A review of heat and fluid flow characteristics in microchannel heat sinks

Abstract

Heat transfer and flow characteristic in microchannel heat sinks (MCHS) are extensively studied in the literature due to high heat transfer rate capability by increased heat transfer surface area relative to the macroscale heat sinks. However, heat transfer and fluid flow characteristics in MCHS differ from conventional ones because of the scaling effects. This review summarizes the studies that are mainly based on heat transfer and fluid flow characteristic in MCHS. There is no consistency among the published results; however, everyone agrees on that there is no new physical phenomenon in microscale that does not exist at macroscale. Only difference between them is that the effect of some physical phenomena such as viscous dissipation, axial heat conduction, entrance effect, rarefaction, and so forth, is negligibly small at macroscale, whereas it is not at microscale. The effect of these physical phenomena on the heat transfer and flow characteristics becomes significant with respect to specified conditions such as Reynolds number, Peclet number, hydraulic diameter, and heat transfer boundary conditions. Here, the literature was reviewed to document when these physical phenomena become significant and insignificant.

Understanding Inconsistencies in Thermohydraulic Characteristics Between Experimental and Numerical Data for DI Water Flow Through a Rectangular Microchannel

“…This question is of great importance because of the huge potential of microchannel applications in various engineering systems, such as cooling systems for electronic devices or in chemical process engineering to provide high-quality steam. To better understand the behavior of fluid flow and heat transfer in microchannels, researchers have conducted numerous experimental studies [2,3].…”

“…Rosa et al [7] investigate scaling effects on single-phase flow in microchannels and conclude that macroscale theory and correlations are valid at the microscale if measurement uncertainty and scaling effects are carefully considered. These scaling effects include entrance effects, viscous heating, conjugate heat transfer, electric double-layer effects, surface roughness, and temperaturedependent properties [3].…”

A Review of the Complex Flow and Heat Transfer Characteristics in Microchannels

“…The literature on microchannel heat exchangers can be classified based on fluid flow characteristics, heat transfer mechanisms, boundary condition types, and solution methods [ 27 ], as shown in Figure 2 . This article focuses on the mechanism of flow and heat transfer in microchannels, so it will be elaborated from the following two perspectives.…”

Capillary trees for passively pumping water

“…They showed that when the fluid volume is fixed, dendritic architectures with controlled geometrical features such as diameter ratios, bifurcation angles and levels of dendrite generation can be obtained following a single principle: the flow configuration morphing in time for maximum flow access. The shape of the dendritic network changes as a function of the type of flow regime [15][16][17][18]. It also varies when fluid mechanics constraints are combined with other constraints such as heat transfer performance [19][20][21][22].…”