Effects of modified VOF method on gas-liquid two-phase flow oscillating flow and heat transfer calculation

On the basis of VOF (volume of fluid) model, the level set function was introduced, and the CLSVOF (coupled level set volume of fluid) model was formed to numerically simulate the process of gas-liquid two-phase oscillating flow and heat transfer. The simulation results of CLSVOF model were compared with that of VOF model, and also compared with the experimental results. The results show that either for the oscillating flow and heat transfer process of two-phase flow in rectangular cavity, or for the oscillating cooling process of engine-oil in piston oil cooling gallery, CLSVOF model can more accurately simulate the oscillating flow rules of gas-liquid two-phase flow, and the calculation values of heat transfer coefficient consist with experimental results much better. For the oscillating cooling calculation of engine-oil in piston oil cooling gallery, with the increase of speed, i. e. Reynolds number, the error of calculation values of heat transfer coefficient increase accordingly. At the ultimate speed of 3 000 r/min, the error of CLSVOF model is 3.8%, and the error of VOF model is 7.5%; the error increase amplification of CLSVOF model is about 0.6%. The error increase amplification of CLSVOF model is relatively small and stable, so its higher calculation accuracy can be illustrated.