Augmentation of single phase convective heat transfer with in-line static mixers

Average heat transfer coefficients and pressure drop were measured during heating of liquid refrigerant-113 inside 1.27 cm I.D. and 101.6 cm long electrically heated vertical tubes with and without in-line static mixers. Six different mixer arrangements were tested. They ranged from three mixer elements placed at the upstream inlet section of the tube to 50 elements placed to cover the entire length of the tube. The results showed that the average heat transfer coefficient increased with an increase in the Reynolds number in all mixer arrangements. The range of the Reynolds number was between 980 and 5500. Also, the ratio of the pumping power to the total heat transfer rate increased with an increase in the Reynolds number. However, this ratio decreased with an increase in the number of static mixer elements in the tube, at the same Reynolds number. Heat transfer and pressure drop correlations were developed.