Experimental study on condensation heat transfer in vertical helically coiled tubes

In the present experimental study, condensation of steam inside helically coiled tubes was investigated. Three helical coils of coil diameter 110, 135 and 160 mm were tested. The effect of mass flux, coil curvature ratio and temperature difference between steam and tube inner wall on the condensation heat transfer coefficient were analysed. The condensation heat transfer coefficient increases with the increase in the value of mass flux. Temperature difference has substantial effect on the heat transfer coefficient. For the first time, the effect of coil curvature ratio on condensation heat transfer is studied and discussed in the paper. It is found that helical coil having greater coil curvature ratio has high values of condensation heat transfer coefficient in comparison to a low curvature ratio. Experimental results are compared with the work of earlier investigators. A new empirical correlation is developed to predict the condensation heat transfer coefficient.