THE EFFECT OF TURBULENCE PROMOTERS ON THE PERFORMANCE OF A COAXIAL TUBULAR HEAT EXCHANGER

Abstract

The present work has been carried out in order to investigate the improvement in the heat transfer rate as a result of induced turbulence in the case of coaxial heat exchanger. The turbulence inducers were used to break laminar .layer on the heated surface. The inner copper tube was heated by circulating heated water through its and the. water at room temperature was circulated in the annulus. The range of Reynold's number used varied from 14,000 to 50,000 for shell while for tube it varied from 1000 to 6000. Experiments were performed on four copper tubes, one having smooth surface and the other three having grooves at regular intervals acting as turbulence promotees. The width chosen were as 3/4", 1/2", and 1/4". The spacing and depth of grooves was kept constant as 1/8" and 1/16" respectively. A dimensional re-lationship between Nu, Pr and Re number has been found out for flow through annulus. The observed data have been plotted on graphs and discussed. Significant increase in heat transfer rates have been observed from tubes having turbulence promoters.