Second Law Analysis for Turbulent Flow in Helical Pipes subject to Variable Viscosity

The present work provides a theoretical analysis of the entropy generation due to turbulent flow and heat transfer in a helical coil. To consider the effect of viscosity, three different viscosity models of constant, linear and exponential variation have been used in this study. The geometrical, fluid and temperature parameters on entropy generation in helical coils is presented. Bejan number is plotted for varying wall temperatures at heat transfer to and from fluid. Water and glycerol are chosen as working fluids for the study. It is found that the results obtained from exponential viscosity assumption yields a considerable effect in entropy generation from those of the temperature dependent linear viscosity models.