An experimental study of pulsating flow heat transfer and pressure drop for channel with attached rhombus and detached hexagon pin-fins

Abstract

The present experiment study adopts the bionic simulation of the tracheal geometry of the human lung to emulate the flow pathways through a rectangular channel aimed at improving the heat transfer performance of pulsating flow To formulate the flow pathways similar to the trachea in a human lung the staggered array of attached rhombic columnar pin-fins and detached hexagonal columnar pin-fin is proposed as a newly hybrid columnar pin-fin array The average Reynolds numbers (Re) tested are 1500 2000 5000 10000 15000 and 20000 The flow pulsations are generated by releasing coolant flow prior to the channel entrance at the frequency of 1/4 1/6 and 1/12 Hz to alter the frequency of flow pulsation At each set of Re and pulsating frequency the coolant release over 1/4 1/2 or 3/4 pulse cycle is tested to modify the waveform of the flow pulsation The range of Strouhal number (Sr) tested is 0 0004-0 017 The experimental results confirm that the thermal performance factors evaluated at the constant pumping power consumptions are greater than unity at Re>5000 suggesting the high-efficiency heat transfer enhancements at Re>5000 Based on the databases generated by the present study two sets of empirical correlations that permit the evaluations of the temporally mean area-averaged Nusselt numbers and Fanning friction factors of the present pin-fin channel under steady-flow and pulsating-flow conditions are proposed for relevant engineering applications

Date of Award	2020
Original language	English
Supervisor	Shyy-Woei Chang (Supervisor)