圆管内熔融盐强迫对流换热的实验研究

EXPERIMENTAL STUDY FOR FORCED CONVECTIVE HEAT TRANSFER WITH MOLTEN SALTS IN A CIRCULAR TUBE

为了验证现有的经典对流换热关联式是否仍然适用于高温熔融盐管内强迫对流的换热规律,搭建了熔融盐传热蓄热循环实验台进行实验研究.实验台系统已经在实验室安全成功运行了上千小时,实验中,设计了熔融盐-导热油换热器,通过测量熔融盐进出口温降和导热油进出口温升得到了换热器的总传热效率,然后利用最小二乘法对管内熔融盐对流换热系数进行分离,拟合出了熔融盐管内过渡流和充分发展紊流的实验关联式.通过和经典的传热关联式进行比较发现,熔融盐管内强迫对流换热特性仍然适用于Sieder-Tate方程,Petukhov方程,Hausen方程以及Gnielinski方程.

In order to understand the heat transfer characteristics of molten salt and testify the validity of the well known empirical convective heat transfer correlations, an experimental study on forced convective heat transfer with molten salt in a circular tube was conducted. Molten salt circulations were realized and operated in a specially designed system over 1000 h. The average forced convective heat transfer coefficients of molten salt were determined by least-squares method based on the measured data of flow rates and temperatures. Finally, heat transfer correlations of transition flow and turbulent flow with molten salt in a circular tube were obtained and good agreement was observed between the experimental data of molten salt and the well-known correlations presented by Sieder-Tate, Hausen and Gnielinski, respectively.