Experimental study on the pressure drop and heat transfer characteristics in corrugated tubes

The characteristics of turbulent flow and heat transfer in corrugated tubes with three kinds of diameter were investigated experimentally. The outer tube surfaces were electrically heated to simulate the condition of constant heat flux. Average heat transfer coefficients and friction factors were measured for different tubes. The corresponding correlation for the friction factors and Nusselt numbers to the Reynolds numbers were obtained for the corrugated tubes. The results of the above corrugated tubes were compared with that of the smooth tubes. It was found that the corrugated tubes can significantly enhance the heat transfer under any of the three kinds of comparison conditions.