CN108181423B - Apparatus and method for measuring velocity coupled response function of propellant first-order oscillation mode - Google Patents

Abstract

The invention discloses a method for measuring a velocity coupling response function of a first-order oscillation mode of a propellant. A T-shaped burner with a length of L is selected. The T-shaped burner includes a burner body, and two ends in the burner body are respectively A propellant specimen holder with the same configuration and formula is installed, a nozzle connected to the inside of the burner body is installed at L/2, and a high-frequency response pressure sensor is installed on the outer walls of both ends of the burner body. A trigger excitation device is respectively installed on the outer walls of both ends. By installing the tablet medicine and the ring-shaped test medicine on the T-shaped burner, the velocity coupling response function at the first-order acoustic vibration frequency is solved; the first-order frequency obtained in the prior art is solved. The problem of low accuracy of pressure oscillation characteristics.

Description

Apparatus and method for measuring velocity coupled response function of propellant first-order oscillation mode

【Technical field】

The invention belongs to the technical field of solid propellants, in particular to a device and a method for measuring a velocity coupling response function of a first-order oscillation mode of a propellant.

【Background technique】

The velocity coupling method of the first-order oscillation mode of solid propellant that is often used at present has the following shortcomings: (1) In the experiment, the driving charge is used to generate excitation, while for the composite propellant, the combustion products of the composite propellant contain a large number of solid particles and dust, particles. The damping is relatively large, and it is difficult to form self-excited oscillation; (2) the propellant formulations of the driving drug and the test drug are different, and the pressure coupling response functions of the two drugs need to be measured separately, and each experiment needs to be measured several times, the number of experiments more.

[Content of the invention]

The purpose of the present invention is to provide a velocity coupling response function measurement device and method for the first-order oscillation mode of propellant, so as to solve the problem of low precision of the pressure oscillation characteristic of the first-order frequency obtained in the prior art.

The present invention adopts the following technical scheme: a method for measuring the velocity coupling response function of the first-order oscillation mode of the propellant, which specifically includes the following steps:

Step 1. According to f=a/(2L), select a T-shaped burner with a length of L, where f is the fundamental frequency of pressure oscillation, and a is the theoretical sound speed at the combustion temperature of the propellant; the T-shaped burner includes combustion The two ends of the burner body are respectively equipped with propellant test specimen clips, the L/2 position on the burner body is installed with a nozzle that communicates with its interior, and the outer walls of both ends of the burner body are respectively installed with a high-frequency response pressure sensor , each pressure sensor is used to measure the pressure oscillation signal in the burner body; a trigger excitation device is respectively installed on the outer walls of both ends of the burner body, and each trigger excitation device 3 is used to generate pressure oscillation in the burner body;

Step 2. Test by installing the test tablet medicine and ring medicine on the T-type burner, and obtain the velocity coupling response function at the first-order acoustic vibration frequency through the test result:

为平均压强；S_C为通道面积；S_B为推进剂燃面面积；r为推进剂燃速；ρ_p为推进剂密度；α_V(L/4)为将测试用片状药推进剂安装于两端的推进剂试剂夹5、且将测试用环状药安装于T型燃烧器内L/4位置时的速度耦合项；α_V(3L/4)为将测试用片状药推进剂安装于两端的推进剂试剂夹5、且将测试用环状药安装于T型燃烧器内3L/4位置时的速度耦合项。Among them, γ is the specific heat ratio;

is the average pressure; S _C is the channel area; S _B is the propellant burning surface area; r is the propellant burning rate; ρ _p is the propellant density; α _{V (L/4)} is the test tablet propellant installed The velocity coupling term when the propellant reagent clips 5 at both ends and the test ring drug is installed at the L/4 position in the T-type burner; α _V(3L/4) is the test tablet propellant installed The velocity coupling term when the propellant reagent clips 5 at both ends and the annular drug for testing are installed at the 3L/4 position in the T-type burner.

Further, the specific method of step 2 is:

Step 2.1. Install the test tablet propellant on the propellant specimen clips at both ends of the T-type burner, turn on the data acquisition system, activate the pressure sensor, and simultaneously activate the ignition switches of the two propellant specimen clips, so that the two The test propellant at the end is ignited at the same time;

At time _t1 after ignition, one of the trigger excitation devices is triggered to form the first trigger excitation, and the pressure sensor measures the oscillation attenuation coefficient α ₁ of the working pressure in the burner body;

After the first triggering excitation is successful, delay time _t2 , trigger another triggering excitation device to form the second triggering excitation, and measure the working pressure oscillation attenuation coefficient _α2 in the burner body by the pressure sensor;

Among them, t ₁ =t/2, t is the total combustion time of the propellant; t ₂ =tt ₁ +t ₃ , when the propellant placed at both ends is a cup-shaped charge, t ₃ =10ms; when the propellant is a sheet-shaped charge During medicine, t ₃ =0ms;

According to the working pressure attenuation coefficients α ₁ and α ₂ , the net sound pressure growth rate α _G =α _c0 =α ₁ -α ₂ produced by propellant combustion is obtained, where α _c0 is the combustion surface of the propellant specimen at both ends gain, and according to the pressure coupling response function expression, the response function value with the oscillation frequency f is obtained;

为测得的平均燃速；a为推进剂燃烧温度下的理论声速；a_m为实测声速，a_m＝2fL；in,

is the measured average burning speed; a is the theoretical sound speed at the combustion temperature of the propellant; a _m is the measured sound speed, a _m = 2fL;

Step 2.2. Install the test tablet propellant on the propellant specimen clips at both ends of the T-type burner, and install the test ring-shaped charge at the L/4 position in the T-type burner. Follow the steps in step 2.1. The method performs ignition and two trigger excitations, and through the recorded data of the pressure sensor 4, the net sound pressure growth rate α _G(L/4) = α _c0 +α _c(L/4) + α _V generated by the propellant combustion is obtained. _(L/4) ;

Among them, α _c(L/4) is the pressure coupling when the test tablet propellant is installed on the propellant reagent clips at both ends, and the test ring is installed at the L/4 position in the T-type burner item, and have

Wherein, at this time x=L/4, is the distance between the annular drug for testing and the end of the combustion chamber;

Step 2.3. Install the test tablet propellant on the propellant specimen clips 5 at both ends of the T-type burner, and install the test ring-shaped drug at the 3L/4 position in the T-type burner. Follow step 2.1. Ignition and two trigger excitations are carried out in the medium method, and through the recorded data of the pressure sensor, the net sound pressure growth rate α _G(3L/4) = α _c0 +α _c(3L/4) + α _V generated by the propellant combustion is obtained. _(3L/4) ;

Among them, α _{c (3L/4)} is the pressure coupling when the test tablet propellant is installed on the propellant reagent clips at both ends, and the test ring drug is installed at the 3L/4 position in the T-type burner item;

Among them, at this time x=3L/4, which is the distance between the annular drug for testing and the end of the combustion chamber;

Step 2.4. According to α _V(L/4) obtained in step 2.2 and α _V(3L/4) obtained in step 2.3, the velocity coupling response function at the first-order acoustic vibration frequency f is obtained:

Further, the specific method of step 2 is:

Step 2.1', install the test tablet propellant on the propellant specimen clips at both ends of the T-type burner, and install two identical test ring-shaped powders in the T-type burner L/4 and At the 3L/4 position, turn on the data acquisition system, activate the pressure sensor, and activate the ignition switches of the two propellant specimen clips at the same time, so that the test propellants at both ends are ignited at the same time;

At _t1 time after ignition, one of the triggering excitation devices is triggered to form the first triggering excitation; after the first triggering excitation is successful, the other triggering excitation device is triggered with a delay of _t2 time to form the second triggering excitation; Among them, t ₁ =t/2, t is the total combustion time of the propellant; t ₂ =tt ₁ +t ₃ , when the propellant placed at both ends is a cup-shaped charge, t ₃ =10ms; when the propellant is a sheet-shaped charge During medicine, t ₃ =0ms;

The sound pressure growth rate is obtained from the recorded data of the pressure sensor

α _G(L/4+3L/4) =α _c0 +α _c(L/4) +α _V(L/4) +α _c(3L/4) +α _V(3L/4) ;

Among them, α _c0 is the combustion surface gain of the propellant sample at both ends, α _c(L/4) is the test tablet propellant installed on the propellant reagent clips at both ends, and the test ring α _c(3L/4) installs the test tablet propellant on the propellant reagent clips at both ends, and attaches the test ring drug The pressure coupling term when installed in the 3L/4 position in the T-type burner;

Step 2.2', install the test tablet propellant on the propellant specimen clips at both ends of the T-type burner, and install the test ring-shaped drug at the L/4 position of the T-type burner, follow step 2.1' Ignition and two trigger excitations are carried out in the middle method, and through the recorded data of the pressure sensor, the net sound pressure growth rate α _G(L/4) = α _c0 +α _c(L/4) + α _V generated by the propellant combustion is obtained. _(L/4) ; and there is

Wherein, at this time x=L/4, is the distance between the annular drug for testing and the end of the combustion chamber;

Step 2.3', install the test tablet propellant on the propellant specimen clips at both ends of the T-type burner, and install the test ring-shaped drug at the 3L/4 position in the T-type burner, follow step 2.1 'In the method of ignition and two trigger excitations, through the recorded data of the pressure sensor, the net growth rate of sound pressure generated by propellant combustion α _G(3L/4) = α _c0 +α _c(3L/4) +α _V(3L/4) ;

Among them, α _{c (3L/4)} is the pressure coupling when the test tablet propellant is installed on the propellant reagent clips at both ends, and the test ring drug is installed at the 3L/4 position in the T-type burner item;

Among them, at this time x=3L/4, which is the distance between the annular drug for testing and the end of the combustion chamber;

Step 2.4', according to step 2.1', step 2.2', and step 2.3', α _c0 =α ₁ -α ₂ is obtained, where α ₁ and α ₂ are respectively the test tablet propellants installed on both ends of the T-type burner. When the propellant specimen is clamped on, the working pressure oscillation attenuation coefficient in the burner body after the first trigger excitation and the second trigger excitation;

And the response function value R _p (f) is obtained:

为测得的平均燃速；a为推进剂燃烧温度下的理论声速；a_m为实测声速，a_m＝2fL；in,

is the measured average burning speed; a is the theoretical sound speed at the combustion temperature of the propellant; a _m is the measured sound speed, a _m = 2fL;

Step 2.5', according to step 2.4', obtain the velocity coupling response function at the first-order acoustic vibration frequency:

Further, the thickness of the test ring medicine is less than or equal to 3%L.

Another technical solution of the present invention is: the measuring device used in the method for measuring the velocity coupling response function of the first-order oscillation mode of the propellant includes a T-shaped burner with a length of L, the T-shaped burner includes a burner body, and the combustion The two ends of the burner body are installed with propellant specimen clips of the same configuration and the same formula, and a trigger excitation device is respectively installed on the outer walls of the two ends of the burner body to generate pressure oscillations in the burner body; the burner The outer walls of the two ends of the body are also respectively equipped with high-frequency response pressure sensors, which are used to measure the pressure oscillation signal in the burner body;

It also includes a data acquisition system and an ignition sequence control system. The data acquisition system is respectively connected with the pressure sensor and the triggering excitation device; the triggering excitation device and the propellant test piece holder are both connected with the ignition sequence control system.

The beneficial effects of the present invention are: the present invention can accurately obtain the velocity coupling response function characteristics of the solid propellant under the action of the first-order acoustic oscillation frequency, so as to accurately analyze the propellant velocity in the non-linear combustion unstable oscillation environment of the solid rocket motor The coupled response characteristics lay the foundation for the experiment. Through the external trigger excitation, a precise and controllable single first-order frequency pressure oscillation phenomenon occurs during the working process of the T-type burner, so that the solid propellant velocity coupling response function can be obtained under the precise external trigger excitation control.

【Description of drawings】

Fig. 1 is the structural representation of T-type burner in the present invention;

Fig. 2 is the schematic diagram of sheet-like medicine and annular medicine for testing in the present invention;

Fig. 3 is the test result graph among the present invention;

FIG. 4 is a distribution diagram of sound pressure and sound vibration velocity of the first-order mode shape in the present invention.

Among them: 1. T-type burner; 2. Burner body; 3. Trigger excitation device; 4. Pressure sensor; 5. Propellant specimen holder; 6. Data acquisition system; 7. Ignition sequence control system; 9. Nozzle.

【Detailed ways】

The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

The invention discloses a method for measuring the velocity coupling response function of the first-order oscillation mode of propellant. The T-type burner 1, where f is the fundamental frequency of pressure oscillation, and a is the theoretical speed of sound at the combustion temperature of the propellant. On the premise that the length L (oscillation fundamental frequency f) of the T-type burner 1 remains unchanged, a two-way excitation trigger is used for triggering. In order to ensure that only a single first-order oscillation frequency (f=f ₁ ) is generated, the trigger excitation The device 3 needs to be placed at the two ends of the T-shaped burner 1, and the nozzle needs to be placed at the L/2 position, that is, the wave node of the first-order oscillation mode, to ensure the minimum loss of first-order sound energy. The test measurement adopts the double trigger excitation method. The trigger excitation is carried out at the middle and just end of the solid propellant combustion in the T-type burner 1, and the single-order pressure oscillation attenuation data is obtained. The Galerkin method is used to obtain two triggers respectively. The post-pressure oscillation attenuation coefficient is obtained to obtain the velocity coupling response function value under the action of the first-order oscillation frequency, which specifically includes the following steps:

Step 1. According to the fundamental frequency f of the pressure oscillation, a T-shaped burner 1 with a length of L is selected.

As shown in Figure 1, according to f=a/(2L), a T-shaped burner 1 with a length of L is selected. The T-shaped burner 1 includes a burner body 2, and two ends of the burner body 2 are respectively installed with The propellant sample holder 5 of the same configuration and formula, the burner body 2 is installed with a nozzle 9 communicating with its interior at L/2, and a high-frequency response pressure sensor 4 is installed on the outer walls of both ends of the burner body 2 respectively. Each of the pressure sensors 4 is used to measure the pressure oscillation signal in the burner body 2 . A trigger excitation device 3 is respectively installed on the outer walls of both ends of the burner body 2 , and each trigger excitation device 3 is used to generate pressure oscillation in the burner body 2 .

Step 2. By installing the test tablet and ring-shaped drug in the T-type burner 1, the tablet-shaped drug and the ring-shaped drug are shown in Figure 2, and the test is carried out, and the first-order acoustic vibration frequency is obtained through the test results. Velocity coupled response function:

为平均压强；S_C为通道面积；S_B为推进剂燃面面积；r为推进剂燃速；ρ_p为推进剂密度；α_V(L/4)为将测试用片状药推进剂安装于两端的推进剂试剂夹5、且将测试用环状药安装于T型燃烧器1内L/4位置时的速度耦合项；α_V(3L/4)为将测试用片状药推进剂安装于两端的推进剂试剂夹5、且将测试用环状药安装于T型燃烧器1内3L/4位置时的速度耦合项。Among them, γ is the specific heat ratio;

is the average pressure; S _C is the channel area; S _B is the propellant burning surface area; r is the propellant burning rate; ρ _p is the propellant density; α _{V (L/4)} is the test tablet propellant installed The velocity coupling term when the propellant reagent clips 5 at both ends and the test ring drug is installed at the L/4 position in the T-type burner 1; α _V(3L/4) is the test tablet propellant The velocity coupling term when the propellant reagent clips 5 are installed at both ends, and the test ring medicine is installed at the 3L/4 position in the T-type burner 1 .

Step 2 can be implemented by two methods, the first method is:

Step 2.1. Install the test tablet propellant on the propellant specimen clips 5 at both ends of the T-type burner 1, turn on the data acquisition system 6, activate the pressure sensor 4, and use the multi-channel ignition sequence control device to activate the two at the same time. The ignition switch of each propellant test piece clip 5 makes the test propellants at both ends ignite at the same time;

At time _t1 after ignition, one of the trigger excitation devices 3 is triggered to form the first trigger excitation, and the pressure sensor 4 measures the working pressure oscillation attenuation coefficient α ₁ in the burner body 2;

After the first path triggering excitation is successful, delay time _t2 to trigger another triggering excitation device 3 to form the second path triggering excitation, and measure the working pressure oscillation attenuation coefficient α2 in the burner body ₂ by the pressure sensor 4;

Among them, t ₁ =t/2, t is the total combustion time of the propellant; t ₂ =tt ₁ +t ₃ , when the propellant is a cup-shaped drug, t ₃ =10ms; when the propellant is a tablet-shaped drug, t ₃ = 0ms;

According to the oscillation attenuation coefficients α ₁ and α ₂ of the working pressure, the net sound pressure growth rate α _G =α _c0 =α ₁ -α ₂ can be obtained from the propellant combustion, where α _c0 is the combustion surface of the propellant specimen at both ends gain, and according to the pressure coupling response function expression, the response function value with the oscillation frequency f is obtained;

为测得的平均燃速；a为推进剂燃烧温度下的理论声速；a_m为实测声速，a_m＝2fL；in,

is the measured average burning speed; a is the theoretical sound speed at the combustion temperature of the propellant; a _m is the measured sound speed, a _m = 2fL;

Step 2.2. Install the test tablet propellant on the propellant specimen clips 5 at both ends of the T-type burner 1, and install the test ring-shaped propellant at the L/4 position in the T-type burner 1. The method in step 2.1 performs ignition and two trigger excitations, and through the recorded data of the pressure sensor 4, the net sound pressure growth rate α _G(L/4) = α _c0 +α _c(L/4) generated by propellant combustion is obtained. +α _V(L/4) ;

Among them, α _{c (L/4)} is the time when the test tablet propellant is installed on the propellant reagent clips 5 at both ends, and the test ring is installed at the L/4 position in the T-shaped burner 1 The pressure coupling term, and has

Among them, at this time x=L/4, which is the distance between the annular drug for testing and the end of the combustion chamber.

Step 2.3. Install the test tablet propellant on the propellant specimen clips 5 at both ends of the T-type burner 1, and install the test ring-shaped drug at the 3L/4 position in the T-type burner 1. The method in step 2.1 performs ignition and two trigger excitations, and through the recorded data of the pressure sensor 4, the net sound pressure growth rate α _G(3L/4) = α _c0 +α _c(3L/4) generated by the propellant combustion is obtained. +αV _(3L/4) ;

Among them, α _{c (3L/4)} is when the test tablet propellant is installed on the propellant reagent clips 5 at both ends, and the test ring medicine is installed in the 3L/4 position in the T-shaped burner 1 pressure coupling term;

Among them, at this time x=3L/4, which is the distance between the annular drug for testing and the end of the combustion chamber.

Step 2.4. According to α _V(L/4) obtained in step 2.2 and α _V(3L/4) obtained in step 2.3, the velocity coupling response function at the first-order acoustic vibration frequency is obtained:

The second specific method that can be used in step 2 is:

Step 2.1', install the tablet propellant for testing on the propellant specimen clips 5 at both ends of the T-type burner 1, and install two identical ring-shaped drugs for testing in the T-type burner 1 respectively. At the positions of /4 and 3L/4, turn on the data acquisition system 6, activate the pressure sensor 4, and simultaneously activate the ignition switches of the two propellant specimen clips 5, so that the test propellants at both ends are ignited at the same time;

At _t1 time after ignition, one of the triggering excitation devices ₃ is triggered to form the first triggering excitation; after the first triggering excitation is successful, the other triggering excitation device 3 is triggered after the first triggering excitation is successful, and the other triggering excitation device 3 is triggered to form the second triggering Excitation; where, t ₁ =t/2, t is the total combustion time of the propellant; t ₂ =tt ₁ +t ₃ , when the propellant placed at both ends is a cup charge, t ₃ =10ms; when the propellant is For tablet medicine, t ₃ =0ms;

Through the recorded data of the pressure sensor 4, the sound pressure growth rate is obtained

α _G(L/4+3L/4) =α _c0 +α _c(L/4) +α _V(L/4) +α _c(3L/4) +α _V(3L/4) ;

Among them, α _c0 is the combustion surface gain of the propellant sample at both ends, α _c(L/4) is the test tablet propellant installed on the propellant reagent clips 5 at both ends, and the test The annular medicine is installed in the pressure coupling item at the L _/ 4 position in the T-type burner 1; The pressure coupling term when the shape medicine is installed in the 3L/4 position in the T-type burner 1;

Step 2.2', install the tablet propellant for testing on the propellant sample clips 5 at both ends of the T-type burner 1, and install the ring-shaped drug for testing at the L/4 position in the T-type burner 1, Carry out ignition and two trigger excitations according to the method in step 2.1', through the recorded data of the pressure sensor 4, the net sound pressure growth rate α _G(L/4) = α _c0 +α _{c(L/ 4)} +α _V(L/4) ; and there is

Among them, at this time x=L/4, which is the distance between the annular drug for testing and the end of the combustion chamber.

Step 2.3', install the tablet propellant for testing on the propellant test clips 5 at both ends of the T-type burner 1, and install the ring-shaped drug for testing at the 3L/4 position in the T-type burner 1, Carry out ignition and two trigger excitations according to the method in step 2.1', through the recorded data of pressure sensor 4, obtain the net growth rate of sound pressure α _G(3L/4) = α _c0 +α _{c(3L/ 4)} +α _V(3L/4) ;

Among them, α _{c (3L/4)} is when the test tablet propellant is installed on the propellant reagent clips 5 at both ends, and the test ring medicine is installed in the 3L/4 position in the T-shaped burner 1 pressure coupling term;

Among them, at this time x=3L/4, which is the distance between the annular drug for testing and the end of the combustion chamber.

In step 2.4', according to step 2.1', step 2.2', and step _2.3 ', α _{c0 =} α ₁ -α ₂ is obtained. When the propellant specimen clamp 5 at the end of the burner is on, the working pressure oscillation attenuation coefficient in the burner body 2 after the first trigger excitation and the second trigger excitation;

And the response function value R _p (f) is obtained:

为测得的平均燃速；a为推进剂燃烧温度下的理论声速；a_m为实测声速，a_m＝2fL；in,

is the measured average burning speed; a is the theoretical sound speed at the combustion temperature of the propellant; a _m is the measured sound speed, a _m = 2fL;

Step 2.5', according to step 2.4', obtain the velocity coupling response function at the first-order acoustic vibration frequency:

The thickness of the test ring drug in each step of the above two methods is less than or equal to 3%L.

The invention also discloses a measuring device used in the method for measuring the velocity coupling response function of the first-order oscillation mode of the propellant. The two ends of the burner body 2 are installed with propellant sample holders 5 of the same configuration and the same formula, and a trigger excitation device 3 is respectively installed on the outer walls of both ends of the burner body 2 for generating in the burner body 2. Pressure oscillation; high-frequency response pressure sensors 4 are respectively installed on the outer walls of the two ends of the burner body 2 for measuring the pressure oscillation signal in the burner body 2;

It also includes a data acquisition system 6 and an ignition timing control system 7. The data acquisition system 6 is respectively connected with the pressure sensor 4 and the trigger excitation device 3; the trigger excitation device 3 and the propellant sample holder 5 are connected with the ignition timing control system 7. .

Claims (4)

1. the velocity coupling response function measurement method of propellant first-order oscillation mode, is characterized in that, specifically comprises the following steps: Step 1. According to f=a/(2L), select a T-shaped burner (1) with a length of L, where f is the fundamental frequency of pressure oscillation, and a is the theoretical sound speed at the combustion temperature of the propellant; the T-shaped combustion The burner (1) includes a burner body (2), two ends of the burner body (2) are respectively installed with propellant test piece clamps (5), and the burner body (2) is installed at L/2 There is a nozzle (9) communicating with the inside thereof, and a high-frequency response pressure sensor (4) is respectively installed on the outer walls of both ends of the burner body (2), and each of the pressure sensors (4) is used to measure the burner body. (2) pressure oscillation signal; a trigger excitation device (3) is respectively installed on the outer walls of both ends of the burner body (2), and each trigger excitation device (3) is used for the burner body (2). ) produces pressure oscillations; Step 2. The test is carried out by installing the test tablet medicine and ring-shaped medicine in the T-type burner (1), and the velocity coupling response function at the first-order acoustic vibration frequency is obtained through the test result:

Among them, γ is the specific heat ratio;

is the average pressure; S _C is the channel area; S _B is the propellant burning surface area; r is the propellant burning rate; ρ _p is the propellant density; α _{V (L/4)} is the test tablet propellant installed The speed coupling term when the propellant reagent clips (5) at both ends and the test ring drug is installed in the T-type burner (1) at the L/4 position; α _{V (3L/4)} is the test piece The speed coupling term when the drug-like propellant is installed in the propellant reagent clips (5) at both ends, and the annular drug for testing is installed at the 3L/4 position in the T-shaped burner (1). 2. the velocity coupling response function measuring method of propellant first-order oscillation mode as claimed in claim 1, is characterized in that, the concrete method of step 2 is: Step 2.1. Install the tablet propellant for testing on the propellant specimen clamps (5) at both ends of the T-type burner (1), turn on the data acquisition system (6), activate the pressure sensor (4), and simultaneously activate the two The ignition switches of the propellant test specimen clips (5) make the test propellants at both ends ignite simultaneously; At time _t1 after ignition, one of the trigger excitation devices (3) is triggered to form the first trigger excitation, and the pressure sensor (4) measures the working pressure oscillation attenuation coefficient α ₁ in the burner body (2); After the first path of trigger excitation is successful, delay time t ₂ to trigger another trigger excitation device (3) to form a second path of trigger excitation, and the pressure sensor (4) measures the working pressure oscillation attenuation coefficient in the burner body (2) α ₂ ; Among them, t ₁ =t/2, t is the total combustion time of the propellant; t ₂ =tt ₁ +t ₃ , when the propellant is a cup-shaped drug, t ₃ =10ms; when the propellant is a tablet-shaped drug, t ₃ = 0ms; According to the oscillation attenuation coefficients α ₁ and α ₂ of the working pressure, the net sound pressure growth rate α _G =α _c0 =α ₁ -α ₂ can be obtained from the propellant combustion, where α _c0 is the combustion surface of the propellant specimen at both ends gain, and according to the pressure coupling response function expression, the response function value with the oscillation frequency f is obtained;

in,

is the measured average burning speed; a is the theoretical sound speed at the combustion temperature of the propellant; a _m is the measured sound speed, a _m = 2fL; Step 2.2. Install the test tablet propellant on the propellant specimen clips (5) at both ends of the T-shaped burner (1), and install the test ring-shaped drug on the T-shaped burner (1) At the inner L/4 position, ignition and two trigger excitations are carried out according to the method in step 2.1, and through the recorded data of the pressure sensor (4), the net sound pressure growth rate α _{G (L/4 )} =α _c0 +α _c(L/4) +α _V(L/4) ; Wherein, α _c(L/4) is the test tablet propellant installed on the propellant reagent clips (5) at both ends, and the test ring medicine installed in the T-shaped burner (1) L/4 The pressure coupling term at position 4, and has

Wherein, at this time x=L/4, is the distance between the annular drug for testing and the end of the combustion chamber; Step 2.3. Install the tablet propellant for testing on the propellant specimen clips (5) at both ends of the T-shaped burner (1), and install the annular drug for testing on the T-shaped burner (1) At the inner 3L/4 position, ignition and two trigger excitations are carried out according to the method in step 2.1, and through the recorded data of the pressure sensor (4), the net sound pressure growth rate α _{G (3L/4 )} =α _c0 +α _c(3L/4) +α _V(3L/4) ; Among them, α _{c (3L/4)} is the test tablet propellant installed on the propellant reagent clips (5) at both ends, and the test ring medicine installed in the T-shaped burner (1) 3L/ Pressure coupling term at position 4;

Among them, at this time x=3L/4, which is the distance between the annular drug for testing and the end of the combustion chamber; Step 2.4. According to α _V(L/4) obtained in step 2.2 and α _V(3L/4) obtained in step 2.3, the velocity coupling response function at the first-order acoustic vibration frequency f is obtained:

3. the velocity coupling response function measuring method of propellant first-order oscillation mode as claimed in claim 1, is characterized in that, the concrete method of step 2 is: Step 2.1', install the test tablet propellant on the propellant test clips (5) at both ends of the T-type burner (1), and install two identical test ring drugs on the T-shaped burner (1). At the L/4 and 3L/4 positions in the burner (1), the data acquisition system (6) is turned on, the pressure sensor (4) is activated, and the ignition switches of the two propellant test specimen holders (5) are activated at the same time, so that the two The test propellant at the end is ignited at the same time; At _t1 time after ignition, one of the triggering excitation devices (3) is triggered to form the first triggering excitation; after the first triggering excitation is successful, the other triggering excitation device (3) is triggered with a delay of _t2 time to form The second trigger excitation; wherein, t ₁ =t/2, t is the total combustion time of the propellant; t ₂ =tt ₁ +t ₃ , when the propellants placed at both ends are cup-shaped, t ₃ =10ms; When the propellant is a tablet, t ₃ =0ms; Through the recorded data of the pressure sensor (4), the sound pressure growth rate is obtained α _G(L/4+3L/4) =α _c0 +α _c(L/4) +α _V(L/4) +α _c(3L/4) +α _V(3L/4) ; Among them, α _c0 is the combustion surface gain of the propellant sample at both ends, α _c(L/4) is the test tablet propellant installed on the propellant reagent clips (5) at both ends, and the The annular charge for testing is installed in the pressure coupling item at the L/4 position in the T-type burner (1); α _{c (3L/4)} is used to install the tablet propellant for testing on the propellant reagent clips (5) at both ends and the pressure coupling term when the annular drug for testing is installed at the 3L/4 position in the T-type burner (1); Step 2.2', install the test tablet propellant on the propellant test clips (5) at both ends of the T-shaped burner (1), and install the test ring-shaped drug on the T-shaped burner (1). ) at the position of L/4, according to the method in step 2.1' to carry out ignition and two trigger excitations, through the recorded data of the pressure sensor (4), the net sound pressure growth rate α _{G (L /4)} =α _c0 +α _c(L/4) +α _V(L/4) ; and there is

Wherein, at this time x=L/4, is the distance between the annular drug for testing and the end of the combustion chamber; Step 2.3', install the tablet propellant for testing on the propellant test clips (5) at both ends of the T-shaped burner (1), and install the annular drug for testing on the T-shaped burner (1). ), at the position of 3L/4 in the 3L/4, according to the method in step 2.1' to carry out ignition and two trigger excitations, through the recorded data of the pressure sensor (4), the net sound pressure growth rate α _{G (3L /4)} =α _c0 +α _c(3L/4) +α _V(3L/4) ; Among them, α _{c (3L/4)} is the test tablet propellant installed on the propellant reagent clips (5) at both ends, and the test ring medicine installed in the T-shaped burner (1) 3L/ Pressure coupling term at position 4;

Among them, at this time x=3L/4, which is the distance between the annular drug for testing and the end of the combustion chamber; Step 2.4', according to step 2.1', step 2.2', step 2.3', obtain α _c0 =α ₁ -α ₂ , where α ₁ and α ₂ are respectively the test tablet propellants installed on the T-type burner (1 ) on the propellant specimen clamps (5) at both ends, the damping coefficient of the working pressure oscillation in the burner body (2) after the first trigger excitation and the second trigger excitation; And the response function value R _p (f) is obtained:

in,

is the measured average burning speed; a is the theoretical sound speed at the combustion temperature of the propellant; a _m is the measured sound speed, a _m = 2fL; Step 2.5', according to step 2.4', obtain the velocity coupling response function at the first-order acoustic vibration frequency:

4. The method for measuring the velocity coupled response function of the first-order oscillation mode of propellant according to any one of claims 1-3, wherein the thickness of the annular drug for testing is less than or equal to 3%L.

Images