Effects of Pin Shape and Array Orientation on Heat Transfer and Pressure Loss in Pin Fin Arrays

Abstract

Modern high-performance gas turbine engines operate at high turbine inlet temperatures and require internal convection cooling of many of the components exposed to the hot gas flow. Cooling air is supplied from the engine compressor at a cost to cycle performance and a design goal is to provide necessary cooling with the minimum required cooling air flow. In conjunction with this objective, two families of pin fin array geometries which have potential for improving airfoil internal cooling performance were studied experimentally. One family utilizes pins of a circular cross section with various orientations of the array with respect to the mean flow direction. The second family utilizes pins with an oblong cross section with various pin orientations with respect to the mean flow direction. Both heat transfer and pressure loss characteristics are presented. The results indicate that the use of circular pins with array orientation between staggered and inline can in some cases increase heat transfer while decreasing pressure loss. The use of elongated pins increases heat transfer, but at a high cost of increased pressure loss. In conjunction with the present measurements, previously published results were reexamined in order to estimate the magnitude of heat transfer coefficients on the pin surfaces relative to those of the endwall surfaces. The estimate indicates that the pin surface coefficients are approximately double the endwall values.

Experimental Investigation of Innovative Internal Trailing Edge Cooling Configurations with Pentagonal Arrangement and Elliptic Pin Fin

“…Recently, [16], using a "lumped heat capacity method" for the pin fins, reported an inverse result; they mesured a higher HTC over the endwall by about 3-40% than that on the corresponding pin fin of the same row. Figures 7 and 8 present all the experimental data in the two different definitions of Reynolds and Nusselt number reported in (1) and (2).…”

“…Being easier to manufacture, pin fins with circular cross-sections are the most used and investigated. The first experimental investigations on circular pin fins were carried out by [1][2][3]. They measured row by row heat transfer coefficients and pressure losses for inline and staggered configurations.…”

Current Status and Prospects of Supercomputing Used for Gas Turbine Engines Design

“…Metzger, et al [11] reported the effect of flow incident angle on oblong pins. All incident angles except 90° yield higher Nusselt numbers than circular pins.…”

Experimental, Mathematical and Finite Element Analysis (FEA) of Temperature Distribution through Rectangular Fin with Circular Perforations

“…Metzger et al [16] investigated the effects of pin-edge shape and show presentation on the glow trade and the weight incident in pin-equalization bunches. They demonstrated by their results that the use of round and empty pin-parities with a group introduction amongst astonished and in-line can now and again propel the glow trade, while fundamentally decreasing weight.…”