Study on Heat Transfer and Hydraulic Model of Spiral-Fin Fuel Rods Based on Equivalent Annulus Method

Tight lattice fuel assembly usually adopts spiral-fin fuel elements.Compared with the traditional PWR fuel rods,the closely packed and spiral fin spacers make the heat transfer and hydraulic phenomena in sub-channels very complicated,and there was no suitable model and correlation to study it.This paper studied the effect of spiral spacers on the channel geometry in the equivalent annulus and physical performance based on the Rehme equivalent annulus methods,and the heat transfer of the spiral fin fuel rodsand hydraulic model were obtained.The new model was verified with the traditional one,and the verification showed that two new models agreed well,which could provide certain theoretical explanation to the effect of the spiral spacer on the thermal hydraulics.