A method and system for obtaining spectral absorptance distribution

Abstract

The invention belongs to the technical field of laser absorption spectroscopy, and discloses a method and system for obtaining spectral absorptivity distribution. The method for obtaining spectral absorptivity distribution includes: using an adaptive step size-based The real transmission trajectory in the deflection field and the deflection characteristic parameters including the deflection path and deflection angle; based on the deflection characteristic parameters, the spectral absorptivity projection matrix and path matrix are rearranged and corrected to establish the deflection path Spectral absorptivity distribution reconstruction equations; the improved synchronous iterative reconstruction algorithm is used to optimize and solve the reconstruction equations stably, and finally achieve high-precision acquisition of spectral absorptivity distribution in a strongly deflected combustion field. The invention can reduce the computational complexity while ensuring the solution accuracy, realize high-precision acquisition of the spectral absorption rate distribution in the strongly deflected combustion field, and has good application potential in the refined diagnosis of the strongly deflected combustion field.

Description

technical field [0001] The invention belongs to the technical field of laser absorption spectroscopy, and in particular relates to a method and system for acquiring spectral absorption rate distribution. Background technique [0002] At present, the engine has an important strategic position in my country's energy and power field, and its development level directly reflects my country's national defense strength and comprehensive national strength. The combustion chamber of the engine will encounter a series of problems during the development process, among which the oscillating combustion problem caused by the thermoacoustic coupling is the key problem to be solved. The refined and low-cost diagnosis of key parameters in oscillating combustion is helpful to deeply explore the mechanism of oscillating combustion, and then effectively control the problem of oscillating combustion, reduce the development cost of the engine and improve its safety and reliability. Laser absorpt...

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Problems solved by technology

[0007] (2) Compared with the conventional steady-state combustion state in the engine, the oscillating combustion process is accompanied by large-scale pressure, heat oscillation, and extremely high combustion and heat transfer rates. The flame structure changes significantly, and the flow and coupling mechanism are more complex. complex

[0008] (3) Under the strong deflection effect, the mathematical premise of straight optical path is destroyed by the strong physical deflection effect, and continuing to use the approximation of straight optical path in the reconstruction process will bring significant reconstruction errors

[0009] (4) At present, the research on the light deflection effect in the laser absorption spectroscopy technology mainly focuses on taking corresponding measures at the laser receiving end to eliminate the light intensity distortion caused by the deflection, but it cannot suppress the influence of the light deflection transmission process on tomography

[0010] The difficulty of solving the above problems and defects is: under the light deflection effect, the laser light no longer propagates along a straight line, but along a curve. The problem of tomographic reconstruction under a curved path is a complex nonlinear inversion problem, which is difficult to solve

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