Effect of Partial 3-Dimensional Pin Fin Geometry for Heat Transfer Enhancement in High Aspect Ratio Channels

Abstract

The efficiency of a TEG (Thermoelectric Generator) may be thought of as the ratio of the power output to the heat input at the hot junction. This ratio is governed by the laws of thermodynamics and cannot thus exceed the Carnot efficiency. It follows that the greater the difference between the hot and cold side temperatures, the greater the efficiency of the TEG. Heat transfer enhancement measurements with 3-Dimensional partial pin-fin arrays of varying shapes on a flat plate are presented. The fin height is fixed at 15% of channel height. The hydraulic diameter and configuration of the fins are chosen based on existing literature. The study is carried out at various Reynolds numbers based on full channel height. The shapes studied are circular, semi-circular, triangular, hexagonal and diamond shaped. These shapes are compared against a baseline case without fins. The experiment uses the transient liquid crystal (TLC) method to calculate the heat transfer coefficient on the test surface. The data shows that diamond shaped fins provide the highest turbulent mixing downstream of the pins leading to the highest heat transfer coefficients.