MicroChannel cooling

Rahman, M.M. and Gui, F., Experimental Measurements of Fluid Flow and Heat Transfer in MicroChannel Cooling Passages in A Chip Substrate, Advances in Electronic Packaging, ASME EEP-4-2, 1993, 685-692. 

The flow velocity, pressure and dynamic viscosity are denoted as u, p and fi and the symbol. .. )f represents an average over the fluid phase. Kim et al. [39] used an extended Darcy equation to model the flow distribution in a microchannel cooling device. In general, the permeability K has to be regarded as a tensor quantity accounting for the anisotropy of the medium. Furthermore, the description can be generalized to include heat-transfer effects in porous media. 

Pokhama H, Masahiro K, DiStefano E, Mongia R, Barry J, Crowley C, Chen W, Izenson M (2004) MicroChannel cooling in computing platforms performance needs and challenges in implementation. 2nd international conference on microchannels minichannels (ICNMM2004), ASME, pp 109-118... 

Heat transfer to a digitized flow in a microchannel is similar in many ways to single-phase forced convection in microchannels. The thermal boundary conditions that exist are the same however, due to the unique rolling-type flow, DHT behaves in a significantly different fashion. In Fig. 3, the temperature field shows that heat is convected by the vortices and circulates within the droplet. As a droplet rolls down a heated microchannel, cool fluid from the center of the droplet is continually transported to the outer edges of the droplet while hot fluid at the wall is convected inward. Heat gradually diffuses... 

Microscale Cooling Devices, Fig. 4 3D rendering of assembled microchannel cooling device [16]... 

In this entry the effect of the viscous heating in microchannels is highlighted by means of two examples. First of all, a steady-state liquid flow in the laminar regime through a microchannel with an imposed constant linear heat flux at the walls q is considered (HI boundary condition see Convective Heat Transfer in Microchannels ). Then, the case of a steady-state liquid flow in the laminar regime through a microchannel with an axially constant outer wall temperature, while the wall heat flux is linearly proportional to the difference between the external temperature and the wall temperature, is considered. This is the case of a microchannel cooled by convection of an external fluid (T3 botmdary condition see Convective Heat Transfer in Microchannels ). 

In the case of a microchannel cooled for convection by an external fluid (T3 boundary condition), the heat flux at the walls can be written as... 

J.-T. Liu, X.-F. Peng, W.-M. Yan, Numerical study of fluid flow and heat transfer in microchannel cooling passages, Int.J. Heat Mass Tranter, 2007, 50, 1855-1864. 

When the conventional cooling techniques discussed in the previous sections cannot be used, then the physical designer may want to use some advanced techniques. These include thermoelectric, jet impingement, heat pipes, and microchannel cooling. 

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