Experimental study of the Leidenfrost effect in the context of high heat flux cooling

Abstract

The behavior of water droplet on heated surfaces is experimentally observed to investigate the properties of the insulating vapor layer, a key element of the boiling crisis phenomenon. The lifetime of droplets on the heated surface is measured and compared with analytical models to examine the formation of the insulating vapor layer thickness between the coolant and the heated wall. The potential for reducing the Leidenfrost effect and increasing the critical heat flux by adjusting the surface roughness is examined to improve the thermohydraulic properties of the first-wall cooling channels. The behavior of water droplets on the heated surface with variable roughness is observed through the acoustic emission method. The behavior of water droplets on heated copper surfaces was experimentally studied using inductive and electrical heating with thermocouple temperature control, camera recording and acoustic emission analysis. The measured droplet lifetimes were compared with analytical models to evaluate the insulating vapor layer thickness. The practical relevance lies in reducing the Leidenfrost effect and increasing the critical heat flux, which can improve the cooling performance of high heat flux components such as tokamak first-wall channels.