Experimental study on heat transfer characteristics of sub-cooled flow boiling in tube bundle channel under rolling motion

Abstract

Rolling motion usually shows great influence on the dynamic and heat transfer characteristics in some marine nuclear power plants compared with land-based ones. The existence of two-phase fluid will aggravate the effect of rolling motion, indicating significant difference on the heat transfer mechanism. In present study, sub-cooled flow boiling in a vertically arranged tube bundle channels is experimentally investigated under various rolling motions. Results show that, when the rolling motion illustrates negligible effect on the mass flow rate, the influence of rolling motion can be attributed to the periodic change of the interface between hot and cold fluids as well as the circumferential transverse flow. A delay may occur on the fluid temperature since the rolling motion starts, while the delay of wall temperature variation is negligible. In addition, the farther away the flow channel is from the rolling axis, the more obvious the effect of the rolling motion is. Various rolling parameters including period and amplitude are considered. Note that the period of relevant parameters increases with after rising the rolling period, and the amplitude of fluid temperature increases with the increase of rolling frequency and amplitude. In comparison to the parameter of rolling amplitude, the rolling period displays a more critical role on the changes of wall temperature.