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Autocorrelation theory-based engine instability prediction and assessment method

An engine and autocorrelation technology, applied in the direction of electrical digital data processing, special data processing applications, instruments, etc., can solve the problems of inability to evaluate engine instability in real time, high time and capital costs, and inability to monitor engines in real time

Active Publication Date: 2017-05-24
PLA PEOPLES LIBERATION ARMY OF CHINA STRATEGIC SUPPORT FORCE AEROSPACE ENG UNIV
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Problems solved by technology

[0005] The spontaneous instability evaluation method is to evaluate the instability by the probability of the number of occurrences of spontaneous instability, which requires multiple tests, and the time and capital costs are relatively large
[0006] 2. Finite perturbation instability method
[0008] The limitation of the finite perturbation instability method is that it cannot monitor the engine instability in real time, that is, it cannot evaluate the engine instability in working state in real time
Unable to assess the extent of steady-state engine distance instability

Method used

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  • Autocorrelation theory-based engine instability prediction and assessment method
  • Autocorrelation theory-based engine instability prediction and assessment method
  • Autocorrelation theory-based engine instability prediction and assessment method

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Embodiment Construction

[0054] The present invention will be further described in detail below in conjunction with the accompanying drawings and specific preferred embodiments.

[0055] Before introducing the present invention in detail, a brief description of the autocorrelation theory is given.

[0056] Autocorrelation reflects the degree of correlation of the same signal at different times, and the degree of correlation gradually decays with time. The inherent noise in the combustion chamber of the liquid rocket engine continuously excites the pressure pulsation. Due to the dissipation effect of the combustion chamber, the amplitude of the pressure pulsation excited at a certain moment gradually decays with time. The pressure amplitude decay rate is characterized by the correlation degree decay rate.

[0057] Taking the high-frequency unstable combustion of a model engine as an example, the calculation process of the method of the present invention is specifically described. The structure of the...

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Abstract

The invention discloses an autocorrelation theory-based engine instability prediction and assessment method. The method comprises the steps of firstly filtering a pulsating pressure signal of a combustion chamber, separating out pressure oscillation of each order mode and performing autocorrelation calculation; secondly performing Hilbert transform on an autocorrelation result to obtain an outside envelope of the autocorrelation result; and finally fitting the outside envelope by applying a least square method to determine a first-order mode dissipation coefficient of an engine, and taking the first-order mode dissipation coefficient of the engine as an assessment tool of engine stability margin for predicting and assessing high-frequency combustion instability of the liquid rocket engine. According to the method, the engine can be subjected to instability quantitative prediction and assessment under the condition of not applying external force interference.

Description

technical field [0001] The invention relates to the field of liquid rocket engine research, in particular to an engine instability prediction and evaluation method based on autocorrelation theory. Background technique [0002] The unstable combustion of the liquid rocket engine can lead to the instantaneous destruction of the engine, and the stability margin of the engine needs to be evaluated during the development period. [0003] At present, there are mainly the following methods for evaluating the stability margin of an engine. [0004] 1. Spontaneous instability assessment method [0005] The spontaneous instability evaluation method is to evaluate the instability by the probability of the occurrence of spontaneous instability, which requires multiple tests, and the time and capital costs are relatively large. [0006] 2. Finite perturbation instability method [0007] The finite disturbance instability method is to excite high-amplitude pressure oscillations through...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G06F17/50
CPCG06F30/17G06F30/20
Inventor 聂万胜安红辉王迪
Owner PLA PEOPLES LIBERATION ARMY OF CHINA STRATEGIC SUPPORT FORCE AEROSPACE ENG UNIV
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