CN108181424A - The speed coupling response function measurement device and method of propellant order Oscillating mode - Google Patents

Abstract

The invention discloses a method for measuring the velocity coupling response function of the second-order oscillation mode of the propellant. A T-shaped burner is selected. The T-shaped burner includes a burner body, and the two ends of the burner body are respectively installed with the same configuration and formula. The propellant sample clamp is installed at L/4 or 3L/4 of the length of the burner body with a nozzle connected to the inside, and a high-frequency response pressure sensor is installed on the outer wall of the burner body at both ends, and the pressure sensor is used to measure The pressure oscillation signal in the burner body; two trigger excitation devices are installed at L/2 of the length of the burner body, and the second-order Velocity coupling response function at the acoustic-vibration frequency; the present invention can obtain the pressure oscillation characteristics of a single second-order frequency without changing the length of the fundamental frequency T-type combustion experiment device.

Description

Velocity coupling response function measurement device and method for propellant second-order oscillation mode

technical field

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

Background technique

The velocity coupling method of the second-order oscillation mode of the solid propellant commonly used at present has the following disadvantages: (1) The driving charge is used to generate excitation in the experiment, and for the composite propellant, the combustion product contains a large amount of solid particles and dust, particles The damping is relatively large, and it is difficult to form self-excited oscillations; (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. There are many; (3) The second-order excitation is maintained by offset nozzles and combustible baffles, and how to place the combustible baffles is very difficult to operate in practice. A slight deviation in the position may excite other mode shapes.

Contents of the invention

The technical problem to be solved by the present invention is to provide a kind of not changing fundamental frequency length T-shaped combustion experimental device premise, obtain the pressure oscillation characteristic of single second-order frequency for the deficiency of above-mentioned prior art.

In order to solve the problems of the technologies described above, the technical solution adopted in the present invention is, the velocity coupling response function measurement method of propellant second-order oscillation mode, and this measurement method comprises as follows:

Step 1. Select a T-shaped burner with a length of L. The T-shaped burner includes a burner body. The two ends of the burner body are respectively equipped with propellant sample holders of the same configuration and formula. The length of the burner body is The L/4 or 3L/4 of the burner is equipped with a nozzle connected to the inside, and a high-frequency response pressure sensor is installed on the outer wall of the burner body at both ends, and the pressure sensor is used to measure the pressure oscillation signal in the burner body; Two trigger excitation devices are installed at L/2 of the body length, and the trigger excitation devices are used to generate pressure oscillation in the burner body;

Step 2. Test by installing the test flakes and rings on the T-shaped burner, and obtain the velocity coupling response function at the second-order acoustic-vibration frequency according to the test results:

or

Among them, α _G(L8) is when the test flake propellant is installed on the propellant specimen clamps at both ends of the T-shaped burner, and the test annular charge is installed at the L/8 position of the T-shaped burner The net growth rate of sound pressure produced by propellant combustion; α _G(3L/8) is the test piece propellant installed on the propellant specimen clamps at both ends of the T-shaped burner, and the test ring propellant installed The net growth rate of sound pressure generated by propellant combustion at the L/8 position of the T-shaped burner, α _G(L/8&5L/8) is the propellant installed at both ends of the T-shaped burner The net growth rate of the sound pressure generated by the propellant combustion when the test annular charge is installed at the positions L/8 and 5L/8 of the T-shaped burner, α _G(3L/8&7L/8) is the The propellant propellant for the test is installed on the propellant sample holders at both ends of the T-shaped burner, and the propellant combustion is generated when the annular charge for the test is installed at the positions 3L/8 and 7L/8 of the T-shaped burner. The net growth rate of sound pressure, γ is the specific heat ratio; S _C is the channel area; S _B is the propellant burning surface area; f is the fundamental frequency of pressure oscillation; r is the propellant burning rate; ρ _p is the propellant density.

Further, the specific method of step two is:

Step a, install the test propellant on the propellant sample holder, open the data acquisition system, start the pressure sensor, start the ignition switches of the two propellant sample holders simultaneously, so that the test propellants at both ends are ignited simultaneously;

At time t ₁ after ignition, trigger one of the trigger excitation devices to form the first trigger excitation, and measure the working pressure decay coefficient α ₁ in the burner body by the pressure sensor;

After the first trigger excitation is successful, delay the _t2 time to trigger another trigger excitation device to form the second trigger excitation, and measure the working pressure decay coefficient α ₂ in the burner body by the pressure sensor;

Among them, t ₁ =t/2, t is the total burning 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 working pressure attenuation coefficients α ₁ and α ₂ , the net growth rate of sound pressure generated by propellant combustion α _G ＝ α _c0 ＝ α ₁ - α ₂ , α _c0 is the combustion surface gain of the propellant specimen at both ends , and according to the pressure coupling response function expression, the response function value of the second-order oscillation frequency is obtained;

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

Step b. Install the flake propellant for the test on the propellant sample holders at both ends of the T-shaped burner, and install the ring-shaped charge for the test at the L/8 position in the T-shaped burner, and follow the steps in step a. The method is to carry out ignition and trigger excitation twice, and obtain the net growth rate of sound pressure generated by propellant combustion α _G(L/8) ＝ α _c0 + α _c(L/8) + α _{V( L/8)} ;

Among them, α _V(L/8) is the velocity coupling term when the test propellant is installed on both ends of the propellant reagent clip, and the test ring drug is installed at the L/8 position in the T-shaped burner ; α _c(L/8) is the pressure coupling item when the test propellant is installed on the propellant reagent clip at both ends, and the test ring drug is installed at the L/8 position in the T-shaped burner, and have

Wherein, at this moment x=L/8, is the distance between the annular drug and the end of the combustion chamber for testing;

Step c. Install the flake propellant for the test on the propellant sample holders at both ends of the T-shaped burner, and install the ring-shaped charge for the test at the position 3L/8 in the T-shaped burner. Follow the steps in step a. The method is to carry out ignition and trigger excitation twice, and obtain the net growth rate of sound pressure generated by propellant combustion α _G(3L/8) ＝ α _c0 + α _c(3L/8) + α _{V( 3L/8)} ;

Among them, α _V(3L/8) is the velocity coupling item when the propellant propellant of the test tablet is installed at both ends of the propellant reagent clip, and the test annular drug is installed at the position of 3L/8 in the T-shaped burner ; α _{c (3L/8)} is the pressure coupling item when the propellant of the test tablet is installed on the propellant reagent clip at both ends, and the ring drug for the test is installed at the position of 3L/8 in the T-shaped burner;

Wherein, this moment x=3L/8, is the distance of test ring drug and combustion chamber end;

Step d, according to step a, step b, step c obtain the velocity coupling response function under the second-order acoustic vibration frequency:

Further, the specific method of step two is:

Step a', the propellant for testing is installed on the propellant sample clip, the data acquisition system is turned on, the pressure sensor is started, and the ignition switches of the two propellant sample clips are started simultaneously, so that the test propellants at both ends are ignited simultaneously;

At time t ₁ after ignition, trigger one of the trigger excitation devices to form the first trigger excitation, and measure the working pressure oscillation attenuation coefficient α ₁ in the burner body by the pressure sensor;

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

Among them, t ₁ =t/2, t is the total burning 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 working pressure oscillation attenuation coefficients α ₁ and α ₂ , the net growth rate of sound pressure generated by propellant combustion α _G ＝ α _c0 ＝ α ₁ - α ₂ , α _c0 is the burning surface of the propellant specimen at both ends Gain, and the response function value of the second-order oscillation frequency is obtained according to the pressure coupling response function expression;

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

Step b', install the propellant of the flake propellant for testing on the propellant sample holders at both ends of the T-shaped burner, and install the ring-shaped propellant for the test at positions L/8 and 5L/8 in the T-shaped burner , according to the method in step a', carry out ignition and two trigger excitations, and obtain the net growth rate of sound pressure generated by propellant combustion through the recorded data of the pressure sensor

α _G(L/8&5L/8) ＝α _c0 +α _c(L/8) +α _c(5L/8) +α _V(L/8) +α _V(5L/8) ;

Among them, α _c0 is the burning surface gain of the propellant specimen at both ends, α _v(L/8) and α _v(5L/8) are the propellant propellants installed at both ends of the propellant propellant for testing Reagent clip, and the speed coupling item when the annular drug for testing is installed in the position L/8, 5L/8 in the T-shaped burner; α _c(L/8) and α _c(5L/8) are respectively the The pressure coupling item when the propellant propellant is installed at both ends of the propellant reagent clip and the annular drug for testing is installed at the L/8 and 5L/8 positions in the T-shaped burner, and there are

Wherein, at this moment x=L/8, is the distance between the annular drug and the end of the combustion chamber for testing;

Wherein, at this moment x=5L/8, is the distance between the annular drug and the end of the combustion chamber for testing;

Step c', install the propellant of flake propellant for testing on the propellant sample holders at both ends of the T-shaped burner, and install the ring-shaped propellant for testing at positions 3L/8 and 7L/8 in the T-shaped burner According to the method in step a', the ignition and two trigger excitations are carried out, and through the recorded data of the pressure sensor, the net growth rate of the sound pressure generated by the propellant combustion is obtained α _G(3L/8&7L/8) = α _c0 + α _{c( 3L/8)} +α _c(7L/8) +α _V(3L/8) +α _V(7L/8) ;

Among them, α _v(3L/8) and α _v(7L/8) are the propellant reagent clips with the test tablet propellant installed at both ends, and the test ring drug installed in the T-shaped burner The velocity coupling items at the positions of 3L/8 and 7L/8, α _c(3L/8) and α _c(7L/8) are respectively the propellant reagent clips that install the propellant of the tablet drug used in the test at both ends, and the The pressure coupling item when the test ring drug is installed at the positions of 3L/8 and 7L/8 in the T-shaped burner, and there are

Wherein, this moment x=3L/8, is the distance of test ring drug and combustion chamber end;

Wherein, at this moment x=7L/8, is the distance between the ring drug and the end of the combustion chamber for testing;

Step d', according to step a', step b', step c' get the velocity coupling response function under the second-order acoustic vibration frequency:

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

Another technical solution of the present invention: a measuring device used in the method for measuring the velocity coupling response function of the second-order oscillation mode of the propellant, including a T-shaped burner with a length of _L , and the T-shaped burner includes a burner body , the two ends of the burner body are installed with propellant sample clips of the same configuration and the same formula, and two trigger excitation devices are installed at the L/2 position on the outer wall of the burner body for Generate pressure oscillations; high-frequency response pressure sensors are installed on the outer walls of the two ends of the burner body to measure the pressure oscillation signal in the burner body; L/8 and 5L/8 of the length of the burner body, or 3L /8 and 7L/8 are provided with ring-shaped test drug specimen holders;

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

The device and method for measuring the velocity coupling response function of the propellant second-order oscillation mode of the present invention have the following advantages: under the premise of not changing the length of the fundamental frequency T-shaped combustion experiment device, the single second-order frequency can be obtained through an accurate and controllable trigger excitation method Pressure oscillation characteristics, and based on the oscillation characteristics, a measurement method of velocity coupling response function under the second-order pressure oscillation condition is proposed to obtain the velocity coupling response function characteristics of solid propellant.

Description of drawings

Fig. 1 is the structural representation of the velocity coupling response function measuring device of solid propellant second-order oscillation mode of the present invention;

Fig. 2 is the structural representation of used solid propellant tablet medicine and ring medicine among the present invention;

Fig. 3 is a time-pressure diagram obtained by a pressure sensor in an embodiment of 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; State test drug sample folder; 9. Nozzle.

Detailed ways

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

The invention discloses a method for measuring the velocity coupling response function of the second-order oscillation mode of the propellant. On the premise that the length L of the T-shaped burner 1 (oscillation fundamental frequency f=f ₁ ) remains unchanged, two excitation triggers are used. triggering in the same way, in order to ensure only a single second-order oscillation frequency (f ₂ =2f ₁ ), the trigger excitation device 3 needs to be placed at the L/2 position in the T-shaped burner 1, and in order to ensure the second-order sound energy loss The smallest nozzle needs to be placed at the L/4 (3L/4) position, which is the wave node of the second-order oscillation mode. The test measurement adopts the secondary trigger excitation method, and triggers the excitation at the middle moment and the moment just after the solid propellant burns in the T-shaped burner 1 to obtain a single second-order pressure oscillation attenuation data, and uses the Galerkin method to obtain two The attenuation coefficient of the pressure oscillation after the first trigger, so as to obtain the value of the velocity coupling response function under the action of the second-order oscillation frequency

The measurement method specifically includes the following steps:

Step 1. Select a T-shaped burner ₁ with a length of L according to the pressure oscillation fundamental frequency f 1, satisfying f ₁ =a/(2L), the T-shaped burner 1 includes a burner body 2, and the burner body 2 Propellant sample holders 5 of the same configuration and formula are respectively installed at both ends, and a nozzle 9 communicating with the interior of the burner body 1 is installed at L/4 or 3L/4 of the length of the burner body 1, and the outer walls of the two ends of the burner body 1 are uniform. A high-frequency response pressure sensor 4 is respectively installed, and the pressure sensor 4 is used to measure the pressure oscillation signal in the burner body 2; two trigger excitation devices 3 are installed at L/2 of the length of the burner body 2, and the trigger excitation device 3 is used for In order to generate pressure oscillation in the burner body 2, the trigger excitation device 3 can be selected from the device in ZL201310014235.1, which satisfies P _pulser = ~ 20MPa, P _pulser = ~ 50MPa, P _pulser = ~ 90MPa and P _pulser = ~ 150MPa. types.

Step 2. Test by installing the test tablet and ring drug on the T-shaped burner 1, and obtain the velocity coupling response function at the second-order acoustic vibration frequency according to the test results:

or

Among them, α _G(L/8) is to install the propellant of flake propellant for testing on the propellant specimen clamps at both ends of the T-shaped burner, and install the ring-shaped propellant for testing at the L/8 position of the T-shaped burner The net growth rate of sound pressure produced by propellant combustion; α _G(3L/8) is the propellant propellant installed on the propellant specimen clamps at both ends of the T-shaped burner, and the ring-shaped test propellant When the propellant is installed at the L/8 position of the T-shaped burner, the net growth rate of the sound pressure generated by the propellant combustion, α _G(L/8&5L/8) is the propellant installed at both ends of the T-shaped burner for the test propellant The net growth rate of sound pressure generated by propellant combustion when the propellant sample is clamped and the annular charge for testing is installed at the positions L/8 and 5L/8 of the T-shaped burner, α _G(3L/8&7L/8) In order to install the propellant of the tablet charge for testing on the propellant sample holders at both ends of the T-shaped burner, and the propellant burns when the annular charge for testing is installed at the positions 3L/8 and 7L/8 of the T-shaped burner The net growth rate of sound pressure generated, γ is the specific heat ratio; S _C is the channel area; S _B is the propellant burning surface area; f is the fundamental frequency of pressure oscillation; r is the propellant burning rate; ρ _p is the propellant density.

Step 2 can be implemented in two ways. The first method is specifically:

Step a, the test propellant is installed on the propellant specimen holder 5, the data acquisition system 6 is turned on, the pressure sensor 4 is started, and the ignition switches of the two propellant specimen holders 5 are started at the same time, so that the test propellants at both ends are simultaneously ignition;

After _t1 time of ignition, trigger one of the trigger excitation devices 3 to form the first trigger excitation, and measure the working pressure decay coefficient _α1 in the burner body 2 by the pressure sensor 4;

After the first trigger excitation succeeds, delay _t2 time again, trigger another trigger excitation device 3, form the second trigger excitation, and measure the working pressure decay coefficient α ₂ in the burner body 2 by the pressure sensor 4;

Among them, t ₁ =t/2, t is the total burning 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 working pressure attenuation coefficients α ₁ and α ₂ , the net growth rate of sound pressure generated by propellant combustion α _G ＝ α _c0 ＝ α ₁ - α ₂ , α _c0 is the combustion surface gain of the propellant specimen at both ends , and according to the pressure coupling response function expression, the response function value of the second-order oscillation frequency is obtained;

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

Step b. Install the propellant of flakes for testing on the propellant specimen holders 5 at both ends of the T-shaped burner 1, and install the annular drug for testing at the L/8 position in the T-shaped burner 1, according to The method in step a performs ignition and trigger excitation twice, and obtains the net growth rate of sound pressure generated by propellant combustion α _G(L/8) = α _c0 +α _c(L/8) through the recorded data of pressure sensor 4 +α _V(L/8) ;

Among them, α _{V (L/8)} is the speed when the propellant propellant of the test tablet is installed on the propellant reagent clip 5 at both ends, and the annular drug for the test is installed at the L/8 position in the T-shaped burner 1 Coupling term; α _c(L/8) is the propellant reagent clip 5 installed at both ends of the propellant propellant for the test, and the ring drug for the test is installed at the L/8 position in the T-shaped burner 1 pressure coupling term, and there are

Wherein, at this time x=L/8, which is the distance between the test ring drug and the end of the combustion chamber.

Step c, install the flake propellant for testing on the propellant sample holders 5 at both ends of the T-shaped burner 1, and install the annular drug for testing at the position 3L/8 in the T-shaped burner 1, according to The method in step a carries out ignition and two trigger excitations, and through the recorded data of the pressure sensor 4, the net growth rate of the sound pressure generated by the propellant combustion is obtained α _G(3L/8) = α _c0 +α _c(3L/8) +α _V(3L/8) ;

Among them, α _V(3L/8) is the speed when the propellant of the tablet drug propellant for the test is installed on the propellant reagent clip 5 at both ends, and the annular drug for the test is installed at the position of 3L/8 in the T-shaped burner 1 Coupling term; α _c(3L/8) is the propellant reagent clip 5 installed at both ends of the propellant propellant for the test, and the ring drug for the test is installed at the 3L/8 position in the T-shaped burner 1 pressure coupling term;

Wherein, at this time x=3L/8, which is the distance between the test ring drug and the end of the combustion chamber.

Step d, according to step a, step b, step c obtain the velocity coupling response function under the second-order acoustic vibration frequency:

Another method is specifically:

Step a', install the test propellant on the propellant sample holder 5, open the data acquisition system 6, start the pressure sensor 4, and start the ignition switches of the two propellant sample holders 5 at the same time, so that the test propellant at both ends Simultaneous ignition;

After _t1 time of 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 _α1 in the burner body 2;

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

Among them, t ₁ =t/2, t is the total burning 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 working pressure oscillation attenuation coefficients α ₁ and α ₂ , the net growth rate of sound pressure generated by propellant combustion α _G ＝ α _c0 ＝ α ₁ - α ₂ , α _c0 is the burning surface of the propellant specimen at both ends Gain, and get the response function value according to the pressure coupling response function expression;

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

Step b', install the propellant of flakes for testing on the propellant sample holders 5 at both ends of the T-shaped burner 1, and install the ring-shaped drug for testing in L/8 and 5L/ in the T-shaped burner 1 At position 8, according to the method in step a', carry out ignition and trigger excitation twice, and obtain the net growth rate of sound pressure generated by propellant combustion through the recorded data of pressure sensor 4

α _G(L/8&5L/8) ＝α _c0 +α _c(L/8) +α _c(5L/8) +α _V(L/8) +α _V(5L/8) ;

Among them, α _c0 is the burning surface gain of the propellant specimen at both ends, α _v(L/8) and α _v(5L/8) are the propellant propellants installed at both ends of the propellant propellant for testing Reagent clip 5, and the speed coupling item when the annular drug for testing is installed in the positions L/8 and 5L/8 in the T-shaped burner 1; α _c(L/8) and α _c(5L/8) are respectively The pressure coupling item when the propellant of the test tablet is installed on the propellant reagent clip 5 at both ends, and the ring drug for the test is installed at the positions L/8 and 5L/8 in the T-shaped burner 1, and has

Wherein, at this moment x=L/8, is the distance between the annular drug and the end of the combustion chamber for testing;

Wherein, at this time, x=5L/8, which is the distance between the test ring drug and the end of the combustion chamber.

Step c', install the propellant of flakes for testing on the propellant sample holders 5 at both ends of the T-shaped burner 1, and install the ring-shaped drug for testing in the T-shaped burner 1 at 3L/8 and 7L/ At position 8, according to the method in step a', carry out ignition and trigger excitation twice, and obtain the net growth rate of sound pressure generated by propellant combustion α _G(3L/8&7L/8) = α _c0 through the recorded data of pressure sensor 4 +α _c(3L/8) +α _c(7L/8) +α _V(3L/8) +α _V(7L/8) ;

Among them, α _v(3L/8) and α _v(7L/8) are the propellant reagent clips 5 that install the propellant of the tablet drug for testing at both ends, and the ring drug for testing is installed on the T-shaped burner Velocity coupling items at the positions of 3L/8 and 7L/8 in 1, α _c(3L/8) and α _c(7L/8) are the propellant reagent clips with the propellant of the test tablet installed at both ends respectively 5 , and the pressure coupling item when the annular drug for testing is installed in the position of 3L/8 and 7L/8 in the T-shaped burner 1, and there is

Wherein, this moment x=3L/8, is the distance of test ring drug and combustion chamber end;

Wherein, at this time x=7L/8, which is the distance between the test ring drug and the end of the combustion chamber.

Step d', according to step a', step b', step c' get the velocity coupling response function under the second-order acoustic vibration frequency:

Wherein, the thickness of the ring drug used for testing in the above steps is less than or equal to 3%L.

The present invention also discloses a measurement device used in the method for measuring the velocity coupling response function of the second-order oscillation mode of the propellant, as shown in FIG. The burner body 2, the two ends of the burner body 2 are equipped with propellant sample holders 5 of the same configuration and the same formula, and two trigger excitation devices 3 are installed at the L/2 position on the outer wall of the burner body 2 , used to generate pressure oscillation in the burner body 2; high-frequency response pressure sensors 4 are respectively installed on the outer walls of the two ends of the burner body 2, used to measure the pressure oscillation signal in the burner body 2; the burner body 2 L/8 and 5L/8, or 3L/8 and 7L/8 of the length are provided with ring-shaped test drug specimen holders 8 .

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

In the present embodiment, the length of T-type burner 1 is 3.438m, and diameter is 0.09m, and nozzle diameter is 0.006m. The working pressure of the T-shaped burner 1 is taken as 10MPa, and the frequency of the pulse excitation is the natural frequency of the second-order mode, that is, 340Hz. As shown in Figure 2, the flake propellant and ring propellant are the same formula. Considering the shortcomings of composite propellants, aluminum-free double-base propellants are used here. The test charges located at both ends are end-face burning charges, which are used to measure the pressure coupling response function, and the test charges located at L/8 and 3L/8 are annular charges, which are used to measure the velocity coupling response function. As shown in FIG. 3 , it is a time-pressure relationship graph obtained by the pressure sensor 4 .

Claims (5)

1. The velocity coupling response function measurement method of propellant second-order oscillation mode, it is characterized in that, this measurement method comprises as follows: Step 1. Select a T-shaped burner (1) whose length is L. The T-shaped burner (1) includes a burner body (2), and the two ends of the burner body (2) are respectively equipped with the same structure. type and formula propellant sample holder (5), the L/4 or 3L/4 of the length of the burner body (1) is equipped with a nozzle (9) communicating with the inside, the burner body (1 ) are equipped with a high-frequency response pressure sensor (4) on the outer walls at both ends, and the pressure sensor (4) is used to measure the pressure oscillation signal in the burner body (2); the length L of the burner body (2) Two trigger excitation devices (3) are installed at /2, and the trigger excitation devices (3) are used to generate pressure oscillation in the burner body (2); Step 2. Test by installing the test tablet and ring drug on the T-shaped burner (1), and obtain the velocity coupling response function at the second-order acoustic vibration frequency according to the test results: or Among them, α _G(L/8) is to install the propellant of flake propellant for testing on the propellant specimen clamps at both ends of the T-shaped burner, and install the ring-shaped propellant for testing at the L/8 position of the T-shaped burner The net growth rate of sound pressure produced by propellant combustion; α _G(3L/8) is the propellant propellant installed on the propellant specimen clamps at both ends of the T-shaped burner, and the ring-shaped test propellant When the propellant is installed at the _L/8 position of the T-shaped burner, the net growth rate of the sound pressure generated by the propellant combustion; The net growth rate of the sound pressure generated by the propellant combustion when the propellant sample is clamped and the annular charge for testing is installed at the positions L/8 and 5L/8 of the T-shaped burner; α _G(3L/8&7L/8) In order to install the propellant of the tablet charge for testing on the propellant sample holders at both ends of the T-shaped burner, and the propellant burns when the annular charge for testing is installed at the positions 3L/8 and 7L/8 of the T-shaped burner γ is the specific heat ratio; p is the average pressure; S _C is the channel area; S _B is the propellant burning surface area; f is the fundamental frequency of pressure oscillation; r is the propellant burning rate; ρ _p is Propellant density. 2. the velocity coupling response function measurement method of propellant second-order oscillation mode as claimed in claim 1, is characterized in that, the concrete method of step 2 is: Step a, install the test propellant on the propellant sample holder (5), turn on the data acquisition system (6), start the pressure sensor (4), and start the ignition switches of the two propellant sample holders (5) simultaneously , so that the test propellants at both ends are ignited simultaneously; After _t1 time of ignition, trigger one of the trigger excitation devices (3) to form the first trigger excitation, and measure the working pressure decay coefficient _α1 in the burner body (2) by the pressure sensor (4); After the first trigger excitation is successful, delay _t2 time to trigger another trigger excitation device (3) to form the second trigger excitation, and the pressure sensor (4) measures the working pressure decay in the burner body (2) Coefficient α ₂ ; Among them, t ₁ =t/2, t is the total burning 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 working pressure attenuation coefficients α ₁ and α ₂ , the net growth rate of sound pressure generated by propellant combustion α _G ＝ α _c0 ＝ α ₁ - α ₂ , α _c0 is the combustion surface gain of the propellant specimen at both ends , and according to the pressure coupling response function expression, the response function value of the second-order oscillation frequency is obtained; in, is the measured average burning velocity; a is the theoretical sound velocity at the propellant combustion temperature; a _m is the measured sound velocity, a _m =2fL; Step b, install the propellant of flakes for testing on the propellant sample holders (5) at both ends of the T-shaped burner (1), and install the ring-shaped drug for testing on the T-shaped burner (1) At the inner L/8 position, according to the method in step a, carry out ignition and trigger excitation twice, through the recorded data of the pressure sensor (4), obtain the sound pressure net growth rate α _{G (L/8 )} =α _c0 +α _c(L/8) +α _V(L/8) ; Among them, α _V(L/8) is the propellant reagent clip (5) that installs the propellant of the tablet drug for the test at both ends, and installs the ring drug for the test in the T-shaped burner (1) L/8 The velocity coupling term at position; α _c(L/8) is the propellant reagent clip (5) that installs the propellant of the flake drug propellant for the test at both ends, and installs the annular drug for the test on the T-shaped burner (1 ) at the L/8 position in the pressure coupling term, and have Wherein, at this moment x=L/8, is the distance between the annular drug and the end of the combustion chamber for testing; Step c, installing the propellant of flakes for testing on the propellant sample holders (5) at both ends of the T-shaped burner (1), and installing the ring-shaped drug for testing on the T-shaped burner (1) At the inner 3L/8 position, according to the method in step a, carry out ignition and trigger excitation twice, through the recorded data of the pressure sensor (4), obtain the sound pressure net growth rate α _{G(3L/8 )} =α _c0 +α _c(3L/8) +α _V(3L/8) ; Among them, α _{V (3L/8)} is the propellant reagent clip (5) that installs the propellant of the tablet drug propellant for the test at both ends, and installs the ring drug for the test in the T-shaped burner (1) 3L/8 The velocity coupling term at the position; α _c(3L/8) is the propellant reagent clip (5) that installs the propellant of the flake drug for testing at both ends, and installs the annular drug for testing on the T-shaped burner (1 ) The pressure coupling item at the position of 3L/8 within ); Wherein, this moment x=3L/8, is the distance of test ring drug and combustion chamber end; Step d, according to step a, step b, and step c, obtain the velocity coupling response function at the second-order acoustic vibration frequency: 3. the velocity coupling response function measurement method of propellant second-order oscillation mode as claimed in claim 1, is characterized in that, the concrete method of step 2 is: Step a', install the test propellant on the propellant sample holder (5), turn on the data acquisition system (6), start the pressure sensor (4), and simultaneously start the ignition of the two propellant sample holders (5) switch, so that the test propellants at both ends are ignited simultaneously; After _t1 time of ignition, trigger one of the trigger excitation devices (3) to form the first trigger excitation, and measure the working pressure oscillation attenuation coefficient _α1 in the burner body (2) by the pressure sensor (4); After the first trigger excitation is successful, delay _t2 time to trigger another trigger excitation device (3) to form the second trigger excitation, and the pressure sensor (4) measures the working pressure oscillation in the burner body (2) Attenuation coefficient α ₂ ; Among them, t ₁ =t/2, t is the total burning 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 working pressure α ₁ and α ₂ , the net growth rate of sound pressure generated by propellant combustion is obtained α _G ＝ α _c0 ＝ α ₁ - α ₂ , α _c0 is the burning surface gain of the propellant specimen at both ends, and According to the pressure coupling response function expression, the response function value of the second order oscillation frequency is obtained; in, is the measured average burning velocity; a is the theoretical sound velocity at the propellant combustion temperature; a _m is the measured sound velocity, a _m =2fL; Step b', installing the propellant propellant for the test on the propellant sample holders (5) at both ends of the T-shaped burner (1), and installing the ring drug for the test on the T-shaped burner (1) ) at positions L/8 and 5L/8, according to the method in step a', carry out ignition and trigger excitation twice, and obtain the net growth rate of sound pressure generated by propellant combustion through the recorded data of the pressure sensor (4) α _G(L/8&5L/8) ＝α _c0 +α _c(L/8) +α _c(5L/8) +α _V(L/8) +α _V(5L/8) ; Among them, α _c0 is the burning surface gain of the propellant specimen at both ends, α _v(L/8) and α _v(5L/8) are the propellant propellants installed at both ends of the propellant propellant for testing Reagent clip (5), and the speed coupling item when the annular medicine for testing is installed in the position L/8, 5L/8 in the T-shaped burner (1); α _c(L/8) , α _{c(5L/ 8)} When installing the propellant of the tablet drug for testing on the propellant reagent clips (5) at both ends, and installing the annular drug for testing at the positions L/8 and 5L/8 in the T-shaped burner (1) The pressure coupling term of , and there is Wherein, at this moment x=L/8, is the distance between the annular drug and the end of the combustion chamber for testing; Wherein, at this moment x=5L/8, is the distance between the annular drug and the end of the combustion chamber for testing; Step c', installing the propellant of flakes for testing on the propellant sample holders (5) at both ends of the T-shaped burner (1), and installing the annular drug for testing on the T-shaped burner (1) ) at positions 3L/8 and 7L/8, perform ignition and trigger excitation twice according to the method in step a', and obtain the net growth rate α of sound pressure generated by propellant combustion through the recorded data of the pressure sensor (4) _G(3L/8&7L/8) ＝α _c0 +α _c(3L/8) +α _c(7L/8) +α _V(3L/8) +α _V(7L/8) ; Among them, α _v(3L/8) and α _v(7L/8) are the propellant reagent clips (5) that install the propellant of the tablet drug for testing at both ends, and the ring drug for testing is installed in the T-shaped Velocity coupling terms at the positions of 3L/8 and 7L/8 in the burner (1), α _c(3L/8) and α _c(7L/8) are respectively Reagent clip (5), and the pressure coupling item when the annular medicine for testing is installed in the positions 3L/8 and 7L/8 in the T-shaped burner (1), and there are Wherein, this moment x=3L/8, is the distance of test ring drug and combustion chamber end; Wherein, at this moment x=7L/8, is the distance between the ring drug and the end of the combustion chamber for testing; Step d', according to step a', step b', step c' get the velocity coupling response function under the second-order acoustic-vibration frequency: 4. The method for measuring the velocity coupling response function of the propellant's second-order oscillation mode according to any one of claims 1-3, characterized in that the thickness of the test ring charge is less than or equal to 3%L. 5. a measuring device used in the velocity-coupled response function measuring method of the arbitrary described propellant second-order oscillation mode of claim 1-4, is characterized in that, comprises the T-shaped burner (1) that length is L, The T-shaped burner (1) includes a burner body (2), and propellant sample holders (5) of the same configuration and the same formula are installed at both ends of the burner body (2), and are mounted on the burner body ( 2) Two trigger excitation devices (3) are installed at the L/2 position on the outer wall to generate pressure oscillation in the burner body (2); The frequency response pressure sensor (4) is used to measure the pressure oscillation signal in the burner body (2); it is set at L/8 and 5L/8, or 3L/8 and 7L/8 of the length of the burner body (2) There is a ring-shaped test drug sample holder (8); It also includes a data acquisition system (6) and an ignition timing control system (7), the data acquisition system (6) is connected with the pressure sensor (4) and the trigger excitation device (3) respectively; the trigger excitation device (3) and the propellant sample holder (5) are all connected with the ignition timing control system (7).