Geometric Evaporator Enhancements of an Oscillating Heat Pipe

The oscillating heat pipe (OHP) is a passive two-phase cooling device that is capable of transferring large amounts of thermal energy. Previous research conducted on OHPs indicates that it is a viable option for developing high-heat flux cooling requirements, particularly in the field of electronics cooling. OHPs consist of evaporator, adiabatic, and condenser sections connected by multiple interconnected meandering channels. A two-phase working fluid, in this study acetone, fills the channels and acts as the heat transfer medium. The focus of this study is to further the development of OHPs to improve performance and operation by conducting a comparison between two different evaporator geometries. The first was a traditional straight channel geometry. The second consisted of circular pins centered in the channels with circular cavities surrounding the pins to allow fluid flow. The results of this study showed that the traditional straight channel configuration preformed best. The lowest fill ratio, 35%, performed best for all cases. The lowest thermal resistance observed was 0.11 K/W for the straight channels, and 0.16 K/W for the enhanced channels. The enhanced channels likely did not improve the performance because of an increase in pressure drop through the evaporator section.