A hybrid method for the direct numerical simulation of phase change heat transfer in fluid–particle systems

This paper presents a hybrid numerical method for simulating the boiling heat transfer in particle-laden fluids. The coupled volume of fluid and level set method, immersed boundary method, and discrete element method are integrated for gas–liquid flow, fluid–solid interaction, and the collision between particles. The energy jump model is adopted to compute mass transfer during phase change. The height-function technique and improved continuum surface force (CSF) model are coupled to decrease the spurious currents. Multiple validation results are provided to test the effectiveness of all sub-models. The test cases include particle sedimentation, stationary droplets without gravity, bubble rise, droplet spreading on particle surfaces, and bubble growth. The test results are in good agreement with analytical results and previous studies. Notably, the average spurious velocity is reduced to less than 10−5 m/s, which is three orders of magnitude smaller than that obtained by traditional CSF model. Moreover, the hybrid method is employed to explore the boiling heat transfer of particle-laden fluids, thereby further validating its reliability. It was found that particles facilitate bubble detachment and enhance heat transfer.