HEAT-TRANSFER AND PRESSURE-DROP IN A TUBE WITH INTERNAL MICROFINS UNDER TURBULENT WATER-FLOW CONDITIONS

An experimental study was performed using 15.9 mm O.D. plain and micro finned copper tubes to determine the heat transfer and friction factor coefficients. The heat transfer results were obtained in a test secti on with an isothermal wall boundary condition using saturated steam as the heating medium and water as a test fluid. Both heat transfer and pressure drop enhancements were observed for a Reynolds number range o f 10,000 less-than-or-equal-to Re less-than-or-equal-to 30,000. It was noted that the heat transfer coefficient was 1.2-1.8 times and the is othermal friction factor 1.3-1.8 times that of a plain tube under simi lar conditions. The experimental data were statistically analyzed, and empirical correlations were derived for both heat transfer coefficien t and friction factor.