647 / 2019-03-28 20:07:09

Numerical investigation of supercritical water flow in a rifled tube heated under axially non-uniform heat flux

supercritical water; rifled tube; Non-uniform heating; inlet temperature

全体主题 > 节能、联产、热泵

Numerical simulation was performed to investigate the heat transfer characteristics of supercritical water flow through a internal rifled tube in this paper. The vertical upward flow of supercritical water run in a four-head vertical rifled tube with 1316mm heat length and 21mm inner diameter.The average value of the non-uniform heat flow is equal to the compared uniform heat flux.This paper studied the effect of heat flux,pressure, buoyancy and inlet temperature on heat transfer characteristics .The results show that the stability of the system will be affected when non-uniform heat flux is applied axially at the wall compared with uniform heating,and the variation trend of wall temperature is the same as that of heat flux. Heat transfer enhancement(HTE) and heat transfer deterioration(HTD) are found be weakened when the operating pressure is far away from the critical pressure,and the rate of thermal physical property changes slowly. The effect of buoyancy on heat transfer is mainly concentrated in the area in which the inner wall temperature is higher than the pseudo-critical temperature and the fluid temperature is less than the pseudo-critical temperature. When the inlet temperature is changed, HTD only appears within a certain Tin range and the peak of the inner wall temperature moves toward the entrance of rifled tube.When the degree of deterioration is serious, inlet temperature has little effect on the peak value of the wall temperature.