Abstract
Numerical simulation was performed to establishing a two-dimensional pulsating heat pipe model, to investigate the flow and heat transfer characteristics in the pulsating heat pipe by using the Mixture and Euler models, which were unsteady models of vapor-liquid two-phase, based on the control-volume numerical procedure utilizing the semi-implicit method. Through comparing and analyzing the volume fraction and velocity magnitude of gas phase to decide which model was more suitable for numerical simulation of the pulsating heat pipe in heat and mass transfer research. It was showed there had gas phase forming in stable circulation flow in the heating section, the adiabatic section using the Mixture and Euler models respectively, and they were all in a fluctuating state at 10s, besides, the pulsating heat pipe had been starting up at 1s and stabilizing at 5s, it was all found that small bubbles in the heat pipe coalescing into large bubbles and gradually forming into liquid plugs and gas columns from the contours of volume fraction of the gas phase; through comparing the contours of gas phase velocity, it could be seen that there had further stably oscillating flow and relatively stabler gas-liquid two-phase running speed in the pulsating heat pipe used the Mixture model, the result was consistent with the conclusion of the paper[11] extremely, from this it could conclude that the Mixture model could be better simulate the vaporization-condensation process in the pulsating heat pipe, which could provide an effective theoretical support for further understanding and studying the phase change heat and mass transfer mechanism of the pulsating heat pipe.
Numerical simulation of heat and mass transfer in a 3D model of a loop heat pipe evaporator