Heat Transfer in Microchannels

Peng et al. [51] conducted experiments to measure the bubble nucleation temperatures for four working fluids boiled on a platinum wire confined in capillary tubes. The bubble nucleation temperature markedly depended on the size of the 

Kroeker et al. [52] investigated the pressure drop and thermal characteristics of heat sinks with circular microchannels using the continuum model consisting of the conventional Navier-Stokes equations and the energy conservation equation. 

Steinke et al. carried out experimental investigation to study the control of dissolved gases and their effects on heat transfer and pressure drop during the flow of water in a microchannel [53], 

As a fundamental investigation on heat pipes, Tchikanda et al. [54] derived analytical expressions for the mean velocity of a liquid flowing in an open rectangular microchannel. The flow is driven by pressure gradients and shear stress on the liq-uid/vapor interface. Koizumi et al. [55] developed a microheat pipe with asymmetric cross-section and observed boiling two-phase flow. 

The effects of microchannel size, mass flow rate, and heat flux on boiling incipience or bubble cavitation in a microchannel were investigated by Li and Cheng [56], The effects were also estimated of contact angle, dissolved gas, and the existence of microcavities and corners in the microchannel on bubble nucleation and cavitation temperature. 

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Plam B (2000) Heat transfer in microchannels. In Heat Transfer and Transport Phenomena in Microscale. Banff Oct 54-64... 

Mala GM, Li D, Werner C (1997b) Flow characteristics of water through a micro-channel between two parallel plates with electro kinetic effects. Int J Heat Fluid Flow 18 491 96 Male van P, Croon de MHJM, Tiggelaar RM, Derg van den A, Schouten JC (2004) Heat and mass transfer in a square micro-channel with asymmetric heating. Int J Heat Mass Transfer 47 87-99 Maranzana G, Perry I, Maillet D (2004) Mini- and micro-channels influence of axial conduction in the walls. Int J Heat Mass Transfer 47 3993 004 Maynes D, Webb BW (2003) Full developed electro-osmotic heat transfer in microchannels. Int J Heat Mass Transfer 46 1359-1369... 

Palm, B.. Heat transfer in microchannels, Microscale Therm. Eng. 5 (2001) 155-175. 

The use of convective heat transfer in microchannels to cool microchips has been proposed over the last two decades. Many analytical and experimental studies, involving both liquids and gases, have been carried out to gain a better understanding of huid how and heat transfer phenomena at the micro level. 

Weisberg et al. [54] are among other researchers who all provided additional information and considerable evidence that the behavior of fluid flow and heat transfer in microchannels or microtubes without phase change is substantially different from that which occurs in large channels and/or tubes. 

Convective heat transfer in microchannels is significantly enhanced, depending on the values of the Knudsen, the Prandtl and the Brinkman numbers and the aspect ratio. Heat transfer characteristics can be significantly different from conventionally sized channels. 

Maynes, D. and Webb, B.W., Fully Developed Electro-Osmotic Heat Transfer in Microchannels, Int. J. Heat Mass Transfer, 2003, 46, 1359-1369. 

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. 

Maynes D., B. W. Webb, 2003, Fully-developed electro-osmotic heat transfer in microchannels, Int. J. Heat and Mass Transfer, 46, 1359-1369. 

Tunc, G (2002) Convective Heat Transfer in MicroChannel Gaseous Slip Flow, PhD. Thesis, Rice University, Houston, TX. 

Heat transfer in microchannels has gained more interest in the last deeade due to developments in the aerospaee, biomedical and electronics industries. It has been a critical issue since the performance of the devices is primarily determined by temperature. As the size decreases, more efficient ways of cooling are sought due to the reduction in the heat transfer area. 

Convection and conduction are the two major heat transfer mechanisms that have been investigated at microscale. Convective heat transfer in microchannels has been intensively analyzed by both experimental and analytical means. Conduction studies have focused mostly on thin films in recent years to address such questions as How is the heat transferred How does it differ from large-scale conduction ... 

CONDENSATION FLOW MECHANISMS, PRESSURE DROP AND HEAT TRANSFER IN MICROCHANNELS... 

Bandhauer, T. M. (2002) Heat Transfer in MicroChannel Geometries During Condensation cfRI34a, Master of Science Thesis, Mechanical Engineering, Iowa State University, Ames, lA, p. 201. 

The nature of boiling heat transfer in a channel with the gap less than the capillary is also studied and presented. The condensation flow mechanisms, pressure drop and heat transfer in microchannels, role of microscale heat transfer in augmentation of nucleate boiling and flow boiling heat transfer, binary-fluid heat and mass transfers in microchannel geometries for miniaturized thermally activated absorption heat pumps, evaporation heat... 

In this lecture, the effects of the abovementioned dimensionless parameters, namely, Knudsen, Peclet, and Brinkman numbers representing rarefaction, axial conduction, and viscous dissipation, respectively, will be analyzed on forced convection heat transfer in microchannel gaseous slip flow under constant wall temperature and constant wall heat flux boundary conditions. Nusselt number will be used as the dimensionless convection heat transfer coefficient. A majority of the results will be presented as the variation of Nusselt number along the channel for various Kn, Pe, and Br values. The lecture is divided into three major sections for convective heat transfer in microscale slip flow. First, the principal results for microtubes will be presented. Then, the effect of roughness on the microchannel wall on heat transfer will be explained. Finally, the variation of the thermophysical properties of the fluid will be considered. 

J.T. Liu, X.F. Peng, and B.X. Wang, Variable-property effect on liquid flow and heat transfer in microchannels. Chemical Engineering Journal 141, 346-353 (2008). 

G.L. Morini, Single-phase convective heat transfer in microchannels A review of experimental results. International Journal of Thermal Sciences 43, 631-651 (2004). 

P. Rosa, T.G. Karayiannis, and M.W. Collins, Single-phase heat transfer in microchannels The importance of scaling. Applied Thermal Engineering 29, 3447-3468 (2009). 

F.V. Castelloes, C.R. Cardoso, P. Couto, and R.M. Cotta, Transient Analysis of Slip Flow and Heat Transfer in Microchannels, Heat Transfer Engineering, Vol. 28, 549-558 (2007). 

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