effect of non-uniform temperature distribution on entropy generation and enthalpy for the laminar developing pipe flow of a high prandtl number fluid

in this article, entropy generation and enthalpy are investigated on the pipe wall in developed laminar flow for 7 cases. variation of entropy generation and enthalpy are shown along the radius. entropy generation and enthalpy along the radius are obtained. heat transfer is increased with the flow of fluid through the pipe, in inlet of pipe points to the output. the amount of entropy generation in the pipes of higher temperature is more than other points. enthalpy is proportional to temperature in surface variation of 7 cases. in the points of higher temperature in elementary cases, the enthalpy value is increasing and it is increasing in other cases.

fluctuations of enthalpy and entropy generation are producted in interface points of pipe surfaces. the diagram data can be used to measure the minimum entropy generation in pipe heat transfer. minimum entropy generation is in surface whit high temperature. the enthalpy in centerline is constant and inlet enthalpy of the tube is greater than other point with higher temperatures in radial flow. the lowest enthalpy is obtained in tubes with lowest initial temperature (case 7). minimum entropy generation is presented in surface whit high temperature at the beginning (case 1-3) or high at the ending (case 5-7).