Investigation of a gas-propelled liquid droplet impinging onto a heated surface

Abstract

This paper presents an experimental and numerical investigation of a water droplet carried by a gas stream impinging on a heated surface. Temperature measurements at the point of impact were performed using an intrinsic fast-response thermocouple. Computational simulations were conducted using a conjugate solution and the VOF model. A theoretical model was developed to estimate the heat transfer enhancement due to augmentations in wetted area as a consequence of both the increase in the droplet initial kinetic energy and the stagnation pressure imposed by the propellant gas during the spreading. It was found that the heat transfer process during the early stage of impact was mainly dominated by diffusion, where heat transfer enhancement due to the action of the carrier gas is expected to occur when Ω>0.1. Good agreement was obtained among the different approaches.