NUMERICAL INVESTIGATION ON THE HEAT TRANSFER ENHANCEMENT BEHAVIOR OUTSIDE LONGITUDINAL FINNED TUBES

摘要

With the purpose of enhancement of heat transfer performance and reduction of the volume of steam generator (SG), a structure of longitudinal finned tubes was proposed to replace the smooth tubes of SG in this paper. Taking the SG smooth tubes of Daya bay Nuclear Power plant as a reference, the simplified heat transfer model of new longitudinal finned tubes was established by ANSYS CFX. Three-dimensional numerical model was developed to investigate the fluid-solid coupled thermal hydraulic characteristics of different types of the longitudinal finned tubes compared with the smooth tubes. Analysis of calculation results were sufficiently discussed for the effect of mass flow rate, fin array, solid thermal conductivity and frictional resistance. The numerical results revealed that the heat transfer coefficient increase with the increasing mass flow rate in the secondary side. The material of the tubes has significantly influence on the heat transfer process. Different flow conditions have different thermal hydraulic characteristics. The evaluated criterion to judge the enhancement of the heat transfer of the coupled process was also proposed. The numerical results can provide some useful guidance for design optimization of longitudinal finned tubes in SG.