为了解决汽轮机通流部分蒸汽湿度的在线测量问题, 提出了一种基于散射相函数的半经验公式快速反演散射光强分布的计算方法。该算法采用MATLAB自带的cftool进行相函数的双高斯拟合, 拟合误差低, 且拟合函数可以快速得到Mie散射理论的近似解析解, 即从散射光强分布到水滴质量中间半径的快速反演。结果表明, 在约束水滴粒径范围内, 得到了颗粒大小与散射比之间的半经验模型, 对比实验测得散射比, 吻合良好, 且由半经验模型反演得到水滴质量中间半径为1.1μm。在一定条件下, 可以有效解决蒸汽湿度的在线测量问题。

In order to solve the problem confronted with the online steam humidity measurement of turbine flow pass, a semi-empirical formula of phase function computing method was proposed to improve the inversion algorithm on scattering light distribution. Phase function of double Gaussian fitting by using MATLAB with cftool was adopted in this algorithm. The fitting result shows that the relative error is in small, and the approximate analytic solution of the Mie scattering theory could be got by the fitting function, which means that a rapid inversion from the scattering light intensity distribution to water quality radius. According to the results, with the restriction of the range of the droplet size, the approximation of the theory between the droplet size and scattering ratio was got. Contrast experiment showed the measured scattering ratio was similar with the simulated scattering ratio. Based on the semi-empirical model, the water quality of middle radius was 1.1μm.The fast inversion algorithm can well resolve the online measurement of steam humidity.