Numerical and experimental analysis of the performance of staggered short pin-fin heat exchangers

Abstract

A three dimensional finite element based numerical model was used to analyze the heat transfer characteristics of various staggered short pin-fin array heat exchangers. The simulation was validated against data from an experimental rig as well as historical data and then used to estimate the heat transfer coefficient and pressure drop for a wide range of Reynolds numbers for circular and airfoil-shaped pin fins. Circular pin configuration variations included changes in pin spacing, axial pitch and pin height ratio. Airfoil pin variations also included changes in length and aspect ratio. Correlations for Nusselt number and friction factor were developed. Using established performance metrics, optimum configurations for both pin shapes were determined. The optimum airfoil pin array was shown to match the heat transfer rates obtained by the optimum circular pin configuration while incurring less than one third the specific fluid friction power loss. The results from this study would be of direct value in the design of a shroud enclosed heat exchanger concept being proposed for turbine blade cooling, or for cooling of high power electronic components, or in other high heat flux dissipation applications requiring a low-profile, high area-density based micro-heat exchanger design.