Microscale Pumping Technologies for Microchannel Cooling Systems

A review of the state of the art in micropumping technologies for driving fluid through micro-channels is presented with a particular emphasis on small-scale cooling applications. An extensive variety of micropumping techniques developed over the past fifteen years in the literature is reviewed. The physical principles, engineering limitations, and advantages of approximately twenty different kinds of micropumps are reviewed. The available micropump-ing techniques are compared quantitatively, primarily in terms of the maximum achievable flow rate per unit cross-sectional area of the microchannel and the maximum achievable back pressure. A concise table is developed to facilitate the convenient comparison of the micro-pumps based on different criteria including their miniaturization potential, size ͑in-plane and out-of-plane͒, actuation voltage and power required per unit flow rate, ease and cost of fabrication , minimum and maximum frequency of operation, and suitability for electronics cooling. Some important performance characteristics of the micropumps, which are likely to be decisive for specific applications, are also discussed. The current state of the art in micropump design and fabrication is also comprehensively reviewed. There are 171 references cited in this review article.