内置涡流发生器的管内过冷沸腾与强化换热的模拟

Simulation of enhanced heat transfer in subcooled boiling tube of vortex generator inserts

采用欧拉双流体模型结合RPI沸腾模型对高压管内过冷沸腾进行三维非稳态模拟,考察了涡流发生器对管内过冷沸腾的影响,模拟了高压下光管内的过冷沸腾、层流下内置涡流发生器的换热管内的流动和湍流下内置涡流发生器的换热管内的过冷沸腾。结果表明,内置涡流发生器的换热管在层流状态下换热能力明显提升,过冷沸腾时管内换热能力有一定提升,且壁面附近的气泡由于扰流作用被大量卷入锥形片内,降低了壁面附近产生气膜的可能性,延迟了过冷沸腾起始点的位置。

An Eulerian-Eulerian two-fluid model together with the RPI boiling model was used to simulate the three-dimensional unsteady subcooled boiling flow in high pressure tubes. The effect of vortex generator on the subcooled boiling was investigated through the simulation. The tube fluid dynamics of vortex generator in laminar flow and the subcooled boiling process with the vortex generator in turbulent flow were simulated. The simulation indicated that the heat transfer capacity was obviously enhanced under laminar flow conditions by the vortex generator. The heat transfer capacity in the tube wasonly slightly improved in the case of subcooled boiling, and the bubbles near the wall were affected by the disturbance of the fluid. The bubbles near the wall surface were largely entangled into the delta wing due to the disturbance of the fluid. Therefore, the possibility of generating a gas film near the wall surface was reduced, and delayed the starting point position of subcooled boiling.