Pool Boiling Heat Transfer Enhancement With Structured Surfaces

Abstract

With the increasing power of electronic devices in recent years, thermal management has become an obstacle in scaling down chip designs. Direct liquid cooling is a great option for heat dissipation from high powered electronic systems due to its ability to remove large amounts of heat [1–2]. The aim of this study is to investigate pool boiling performance of water under atmospheric pressure by using structured surfaces. Surfaces with rectangular channels, holes, and mushroom fins are manufactured and tested. The results showed that boiling heat transfer can be enhanced by macroscopically structured surfaces. Heat transfer coefficient (h) enhancement ranged between 23–44% for structured surfaces compared to plain surface. Heat flux is varied in the range of 16–18kW/m2. The maximum enhancement in heat transfer coefficient is ranged between 39–44.4% measured by 405 holed surface compared to the plain surface. The measured excess temperature drops ranged between 12–34% for different surfaces compared to plain surface. The excess temperature dropped around 29–34% for 405-holed surface compared to the plain surface. As the spacing between channels or holes is decreased, the heat transfer coefficient is increased. Base temperature measurements are carried out using an Infrared Camera. A digital camera was used to record pool boiling phenomena and evaluate bubble dynamics. The bubbles with holed surfaces and mushroomed surface observed to have almost spherical shape, while in plain and grooved surfaces they have an irregular shape.