Heat Transfer Characteristics of Pin-Fins with In-Line Arrangement : 3rd Report, Measurement of Heat Transfer Coefficient Utilizing Local Heating Method

Abstract

Experiments using a wind tunnel were conducted to clarify the distribution of the local heat transfer coefficient in a pin-fin array. Pin-fin test cores were constructed of pin rows arranged regularly in the flow direction. A local heating method was utilized to measure the heat transfer performace. Pin rows were heated through direct application of an electric current, and their individual temperatures were determined by measuring the electric resistance. Measurements were carried out under two conditions : when the individual pin rows in the pin-fin array were heated separately, and when all the pin rows were heated simultaneously in a uniform heat flux. The range of the Reynolds number tested was 20-100. Flow visualization experiments were also carried out to observe the flow pattern in the pin arrays utilizing a fifteen-times-enlarged model and a water tunnel. The test results revealed the heat transfer performance of the fins, and the effects of an oscillating flow on the heat transfer mechanism are discussed.