High-Heat Flux Management Schemes

We attempt here to describe the fundamental equations of fluid mechanics and heat transfer. The main emphasis, however, is on understanding the physical principles and on application of the theory to realistic problems. The state of the art in high-heat flux management schemes, pressure and temperature measurement, pressure drop and heat transfer in single-phase and two-phase micro-channels, design and fabrication of micro-channel heat sinks are discussed. 

Fluid Flow, Fleat Transfer and Boiling in Micro-Channels Springer 2009 

In all cooled appliances, the heat from the device s heat sources must first arrive via thermal conduction at the surfaces exposed to the cooling fluid before it can be transferred to the coolant. For example, as shown in Fig. 2.2, it must be conducted from the chip through the lid to the heat sink before it can be discharged to the ambient air. As can be seen, thermal interface materials (TIMs) may be used to facilitate this process. In many cases a heat spreader in the form of a flat plate with high thermal conductivity may be placed between the chip and the lid. 

Piezoelectric fans are small, low-power, relatively low-noise, solid-state devices that provide viable thermal management solutions for a variety of portable electronic appliances, including laptop computers and cellular phones. In these fans piezoceramic patches are bonded onto thin, low-frequency flexible blades driven at resonance frequency, thereby creating an air stream directed at the electronics components. Thereby, up to 100% improvement over natural convective heat transfer can be achieved (Acikalin et al. 2004). 

Heat pipes are an enhanced means of transporting heat (in certain circumstances much better than copper) from a source to a heat sink where it can be transmit- 

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High-Heat Flux Management Schemes Kaat Sfnk----... 

Morini Gl, Lorenzini M, Salvigini S (2006) Friction characteristics of compressible gas flows in micro-tubes. Exp. Thermal and Fluid Science 30 733-744 Mudawar 1 (2001) Assessment of high-heat-flux thermal management schemes. IEEE CPT Trans 24 122-141... 

Mills, A.F., 1999, Basic Heat and Mass Transfer, 2", Prentice-Hall, New Jersey, p 22 Mudawar, I., 2001, Assessment of High-Heat-Flux Thermal Management Schemes , IEEE Transactions on Components and Packaging Technologies, Part A, Vol. 24 (2), pp.122-141 Bar-Cohen, A., 1993, Thermal Management of Electronic Components With Dielectric Liquids , JSME Int. J., Ser. B, Vol.36, pp.1-25... 

Mudawar, I. 2001, Assessment of High-Heat-Flux Thermal Management Schemes, IEEE Transactions on Components and Packaging Technologies, Vol. 24 (2), pp.122-141. 

Several applications such as lasers. X-ray medical systems, avionics, and computer data centers require dissipation of a large amount of heats from small areas. Two-phase cooling schemes are one of the actively pursued high heat flux thermal management systems. It has many unique attributes, that is, high heat dissipation-to-volume ratio, small coolant inventory, relative ease of fabrication, and compactness. Various experimental results have been reported to understand the heat transfer phenomena and develop appropriate correlations for accounting various features unique to microchannel heat sinks. 

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