Infrared thermography investigation of local heat transfer in a plate fin and two-tube rows assembly

Abstract

An experimental study is performed using an infrared thermography system. The experimental method uses the temperature transient variation of a thin plate (tested fin) in order to obtain detailed quantitative heat transfer coefficients. The method developed is similar to the lumped capacitance method usually used to measure heat transfer coefficient on heat exchanger fin models. But the method presented here exploits the capabilities of infrared thermography to measure surface temperatures in a transient technique in order to take into account errors effects due to tangential conduction and radiation of the tested fin. The method is validated using a two-dimensional channel experiment and its advantages are highlighted using a plate fin and two-tube rows assembly experiment. Moreover, convection coefficient variations with fin pitch and frontal air velocity of an automotive plate fin and two-tube rows assembly are also examined.