CN113217229B - Method and system for testing instantaneous nozzle throat diameter - Google Patents
Method and system for testing instantaneous nozzle throat diameter Download PDFInfo
- Publication number
- CN113217229B CN113217229B CN202110509520.5A CN202110509520A CN113217229B CN 113217229 B CN113217229 B CN 113217229B CN 202110509520 A CN202110509520 A CN 202110509520A CN 113217229 B CN113217229 B CN 113217229B
- Authority
- CN
- China
- Prior art keywords
- sound pressure
- pressure signal
- throat diameter
- time
- frequency
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Images
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02K—JET-PROPULSION PLANTS
- F02K9/00—Rocket-engine plants, i.e. plants carrying both fuel and oxidant therefor; Control thereof
- F02K9/96—Rocket-engine plants, i.e. plants carrying both fuel and oxidant therefor; Control thereof characterised by specially adapted arrangements for testing or measuring
Landscapes
- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Combustion & Propulsion (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Measurement Of Mechanical Vibrations Or Ultrasonic Waves (AREA)
Abstract
The invention relates to a method and a system for testing instantaneous nozzle throat diameter, wherein the method comprises the following steps: acquiring the throat diameters of a front spray pipe and a rear spray pipe of the rocket engine before working and the sound pressure signals in the working process; constructing a first function model of the change of the instantaneous frequency of the sound pressure signal along with time according to the sound pressure signal; constructing a second function model of the instantaneous frequency of the sound pressure signal changing along with the size of the throat diameter of the jet pipe according to the change of the instantaneous frequency of the sound pressure signal along with time and the size of the throat diameters of the jet pipe before and after the rocket engine works; and obtaining the change relation of the nozzle throat diameter size along with time by combining the first function model and the second function model, and further obtaining the dynamic rule of the nozzle throat diameter instantaneous value. The method can test the sound pressure signal in the whole engine working process in real time, effectively invert the dynamic rule of the throat diameter transient value, and provide support for rocket flight performance evaluation and key technical parameter design.
Description
Technical Field
The invention relates to the technical field of aircraft performance testing, in particular to a method and a system for testing a nozzle throat diameter transient value.
Background
The erosion of the throat insert can reduce the thrust and the performance of the solid rocket engine and even cause the problems of the failure of the engine and the like. The transient ablation performance of the throat insert directly affects the flight performance of the solid rocket engine.
At present, a small-sized test engine is mainly adopted at home and abroad to research the ablation rule of the throat lining material, and the average ablation rate of the throat lining is calculated by testing the throat diameter sizes of the front and rear jet pipes of the engine before and after working. But the small test engine was unable to test the dynamic ablation performance of the throat diameter.
Therefore, how to design a method and a system capable of testing the transient value of the throat diameter of the rocket engine nozzle becomes a problem to be solved in the field at present.
Disclosure of Invention
The invention aims to provide a method and a system for testing instantaneous throat diameter variation of a spray pipe, wherein throat diameter variation can influence the frequency spectrum distribution of jet noise of a rocket engine; then establishing a relation model of instantaneous frequency and throat diameter size; and finally, calculating the dynamic rule of the nozzle throat diameter transient value by using the instantaneous frequency.
In order to achieve the purpose, the invention provides the following scheme:
a method for testing instantaneous nozzle throat diameter comprises the following steps:
obtaining the throat diameter size of a front spray pipe and a rear spray pipe of the rocket engine before and after working and the sound pressure signal of the working process, wherein the sound pressure signal is as follows:
x(t)＝s(t)+n(t) (1)
wherein t is a time variable, s (t) is a sound pressure signal generated by rocket engine jet noise, and n (t) is test circuit noise;
constructing a first function model of the change of the instantaneous frequency of the sound pressure signal along with time according to the sound pressure signal;
constructing a second function model of the instantaneous frequency of the sound pressure signal changing along with the size of the throat diameter of the jet pipe according to the change of the instantaneous frequency of the sound pressure signal along with time and the size of the throat diameters of the jet pipe before and after the rocket engine works;
and obtaining the change relation of the throat diameter size of the spray pipe along with time by combining the first function model and the second function model, and further obtaining the dynamic rule of the instantaneous change value of the throat diameter of the spray pipe.
Optionally, constructing a first function model of temporal change of instantaneous frequency of the sound pressure signal according to the sound pressure signal specifically includes:
performing time-frequency analysis on the sound pressure signal by adopting short-time Fourier transform to obtain the time-frequency energy spectrum distribution of the sound pressure signal, wherein the formula of the time-frequency analysis is as follows:
wherein, STFTx(t, f) is the result of time-frequency analysis, x (tau) represents the sound pressure signal at time tau, g (t) is a moving window function, g (tau-t) is the conjugate function of the window function g (t) after shifting tau, tau is the time offset of the window function,*representing the conjugate of the function, t is a time variable, f is the instantaneous frequency of the sound pressure signal, and j is a complex unit;
extracting the maximum energy ridge line of the time-frequency energy spectrum to obtain a change curve of the instantaneous frequency of the sound pressure signal along with time;
obtaining the first function model according to the variation curve, wherein the first function model is as follows:
wherein, F1(t) is a first function model of the instantaneous frequency of the acoustic pressure signal over time, STFTxAnd (t, f) is the result of time-frequency analysis, t is a time variable, and f is the instantaneous frequency of the sound pressure signal.
Optionally, constructing a second function model of the change of the instantaneous frequency of the sound pressure signal along with the size of the throat diameter of the nozzle according to the change of the instantaneous frequency of the sound pressure signal along with time and the sizes of the throat diameters of the nozzle before and after the rocket engine works specifically includes:
according to a change curve of the instantaneous frequency of the sound pressure signal along with time, obtaining a high-point frequency and a low-point frequency of the instantaneous frequency of the sound pressure signal in a linear descending region, wherein at the moment of the high-point frequency, the throat diameter of the spray pipe corresponds to the size of the rocket engine before working, and at the moment of the low-point frequency, the throat diameter of the spray pipe corresponds to the size of the rocket engine after working;
according to the sizes of the throat diameters of the front and rear jet pipes of the rocket engine before and after working and the high-point frequency and the low-point frequency of the instantaneous frequency of the sound pressure signal in a linear descending region, a second function model of the change of the instantaneous frequency of the sound pressure signal along with the size of the throat diameter of the jet pipe is constructed, and the second function model is as follows:
wherein, F2(r) is a second function model of the change of the instantaneous frequency of the sound pressure signal along with the size of the throat diameter of the jet pipe, r is the size of the throat diameter of the jet pipe, d1The size of the throat diameter of the nozzle before the rocket engine works, d2The size of the throat diameter of the nozzle after the rocket engine works, f1At high point frequency, f2Is the low point frequency.
Optionally, the relationship of the change of the throat diameter size of the nozzle along with time obtained by combining the first function model and the second function model is as follows:
wherein r is the nozzle throat diameter size, d1The size of the throat diameter of the nozzle before the rocket engine works, d2The size of the throat diameter of the nozzle after the rocket engine works, f1At high point frequency, f2At low spot frequency, STFTxAnd (t, f) is the result of time-frequency analysis, t is a time variable, and f is the instantaneous frequency of the sound pressure signal.
The invention also provides a test system for the instantaneous nozzle throat diameter, which comprises:
the acoustic signal acquisition unit is used for acquiring a sound pressure signal in the working process of the rocket engine;
the nozzle throat diameter size obtaining unit is connected with the rocket engine and used for obtaining the sizes of the nozzle throat diameters before and after the rocket engine works;
and the data processing unit is respectively connected with the acoustic signal acquisition unit and the nozzle throat diameter size acquisition unit and is used for constructing the change relation of the instantaneous frequency of the sound pressure signal along with time and the change relation of the instantaneous frequency of the sound pressure signal along with the nozzle throat diameter size, and further obtaining the dynamic rule of the nozzle throat diameter instantaneous change value by simultaneously establishing the change relation of the instantaneous frequency of the sound pressure signal along with time and the change relation of the instantaneous frequency of the sound pressure signal along with the nozzle throat diameter size.
Optionally, the acoustic signal acquiring unit includes:
the acoustic testing module is used for acquiring a sound pressure signal;
and the data transmission module is connected with the acoustic testing module and is used for transmitting the sound pressure signal.
Optionally, the acoustic testing module includes:
the acoustic sensors are arranged around the rocket engine to form an acoustic sensor testing cluster and used for acquiring sound pressure signals in different directions;
the power supply module is connected with the plurality of acoustic sensors and used for supplying electric energy to the plurality of acoustic sensors;
the safety protection sub-module is connected with the plurality of acoustic sensors and used for protecting the plurality of acoustic sensors;
the synchronous control submodule is connected with the plurality of acoustic sensors and is used for controlling the plurality of acoustic sensors to simultaneously acquire sound pressure signals of the engine tail nozzle;
and the multi-channel data acquisition submodule is connected with the plurality of acoustic sensors and is used for filtering, pre-amplifying and A/D (analog to digital) converting the sound pressure signals acquired by the plurality of acoustic sensors.
Optionally, the data transmission module includes:
the data coding submodule is used for carrying out data coding on the acquired sound pressure signal to obtain a digital acoustic signal;
and the data receiving and transmitting submodule is connected with the data coding submodule and is used for receiving and transmitting the digital sound pressure signal in real time in a wireless data transmission mode.
Optionally, the data processing unit includes:
the data receiving module is used for receiving the sound pressure signal;
the data storage module is connected with the data receiving module and used for storing and managing the sound pressure signals in a disk array mode;
and the data analysis module is connected with the data receiving module and used for carrying out data analysis on the sound pressure signal, constructing the change relation of the instantaneous frequency of the sound pressure signal along with time and the change relation of the instantaneous frequency of the sound pressure signal along with the size of the throat diameter of the spray pipe, and obtaining the dynamic rule of the instantaneous change value of the throat diameter of the spray pipe by simultaneously establishing the change relation of the instantaneous frequency of the sound pressure signal along with time and the change relation of the instantaneous frequency of the sound pressure signal along with the size of the throat diameter of the spray pipe.
Optionally, the data analysis module includes:
the data decoding submodule is used for decoding the sound pressure signal;
the time-frequency analysis submodule is connected with the data decoding submodule and is used for carrying out time-frequency analysis on the decoded sound pressure signal;
the ridge line extraction submodule is connected with the time-frequency analysis submodule and used for carrying out ridge line extraction on the sound pressure signal after time-frequency analysis to obtain the change relation of the instantaneous frequency of the sound pressure signal along with time;
the model analysis submodule is connected with the ridge line extraction submodule and used for constructing a function model of the instantaneous frequency along with the size of the throat diameter of the spray pipe;
and the throat diameter inversion submodule is connected with the model analysis submodule and is used for obtaining the dynamic rule of the nozzle throat diameter transient value.
According to the specific embodiment provided by the invention, the invention discloses the following technical effects:
the invention provides a method and a system for testing a throat diameter transient value of a spray pipe.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings needed in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings without creative efforts.
Fig. 1 is a flowchart of a method for testing a nozzle throat diameter transient according to embodiment 1 of the present invention;
FIG. 2 is a flow chart of instantaneous frequency of an acoustic pressure signal over time;
FIG. 3 is a graph of instantaneous frequency of an acoustic pressure signal over time;
FIG. 4 is a flow chart of the instantaneous frequency of the acoustic pressure signal as a function of the nozzle throat diameter size;
fig. 5 is a schematic structural diagram of a system for testing a nozzle throat diameter transient according to embodiment 2 of the present invention.
Description of the symbols: 1. an acoustic signal acquisition unit; 2. a nozzle throat diameter size obtaining unit; 3. a data processing unit; 4. an acoustic testing module; 401. an acoustic sensor; 402. a power supply module; 403. a safety protection sub-module; 404. a synchronization control sub-module; 405. a multi-channel data acquisition submodule; 5. a data transmission module; 501. a data encoding submodule; 502. a data receiving and transmitting sub-module; 6. a data receiving module; 7. a data storage module; 8. a data analysis module; 801. a data decoding sub-module; 802. a time-frequency analysis submodule; 803. a ridge line extraction submodule; 804. a model analysis submodule; 805. a throat diameter inversion submodule; 9. a rocket motor.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
The invention aims to provide a method and a system for testing a nozzle throat diameter transient value, provides a method and a system for testing a nozzle throat diameter transient value by inverting a sound pressure signal, and can solve the problem that the nozzle throat diameter transient value is difficult to measure in the working process of an engine. The nozzle throat diameter transient data obtained by the testing method can provide support for rocket flight performance evaluation and key technical parameter design.
In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in further detail below.
Example 1:
referring to fig. 1, the present invention provides a method for testing a nozzle throat diameter transient, which includes the following steps:
s1: obtaining the throat diameter size of a front spray pipe and a rear spray pipe of the rocket engine before and after working and the sound pressure signal of the working process, wherein the sound pressure signal is as follows:
x(t)＝s(t)+n(t) (1)
wherein t is a time variable, s (t) is a sound pressure signal generated by rocket engine jet noise, and n (t) is test circuit noise;
s2: constructing a first function model of the change of the instantaneous frequency of the sound pressure signal along with time according to the sound pressure signal, and specifically comprising the following steps: (see FIG. 2)
S201: performing time-frequency analysis on the sound pressure signal by adopting short-time Fourier transform to obtain the time-frequency energy spectrum distribution of the sound pressure signal, wherein the formula of the time-frequency analysis is as follows:
wherein, STFTx(t, f) is the result of time-frequency analysis, x (tau) represents the sound pressure signal at time tau, g (t) is a moving window function,g (tau-t) is a conjugate function of a window function g (t) shifted by tau, tau being the time shift of the window function,*representing the conjugate of the function, t is a time variable, f is the instantaneous frequency of the sound pressure signal, and j is a complex unit;
s202: extracting the maximum energy ridge line of the time-frequency energy spectrum to obtain a change curve of the instantaneous frequency of the sound pressure signal along with time, wherein the specific change curve is shown in figure 3;
s203: obtaining the first function model according to the variation curve, wherein the first function model is as follows:
wherein, F1(t) is a first function model of the instantaneous frequency of the acoustic pressure signal over time, STFTxAnd (t, f) is the result of time-frequency analysis, t is a time variable, and f is the instantaneous frequency of the sound pressure signal.
S3: according to the change of the instantaneous frequency of the sound pressure signal along with time and the size of the throat diameter of the jet pipe before and after the rocket engine works, a second function model of the change of the instantaneous frequency of the sound pressure signal along with the size of the throat diameter of the jet pipe is constructed, and the method specifically comprises the following steps: (see FIG. 4)
S301: according to a change curve of the instantaneous frequency of the sound pressure signal along with time, obtaining a high-point frequency and a low-point frequency of the instantaneous frequency of the sound pressure signal in a linear descending region, wherein at the moment of the high-point frequency, the throat diameter of the spray pipe corresponds to the size of the rocket engine before working, and at the moment of the low-point frequency, the throat diameter of the spray pipe corresponds to the size of the rocket engine after working;
s302: according to the sizes of the throat diameters of the front and rear jet pipes of the rocket engine before and after working and the high-point frequency and the low-point frequency of the instantaneous frequency of the sound pressure signal in a linear descending region, a second function model of the change of the instantaneous frequency of the sound pressure signal along with the size of the throat diameter of the jet pipe is constructed, and the second function model is as follows:
wherein, F2(r) is a second function model of the change of the instantaneous frequency of the sound pressure signal along with the size of the throat diameter of the jet pipe, r is the size of the throat diameter of the jet pipe, d1The size of the throat diameter of the nozzle before the rocket engine works, d2The size of the throat diameter of the nozzle after the rocket engine works, f1At high point frequency, f2Is the low point frequency.
S4: and obtaining the change relation of the throat diameter size of the spray pipe along with time by combining the first function model and the second function model, and further obtaining the dynamic rule of the instantaneous change value of the throat diameter of the spray pipe. I.e. F ═ F1(t)＝F2(r) from this equation the change in the size of the nozzle throat over time is given by:
wherein r is the nozzle throat diameter size, d1The size of the throat diameter of the nozzle before the rocket engine works, d2The size of the throat diameter of the nozzle after the rocket engine works, f1At high point frequency, f2At low spot frequency, STFTxAnd (t, f) is the result of time-frequency analysis, t is a time variable, and f is the instantaneous frequency of the sound pressure signal.
According to the formula, the dynamic change rule of the throat diameter transient value in the process of ablating the throat insert of the solid rocket engine can be calculated.
The method for testing the instantaneous change value of the throat diameter of the spray pipe mainly utilizes the principle that the throat expansion of the spray pipe can cause the change of a sound pressure frequency spectrum in the working process of an engine, firstly, a function model of the change of the instantaneous frequency of a sound pressure signal along with time and a function model of the change of the instantaneous frequency of the sound pressure signal along with the size of the throat diameter of the spray pipe are established, and secondly, the instantaneous change value of the throat diameter of the spray pipe can be obtained by connecting the two function models. The test method can solve the problem that the nozzle throat diameter transient value is difficult to measure in the working process of the engine. And the obtained nozzle throat diameter transient data can provide support for rocket flight performance evaluation and key technical parameter design.
Example 2:
referring to fig. 5, the present invention provides a system for testing transient throat diameter of a nozzle, the system comprising:
the acoustic signal acquisition unit 1 is used for acquiring a sound pressure signal of the rocket engine 9 in the working process;
the nozzle throat diameter size obtaining unit 2 is connected with the rocket engine 9 and is used for obtaining the sizes of the nozzle throat diameters before and after the rocket engine 9 works;
and the data processing unit 3 is respectively connected with the acoustic signal acquisition unit 1 and the nozzle throat diameter size acquisition unit 2 and is used for constructing the change relation of the instantaneous frequency of the sound pressure signal along with time and the change relation of the instantaneous frequency of the sound pressure signal along with the nozzle throat diameter size, and further obtaining the dynamic rule of the nozzle throat diameter instantaneous change value by simultaneously establishing the change relation of the instantaneous frequency of the sound pressure signal along with time and the change relation of the instantaneous frequency of the sound pressure signal along with the nozzle throat diameter size.
Specifically, the acoustic signal acquiring unit 1 includes:
the acoustic testing module 4 is used for acquiring a sound pressure signal;
and the data transmission module 5 is connected with the acoustic testing module 4 and is used for transmitting the sound pressure signal.
As a possible implementation, the acoustic testing module 4 includes:
the acoustic sensors 401 are installed around the rocket engine 9 in a mechanical coupling mode to form an acoustic sensor testing cluster for collecting sound pressure signals in different directions; the acoustic sensor has an ultra-high sampling rate and a wide dynamic range.
A power supply module 402 connected to the plurality of acoustic sensors 401 for supplying power to the plurality of acoustic sensors;
the safety protection submodule 403 is connected with the plurality of acoustic sensors 401, and is used for protecting the plurality of acoustic sensors from safe and stable operation in a severe environment;
the synchronous control submodule 404 is connected with the plurality of acoustic sensors 401, and is used for controlling the plurality of acoustic sensors to simultaneously acquire sound pressure signals of the engine exhaust nozzle;
and the multi-channel data acquisition submodule 405 is connected with the plurality of acoustic sensors 401, and is configured to filter, pre-amplify and perform a/D analog-to-digital conversion on the sound pressure signals acquired by the plurality of acoustic sensors 401.
Specifically, the data transmission module 5 includes:
the data coding submodule 501 is configured to perform data coding on the acquired sound pressure signal to obtain a digital acoustic signal;
and the data receiving and transmitting submodule 502 is connected with the data encoding submodule 501 and is used for receiving and transmitting the digital sound pressure signal in real time in a wireless data transmission mode.
Specifically, the data processing unit 3 includes:
a data receiving module 6, configured to receive the sound pressure signal;
the data storage module 7 is connected with the data receiving module 6 and is used for storing and managing the sound pressure signals in a disk array mode;
and the data analysis module 8 is connected with the data receiving module 6 and used for carrying out data analysis on the sound pressure signal, constructing the change relation of the instantaneous frequency of the sound pressure signal along with time and the change relation of the instantaneous frequency of the sound pressure signal along with the size of the throat diameter of the spray pipe, and obtaining the dynamic rule of the instantaneous change value of the throat diameter of the spray pipe by simultaneously establishing the change relation of the instantaneous frequency of the sound pressure signal along with time and the change relation of the instantaneous frequency of the sound pressure signal along with the size of the throat diameter of the spray pipe.
As a possible implementation, the data analysis module 8 includes:
a data decoding sub-module 801 for decoding the sound pressure signal;
the time-frequency analysis sub-module 802 is connected with the data decoding sub-module 801 and is used for performing time-frequency analysis on the decoded sound pressure signal;
the ridge line extraction submodule 803 is connected with the time-frequency analysis submodule 802, and is used for performing ridge line extraction on the sound pressure signal after time-frequency analysis to obtain the change relation of the instantaneous frequency of the sound pressure signal along with time;
the model analysis submodule 804 is connected with the ridge line extraction submodule 803 and is used for constructing a function model of the instantaneous frequency along with the size of the throat diameter of the spray pipe;
and the throat diameter inversion submodule 805 is connected with the model analysis submodule 804 and is used for obtaining the dynamic rule of the nozzle throat diameter transient value.
In conclusion, the test system for the instantaneous throat diameter of the jet pipe provided by the invention arranges a plurality of acoustic sensors around the rocket engine, and the acoustic sensors are not influenced by the high-temperature and high-pressure environment in the jet pipe, so that the sound pressure signal in the working process of the whole engine can be tested in real time, the dynamic rule of the instantaneous throat diameter can be effectively inverted, and support is provided for rocket flight performance evaluation and key technical parameter design.
The embodiments in the present description are described in a progressive manner, each embodiment focuses on differences from other embodiments, and the same and similar parts among the embodiments are referred to each other.
The principles and embodiments of the present invention have been described herein using specific examples, which are provided only to help understand the method and the core concept of the present invention; meanwhile, for a person skilled in the art, according to the idea of the present invention, the specific embodiments and the application range may be changed. In view of the above, the present disclosure should not be construed as limiting the invention.
Claims (8)
1. A method for testing the instantaneous value of the throat diameter of a spray pipe is characterized by comprising the following steps:
obtaining the throat diameter size of a front spray pipe and a rear spray pipe of the rocket engine before and after working and the sound pressure signal of the working process, wherein the sound pressure signal is as follows:
x(t)＝s(t)+n(t)
wherein t is a time variable, s (t) is a sound pressure signal generated by rocket engine jet noise, and n (t) is test circuit noise;
constructing a first function model of the change of the instantaneous frequency of the sound pressure signal along with time according to the sound pressure signal;
constructing a second function model of the instantaneous frequency of the sound pressure signal changing along with the size of the throat diameter of the jet pipe according to the change of the instantaneous frequency of the sound pressure signal along with time and the size of the throat diameters of the jet pipe before and after the rocket engine works;
obtaining the change relation of the throat diameter size of the spray pipe along with time by combining the first function model and the second function model, and further obtaining the dynamic rule of the instantaneous change value of the throat diameter of the spray pipe;
obtaining the change relation of the throat diameter size of the nozzle along with time by combining the first function model and the second function model as follows:
wherein r is the nozzle throat diameter size, d1The size of the throat diameter of the nozzle before the rocket engine works, d2The size of the throat diameter of the nozzle after the rocket engine works, f1At high point frequency, f2At low spot frequency, STFTxAnd (t, f) is the result of time-frequency analysis, t is a time variable, and f is the instantaneous frequency of the sound pressure signal.
2. The method for testing the transient of the throat diameter of the nozzle according to claim 1, wherein the step of constructing a first function model of the transient frequency of the sound pressure signal changing with time according to the sound pressure signal specifically comprises the following steps:
performing time-frequency analysis on the sound pressure signal by adopting short-time Fourier transform to obtain the time-frequency energy spectrum distribution of the sound pressure signal, wherein the formula of the time-frequency analysis is as follows:
wherein, STFTx(t, f) is the result of time-frequency analysis, x (tau) represents the sound pressure signal at time tau, g (t) is a moving window function, g (tau-t) is the conjugate function of the window function g (t) after shifting tau, tau is the time offset of the window function,*representing the conjugate of the function, t is a time variable, f is the instantaneous frequency of the sound pressure signal, and j is a complex unit;
extracting the maximum energy ridge line of the time-frequency energy spectrum to obtain a change curve of the instantaneous frequency of the sound pressure signal along with time;
obtaining the first function model according to the variation curve, wherein the first function model is as follows:
wherein, F1(t) is a first function model of the instantaneous frequency of the acoustic pressure signal over time, STFTxAnd (t, f) is the result of time-frequency analysis, t is a time variable, and f is the instantaneous frequency of the sound pressure signal.
3. The method for testing nozzle throat diameter transient values according to claim 1, wherein the step of constructing a second function model of the instantaneous frequency of the sound pressure signal changing with the size of the nozzle throat diameter according to the change of the instantaneous frequency of the sound pressure signal with time and the sizes of the nozzle throat diameters before and after the rocket engine works comprises the following specific steps:
according to a change curve of the instantaneous frequency of the sound pressure signal along with time, obtaining a high-point frequency and a low-point frequency of the instantaneous frequency of the sound pressure signal in a linear descending region, wherein at the moment of the high-point frequency, the throat diameter of the spray pipe corresponds to the size of the rocket engine before working, and at the moment of the low-point frequency, the throat diameter of the spray pipe corresponds to the size of the rocket engine after working;
according to the sizes of the throat diameters of the front and rear jet pipes of the rocket engine before and after working and the high-point frequency and the low-point frequency of the instantaneous frequency of the sound pressure signal in a linear descending region, a second function model of the change of the instantaneous frequency of the sound pressure signal along with the size of the throat diameter of the jet pipe is constructed, and the second function model is as follows:
wherein, F2(r) is a second function model of the change of the instantaneous frequency of the sound pressure signal along with the size of the throat diameter of the jet pipe, r is the size of the throat diameter of the jet pipe, d1The size of the throat diameter of the nozzle before the rocket engine works, d2The size of the throat diameter of the nozzle after the rocket engine works, f1At high point frequency, f2Is the low point frequency.
4. A nozzle throat diameter transient test system is characterized by comprising:
the acoustic signal acquisition unit is used for acquiring a sound pressure signal in the working process of the rocket engine;
the nozzle throat diameter size obtaining unit is connected with the rocket engine and used for obtaining the sizes of the nozzle throat diameters before and after the rocket engine works;
the data processing unit is respectively connected with the acoustic signal acquisition unit and the nozzle throat diameter size acquisition unit and is used for constructing the change relation of the instantaneous frequency of the sound pressure signal along with time and the change relation of the instantaneous frequency of the sound pressure signal along with the nozzle throat diameter size, and further obtaining the dynamic rule of the nozzle throat diameter instantaneous change value by simultaneously establishing the change relation of the instantaneous frequency of the sound pressure signal along with time and the change relation of the instantaneous frequency of the sound pressure signal along with the nozzle throat diameter size;
the data processing unit includes:
the data receiving module is used for receiving the sound pressure signal;
the data storage module is connected with the data receiving module and used for storing and managing the sound pressure signals in a disk array mode;
and the data analysis module is connected with the data receiving module and used for carrying out data analysis on the sound pressure signal, constructing the change relation of the instantaneous frequency of the sound pressure signal along with time and the change relation of the instantaneous frequency of the sound pressure signal along with the size of the throat diameter of the spray pipe, and obtaining the dynamic rule of the instantaneous change value of the throat diameter of the spray pipe by simultaneously establishing the change relation of the instantaneous frequency of the sound pressure signal along with time and the change relation of the instantaneous frequency of the sound pressure signal along with the size of the throat diameter of the spray pipe.
5. The nozzle throat diameter transient test system of claim 4, wherein the acoustic signal acquisition unit comprises:
the acoustic testing module is used for acquiring a sound pressure signal;
and the data transmission module is connected with the acoustic testing module and is used for transmitting the sound pressure signal.
6. The system for testing nozzle throat diameter transients according to claim 5, wherein said acoustic testing module comprises:
the acoustic sensors are arranged around the rocket engine to form an acoustic sensor testing cluster and used for acquiring sound pressure signals in different directions;
the power supply module is connected with the plurality of acoustic sensors and used for supplying electric energy to the plurality of acoustic sensors;
the safety protection sub-module is connected with the plurality of acoustic sensors and used for protecting the plurality of acoustic sensors;
the synchronous control submodule is connected with the plurality of acoustic sensors and is used for controlling the plurality of acoustic sensors to simultaneously acquire sound pressure signals of the engine tail nozzle;
and the multi-channel data acquisition submodule is connected with the plurality of acoustic sensors and is used for filtering, pre-amplifying and A/D (analog to digital) converting the sound pressure signals acquired by the plurality of acoustic sensors.
7. The nozzle throat diameter transient test system of claim 5, wherein the data transmission module comprises:
the data coding submodule is used for carrying out data coding on the acquired sound pressure signal to obtain a digital sound pressure signal;
and the data receiving and transmitting submodule is connected with the data coding submodule and is used for receiving and transmitting the digital sound pressure signal in real time in a wireless data transmission mode.
8. The system for testing nozzle throat diameter transients according to claim 4, wherein said data analysis module comprises:
the data decoding submodule is used for decoding the sound pressure signal;
the time-frequency analysis submodule is connected with the data decoding submodule and is used for carrying out time-frequency analysis on the decoded sound pressure signal;
the ridge line extraction submodule is connected with the time-frequency analysis submodule and used for carrying out ridge line extraction on the sound pressure signal after time-frequency analysis to obtain the change relation of the instantaneous frequency of the sound pressure signal along with time;
the model analysis submodule is connected with the ridge line extraction submodule and used for constructing a function model of the instantaneous frequency along with the size of the throat diameter of the spray pipe;
and the throat diameter inversion submodule is connected with the model analysis submodule and is used for obtaining the dynamic rule of the nozzle throat diameter transient value.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110509520.5A CN113217229B (en) | 2021-05-11 | 2021-05-11 | Method and system for testing instantaneous nozzle throat diameter |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110509520.5A CN113217229B (en) | 2021-05-11 | 2021-05-11 | Method and system for testing instantaneous nozzle throat diameter |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN113217229A CN113217229A (en) | 2021-08-06 |
| CN113217229B true CN113217229B (en) | 2022-02-18 |
Family
ID=77094555
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202110509520.5A Active CN113217229B (en) | 2021-05-11 | 2021-05-11 | Method and system for testing instantaneous nozzle throat diameter |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN113217229B (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2023034291A2 (en) * | 2021-08-30 | 2023-03-09 | Agile Space Industries, Inc. | Systems and methods for design, manufacture, and test of space thruster propulsion systems |
Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP1022455A2 (en) * | 1999-01-21 | 2000-07-26 | Otkrytoe Aktsionernoe Obschestvo Nauchno-Proizvodstvennoe Obiedinenie "Energomash", Imeni Akademika V.P. Glushko, Russian Fed. | Liquid-propellant rocket engine chamber and its casing |
| US6499289B1 (en) * | 2000-03-31 | 2002-12-31 | Alliant Technologies Inc. | Pyrolytic graphite gauge for measuring heat flux |
| CN106198029A (en) * | 2016-08-30 | 2016-12-07 | 北京航天三发高科技有限公司 | Injector for engine testsand gas extraction system |
| CN206397619U (en) * | 2016-12-31 | 2017-08-11 | 上海洲跃生物科技有限公司 | A kind of pulse-knocking engine of side exhaust |
| CN109505712A (en) * | 2019-01-15 | 2019-03-22 | 北京理工大学 | It is a kind of for measuring the impulse generator of solid propellant rocket combustion instability |
| CN111122767A (en) * | 2019-11-29 | 2020-05-08 | 南京理工大学 | Detachable solid rocket engine jet pipe throat lining ablation test device |
| CN112555058A (en) * | 2021-02-19 | 2021-03-26 | 星河动力(北京)空间科技有限公司 | Test device for nozzle throat lining of rocket engine |
Family Cites Families (14)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4606499A (en) * | 1984-07-02 | 1986-08-19 | Langley Jr David T | Variable throat nozzle |
| US7296472B2 (en) * | 2004-02-03 | 2007-11-20 | University Of Denver | Method and apparatus for acoustic sensing of structures |
| US7251925B2 (en) * | 2004-10-14 | 2007-08-07 | Hamilton Sundstrand Corporation | Pressure-based fuel metering unit |
| US8613188B2 (en) * | 2008-05-14 | 2013-12-24 | Purdue Research Foundation | Method of enhancing microthruster performance |
| CN201916075U (en) * | 2010-12-23 | 2011-08-03 | 西北工业大学 | Experiment device for full-scale spray pipe thermal structure of solid-propellant rocket engine |
| US9273634B2 (en) * | 2011-08-18 | 2016-03-01 | Patrick R. E. Bahn | Rocket stage and method of improving an existing rocket stage |
| CN105736184B (en) * | 2014-12-09 | 2018-04-03 | 上海新力动力设备研究所 | High thrust is than, the micro-ablation that works long hours larynx lining and the laryngeal structure of diffuser |
| WO2016137472A1 (en) * | 2015-02-26 | 2016-09-01 | Halliburton Energy Services, Inc. | Methods and systems employing nmr-based prediction of pore throat size distributions |
| CN106152953A (en) * | 2015-03-21 | 2016-11-23 | 内蒙航天动力机械测试所 | A kind of solid engines examination rear jet larynx footpath measuring system and method |
| CN105651809A (en) * | 2015-12-31 | 2016-06-08 | 中国人民解放军国防科学技术大学 | Experimental device for particle combustion under high speed air flow |
| CN105841642A (en) * | 2016-06-03 | 2016-08-10 | 哈尔滨工业大学 | Laval nozzle throat diameter measurement system |
| CN109282989A (en) * | 2018-10-05 | 2019-01-29 | 北京航天三发高科技有限公司 | A kind of supersonic speed engine testsand gas handling system |
| CN208887580U (en) * | 2018-11-29 | 2019-05-21 | 王哲 | A kind of solid engines examination rear jet larynx calipers |
| CN112555057B (en) * | 2021-02-19 | 2021-05-07 | 星河动力(北京)空间科技有限公司 | Test device for nozzle throat lining of rocket engine |
-
2021
- 2021-05-11 CN CN202110509520.5A patent/CN113217229B/en active Active
Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP1022455A2 (en) * | 1999-01-21 | 2000-07-26 | Otkrytoe Aktsionernoe Obschestvo Nauchno-Proizvodstvennoe Obiedinenie "Energomash", Imeni Akademika V.P. Glushko, Russian Fed. | Liquid-propellant rocket engine chamber and its casing |
| US6499289B1 (en) * | 2000-03-31 | 2002-12-31 | Alliant Technologies Inc. | Pyrolytic graphite gauge for measuring heat flux |
| CN106198029A (en) * | 2016-08-30 | 2016-12-07 | 北京航天三发高科技有限公司 | Injector for engine testsand gas extraction system |
| CN206397619U (en) * | 2016-12-31 | 2017-08-11 | 上海洲跃生物科技有限公司 | A kind of pulse-knocking engine of side exhaust |
| CN109505712A (en) * | 2019-01-15 | 2019-03-22 | 北京理工大学 | It is a kind of for measuring the impulse generator of solid propellant rocket combustion instability |
| CN111122767A (en) * | 2019-11-29 | 2020-05-08 | 南京理工大学 | Detachable solid rocket engine jet pipe throat lining ablation test device |
| CN112555058A (en) * | 2021-02-19 | 2021-03-26 | 星河动力(北京)空间科技有限公司 | Test device for nozzle throat lining of rocket engine |
Non-Patent Citations (2)
| Title |
|---|
| Time-Frequency Analysis of Rocket Nozzle Wall;Woutijn J. Baars1等;《European Turbulence Conference》;20110912;全文 * |
| 固体火箭发动机喷管喉部瞬态热流的测量技术;李宏顺等;《武汉工程大学学报》;20111215;全文 * |
Also Published As
| Publication number | Publication date |
|---|---|
| CN113217229A (en) | 2021-08-06 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| Lu et al. | Condition monitoring and fault diagnosis of motor bearings using undersampled vibration signals from a wireless sensor network | |
| CN113217229B (en) | Method and system for testing instantaneous nozzle throat diameter | |
| CN102680860B (en) | Automatic fault-point locating method for traveling-wave based fault location of high-voltage electric power lines | |
| CN108444589B (en) | Hydroelectric generating set state monitoring signal processing method based on frequency domain feature extraction | |
| CN104136896B (en) | For the system for the vibration signal for obtaining rotation motor | |
| CN110987102A (en) | High-interference-resistance high-precision gas ultrasonic flowmeter and measuring method thereof | |
| Hussain et al. | Interpolation of discrete time signals using cubic spline function | |
| KR101840828B1 (en) | SDR Receiver for detecting doppler frequency in CW radar and method for detecting the same | |
| CN104314801A (en) | Test system of propulsive water-jet pump based on echoic environment and test method thereof | |
| CN104391177A (en) | System and method for grid-side harmonic testing of CRH unit | |
| CN107292067B (en) | Gear fault diagnosis method based on compressed sensing and bispectrum analysis | |
| CN110018391B (en) | GIS fault accurate positioning method and positioning system based on vibration signals | |
| CN108776259B (en) | Power analyzer based on digital bandwidth limiting technology | |
| KR100650956B1 (en) | Apparatus for processing electrical signal for automation of electricity delivery | |
| CN103344988B (en) | Based on the vibroseis signal phase detection method that K-L decomposes | |
| CN104394028A (en) | Method and system for measuring frequency amplitude response of communication physical layer channel | |
| CN112067927B (en) | Medium-high frequency oscillation detection method and device | |
| CN203365392U (en) | Rotation type multi-channel ultrasonic transmitting and receiving device | |
| CN111640519B (en) | Reactor neutron noise spectrum analysis method based on improved wavelet fractal algorithm | |
| CN202856959U (en) | Cinema digital film audio processor | |
| CN113992282A (en) | Wireless-like spectrum cognition check detection platform | |
| Cao et al. | A High-Efficiency Optimized Detection Algorithm for Non-Stationary Marine Acoustic Signals in the Time-Frequency Domain | |
| Zhongda et al. | Behavioral Modeling of A High-Resolution Sigma-Delta ADC | |
| Xiao et al. | A real-time test system for wireless distributed transient field signals | |
| CN101695004B (en) | Separation system of radio signals |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |