A comparative study of elliptical and circular sections in one- and two-row tubes and plate fin heat exchangers

Abstract

In this work, a two-dimensional (2-D) heat transfer analysis is performed in one- and two-row tubes and plate fin heat exchangers (circular and elliptical sections), using experimentally determined heat transfer coefficients from a heat and mass transfer analogy. The temperature distribution on the fin and air free stream, and the fin efficiency are determined for heat exchangers, with eccentricity 0.5 and 0.65, as a function of the Reynolds number. For tubes and plate fin heat exchangers, new numerical results of fin efficiency for elliptical tubes are compared with published results for circular tubes. A relative fin efficiency gain of up to 18% is observed in the elliptical arrangement, as compared to the circular one. The efficiency gain, combined with the relative pressure drop reduction of up to 25% observed in previous studies (Brauer 1964; Bordalo and Saboya 1995) show the elliptical arrangement has the potential for a considerably better overall performance than the conventional circular arrangement.