A New Reconstruction Algorithm for CT-TDLAS

摘要

A new reconstruction algorithm for CT-TDLAS (Computer Tomography-Tunable Diode Laser Absorption Spectroscopy) is proposed for the measurements of two-dimensional temperature and concentration distribution of a gas flame.The characteristic wavelengths near 1388nm where water vapor is detected were used for the performance test of the proposed algorithm.The new algorithm is 6-peaks algorithm, in which the absorptions at 6 representative wavelengths are used for the construction of the actual absorption spectra at a certain temperature of gas flame.MART (multiplicative algebraic reconstruction technique) algorithm was adopted for data reconstructions.MSE (Mean Squared Errors) was calculated during the iterative calculations for data reconstructions.In order to evaluate the performances of the new algorithm, a numerical test was performed by the use of phantom data in which two dimensional distribution of temperature and concentration fields were set at 11 ×11 square mesh with Gaussian distribution.Further, the proposed algorithm has been adopted to calculate an actual temperature distribution inside a combustion engine, through which the performance of the newly proposed 6-peaks algorithm has been demonstrated theoretically and experimentally.It is highly expected that the proposed algorithm will be the most appropriate approach for calculating the temperature and concentration fields in CT-TDLAS.