Investigation on the Influence of Buoyancy Force on the Heat Transfer Characteristics of Supercritical Water
In order to investigate the influence of buoyancy effect on heat transfer characteristics of supercritical water,a 3-D numerical model was developed to predict the heat transfer of supercritical water in a vertical smooth tube.This numerical model was used to predict the heat transfer character-isitics of supercritical water under the conditions of system pressure of 25 MPa,mass flux of 600～800 kg·m-2·s-1,and inner wall heat flux of 400～500 kW·m-2.The influence of heat flux and mass flow flux on buoyancy effect and the influence of buoyancy effect on heat transfer characteristics were also analyzed.The results show that when the mass flow flux is 800 kg·m-2·s-1,the buoyancy effect causes local heat transfer deterioration.After the heat transfer deterioration occurs,the heat transfer coefficient rebounds rapidly.When the mass flow flux is 600 kg·m-2·s-1,the influence of buoyancy effect on heat transfer is related to heat flux.When the mass flow flux is 600 kg·m-2·s-1 and the heat flux is 400 kW·m-2,supercritical water heat transfer shows enhanced heat transfer;when the mass flow flux is 600 kg·m-2·s-1 and the heat flux is 500 kW·m-2,the buoyancy effect causes local heat transfer deterioration,and the heat transfer coefficient did not recover after the heat transfer deterio-ration occurred.
supercritical water heat transferbuoyancy effectheat deteriationnumerical simula-tion
NETL
NSTL
万方数据
