the effects of transient radiant flow on pipe in contact with natural convection, for developed laminar flow of fluid with high prandtl number, on enthalpy and entropy generation

convection flow is passed in a pipe wall possessing radiation-convection, in order to find the best case with at least enthalpy and minimum entropy generation, through pipe wall having radiant flow. flow in developed laminar conditions is investigated. radiant flow is simulated passing the natural convection on the wall with for 6 cases. variation of radiation along the pipe touching with natural convection causes to change temperature, entropy generation and enthalpy for each case. different profiles are investigated distributions of temperature, entropy generation and enthalpy along the radius. along the wall are shown variation in enthalpy and entropy generation.

there have been increased in radiation-convection boundary conditions temperature, enthalpy as well as entropy generation. along the radius and axis have appropriately been increased in radiation boundary conditions than convection, the amounts of enthalpy. near the wall are occurred the most changes in temperature, enthalpy and entropy generation. application the thermal boundary conditions are used for minimum entropy generation make fluid with high prandtl number to become high thermal carrier. solar radiation application are used in parabolic trough, parabolic dish, solar chimney and tube furnace in various cases. application are used for minimum entropy generation.