Effect Of Initial Condition On Temperature Distribution And Steam Condensation Behavior During CMT Drainage

The experiment of CMT (Core Makeup Tank) drain has been conducted in this research. It aims to find the initial condition effect on the characteristic of pressure response, fluid. temperature distribution and condensation behavior. The experimental parameters were as follow: the initial pressure of pressurizer P=0.2-0.6MPa and the initial water temperature of CMT T=20-80 ℃. There are three kinds of experiment have been finished: CMT no drain, CMT drain with sparger, CMT drain without sparger . The experimental results show that the fluid temperature distribution and the condensation behavior in the CMT dependent on the initial pressure of pressurizer and the initial temperature of CMT. However, the pressure response of CMT is mainly affected by the initial temperature of CMT.The comparison of results between the CMT drain with sparger and the CMT drain without sparger indicates that the sparger has great affection on the system pressure response, temperature distribution and heat transfer coefficient. The condensation process of saturated steam is divided into three phase: steam supply limit, part steam rapid condensation and steam slow condensation. The heat transfer coefficients between the steam and water have been calculated according to different condensation modes. Also the heat transfer coefficient correlations have been obtained from the experimental data. After analyzing the radial and axial temperature distribution of CMT, the primary result has been concluded: With the same initial pressure of the CMT drainage with sparger, the higher the average temperature of CMT fluid is, the shorter the disturbing time, and the large the temperature difference of the top and bottom layer fluid. If the initial pressure goes beyond 0.3MPa, the disturbing time changes not obvious. With the same initial pressure of the CMT drainage with sparger, the higher the average temperature of CMT fluid is, the shorter the disturbing time, and the large the difference temperature of the top and bottom layer fluid. Once the sparger installed in the CMT, the fluid temperature above the sparger and the initial pressure of pressurizer are the key factor, which affect the condensation characteristic and temperature equilibrium time. The temperature distribution was mainly influenced by the initial pressure of pressurizer under the condition of CMT drainage with sparger, the higher the pressure is, the thicker the hot water layer.After analyzing the pressure response under different initial condition, the primary result has been concluded: When the pressure of pressurizer is higher than 0.3MPa, the pressure equilibrium time of the CMT drainage without sparger is influenced by the average temperature of the CMT fluid. The sparger alleviates the drastic degree of the steam condensation, and greatly shorten the time of pressure equilibrium needed. After analyzing the CMT drainage mass under different initial condition, the primary result has been concluded: The CMT drainage velocity is related to the change of CMT pressure, the drainage mass of CMT without sparger increase monotonously along with time, and has a obvious inflexion. After the inflexion, the slope steep evidently, which show that the drainage velocity augment remarkably. However, the drainage mass of CMT with sparger do not have the obvious inflexion, which shows the drainage velocity increase earlier. The drainage mass of the CMT with sparger varies as the temperature of CMT fluid if the initial pressure of pressurizer is higher. The equilibrium time of drainage velocity is greatly affected by the pressure response of CMT.After analyzing the fluid axial temperature distribution of CMT, the primary result was conduced: The fluid of CMT has the thermal stratification behavior. The upper part is hot water layer. The lower part is cold water layer. The temperature of the hot water layer changes greatly. The temperature of the cold water layer nearly keep a constant. The higher the initial pressure of pressurizer, the higher the velocity of steam jet, the d...