The effect of pulse heating on saturated boiling heat transfer in rough surfaces

Abstract

The boiling heat transfer efficiency in smooth surface can no longer meet the high-power equipment heat dissipation requirements. By changing the surface roughness and pulse heating conditions, we can have higher boiling bubble nucleation point density to achieve higher heat transfer efficiency. However, the influencing mechanism of the surface roughness and pulse heating conditions on boiling bubbles needs further study. In this paper, the effects of different cavities and pulse heating conditions on the boiling bubbles dynamics and the heat transfer enhancement are investigated by Lattice Boltzmann method (LBM). The results show that compared with constant heating, the nucleation sites of pulse heating are larger. As the pulse amplitude increase, the nucleation rate tends to be faster. The heat transfer curves of the most obvious difference in nucleation phenomenon under different heating conditions are also investigated. Compared with the constant heating at Tb<1.09Tc, the heat transfer coefficient (HTC) maximum increase being up to 30.54%. Under pulse heating, the increase of HTC decreases with the increase of superheat and eventually it is lower than that of constant heating.