Single-phase heat transfer as well as pressure drop characteristics for microfin tubes with a nominal diameter of 9.52mm are reported. Experiments were conducted in a double-pipe heat exchanger with water as the working medium. Two commercially available microfin tubes and a smooth tube were tested. The heat transfer coefficients were obtained using the Wilson plot technique. It was found that the microfin tube exhibits a rough tube's characteristics. In the low and medium Reynolds number range (Re less than 15,000), the roughness Reynolds number lies in the transition range (e+ less than 23). As a result, the Dittus-Boelter-type Wilson plot function cannot correlate the heat transfer in this range. It was found that by using a heat momentum analogy, a better correlation of the present microfin heat transfer data is achieved.

KEYWORDS: year 1995, heat flow, heat exchangers, double pipe heat exchangers, finned tubes, pressure drop, properties, experiment, water, testing, heat transfer coefficient, friction factor