Two-dimensional reconstruction light distribution optimization method based on laser absorption spectrum technology

Abstract

The invention provides a light distribution optimization method for two-dimensional reconstruction of a combustion flow field by combining a tunable semiconductor laser absorption spectrum technology and a computed tomography technology. The method comprises the following steps: a light matrix calculation step, a combustion flow field reconstruction step and a light distribution optimization step and particularly comprises the following steps: step 1, discretizing a region to be tested; pre-setting a light space distribution manner and calculating the length of light penetrating through the discretized region to obtain a light distribution matrix; step 2, selecting a suitable absorption spectrum line and calculating a light projection result of an initial gas distribution model; reconstructing temperatures and concentrations of the tested flow field by using an algebra iterative algorithm and calculating a reconstruction error and a standard deviation; and step 3, wholly searching by using a self-adaption simulated annealing method to obtain an optimal light distribution range and partially searching by using a sequential quadratic programming method to obtain optimal light distribution.

Description

technical field [0001] The invention belongs to the field of optical flow field diagnosis, and relates to semiconductor laser absorption spectrum technology and computerized tomography reconstruction technology, in particular to an optimization method for multi-objective functions, which can be used for light distribution in two-dimensional reconstruction measurement of combustion flow field temperature / gas component concentration design. Background technique [0002] Tunable semiconductor laser absorption spectroscopy (TDLAS) uses a single frequency laser to pass through the flow field area to be measured. When the laser frequency is the same as the transition frequency of the gas absorption component, the laser energy is absorbed. By comparing the incident laser intensity with the transmission Laser intensity, determine the absorption value along the direction of the light path, and then determine the gas temperature and concentration physical parameters. However, since T...

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Problems solved by technology

Since only two directions of projection are used in the experiment, the accuracy of the reconstruction result is not high, so it can only be used for qualitative analysis

[0009] The above literature proves the feasibility of reconstructing gas parameters of the combustion flow field based on TDLAS technology and computer tomography technology, but the number of projection rays used is large (mostly greater than 100), and most of them use parallel beam or fan beam projection, and the light utilization efficiency is not good. High, no research on light distribution optimization methods

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