ENHANCED POOL BOILING PERFORMANCE WITH ENGINEERED STRUCTURES AND MACROCONVECTION

Abstract

The rapid development of modern electronic devices urges an increasing need for better heat transfer techniques. Pool boiling heat transfer has great potential as it can provide high heat transfer capacity during the phase change of the working fluid. In this thesis, the two-phase heat transfer performance of the heat sinks has been enhanced and experimentally investigated with various engineered structures and the macroconvection mechanism. Firstly, the pool boiling chamber size is observed to affect the heat transfer performance of the heat sinks, and five pool boiling chambers with different sizes are fabricated and evaluated. Following this, novel oblique fin designs and flower module design with petal fins are manufactured by CNC method and studied in detail. In order to investigate more complex porous structures, one-layer and two-layer porous fin array are fabricated using SLM methods, and superior performances are reported. Separation of liquid and vapor pathway phenomenon is observed with these designs, and the influence of different building material and manufacturing process are discussed. Lastly, the aging effect which is an essential and often ignored factor in the pool boiling experiments and application is examined.