Abstract: A thermal multiphase lattice Boltzmann (LB) model is used to study the behavior of droplet impact on hot surface and the relevant heat transfer properties. After validating the correctness of the codes through the D² law, the simulations of intrinsic contact angle and the temperature-dependent surface tension are performed. The LB model is then used to simulate the droplet impact on smooth and micro-hole heated surface. On the smooth surface, the impinging droplet is reluctant to rebound, unless the intrinsic wettability of the solid surface is fairly good. On the micro-hole surface, however, the micro-holes provide favorable sites for generating a high-pressure vapor cushion underneath the impinging droplet, which thereby facilitates the continuous droplet rebound. For the continuously rebounding droplet. The time evolution of volume and temperature display obvious oscillations. The achievable height of the rebounding droplet increases as the intrinsic wettability of the solid surface becomes better, and the maximum transient heat flux is found to be directly proportional to the droplet rebounding height. Within a certain time interval, the continuous rebounding behavior of the droplet is favorable for enhancing the total heat quantity/heat transfer efficiency, and the influence of intrinsic wettability on the total heat during droplet impingement is greater than that of the superheat. The LB simulations not only present different states of droplets on hot surfaces, but also guide the design of the micro-hole surface with desirable heat transfer properties.

Key words: droplet rebound, heat transfer, droplet impact, lattice Boltzmann model