A highly stable microchannel heat sink for convective boiling

• Published in: Journal of micromechanics and microengineering 2009-05, Vol.19 (5), p.055013
• Main Authors: Lu, Chun Ting, Pan, Chin
• Format: Article
• Language: English
• Subjects: Applied fluid mechanics; Applied sciences; Convection and heat transfer; Exact sciences and technology; Fluid dynamics; Fluidics; Fundamental areas of phenomenology (including applications); Instruments, apparatus, components and techniques common to several branches of physics and astronomy; Mechanical engineering. Machine design; Mechanical instruments, equipment and techniques; Micromechanical devices and systems; Physics; Precision engineering, watch making; Turbulent flows, convection, and heat transfer
• ISSN: 0960-1317; 1361-6439
• DOI: 10.1088/0960-1317/19/5/055013

To develop a highly stable two-phase microchannel heat sink, we experimented with convective boiling in diverging, parallel microchannels with different distributions of laser-etched artificial nucleation sites. Each microchannel had a mean hydraulic diameter of 120 km. The two-phase flow visualization and the magnitudes of pressure drop and inlet temperature oscillations under boiling conditions demonstrated clearly the merits of using artificial nucleation sites to further stabilize the flow boiling in diverging, parallel microchannels. The stability map showed the plane of subcooling number versus phase change number. It illustrated that diverging, parallel microchannels with artificial nucleation cavities have a much wider stable region than parallel microchannels with uniform cross-sections or diverging, parallel microchannels without artificial nucleation cavities. In addition, the results revealed that the design with cavities distributed uniformly along the downstream half of the channel presented the best stability performance among the three distributions of nucleation sites. This particular design can be regarded as a highly stable microchannel heat sink for convective boiling.