Heat Transfer and Pressure Drop in Mini Channel Heat Sinks

Heat transfer and pressure drop in two types of square minichannel heat sinks for the purpose of cooling are investigated: one with spiral geometry and the other with straight geometry, which has 90-degree bends. The cross section of the channels for both heat sinks is a 1-mm-square channel and fabricated on a copper base plate. A copper cap plate is used to seal the channel. Water and four low-viscosity silicon oils (0.65 cSt, 1 cSt, 3 cSt, and 10 cSt) were used as a coolant; thus, a Prandtl number from 5 to 108 was examined. Heat transfer behavior over a range of flow rates from laminar to turbulent has been examined. Water was employed as the working fluid for pressure drop measurements. It has been shown that heat transfer is increased in comparison to the straight channel of similar length due to the disturbance of the boundary layer. This disturbance also results in the pressure drop increase. The dimensionless mean wall flux and the dimensionless thermal flow length were used to analyze the experimental data instead of conventional Nusselt number and channel length.