直流套管式熔盐的传热研究

Study on heat transfer of molten salt in DC tube heat exchanger

由于高温熔融盐与水换热温差过大,且一般常见的熔盐熔点较高(如混合硝酸盐在120℃以上),如果直接换热易发生熔盐凝固,且水在蒸发过程中发生相变产生较大的热应力从而影响换热器寿命。故设计了真空-水套管来解决熔盐和水换热温差过大的问题,保证出口水不汽化。进行换热器的设计计算,应用Ansys进行数值模拟,实现套管不同内外管径及内管内不同水流速的动态仿真模拟以及计算分析其换热特性、阻力特性以及综合换热性能指标,进行管优化选出最优模型。

Because of the temperature difference between high temperature molten salt and water heat exchange is too large,and the common melting point of molten salt is high(such as mixed nitrate above 120℃),if direct heat exchange is easy to occur molten salt frozen blocking accident,and water in the process of evaporation phase transformation produces large thermal stress and affect the life of heat exchanger.Therefore,vacuum-water sleeve is designed to solve the problem of large temperature difference between molten salt and water exchange,and ensure that the outlet water does not vaporize.Carry on the design calculation of heat exchanger,use Ansys numerical simulation,realize the dynamic simulation of different pipe diameter and different water flow rate in the inner pipe,and calculate and analyze its heat transfer characteristics,resistance characteristics and comprehensive heat transfer performance indicators,the heat exchanger is the best when the outer diameter difference△d is 12mm and the inner diameter of the casing is 33mm.