为了揭示汽轮机内湿蒸汽两相流动机理,提出了基于RGB三波段消光法和单帧单曝光图像法(SFSEI)的湿蒸汽测量探针系统,并采用2 100nm和960nm聚苯乙烯标准颗粒以及粒径范围为50~400μm的标准圆图像标定板对探针系统测量准确性进行了实验验证.利用该探针对某330 MW汽轮机在277 MW定压运行时末级后湿蒸汽进行了测量.结果表明:沿叶高方向,一次水滴的粒径分布在0.7~0.9μm,湿度在6%~9%,二次水滴的最大速度可达225.7m/s,最大粒径约200μm,并且二次水滴的速度、粒径和运动方向角随叶高变化不同;该探针系统可实现汽轮机湿蒸汽参数的有效测量,为湿蒸汽研究提供依据.
To reveal the mechanism of wet steam two-phase flow in steam turbines, a measurement probe was developed based on RGB three wavelength bands light extinction and single frame single exposure ima ging method (SFSEI), of which the measurement accuracy was verified by experiments with 2 100 nm and 960 nm standard polystyrene particles and standard round calibration board with the diameter ranging from 50 μm to 400μm. The probe was then applied to measure the wet steam behind the last stage of a 330 MW steam turbine in fixed pressure operation at 227 MW. Results show that along blade height direction, the size of fine droplets varies from 0.7 μm to 0.9 μm, with wetness ranging from 6 %0 to 9 % the maximum velocity and diameter of coarse droplets may get up to 225.7 m/s and 200 μm, respectively. the velocity,size and flow angle of coarse droplets are different along the blade height. The probe system tively measure the parameters of wet steam in steam turbines, which therefore may serve as further research of wet steam.