Simulation Of Enhanced Heat Transfer In Subcooled Boiling Tube Of Vortex Generator Inserts

The term “subcooled boiling” is used to describe the physical situation where the wall temperature is high enough to cause boiling to occur at the wall even though the bulk volume averaged liquid temperature is less than the saturation value.Subcooled boiling flow occurs in many industrial applications such as boilers,nuclear reactors,Condenser FLNG/LNG and cryogenic fluid systems.In the study of gas-liquid two-phase flow,Computational fluid dynamics(CFD)can not only get the whole flow field information,but also greatly reduce the time and labor costs.In this paper,an Eulerian-Eulerian two-fluid model together with the RPI boiling model is used to simulate the three-dimensional unsteady subcooled boiling flow in high pressure tubes.The effect of vortex generator on the subcooled boiling is investigated through the simulation.The tube fluid dynamics of vortex generator in laminar flow,and the subcooled boiling process with vortex generator in turbulent flow are simulated.The simulation indicates that the heat transfer capacity is obviously enhanced under laminar flow conditions by the vortex generator.The heat transfer capacity in the tube is only slightly improved in the case of subcooled boiling,and the bubbles near the wall are affected by the disturbance of fluid.The bubbles near the wall surface are largely entangled into the delta wing due to the disturbance of fluid.Therefore,the possibility of generating a gas film near wall surface is reduced,which delayed the starting point position of subcooled boiling.