Analysis of the Behavior of Droplet Impinging on a Curved Dry Wall in a Rotating Flow Field

Steam water separator is the core equipment of nuclear power plant. It is very vital for improving the efficiency of the steam separator to study the impact characteristics between the droplets and the curved dry wall of the steam separator under the action of the rotating air flow. In this paper, the characteristics of droplet impinging on the dry wall in the rotating flow field are analyzed by establishing a visualization experimental device. A high-speed camera was used to capture the impact of droplets with different diameters on the dry wall of a non-wetting curved surface at different gas velocities. At the same time, using image processing tool in MATLAB to obtain image boundary information. The characteristics of spreading factor, droplet deformation factor and initial diffusion velocity of droplets impacting the surface dry wall under different wind speeds are studied.

The Hot Test of Primary Separation Equipment of Steam Generator for CAP1400 Nuclear Power Plant

A new type of Steam separator for CAP1400 Steam Generator is introduced. The result of characteristic experiment, the variables of which contain steam load, saturated water flow and water level, shows its separation characteristics are suitable for CAP1400 Steam Generator. Steam generator is a major equipment of pressurized water reactor power plant, one function of which is to transfer heat from reactor to feedwater and to generate qualified steam. Steam separator, located in upper shell of Steam generator, is used to separate steam from saturated water/steam mixture which exits from the tube bundle region. Steam separating process usually consists of three stages. Centrifugal separation first happens in Primary separator, where most of water is separated. Gravity separation is achieved in the space formed between Primary separator and the dryer. Finally, as the relatively low moisture content mixture flows through the chevron-type dryer, the qualified steam is obtained. The new developed primary separator, named SP3 type, consist of raise cylinder, swirl impeller, downcomer and vane. As the steam/water mixture enters the primary separator, a centrifugal force is induced by the swirl. Thus the greater dense water in the steam-water mixture is forced toward the outside diameter of the separator, while the less dense steam stays in the central portion of the separator. The separated water leaved the separator through the downcomer. Relatively high quality steam exits the separator, passing upward through the center of raise cylinder. The paper introduced the SP3 primary separator developed by hot test, which includes test device, device design, test method, and result analysis. Separation characteristics of SP3 primary separator are obtained by various tests. The result of varying steam load test shows the outlet moisture is 13.3% under the condition of 100% steam load and 4.3 recirculation ration. The result of varying saturated water flow test shows the outlet moisture increases as the saturated mixture flow rate increases. The outlet moisture increased slowly as saturated water flow rate increases when steam load is at 50% and 100%, while the outlet moisture increases fast when steam load reaches at 120%. The result of varying water level test shows the water level is not a major factor for the SP3 primary separator performance. By analyzing experimental data, a fitting formula of the primary separator performance is obtained. the steam flow rate is the most sensitive parameter affecting primary separator performance in that formula. The water flow is the subordinate parameter for the primary separator performance. the resistance characteristics of separator is also obtained, which supports the research and development of the CAP1400 steam generator..