Analysis Of Natural Circulation Flow Field In The Air-cooled Channel Of Molten Salt-air Heat Exchanger

The application of passive safety systems can contribute to security and reduce spending of new nuclear power plant designs.The Shanghai Institute of Applied Physics designs the molten salt Nitrate Natural Circulation Loop(NNCL).It is used to study the possible problems in the use of natural circulation to discharge heat.The aim of this article is to research the natural circulation of air inside the chimney of NNCL.Numerical simulation is performed to study the heat transfer performance by the Fluent software.The simulation of the air cooling channel obtains the velocity field and temperature field distribution of air under various operating conditions.The distribution of velocity field and temperature field is made into charts and graphics.The transient distribution variation rules of different section is also obtained.This results are approximately consistent with the record summarized by optical fiber measurement.The results show that the molten salt-air heat ex-changer of air cooling channel can form good natural circulation and take away the heat.The flow field can be relatively stable in 16 s.This model can provide a theoretical basis for the operation and some suggestions for improvement are given.The new nozzle structure of the funnel inlet is designed.The simulation results show that the new structure can effectively improve the inlet air speed and increase the heat exchange power by28.2%.