CN115683642A - System and method for acquiring modal parameters of liquid rocket engine - Google Patents
System and method for acquiring modal parameters of liquid rocket engine Download PDFInfo
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- CN115683642A CN115683642A CN202211280217.3A CN202211280217A CN115683642A CN 115683642 A CN115683642 A CN 115683642A CN 202211280217 A CN202211280217 A CN 202211280217A CN 115683642 A CN115683642 A CN 115683642A
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Abstract
The invention discloses a system and a method for acquiring modal parameters of a liquid rocket engine, which belong to the technical field of mechanical structure vibration mode testing, wherein the system comprises a plurality of triaxial acceleration sensors, a data acquisition unit and a data processing unit, wherein more than one triaxial acceleration sensor is arranged at an excitation signal measuring point position set on the liquid rocket engine and used for acquiring an excitation signal, and the excitation signal is generated by the liquid rocket engine during a thermal test on the ground; more than one triaxial acceleration sensor is arranged at a response signal measuring point position set on the liquid rocket engine and used for acquiring a response signal; each three-axis acceleration sensor is in signal connection with the data acquisition unit; the data processing unit can analyze and process the excitation signal and the response signal to obtain the modal parameters of the liquid rocket engine. The method can obtain the modal parameters of the liquid rocket engine in a wider frequency range.
Description
Technical Field
The invention belongs to the technical field of mechanical structure vibration mode testing, and particularly relates to a system and a method for acquiring mode parameters of a liquid rocket engine.
Background
With the continuous development of aerospace industry, the thrust of a liquid rocket engine is continuously increased, and the dynamic environment of the engine is also more and more severe. However, a large number of pipelines exist in the structure of the liquid rocket engine, and if coupled resonance occurs between the pipelines and excitation, fatigue fracture can be generated in a short time. Therefore, the structural dynamics characteristics of multiple pipelines of the liquid rocket engine are mastered, the dominant frequency of the liquid rocket engine during test is avoided, and the method has important significance for the structural integrity of the liquid rocket engine.
As an important means for understanding the dynamic characteristics of the structure, the experimental modal analysis can improve the structure design and avoid the resonance frequency on one hand; on the other hand, accurate test results can be provided for finite element model correction.
However, in a conventional modal test scheme, a force hammer or a vibration exciter is used as an excitation source in a laboratory, and a frequency response function of each response measuring point relative to an excitation point is measured, so as to obtain a modal parameter of a measured system, or a simulation is performed according to modal simulation software to obtain the modal parameter of the system. The methods are completed based on a laboratory, the amplitude of the excitation is too small, when the excitation is transmitted to a response measuring point, the excitation is greatly attenuated, and the actual requirement for obtaining the modal parameters of the liquid rocket engine in a wider frequency range cannot be met.
Disclosure of Invention
In view of this, the invention provides a system for acquiring modal parameters of a liquid rocket engine, which is used for solving the problem that the traditional modal test scheme cannot effectively excite the liquid rocket engine, so that the modal parameters of the liquid rocket engine in a wider frequency range cannot be acquired.
The system for acquiring the modal parameters of the liquid rocket engine adopts the following technical scheme:
a system for obtaining modal parameters of a liquid rocket engine, comprising: the system comprises a plurality of triaxial acceleration sensors, a data acquisition unit and a data processing unit;
more than one triaxial acceleration sensor is arranged at an excitation signal measuring point position set on the liquid rocket engine and used for collecting an excitation signal, wherein the excitation signal is generated by the liquid rocket engine during ground thermal test; more than one triaxial acceleration sensor is arranged at a response signal measuring point position set on the liquid rocket engine and used for acquiring a response signal; each triaxial acceleration sensor is in signal connection with the data acquisition unit, and the triaxial acceleration sensors can send the excitation signals and the response signals to the data acquisition unit;
the data acquisition unit is in signal connection with the data processing unit and can send the received excitation signal and the response signal to the data processing unit;
the data processing unit can analyze and process the received excitation signal and the response signal to obtain modal parameters of the liquid rocket engine.
Further, the system also comprises a time system device;
the time system equipment is in signal connection with the three-axis acceleration sensors, and can send a trigger instruction to each three-axis acceleration sensor when the liquid rocket engine is in test run and ignited, so that each three-axis acceleration sensor can acquire signals simultaneously.
Further, the excitation signal measuring point position is arranged at the inlet of a thrust chamber of the liquid rocket engine.
Further, the position of the response signal measuring point is arranged on a pipeline of the liquid rocket engine.
Further, the data processing unit can load and display the 3D model of the liquid rocket engine, and can display the current position of the response signal measuring point and the position of the response signal measuring point to be measured on the 3D model of the liquid rocket engine in real time.
Further, the data processing unit is preset with modal parameter analysis software.
Further, the triaxial acceleration sensor is a MEMS sensor.
In addition, the invention also provides a method for acquiring the modal parameters of the liquid rocket engine, and the method acquires the modal parameters of the liquid rocket engine by using the system. The method adopts the following technical scheme:
a method for acquiring modal parameters of a liquid rocket engine comprises the following steps:
the method comprises the following steps: arranging a triaxial force sensor at the position of an excitation signal measuring point and the position of a response signal measuring point of the liquid rocket engine;
step two: the liquid rocket engine is started and ignited, the three-axis acceleration sensor arranged at the position of an excitation signal measuring point sends the acquired excitation signal to the data acquisition unit, and the three-axis acceleration sensor arranged at the position of a response signal measuring point sends the acquired response signal to the data acquisition unit;
step three: the data acquisition unit sends the received excitation signal and the response signal to the data processing unit;
step four: and the data processing unit analyzes and processes the received excitation signal and the response signal to obtain the modal parameters of the liquid rocket engine.
Has the beneficial effects that:
(1) The system for acquiring the modal parameters of the liquid rocket engine comprises a triaxial acceleration sensor, a data acquisition unit and a data processing unit, is simple in composition, can acquire the modal parameters of the liquid rocket engine in a wider frequency range only by analyzing and processing excitation signals and response signals acquired by the triaxial acceleration sensor through the data processing unit when the liquid rocket engine is subjected to a thermal test on the ground, and solves the problem that the traditional modal test scheme cannot apply effective excitation to the liquid rocket engine, so that the modal parameters of the liquid rocket engine in the wider frequency range cannot be acquired.
(2) The time-series device is in signal connection with the three-axis acceleration sensors, and can send a trigger instruction to the three-axis acceleration sensors when the liquid rocket engine is ignited, and the three-axis acceleration sensors simultaneously acquire signals, so that the signals acquired among the three-axis acceleration sensors have a uniform time reference, and the condition that the subsequent data processing unit can accurately obtain the modal parameters of the liquid rocket engine through the signals acquired by the three-axis acceleration sensors is ensured.
(3) An excitation signal measuring point is arranged at an inlet of a thrust chamber of the liquid rocket engine, and a triaxial acceleration sensor is arranged at the position of the excitation signal measuring point, so that the sensor can accurately acquire an excitation signal when the liquid rocket engine is ignited by a ground hot trial run, and further, the accurate acquisition of modal parameters of the liquid rocket engine is ensured.
(4) The pipeline of the liquid rocket engine is provided with the response signal measuring points, and the triaxial acceleration sensor is arranged at the response signal measuring points, so that the response signal can be accurately acquired by the triaxial acceleration sensor at the response signal measuring points under the working condition that the liquid rocket engine generates huge thrust during ground hot trial ignition, and the structural dynamics characteristics of the pipeline of the liquid rocket engine can be accurately mastered.
(5) The current response signal measuring point position and the response signal measuring point position to be measured can be displayed on the 3D model of the liquid rocket engine in real time, the problem that the deviation of a measuring result occurs due to the fact that an actual measuring point does not correspond to a measuring point set by software is solved, the process of obtaining modal parameters of the liquid rocket engine is more visual, and the testing efficiency is improved.
(6) The three-axis acceleration sensor adopts an MEMS sensor, and can meet the requirement of miniaturization.
(7) The method for obtaining the modal parameters of the liquid rocket engine by taking the thrust generated by the ground hot trial ignition of the liquid rocket engine as an excitation signal solves the problem that the traditional modal test scheme by taking a force hammer or a vibration exciter as an excitation source cannot effectively excite the liquid rocket engine so as not to obtain the modal parameters of the liquid rocket engine in a wider frequency range.
Drawings
Fig. 1 is a schematic structural diagram of a system for acquiring modal parameters of a liquid rocket engine according to an embodiment of the present invention;
fig. 2 is a schematic diagram of a functional layout of the modal parameter identification software in fig. 1.
Detailed Description
The invention is described in detail below by way of example with reference to the accompanying drawings.
The first embodiment is as follows:
as shown in fig. 1, a system for obtaining modal parameters of a liquid rocket engine comprises: a plurality of triaxial acceleration sensor, data acquisition unit and data processing unit, wherein:
more than one triaxial acceleration sensor is arranged at an excitation signal measuring point position set on the liquid rocket engine and used for collecting an excitation signal, wherein the excitation signal is generated by the liquid rocket engine during a thermal test on the ground; more than one triaxial acceleration sensor is arranged at the position of a response signal measuring point set on the liquid rocket engine and used for acquiring a response signal. Because the liquid rocket engine can generate huge thrust when the liquid rocket engine is ignited by ground hot test, the huge thrust can be transmitted to each part of the liquid rocket engine, and no obvious attenuation occurs, the acceleration signal acquired by the triaxial acceleration sensor arranged at the measuring point position of the liquid rocket engine can reflect the excitation force (namely the thrust) and can be used as the excitation signal, and the triaxial acceleration sensor arranged at the responding signal measuring point position of the liquid rocket engine can acquire the response signal under the corresponding excitation.
The three-axis acceleration sensors are in signal connection with the data acquisition unit, so that the three-axis acceleration sensors can send excitation signals and response signals to the data acquisition unit, the data acquisition unit is in signal connection with the data processing unit, the data acquisition unit can send the received excitation signals and response signals to the data processing unit, and the data processing unit can analyze and process the received excitation signals and response signals and obtain modal parameters of the liquid rocket engine.
The system for acquiring the modal parameters of the liquid rocket engine further comprises a time system device, the time system device is respectively in signal connection with the three-axis acceleration sensors, and can send a trigger instruction to the three-axis acceleration sensors when the liquid rocket engine is in test run and ignited, so that all the three-axis acceleration sensors can acquire signals simultaneously, the signals acquired among the three-axis acceleration sensors have a uniform time reference, and the follow-up data processing unit can acquire the precise modal parameters of the liquid rocket engine through the signals acquired by the three-axis acceleration sensors.
Specifically, the excitation signal measuring point position of the liquid rocket engine is preferably arranged near the thrust chamber, such as an inlet of the thrust chamber, and the response signal measuring point position is arranged on the pipeline of the liquid rocket engine, so that when the liquid rocket engine is subjected to test run ignition to generate large thrust, the response signal of the pipeline can be accurately acquired by the triaxial acceleration sensor, and further the structural dynamics characteristics of the pipeline of the liquid rocket engine can be accurately mastered.
More specifically, the triaxial acceleration sensor is a MEMS sensor, but may be a PE sensor or other types of sensors, and an inertial measurement unit may be used in addition to the triaxial acceleration sensor. In this embodiment, six triaxial acceleration sensors are used, wherein one triaxial acceleration sensor is disposed at an excitation signal measuring point (or other number of sensors may be disposed to obtain the magnitude and direction of thrust), and five triaxial acceleration sensors are disposed at a response signal measuring point on a pipeline of the liquid rocket engine (which may be flexibly designed according to specific working conditions), so as to obtain sufficient response signals, thereby ensuring that the data processing unit can accurately analyze and process to obtain modal parameters of the liquid rocket engine.
In addition, the triaxial acceleration sensor is connected with the data acquisition unit through a cable, the frequency of data acquired by the triaxial acceleration sensor is 2kHz at most, and the triaxial acceleration sensor transmits acquired excitation and response signals to the data acquisition unit through a gigabit network according to synchronous pulses.
As shown in fig. 2, the data processing unit processes and analyzes the excitation signal and the response signal through a modality parameter recognition software preset inside, and the modality parameter recognition software is divided into two modules, namely a signal analysis module and a test modality analysis module, wherein the signal analysis module includes the following functions:
statistical analysis:
the statistical analysis comprises integration, differentiation, amplitude domain analysis, time difference domain analysis, frequency domain analysis, time domain analysis and the like. Wherein, the signal integration and differentiation can be used for the conversion of acceleration, speed and displacement signals. The amplitude domain analysis comprises the steps of solving a mean value, a maximum value, a minimum value, a variance, a mean square error and the like, and the parameters can intuitively reflect the characteristic information of the signal.
(II) autocorrelation
The autocorrelation function can describe the correlation between a signal at one moment and a signal at another moment, and is often used for checking whether a periodic signal is mixed in random noise in engineering;
(III) Cross-correlation
The method represents the correlation statistics between two different signals, can be used for researching the transmission channel and vibration source conditions of the signals, and can also be used for detecting the signals hidden in external noise.
The modal analysis module includes the following functions:
model input
The modal test usually involves a large number of measuring points, and for example, in the process of the modal analysis of the hammering test, different measuring points are required to be hammered and excited in sequence (or the same measuring point is hammered and excited), and excitation signals of each excitation and response signals of the same measuring point (or different measuring points) are recorded. The test process is relatively complicated, and the situation that the actual measuring point does not correspond to the software setting measuring point is easy to occur, so that the measuring result is deviated.
The modal parameter identification software can load and display a 3D model file of the liquid rocket engine, configure a three-axis acceleration sensor measuring point, display the position of the current measuring point and the position of the measuring point to be measured in real time and the like.
The current measuring point and the position of the measuring point to be measured of the measuring point position are displayed on the displayed 3D model of the liquid rocket engine in real time, so that the modal test process is more visual, and the test efficiency is improved.
(II) frequency response function solving
The excitation and response signals can be preprocessed (including low pass filtering, trend term elimination, etc.) to obtain a Frequency Response Function (FRF).
(III) Modal parameter output
And the modal parameter identification is completed, the modal parameters of the liquid rocket engine are obtained, and the functions of outputting a vibration pattern diagram and the like are realized.
Example two:
on the basis of the first embodiment, the present embodiment provides a method for acquiring modal parameters of a liquid rocket engine, where the method uses the system in the first embodiment, and specifically includes the following steps:
the method comprises the following steps: arranging a triaxial force sensor at the position of an excitation signal measuring point and the position of a response signal measuring point of the liquid rocket engine;
step two: the liquid rocket engine is started and ignited, the three-axis acceleration sensor arranged at the position of an excitation signal measuring point sends the acquired excitation signal to the data acquisition unit, and the three-axis acceleration sensor arranged at the position of a response signal measuring point sends the acquired response signal to the data acquisition unit;
step three: the data acquisition unit sends the received excitation signal and the response signal to the data processing unit;
step four: and the data processing unit analyzes and processes the received excitation signal and the response signal to obtain the modal parameters of the liquid rocket engine.
It is worth noting that when the liquid rocket engine is started up and ignited, the three-axis acceleration sensor arranged at the position of the excitation signal measuring point and the three-axis acceleration sensor arranged at the position of the response signal measuring point receive the trigger signal of the time system device and collect signals at the same time. And modal parameter recognition software in the data processing unit displays the 3D model of the liquid rocket engine in real time, and displays the current excitation signal measuring point position, the current response signal measuring point position, the excitation signal measuring point position to be measured and the response signal measuring point position to be measured on the 3D model of the liquid rocket engine in real time.
The method comprises the steps of installing a triaxial acceleration sensor on a tested system, namely a plurality of test points on the liquid rocket engine, measuring and storing the acceleration of the test points in real time, determining the vibration characteristics of the liquid rocket engine from collected input and output data through modal parameter identification software in a data processing unit, and solving the modal parameters of the liquid rocket engine. Through test verification, the method can be applied to the liquid rocket engine ignition test, can obtain the vibration mode of the liquid rocket engine within 500Hz, and solves the problems that the traditional mode test scheme cannot apply excitation with large enough amplitude to the liquid rocket engine, the excitation is easy to attenuate, and the mode parameters of the liquid rocket engine within a wide frequency range cannot be obtained.
In summary, the above description is only a preferred embodiment of the present invention, and is not intended to limit the scope of the present invention. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (8)
1. A system for obtaining modal parameters of a liquid rocket engine, comprising: the device comprises a plurality of triaxial acceleration sensors, a data acquisition unit and a data processing unit;
more than one triaxial acceleration sensor is arranged at an excitation signal measuring point position set on the liquid rocket engine and used for collecting an excitation signal, wherein the excitation signal is generated by the liquid rocket engine during ground thermal test; more than one triaxial acceleration sensor is arranged at a response signal measuring point position set on the liquid rocket engine and used for acquiring a response signal; each triaxial acceleration sensor is in signal connection with the data acquisition unit, and the triaxial acceleration sensors can send the excitation signals and the response signals to the data acquisition unit;
the data acquisition unit is in signal connection with the data processing unit and can send the received excitation signal and the response signal to the data processing unit;
the data processing unit can analyze and process the received excitation signal and the response signal to obtain modal parameters of the liquid rocket engine.
2. A system for obtaining modal parameters of a liquid rocket engine as recited in claim 1, further comprising time-keeping means;
the time system equipment is in signal connection with the three-axis acceleration sensors, and can send a trigger instruction to each three-axis acceleration sensor when the liquid rocket engine is in test run and ignited, so that each three-axis acceleration sensor can acquire signals simultaneously.
3. A system for acquiring modal parameters of a liquid rocket engine as recited in claim 1 or 2, wherein said excitation signal point location is located at an entrance of a thrust chamber of said liquid rocket engine.
4. A system for acquiring modal parameters of a liquid rocket engine as recited in claim 1 or 2, wherein said response signal point locations are disposed on the lines of said liquid rocket engine.
5. The system for acquiring modal parameters of a liquid rocket engine as recited in claim 1 or 2, wherein said data processing unit is capable of loading and displaying a 3D model of said liquid rocket engine, and displaying the current position of response signal measuring point and the position of response signal measuring point to be measured on said 3D model of said liquid rocket engine in real time.
6. The system for acquiring modal parameters of a liquid rocket engine as recited in claim 1 or 2, wherein said data processing unit is pre-loaded with modal parameter analysis software.
7. A system for acquiring modal parameters of a liquid rocket engine as recited in claim 1 or 2, wherein said three-axis acceleration sensor is a MEMS sensor.
8. A method for obtaining modal parameters of a liquid rocket engine, wherein the following steps are performed by using the system for obtaining modal parameters of a liquid rocket engine as claimed in any one of claims 1 to 7:
the method comprises the following steps: arranging triaxial force sensors at the positions of an excitation signal measuring point and a response signal measuring point of the liquid rocket engine;
step two: the liquid rocket engine is started and ignited, the three-axis acceleration sensor arranged at the position of an excitation signal measuring point sends the acquired excitation signal to the data acquisition unit, and the three-axis acceleration sensor arranged at the position of a response signal measuring point sends the acquired response signal to the data acquisition unit;
step three: the data acquisition unit sends the received excitation signal and the response signal to the data processing unit;
step four: and the data processing unit analyzes and processes the received excitation signal and the response signal to obtain the modal parameters of the liquid rocket engine.
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| CN202211280217.3A CN115683642A (en) | 2022-10-19 | 2022-10-19 | System and method for acquiring modal parameters of liquid rocket engine |
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Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5831155A (en) * | 1996-12-02 | 1998-11-03 | Atlantic Research Corporation | Apparatus and method for simulating rocket-to-ramjet transition in a propulsion system |
| CN112502860A (en) * | 2020-11-27 | 2021-03-16 | 西安航天动力研究所 | Liquid rocket engine frequency characteristic measuring method |
| CN113882973A (en) * | 2021-10-21 | 2022-01-04 | 上海机电工程研究所 | Time-varying acoustic vibration modal frequency identification method and system for combustion chamber of solid rocket engine |
-
2022
- 2022-10-19 CN CN202211280217.3A patent/CN115683642A/en active Pending
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5831155A (en) * | 1996-12-02 | 1998-11-03 | Atlantic Research Corporation | Apparatus and method for simulating rocket-to-ramjet transition in a propulsion system |
| CN112502860A (en) * | 2020-11-27 | 2021-03-16 | 西安航天动力研究所 | Liquid rocket engine frequency characteristic measuring method |
| CN113882973A (en) * | 2021-10-21 | 2022-01-04 | 上海机电工程研究所 | Time-varying acoustic vibration modal frequency identification method and system for combustion chamber of solid rocket engine |
Non-Patent Citations (1)
| Title |
|---|
| 余建新 等: "虚假模态参数识别试验研究", 哈尔滨工业大学学报, no. 07, pages 52 - 55 * |
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