An experimental investigation on drainage performance of a drain device in a steam generator of PWR

This study evaluates the performance of drain device of a steam dryer in steam generator for PWR through experiments with water and air under ambient temperature and pressure. Two different test sections are designed and tested, one of which is equipped with a single drain pipe (test section I) and the other is equipped with double drain pipes (test section II). For the test section I, various slopes of bottom plate (3.5°-5°) and different numbers of water entrance holes (36-136) are investigated to study their effects on drainage performance of the drain device. For the test section II, only the influence of different entrance holes is studied. In experiments, flow fields in the drain device for different flow rates ranging form 13.8 m3/h to 165.7 m3/h are recorded using a video camera and the corresponding video images are processed by MATLAB to obtain the free liquid surface configuration. The experimental results show that the free liquid surface height of the test section I with single drain pipe is much bigger than that of the test section II with double drain pipes. In addition, the maximum free liquid surface height in the drain tank increases linearly with the increase of flow rate for both test sections while the number of entrance holes has no obvious effect on the maximum free liquid surface height. For the test section I, the bottom plate inclination influences the maximum free liquid surface height and 4° inclination meets the optimized value.