异轴角散射法中散射体几何模型的构建与优化

摘要

The measurement of wet steam parameters has a great significance for ensuring the efficient and safe operation of turbine units.The off-axis angular scattering method based on laser scattering is one of optical methods for measuring wet steam parameters.The shortcomings of the scatterer geometrical model in the off-axis angular scattering method were analyzed.The geometrical model of the corresponding scatterer for the single pixel of CCD camera was structured.The volume and relative geometrical parameters of the scatterer were solved,and MATLAB software was used to simulate and calculate.The influences of the middle radius of quantity(r0.5),the density of number(N) and the distribution coefficient(K) in water drop on scattering light were studied and the errors were analyzed.The results show that the relative error decreases,which is between the experimental data and the simulation data gotten by the off-axis angular scattering method based on scatterer geometrical model,and the trend of change is more agreed.The feasibility and superiority of the optimization of the geometric model are verified by the error analysis.It can provide more accurate data for the measurement of wet steam parameters.%湿蒸汽参量测量对于保障汽轮机机组的高效安全运行具有重大意义.基于激光散射的异轴角散射法是湿蒸汽参数测量的光学方法之一.本文在分析异轴角散射法测量模型中激光散射的散射体几何建模存在问题的基础上,构建了CCD相机单个像元所对应的散射体的几何模型,并求解了散射体体积及与散射体相关的几何参数;并采用MATLAB软件进行了仿真计算,计算了水滴群质量中间半径r0.5、水滴数浓度N和尺寸分布系数K变化对散射光强的影响,并进行了误差分析.研究结果表明:采用新构建的散射体几何模型的异轴角散射法所得的仿真理论数据与实验数据间相对误差减小,且变化趋势更趋于一致,验证了几何模型优化的可行性和优越性,可为湿蒸汽参数测量提供更精确的数据.