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Wavy channels were investigated in this paper as a passive scheme to improve the heat transfer performance of laminar fluid flow as applied to microchannel heat sinks. Parametric study of three-dimensional laminar fluid flow and heat transfer characteristics in microsized wavy channels was performed by varying the wavy feature amplitude, wavelength, and aspect ratio for different Reynolds numbers between 50 and 150. Two different types of wavy channels were considered and their thermal performance for a constant heat flux of 47 W / cm 2 was compared. Based on the comparison with straight channels, it was found that wavy channels can provide improved overall thermal performance. In addition, it was observed that wavy channels with a configuration in which crests and troughs face each other alternately (serpentine channels) were found to show an edge in thermal performance over the configuration where crests and troughs directly face each other. The best configuration considered in this paper was found to provide an improvement of up to 55% in the overall performance compared to microchannels with straight walls and hence are attractive candidates for cooling of future high heat flux electronics.

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Displacement of methane (CH4) by injection gas is regarded as an effective way to exploit shale gas and sequestrate carbon dioxide (CO2) simultaneously.

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The characteristics of flow and heat transfer in microchannel with dimples were numerically investigated. The geometric parameters of dimpled channel, including aspect ratio, dimple depth and dimple spacing, were independently studied under constant Reynolds number 500. A constant heat flux 1W/mm 2 was adopted in the central area at the bottom of the microchannel heat sink to simulate a high power device. In comparison to straight channels, dimpled surface reduced the local flow resistance and also improved thermal performance of micro-channel heat sink. Compared to flat channel case, the optimal dimpled case have 3.2K decrease of temperature, 15% gain of Nusselt number and 2% reduce of pressure drop.