The Influence of Reynolds Number and Row Position on Surface Pressure Distributions in Staggered Pin Fin Arrays

Abstract

Full surface pressure distributions over the endwall and pin in a staggered pin fin array have been acquired over a ten to one range in Reynolds numbers. These pressure distributions allow us to visualize the strong inertial pressure gradients that are responsible for driving secondary flows in pin fin passages. These strong pressure gradients include endwall regions near the pin stagnation region and near the pin at 90° from the stagnation region. Pressure distributions have been acquired on pin and endwall surfaces at eight consecutive rows using conventional static pressure measurement techniques. Pressures have been taken at 380 locations per row and, assuming symmetry, provide a well resolved visualization of surface pressure. Generally, surface and pin pressure distributions vary significantly from row to row in the entrance of the array at a given Reynolds number but stay relatively consistent after row four. Dimensionless pressure distributions are quite similar for row one for all Reynolds numbers but vary significantly at a given row downstream with Reynolds number. These data are expected to enhance our understanding of pin array fluid dynamics and to compliment full surface heat transfer data presented in a future paper.