Abstract
The paper presents both three and two-dimensional numerical analysis of convective heat transfer in microchannels. The three-dimensional geometry of the microchannel heat sink followed the details of the experimental facility used during a previous research step. The heat sink consisted of a very high aspect ratio rectangular microchannel. Two channel heights, namely 1mm and 0.3mm (0.1mm), were used for 3D (2D) numerical model respectively. Water was employed as the cooling liquid. The Reynolds number ranged from 200 to 3000. In the paper, the thermal entrance effect is analyzed in terms of heat transfer efficiency. Finally, the comparison between measured and computed heat flux and temperature fields is presented. Contrary to the experimental work, the numerical analysis did not reveal any significant scale effect in heat transfer in microchannel heat sink up to the smallest size considered (0.1 mm).
Highlights
The comparison between the reference curve and the marked numerical points for this particular position in the microchannel allows for the following observations: (1) the entrance effect is weaker for the present results when e = 1 mm
The computations were achieved for the two extreme channel heights used in the experiments, i.e. 0.1 mm and 1 mm, with the corresponding Re number ranges: Re ∈ (200 ÷ 2166) for e = 1 mm Re ∈ (500 ÷ 3000) for e = 0.1 mm Figure 9 shows an excellent agreement between Nu distributions obtained with the 2D and 3D models
The numerical simulation considered the coupling between convection in microchannels and conduction in the walls and in the complete solid material
Summary
The Nu number is defined as where the convective heat transfer coefficient h is given by on Re and channel height separately, contrary to SL reference case where the proper dimensionless group is x+.
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