Research On Flow And Heat Transfer Character Of Air Flow Passage Outside Steel Containment

The air flow passage outside containment is one part of the containment cooling system.After entering the flow, the cooling air from the atmosphere can export the heat generated in the containment through convective heat transfer. The air flow passage can prevent threat to integrity because of the exceedingly high internal temperature and pressure. To find the best solution for conducting out the heat in the containment, analysing flow and heat transfer characteristics of the air flow passage, understanding the effect degree on the air flow passage velocity field and temperature field of different factors have important engineering significance.Based on the structure characteristics of the air flow passage, geometric modeling and meshing for the simplified system was accomplished by the GAMBIT software. The simulation mathematical model was established using the commercial CFD (Computational Fluid Dynamics) software——FLUENT. A range of factors were simulated and analysed for the impact on the air flow passage velocity field and temperature field. By calculating the heat taked away from the steel containment by cooling air per unit time, comparing different factors which can affect the flow field and temperature field, the optimization scheme was obtained.According to the calculation results of FLUENT, the distribution characteristics of air flow passage velocity field and temperature field were obtained respectively. By calculating the heat taked away from the steel containment by cooling air per unit time, maximum heat flow value is determined on the top position of the steel containment. When the temperature of cooling air was low(less than 283K), the heat taked away from containment per unit time was rising with the increase in the flow rate of cooling air. When the temperature of cooling air was high(more than 283K), heat transfer rate between cooling air and the steel containment has little relationship to the air flow rate. Heat transfer rate between cooling air and the steel containment is great dependent on the air temperature in the channel. These conclusions are consistent with the containment system large-scale experimental data. It turned out when the guide plate was translated to the containment shield building, heat transfer rate decreased limitedly, when the guide plate was translated to the steel containment,heat transfer rate increased obviously, low air temperature of cooling air was the most beneficial to heat transfer between cooling air and the steel containment.