基于单波长/双角度法测湿蒸气的波长选择研究

Based Wavelength Selection of Single Wavelength/double Angle Measured wet Steam

为了精准测量汽轮机尾气蒸汽湿度,本文对单波长/双角度测量蒸汽湿度的方法进行了研究。首先将532nm波长的入射光发射至散射区中,通过阵列探测器获取各个散射角对应的散射光强,再采用Mie散射理论求出水滴质量中间半径;通过同种方式再求出655nm波长对应的水滴质量中间半径。实验结果表明,随着背压降低,波长为532nm的激光器测量显示水滴质量中间半径先增后减,波长为655nm的激光器测量显示水滴质量中间半径保持1.6μm左右基本不变。根据热力学原理,波长为532nm的激光器更符合单波长双角度测量法的要求。

In order to accurately measure the turbine exhaust steam humidity,this paper conducted research on single wavelength/double angle measurement method. Firstly,let the 532 nm wavelengths of incident light emitted to the scattering region,gets each corresponding scattering angle scattering intensity by an array of detectors,then using Mie scattering theory,determined the mass median droplet radius; By the same way,determine the mass median droplet radius of the 655 nm wavelengths. The experimental results showed that when the back pressure decreases,the wavelength of 532 nm laser measured the mass median droplet radius decreased after an initial increase,655 nm wavelength laser measured the mass median droplet radius around 1. 6um.According to thermodynamic principles,the wavelength of532 nm wavelength laser is more in line with the requirements of the single dual-angle measurement method.