Numerical investigation of the effect of vibration on spray cooling heat transfer in the non-boiling region

Abstract

Vibrations profoundly influence the liquid film formed by spray droplets in spray cooling applications. However, understanding heat transfer mechanisms in the non-boiling region under vibrating conditions is limited in the existing literature. This study aims to bridge this gap by numerically investigating the heat transfer performance of spray cooling in non-boiling regions under vibration using the Lagrange-Euler method. To validate the computational fluid dynamics (CFD) model, experimental measurements of spray heat transfer were conducted on a heated vibrating surface test rig. The results demonstrate that the average film thickness (AFT) and average film velocity (AFV) increase at lower frequencies, leading to a decrease in the heat transfer coefficient. Conversely, the AFT decreases at higher frequencies while the AFV remains relatively constant. This reduction in AFT enhances the heat transfer coefficient, resulting in an up to 12% improvement in heat transfer performance. When a larger vibration amplitude is introduced, a higher inertial force acts on the liquid film, causing it to converge towards the centre. Generally, the heat transfer coefficient of spray cooling in the non-boiling region decreases as the vibration amplitude increases.