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Abstract
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In this research, a Computational Fluid Dynamics (CFD) technique was used to investigate
the effect of choking on the flow and heat transfer characteristics of a typical
micro-channel heat sink. Numerical simulations have been carried out using Spalart–
Allmaras model. Comparison of the numerical results for the heat transfer rate, mass
flow rate and Stanton number with the experimental data were conducted. Relatively
good agreement was achieved with maximum relative error 16%, and 8% for heat transfer
and mass flow rate, respectively. Also, average relative error 9.2% was obtained for the
Stanton number in comparison with the experimental values. Although, the results show
that the majority of heat was transferred in the entrance region of the channel, but the
heat transfer in micro-channels can also be affected by choking at channel exit. Moreover,
the results clearly show that, the location where the flow is choked (at the vicinity of
the channel exit) is especially important in determining the heat transfer phenomena.
It was found that Spalart–Allmaras model is capable to capture the main features of
the choked flow. Also, the effects of choking on the main characteristics of the flow was
presented and discussed.
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