CN117110516A - Method, device and system for testing flame combustion response of liquid propellant - Google Patents

Abstract

The invention relates to a method, a device and a system for testing flame combustion response of a liquid propellant, which comprise the steps of obtaining target characteristic response frequency; calculating a target combustion chamber length using the target characteristic response frequency; acquiring a target combustion chamber corresponding to the length of the target combustion chamber; respectively applying pulses to the target combustion chamber after ignition and flameout of the target combustion chamber by using a pulser; collecting pressure signals after ignition and flameout of a target combustion chamber by using a pressure sensor; drawing a pressure decay characteristic curve after ignition and flameout according to pressure signals of different positions after ignition and flameout of a target combustion chamber; and calculating the difference value of the attenuation coefficient of the pressure attenuation characteristic curve in the ignition and the attenuation coefficient of the pressure attenuation characteristic curve after flameout according to the pressure attenuation characteristic curve in the ignition and the flameout, and calculating the difference value as the combustion response of the propellant flame corresponding to the target characteristic response frequency. The method has the advantages of larger excitation amplitude and variable excitation frequency.

Description

Test methods, devices and systems for liquid propellant flame combustion response

Technical field

The invention relates to the field of aerospace technology, and in particular to a testing method, device and system for the flame combustion response of liquid propellant.

Background technique

Combustion instability is a common physical phenomenon in power devices involving combustion processes, ranging from solid and liquid rocket engines to aerospace engines and gas turbines. The problem of unstable combustion is caused by the coupling of acoustic oscillations in the combustion chambers of different devices with the combustion process, which may cause serious damage or even destruction of the power device.

Currently, the unsteady response prediction of the power unit can only be obtained by applying external excitation to the power unit. Existing technology centers usually use speakers or similar devices to directly apply acoustic excitation to the combustion chamber acoustic cavity to predict the unsteady response of the liquid propulsion combustion flame under acoustic excitation. For liquid propulsion power devices, the excitation source of this prediction method cannot provide a larger amplitude oscillation pulse, and the estimated value is significantly different from the unsteady response of the real scene. Moreover, this method can only perform a single oscillation pulse frequency. Unsteady state response is estimated.

Contents of the invention

Based on this, it is necessary to provide a testing method, device and system for the flame combustion response of liquid propellant with large excitation amplitude and variable excitation frequency in view of the above technical problems.

In a first aspect, the present invention provides a method for testing the flame combustion response of liquid propellant, which includes the following steps:

Obtain target feature response frequency;

Use the target characteristic response frequency to calculate the target combustion chamber length; specifically, input the target characteristic response frequency into the characteristic response frequency model or the characteristic response frequency software to calculate the target combustion chamber length;

Obtain the target combustion chamber corresponding to the target combustion chamber length;

Use a pulser to apply pulses to the target combustion chamber during ignition and after flameout;

Use a pressure sensor to collect the pressure signal of the target combustion chamber during ignition and after flameout;

Draw the pressure attenuation characteristic curve during ignition and after flameout according to the pressure signals at different positions of the target combustion chamber during ignition and after flameout;

Calculate the attenuation coefficient of the pressure attenuation characteristic curve during ignition and the attenuation coefficient of the pressure attenuation characteristic curve after flameout based on the pressure attenuation characteristic curve during ignition and after flameout respectively;

The difference between the attenuation coefficient of the pressure attenuation characteristic curve during ignition and the attenuation coefficient of the pressure attenuation characteristic curve after flameout is calculated to be the propellant flame combustion response corresponding to the target characteristic response frequency.

In one embodiment, the target combustion chamber is a whole or composed of multiple sub-combustion chambers with known characteristic response frequencies and lengths.

In one embodiment, using a pressure sensor to collect pressure signals of the target combustion chamber during ignition and after flameout is to use multiple pressure sensors to respectively collect pressure signals at different locations of the target combustion chamber during ignition and after flameout.

In one embodiment, the characteristic response frequency model is

In the formula, f is the target characteristic response frequency, l is the length of the combustion chamber, n is the mode order, and c is the sound speed.

In one embodiment, the characteristic response frequency software is COMSOL or ANSYS.

In a second aspect, the present invention provides a test device for the flame combustion response of a liquid propellant, which is used to implement a test method for the flame combustion response of a liquid propellant, including a tubular combustion chamber and sealing chambers located on both sides of the combustion chamber. The nozzle gland and end cover as well as the air inlet joint, the nozzle gland and the end cover are fixedly connected to the combustion chamber respectively, the air inlet joint is fixedly installed on the end cover, and the air inlet joint is connected with the combustion chamber;

The side wall of the combustion chamber is provided with a pulser joint for connecting the pulser, at least one sensor pressure measuring seat for placing the sensor, and an ignition joint. The pulser joint, the sensor pressure measuring seat and the ignition joint are all fixedly connected to the combustion chamber.

In one embodiment, the combustion chamber includes at least one tube section.

In one embodiment, the combustion chamber includes a plurality of sub-combustion chambers with known characteristic response frequencies and lengths, and the outer wall of each sub-combustion chamber is provided with a pulser joint and a sensor pressure measuring seat;

Any two adjacent sub-combustion chambers are fixedly connected through connecting flanges.

In a third aspect, the present invention provides a testing system for the flame combustion response of a liquid propellant, a testing device for controlling the flame combustion response of a liquid propellant, and a method for testing the flame combustion response of a liquid propellant, including:

The pulser module is used to generate pulse excitation, and the pulser module includes multiple pulsers;

a sensor module, the sensor module is used to measure the pressure signal of the combustion chamber, and the sensor module includes at least one sensor;

Control module, the control module is used to control ignition of the combustion chamber and pulser;

The data acquisition module is used to collect the pressure signal of the combustion chamber measured by the sensor module and perform data processing on the pressure signal to calculate the propellant flame combustion response.

Beneficial effects of the present invention:

(1) The present invention uses a pulser to provide pulse excitation to the target combustion chamber where the liquid propellant is located, which can provide a larger amplitude of pulse oscillation to realize the response characteristic test of the liquid propellant combustion flame, and large amplitude oscillations will cause obvious abnormality. The linear effect is more conducive to testing the response characteristics of the combustion flame.

(2) The length of the combustion chamber used in the present invention corresponds to the target response frequency, enabling testing at different frequencies.

(3) The combustion chamber of the present invention can be composed of multiple sub-combustion chambers with known characteristic response frequencies and lengths. To test the response characteristics of liquid propellant combustion flames at different frequencies, multiple characteristic response frequencies can be used. and sub-combustion chambers with known lengths constitute a combustion chamber of required length, so the method of the present invention also has the feature of saving consumables.

Description of drawings

Figure 1 is one of the schematic flow diagrams of the testing method for the flame combustion response of liquid propellant provided by an embodiment of the present invention;

Figure 2 is the pressure attenuation characteristic curve;

Figure 3 is a schematic diagram of the pressure time series in the descending section provided by the embodiment of the present invention;

Figure 4 is a schematic diagram of the FFT curve of the descending section provided by the embodiment of the present invention;

Figure 5 is a schematic diagram of the attenuation coefficient calculation provided by the embodiment of the present invention;

Figure 6 is a schematic structural diagram of a testing device for liquid propellant flame combustion response in an embodiment of the present invention;

Figure 7 is another structural schematic diagram of a testing device for liquid propellant flame combustion response in an embodiment of the present invention.

Explanation of reference signs: 100, combustion chamber; 200, nozzle gland; 300, end cap; 400, air inlet joint; 500, pulser joint; 600, sensor pressure measuring seat; 700, ignition joint; 800, sub Combustion chamber; 900, connecting flange.

Detailed ways

In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described here are only used to explain the present invention and are not intended to limit the present invention.

In one embodiment, as shown in Figure 1, Figure 1 is one of the flow diagrams of a testing method for the flame combustion response of a liquid propellant provided by an embodiment of the present invention. The testing method for the flame combustion response of a liquid propellant includes the following steps:

S101. Obtain target feature response frequency;

S102. Calculate the target combustion chamber length using the target characteristic response frequency; specifically, input the target characteristic response frequency into the characteristic response frequency model or the characteristic response frequency software to calculate the target combustion chamber length.

S103. Obtain the target combustion chamber 100 corresponding to the target combustion chamber length.

Specifically, the function of the target combustion chamber 100 has two aspects. One is to provide a restricted space environment for the propellant combustion flame to generate higher temperature and pressure. The other is to construct a basic acoustic environment. After the introduction of pulse oscillation, all the Required acoustic frequency.

S104. Use a pulser to apply pulses to the target combustion chamber 100 during ignition and after flameout.

The pulser in this embodiment may be, but is not limited to, a high-pressure external pulse exciter for T-type burners. Since the pulser starts working some time after the combustion chamber 100 is ignited, its sealing and heat insulation properties are very important. The high-temperature and high-pressure gas in the combustion chamber 100 entering the pulser may ignite the gunpowder, causing the pulser to fail to work properly. Therefore, it is preferable to have a high-pressure external pulse exciter for a T-type burner that has structures such as plugs and baffles to isolate the environment of the combustion chamber 100 from the pulser combustion chamber 100 . When the high-pressure external pulse exciter for T-type burners is used, the high-pressure external pulse exciter for T-type burners with a charge of 2 to 15 g can correspondingly generate a pressure pulse of 20 to 50 MPa, which reaches The time of the highest pressure peak is within 2~10ms.

The working principle of the high-pressure external pulse exciter for T-type burners is as follows: in the combustion chamber 100, the ignition head is used to ignite the gunpowder of a given mass to produce gas of a certain pressure and temperature, and then the sealing plug is opened. Entering the engine thrust chamber through the nozzle creates the required disturbance.

It should be noted that the excitation frequency of the pulser is controlled by the length of the combustion chamber 100. Different lengths of the combustion chamber 100 will produce different frequencies under the excitation of the same pulser.

S105. Use the pressure sensor to collect the pressure signal of the target combustion chamber 100 during ignition and after flameout.

S106. Draw a pressure attenuation characteristic curve during ignition and after flameout according to the pressure signals at different positions of the target combustion chamber 100 during ignition and after flameout. As shown in Figure 2, Figure 2 is the pressure attenuation characteristic curve. In the figure, P represents the pressure of the combustion chamber 100, t is the time, and τ _d is the decay period.

S107. Calculate the attenuation coefficient of the pressure attenuation characteristic curve during ignition and the attenuation coefficient of the pressure attenuation characteristic curve after flameout based on the pressure attenuation characteristic curve during ignition and after flameout respectively.

Specifically, the calculation formula of the attenuation coefficient is:

In the formula, and are respectively two adjacent pressure extreme values in the pressure attenuation characteristic curve.

S108. Calculate the difference between the attenuation coefficient of the pressure attenuation characteristic curve during ignition and the attenuation coefficient of the pressure attenuation characteristic curve after flameout to be the propellant flame combustion response corresponding to the target characteristic response frequency.

In this embodiment, the attenuation coefficient of the pressure attenuation characteristic curve during ignition and the attenuation coefficient of the pressure attenuation characteristic curve after flameout are defined as and respectively, then the difference between the two is the combustion gain of the propellant combustion flame at this oscillation frequency.

In one embodiment, the target combustion chamber 100 is a whole or is composed of multiple sub-combustion chambers 800 with known characteristic response frequencies and lengths.

In one embodiment, using a pressure sensor to collect the pressure signals of the target combustion chamber 100 during ignition and after flameout is to use multiple pressure sensors to respectively collect pressure signals at different locations of the target combustion chamber 100 during ignition and after flameout. Multiple pressure sensors can more comprehensively obtain pressure oscillation information, such as measuring the pressure mode shape of the combustion chamber 100 .

In one embodiment, the characteristic response frequency model is

In the formula, f is the target characteristic response frequency, l is the length of the combustion chamber, n is the mode order, and c is the sound speed.

In one embodiment, the characteristic response frequency software is COMSOL or ANSYS.

In a specific embodiment, a cold flow triggering experiment was performed on 100 sections of a combustion chamber with a length of 150mm. The pulser charge was 5g of black powder. The selected pressure sensor was 0~5MPa and the sampling frequency was 10kHz. The obtained descending section (3.91s～3.94s) pressure time series and its FFT curve are shown in Figures 3 and 4. It can be seen from Figures 3 and 4 that the pressure in the combustion chamber 100 basically decays exponentially in the decreasing section, and the characteristic frequency is 1422Hz.

As shown in Figure 5, Figure 5 is a schematic diagram of attenuation coefficient calculation. According to the falling envelope, the attenuation coefficient can be calculated, and it can be seen from Figure 5 that the sound wave enters the linear attenuation zone from about 4.78s. Therefore, the development method of this embodiment can test the response characteristics of the liquid propellant combustion flame.

Based on the same inventive concept, the present invention provides a testing device for the flame combustion response of liquid propellant, which is used to implement a testing method for the flame combustion response of liquid propellant. In one embodiment, as shown in Figure 6, Figure 6 is a schematic structural diagram of a test device for the flame combustion response of a liquid propellant in an embodiment of the present invention. The test device for the flame combustion response of a liquid propellant includes a tubular combustion chamber 100, respectively located at The nozzle gland 200 and end cap 300 as well as the air inlet joint 400 on both sides of the combustion chamber 100 seal the combustion chamber 100. The nozzle gland 200 and the end cap 300 are respectively fixedly connected to the combustion chamber 100, and the air inlet joint 400 is fixedly installed on the end cover 300, and the air inlet joint 400 is connected with the combustion chamber 100.

The outer wall of the combustion chamber 100 is provided with a pulser connector 500 for connecting the pulser, at least one sensor pressure measuring seat 600 for placing the sensor, and an ignition connector 700. The pulser connector 500, the sensor pressure measuring seat 600 and the ignition connector 700 are all connected with the pulser. The combustion chamber 100 is fixedly connected.

It should be noted that in this embodiment, only one pulser joint 500 and one sensor pressure measuring seat 600 are provided on the outer wall of the combustion chamber 100. In actual use, the number can be set according to specific conditions.

It should also be noted that the positions and installation angles of the pulser joint 500, the sensor pressure measuring seat 600 and the ignition joint 700 on the outer wall can be specifically set according to actual needs.

In one embodiment, the combustion chamber 100 includes at least one tube section. In this embodiment, the combustion chamber 100 is a whole and can be specifically prepared after its length is calculated.

In a preferred embodiment, as shown in Figure 7, Figure 7 is another structural schematic diagram of a test device for liquid propellant flame combustion response in an embodiment of the present invention. The combustion chamber 100 includes multiple characteristic response frequencies and lengths with known The sub-combustion chambers 800 are provided with a pulser joint 500 and a sensor pressure measuring seat 600 on the outer wall of each sub-combustion chamber 800. Any two adjacent sub-combustion chambers 800 are fixedly connected through a connecting flange 900.

By using multiple sub-combustion chambers 800 with known characteristic response frequencies and lengths to splice the required combustion chamber 100, the combustion chamber 100 required for unknown characteristic response frequencies can be prepared, consumables can be saved, and the excitation frequency can be adjusted through the number of splicings. In addition, the multi-pulser can achieve multiple pulse excitation measurements in one ignition.

The invention also provides a testing system for the flame combustion response of liquid propellant, a testing device used to control the flame burning response of liquid propellant to implement a testing method for the flame combustion response of liquid propellant, including:

The pulser module is used to generate pulse excitation, and the pulser module includes multiple pulsers.

The sensor module is used to measure the pressure signal of the combustion chamber 100, and the sensor module includes at least one sensor.

A control module is used to control ignition of the combustion chamber 100 and the pulser. Specifically, the control module consists of a timing control program (software) and an ignition timing control system (hardware).

The data acquisition module is used to collect the pressure signal of the combustion chamber 100 measured by the sensor module, perform data processing on the pressure signal, and calculate the propellant flame combustion response. Specifically, the data acquisition module includes strain amplifier, data acquisition channel module (hardware), and data acquisition software.

It should be understood that although the steps in the flowcharts involved in the above-mentioned embodiments are shown in sequence as indicated by the arrows, these steps are not necessarily executed in the order indicated by the arrows. Unless explicitly stated in this article, there is no strict order restriction on the execution of these steps, and these steps can be executed in other orders. Moreover, at least some of the steps in the flowcharts involved in the above embodiments may include multiple steps or stages. These steps or stages are not necessarily executed at the same time, but may be completed at different times. The execution order of these steps or stages is not necessarily sequential, but may be performed in turn or alternately with other steps or at least part of the steps or stages in other steps.

The above-mentioned embodiments only express several implementation modes of the present invention, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the patent scope of the present invention. It should be noted that, for those of ordinary skill in the art, several modifications and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the present invention should be determined by the appended claims.

Claims (9)

1. A test method for the flame combustion response of liquid propellant, which is characterized in that it includes the following steps: Obtain target feature response frequency; Calculate the target combustion chamber length using the target characteristic response frequency; specifically, input the target characteristic response frequency into the characteristic response frequency model or the characteristic response frequency software to calculate the target combustion chamber length; Get the target combustion chamber (100) corresponding to the target combustion chamber length; A pulser is used to apply pulses to the target combustion chamber (100) during ignition and after flameout of the target combustion chamber (100); Use a pressure sensor to collect the pressure signal of the target combustion chamber (100) during ignition and after flameout; Draw the pressure attenuation characteristic curve during ignition and after flameout according to the pressure signals at different positions of the target combustion chamber (100) during ignition and after flameout; Calculate the attenuation coefficient of the pressure attenuation characteristic curve during ignition and the attenuation coefficient of the pressure attenuation characteristic curve after flameout based on the pressure attenuation characteristic curve during ignition and after flameout respectively; The difference between the attenuation coefficient of the pressure attenuation characteristic curve during ignition and the attenuation coefficient of the pressure attenuation characteristic curve after flameout is calculated to be the propellant flame combustion response corresponding to the target characteristic response frequency. 2. The testing method of liquid propellant flame combustion response according to claim 1, characterized in that the target combustion chamber (100) is a whole or a plurality of sub-combustion chambers (100) with known characteristic response frequencies and lengths. 800) splicing composition. 3. The testing method of liquid propellant flame combustion response according to claim 2, characterized in that using a pressure sensor to collect the pressure signal of the target combustion chamber (100) during ignition and after flameout is to use multiple pressure sensors to collect the target respectively. Pressure signals at different positions of the combustion chamber (100) during ignition and after flameout. 4. The testing method of liquid propellant flame combustion response according to claim 3, characterized in that the characteristic response frequency model is In the formula, f is the target characteristic response frequency, l is the length of the combustion chamber (100), n is the mode order, and c is the sound speed. 5. The testing method of liquid propellant flame combustion response according to claim 3, characterized in that the characteristic response frequency software is COMSOL or ANSYS. 6. A test device for the flame combustion response of liquid propellant, used to implement the test method for the flame combustion response of liquid propellant according to any one of claims 1 to 5, characterized in that it includes a tubular combustion chamber (100) , the nozzle gland (200) and the end cover (300) and the air inlet joint (400) respectively located on both sides of the combustion chamber (100) to seal the combustion chamber (100), the nozzle gland (200) ) and the end cover (300) are fixedly connected to the combustion chamber (100) respectively. The air inlet joint (400) is fixedly installed on the end cover (300). The air inlet joint (400) Communicated with the combustion chamber (100); The outer wall of the combustion chamber (100) is provided with a pulser joint (500) for connecting a pulser, at least one sensor pressure measuring seat (600) for placing a sensor, and an ignition joint (700). The pulser joint (700) 500), the sensor pressure measuring seat (600) and the ignition joint (700) are all fixedly connected to the combustion chamber (100). 7. The testing device for liquid propellant flame combustion response according to claim 6, characterized in that the combustion chamber (100) includes at least one pipe section. 8. The test device for liquid propellant flame combustion response according to claim 7, characterized in that the combustion chamber (100) includes a plurality of sub-combustion chambers (800) with known characteristic response frequencies and lengths, and each sub-combustion chamber (800) has a known characteristic response frequency and length. The outer walls of the combustion chamber (800) are provided with pulser joints (500) and sensor pressure measuring seats (600); Any two adjacent sub-combustion chambers (800) are fixedly connected through the connecting flange (900). 9. A testing system for liquid propellant flame combustion response, a testing device used to control the liquid propellant flame combustion response as described in any one of claims 6 to 8 to implement as described in any one of claims 1 to 5 The test method for the flame combustion response of liquid propellant is characterized by including: A pulser module, the pulser module is used to generate pulse excitation, the pulser module includes a plurality of pulsers; A sensor module, the sensor module is used to measure the pressure signal of the combustion chamber (100), the sensor module includes at least one sensor; A control module used to control ignition of the combustion chamber (100) and the pulser; A data acquisition module. The data acquisition module is used to collect the pressure signal of the combustion chamber (100) measured by the sensor module, perform data processing on the pressure signal, and calculate the propellant flame combustion response.