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Alternative heat sink to enhance thermo-hydraulic behaviour of an array of short pin fins
Date Issued
01-01-2017
Author(s)
Maiti, Abhilash
Prasad, B. V.S.S.S.
Abstract
Short pin fins are used at the trailing edge of the gas turbine blade for heat transfer augmentation. Accounting per unit mass heat transfer it is proposed to use slotted kidney shaped fins instead of solid cylindrical fins. Within fins a through slot is provided to allow the flow pass normal to the fins. The objective is (a) to increase heat transfer area, (b) reduce pressure drop and (c) decrease weight of the turbine blade. Solid cylindrical and solid kidney shaped; slotted cylindrical and slotted kidney shaped; staggered array geometries of ten rows having streamwise spacing and spanwise spacing of 2.5 times D (diameter of the fin) are placed between the uniform cross section channel. Thermo-hydraulic characteristics of the array geometries are compared within the channel Reynolds number range of 2,000 to 11,000. Numerical results are validated with the previously published experimental results. Pressure drop, local velocity, and total heat transfer values are computed and compared. Values of finwall and unfinned wall heat transfer rate are calculated for all the geometries. Among the array geometries, highest heat transfer rate is observed for slotted kidney shaped fin array. Heat sinks having slotted array geometry shows superior thermo-hydraulic behaviour compared to the corresponding solid fin array geometry. Numerical simulations were carried out using commercial software package ANSYS Fluent 15.0.