Effects of LLC Flow Characteristics and Surface Roughnesses on Nucleate Boiling Heat Transfer Mechanisms in IC Engine Cooling System

Abstract

To improve internal combustion engine cooling systems, it is required to utilize the nucleate boiling heat transfer. Previous studies revealed it is affected by surface roughness, flow velocity, and degree of subcooling. This study investigated the heat transfer mechanisms (latent heat transport mechanism, sensible heat transport mechanism, and bubble agitation mechanism) when changing the above parameters. It was found that the increase in flow velocity and degree of subcooling increased the heat transfer due to the latent and sensible heat transport, while the increase in surface roughness increased the heat transfer due to the sensible heat transport and bubble agitation.