2.4 and the throttling ring 5. The throttling ring 5 compresses the copper gasket to complete the seal.

[0064] like Figure 4The main feature of the glass column tube shown is that it has small holes drilled around its circumference that are aligned with the pressure measuring holes.

[0065] like Figure 5 The main features of the end cap 4 shown include a main housing connecting thread 4.1 and an adapter connecting thread 4.2.

[0066] The main housing connecting thread 4.1 has a circular groove at the top of the relief groove for clamping the custom diaphragm, and the adapter connecting thread 4.2 has a groove for placing the sealing copper.

[0067] like Figure 6 The main features of the throttling ring 5 shown include a throttling orifice 5.1 and a throttling ring sealing groove 5.2.

[0068] The diameter of the throttling orifice 5.1 is adjusted according to the actual flow rate and airflow velocity, and the throttling ring sealing groove 5.2 is used in conjunction with the O-ring to add a circumferential seal.

[0069] like Figure 7 The customized diaphragm 6 shown can be made of brass, and the specific thickness and the relationship between the rupture pressure are determined by experimental data.

[0070] like Figure 8 The main features of the adapter channel 7 shown include: engine connection thread 7.1, pulse trigger connection thread 7.2, and sensor connection thread 7.3.

[0071] The engine connection thread 7.1 mates with the internal thread of the engine chamber; the pulse trigger connection thread 7.2 mates with the thread at position 5 of the pulse trigger end cap; and the sensor connection thread 7.3 is used to connect the pressure sensor.

[0072] like Figure 9 The image shown is an actual picture of the pulse generator mounted on the engine head.

[0073] like Figure 10 The figure shows the measured experimental data within the pulser channel, from... Figure 10 (a) It can be seen that the pressure at measuring point 2 in the channel begins to rise 8.36 ms after ignition. At this time, the pressure value inside the pulse trigger is 50.1 MPa. The pressure data at measuring point 2 indicates that the pulse trigger provides an oscillating pressure signal to the engine chamber, resulting in an increase in average pressure and forced oscillation within the engine acoustic cavity. Spectral analysis of measuring point 2 yields its power spectral density as follows: Figure 10 (a) The pulse trigger is input with a high-frequency oscillation with a main mode of 9.7 kHz, which can excite a mode of at least 9 kHz.

[0074] like Figure 11 The image shows pressure oscillations generated in the cavity of an engine under pulse excitation. Figure 11(a) is the engine pressure oscillation curve. The pulse trigger can excite obvious pressure oscillations in the engine. Figure 11 (b) and (c) show the attenuation coefficients at two measuring points of the engine after low-pass filtering to extract the oscillation signal and then performing logarithmic linear fitting. As can be seen from the figures, the engine pressure oscillation exhibits significant nonlinear characteristics. Meanwhile, the obtained attenuation coefficients can effectively assess engine stability. Figure 11 (d) is the pressure oscillation spectrum diagram. At least 7th order pressure oscillations were excited in the engine, and the clear pressure oscillations reached 3KHz.

[0075] like Figure 1 As shown in the figure, the high-frequency pulse trigger and its working method for engine combustion stability assessment disclosed in this embodiment are implemented in the following specific steps:

[0076] Step 1: Bonding of glass column tube 3

[0077] After applying a small amount of red glue to the glass column tube 3, screw it into the main housing, paying special attention to aligning the small hole on the glass column tube 3 with the sensor small hole 2.3 on the main housing. Do not apply too much red glue to prevent it from being difficult to remove after use.

[0078] Step 2: Install throttling ring 5

[0079] First, place a 28x20x1 copper sheet at the hole at the front end of the main housing. If necessary, a sealing ring can be placed in the circumferential sealing groove 5.2 to assist in sealing.

[0080] Next, insert the throttling ring 5 and apply silicone grease circumferentially as needed for lubrication and sealing.

[0081] Step 3: Install the front cover 4

[0082] Place the custom copper foil sheet 6 in the center of the throttling orifice 5.1, aligning it. If necessary, apply an appropriate amount of silicone grease to secure it. Then tighten the end cap, paying special attention to using a vise and pipe wrench to firmly press the main housing and end cap together, ensuring an indentation in the copper at the throttling orifice 5.1. This will ensure a good seal.

[0083] Step 4: Installation of the adapter channel

[0084] First, insert the 30x24x2 copper piece into the adapter 7 and tighten it onto the end cap 5. The adapter must be tightened during the experiment with the 6mm throttling orifice 5.1, as this will verify whether the exploding copper piece 6 can successfully fly out of the throttling orifice 5.1.

[0085] Step 5: Installation of Medicine Box Holder 1

[0086] The medicine box frame 1 is sealed with copper. After the black powder is bonded, a 30x24x2 copper 2.1 is fitted on and tightened. The medicine box frame 1 has been reprocessed and can be tightened with a wrench.

[0087] Step Six: Installation of Flame Transmission Components

[0088] Screw the standard ignition element into the medicine box holder 1 and tighten it. The copper threads deform to form a seal.

[0089] Step 7: Sensor Installation

[0090] Install the sensor and its adapter on the pulser sensor hole 2.3.

[0091] Step 8: Ignition and Data Acquisition

[0092] Connect the ignition wire, ignite, and collect experimental data.

[0093] Step Nine: Data Processing

[0094] By fitting the attenuation coefficient, the resonant frequency is obtained through spectral analysis.

[0095] The above detailed description further illustrates the purpose, technical solution, and beneficial effects of the invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. An experimental system for evaluating the combustion stability of solid rocket motors, characterized in that: Includes a high-frequency pressure pulse trigger and an oscillating pressure data analysis module; The high-frequency pressure pulse trigger is used to generate an oscillating pressure signal exceeding 6KHz, thereby exciting a lower intrinsic mode frequency in the engine combustion chamber and causing pressure oscillation in the engine combustion chamber; the high-frequency pressure pulse trigger includes a pill holder (1), an ignition pill holder, a main housing (2), an end cap (4), a throttle ring (5), a transfer channel (7), and a custom diaphragm (6). The single gunpowder box holder (1) is used to place the black powder box and has an internal thread (1.1) reserved for installing finished ignition components. The throttling ring (5) is a short cylindrical axial sealing groove with a small hole in the center. The small hole in the center plays a throttling role. Different throttling holes with different diameters are selected according to the actual flow rate indicators. The main housing (2) withstands pressure exceeding 100MPa, including the main housing body, the internal thread (2.2) that mates with the medicine box holder, and the external thread that mates with the end cap; the external thread of the main housing is reserved with a hole (2.4) for placing a throttling ring. The end cap has a groove (4.1) slightly larger than the outer diameter of the throttling ring reserved on its inner side for placing a custom diaphragm (6). The transfer channel is used to allow the gas and diaphragm to pass through the transfer channel. The transfer channel has a pre-drilled threaded hole (7.3) for installing a pressure sensor, and an external thread (7.1) is left on the outside of the channel to install the pulse generator on the outside of the engine. The high-frequency pressure pulse trigger can generate an oscillating pressure signal exceeding 6kHz, thereby exciting a lower intrinsic mode frequency in the engine combustion chamber and causing pressure oscillations in the engine combustion chamber. The oscillation pressure data analysis module determines the pressure oscillation frequency within the pulse generator and the tested object through spectrum analysis, determines the rise in the average pressure of the tested object through low-pass filtering, obtains the oscillation pressure of the tested object at each order through band-pass filtering, obtains the attenuation coefficient of the oscillation pressure through least squares fitting, and performs engine stability assessment based on the attenuation coefficient. A larger attenuation coefficient amplitude indicates a more stable acoustic cavity structure, while a smaller attenuation coefficient amplitude indicates less damping in the acoustic cavity structure and insufficient stability of the engine acoustic cavity structure. Let | be the acoustic cavity attenuation coefficient. |For evaluating the stability of engine acoustic chambers, formula The analytical expression for pressure oscillation within the engine acoustic cavity is derived based on linear stability theory, and the formula for calculating the attenuation coefficient is derived from this. ; The high-frequency pressure pulser exhibits nonlinear characteristics in the early stage of the pressure oscillation excited within the acoustic cavity, which is used to trigger nonlinear oscillations within the combustion chamber of a solid rocket motor.

2. The experimental system for evaluating the combustion stability of solid rocket motors as described in claim 1, characterized in that: The pulse trigger pulse generator performance prediction and structure selection module, based on the internal ballistic prediction model of the pulse trigger and measured basic data, realizes parameter selection, including throttling orifice diameter, chamber size, channel diameter, and channel length.

3. The experimental system for evaluating the combustion stability of solid rocket motors as described in claim 1 or 2, characterized in that: A platform is milled out and threaded holes are tapped on the side of the main housing. Sensors are installed through the milled platform and threaded holes. The sensors include pressure sensors and thermocouples. The main housing has a shallow annular groove at its head for placing a sealing copper piece. When the medicine box holder is tightened, the copper piece is pressed together to complete the seal. The groove prevents the copper gasket from becoming misaligned because the diameter of the medicine box holder's retraction groove is smaller than that of the copper piece. The space in the main housing for placing the throttling ring should have a shallow groove, which is used to place and limit the copper gasket (2.1) to achieve end face sealing under high pressure.

4. The experimental system for evaluating the combustion stability of solid rocket motors as described in claim 3, characterized in that: The throttling ring can be equipped with an O-ring to add a circumferential seal; The end cap front end (4.2) has a shallow groove for placing copper to achieve a seal with the adapter.

5. The experimental system for evaluating the combustion stability of solid rocket motors as described in claim 4, characterized in that: The rupture pressure of the custom-made diaphragm was determined through multiple black powder rupture experiments.

6. The experimental system for evaluating the combustion stability of solid rocket motors as described in claim 5, characterized in that: Steps are milled around the perimeter of the pulse trigger housing.

7. A working method for an experimental system for evaluating the combustion stability of solid rocket engines, based on the experimental system for evaluating the combustion stability of solid rocket engines as described in claim 6, characterized in that: Includes the following steps, Step 1: Apply a small amount of red glue to the glass tube and screw it into the main housing, aligning the small hole on the glass tube with the small hole on the sensor on the main housing; the small amount of red glue refers to the amount of red glue sufficient to lubricate and bond the glass tube into the main housing and to prevent it from being difficult to remove after use. Step 2: Place a copper sheet at the hole at the front end of the main housing; Step 3: Place the copper foil sheet in the center of the throttling orifice, align it, and fix it by applying silicone grease; tighten the end cap, and use vise and pipe wrench to press the main housing and the front end cap firmly, so that the copper at the throttling orifice has an indentation, which has a sealing effect. Step 4: Insert the copper into the adapter channel, tighten the adapter channel (7) and end cap (4), tighten the adapter channel (7) in the throttling hole test, and check whether the exploding copper piece can fly out smoothly from the throttling hole through the adapter. Step 5: The medicine box frame is sealed with copper. After the black powder is bonded, the copper is put on and the medicine box frame (1) is tightened to the main shell (2). The medicine box frame (1) is reprocessed and tightened with a wrench. Step Six: Screw the standard ignition element into the medicine box holder and tighten it until the copper threads deform to form a seal; Step 7: Install the sensor and its adapter onto the pulse generator; Step 8: Customized diaphragm rupture plate (6) for pulse trigger. The customized diaphragm rupture plate (6) for the trigger can rupture the membrane under a specified pressure. This diaphragm ensures that the pulse trigger ruptures the membrane under a specified pressure, avoiding spontaneous rupture of the membrane during engine operation, so that the triggering time of the pulser can be controlled when it is used for hot testing. The pulse trigger outputs a high-frequency signal. The pulse trigger is installed outside the engine acoustic cavity. Only when the pulser inputs a sufficiently high-frequency pressure oscillation can the inherent oscillations of the solid rocket engine acoustic cavity below that frequency be excited as much as possible. After acquiring the pressure oscillation signal, the pressure oscillation signal analysis module obtains two key parameters, the attenuation coefficient and the resonance frequency, through data processing. Based on these two key parameters, the unstable combustion assessment of the solid rocket engine is performed.

8. The experimental system operating method for evaluating the combustion stability of solid rocket motors as described in claim 7, characterized in that: A sealing ring is placed around the circumference to assist in sealing, and then the throttling hole is inserted. Silicon grease is applied around the throttling ring (5) to lubricate and seal it. The copper sheet measures 28x20x1.

9. The experimental system operating method for evaluating the combustion stability of solid rocket motors as described in claim 7, characterized in that: The dimensions of the copper sleeve are 30x24x2; the throttling orifice is 6mm.

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