330MW低压汽轮机湿蒸汽二次水滴测量实验研究

研制了基于单帧单曝光图像法(SFSEI)的测量探针,并将其布置在330MW低压汽轮机末级后侧,有效捕获了湿蒸汽二次水滴图像,对其湿度、粒径和速度进行了测量.实验测量结果表明,二次水滴的粒径与湿度受汽轮机运行负荷影响较大.负荷较低时,汽轮机内湿度较大;负荷增加时,由于叶片表面温度上升的延迟,在工况开始变化的一段时间内,二次水滴的湿度会有一定的增加.末级叶片上的拉筋对二次水滴的形成有一定影响,当蒸汽流经拉筋后,其二次水滴的湿度明显增大.此外,二次水滴的速度受到汽轮机内主蒸汽流量和二次水滴粒径大小等因素的影响.

Experimental Research on the Coarse Water Droplets Measurement in a 330 MW LP Steam Turbine

The measurement probe system based on the method of single fame and single exposure imaging (SFSEI) was developed and applied to measure coarse water droplets in wet steam flow behind the last stage of a 330 MW low-pressure (LP) steam turbine.The wetness,diameter and speed of coarse water droplets were measured.The results show that the diameter and wetness of coarse water droplets are greatly influenced by the operating load of steam turbine.The wetness of coarse water droplets is relatively higher in the lower load operation,and it would raise with the increase of the operating load of steam turbine,because of the time delay in temperature changing on the surface of blades.The lacing wires have impacts on the formation of coarse water droplets.Thus,the wetness of coarse water droplets would raise when the steam flow passes by the lacing wires.Moreover,the speed of coarse water droplets is influenced by the flux of main steam flow and the diameter of coarse water droplets.