A numerical and experimental investigation of heat transfer and fluid flow characteristics of a cross-connected alternating converging-diverging channel heat sink

In this study, the conjugate heat transfer performance of an enhanced planar heat sink design, comprising cross-connected alternating converging-diverging channels, was analyzed for forced air convection conditions. Numerical simulations were performed in ANSYS Fluent 15.0 using the RNG k-ε turbulence model accompanied by the enhanced wall treatment option to resolve the air flow and evaluate the heat transfer. Numerical results, which were validated experimentally, were utilized to investigate the flow and the temperature fields. The converging-diverging channel sections induced secondary flows through the cross connections, repeatedly disturbing the thermal and hydraulic boundary layers over the leading edges of the fin sections. The performance of the proposed heat sink design was benchmarked against the conventional straight channel heat sink of equivalent dimensions. Significant heat transfer enhancement was observed. However, the vortices, generated as a result of the separation of the secondary flows, were observed to prevent the heat transfer performance from being further improved and cause an excessive increase in the pressure drop penalty.