Liquid coating with variable thermal conductivity on a pipe under influence of thermal radiation and heat generation

Abstract

Flow over a pipe or an elongated cylinder is widely applied in many engineering processes like wire coating and pipe coating. This encourages the present study to examine the fluid flow and heat transfer over a horizontal stretching cylinder with the impact of temperature-reliant thermal conductivity and thermal radiation. The influence of heat generation is also considered. The Carreau rheology model is applied to represent the liquid coating. The similarity technique is used to simplify the developed governing equations and then solved by the homotopy analysis method. The effects of the pertinent parameters such as the thermal conductivity parameter and Weissenberg number on the fluid field and heat transfer are studied by applying the calculated series of analytical solutions, which are scrutinized through graphs and tables. The Nusselt number has a negative function with the radiation and thermal conductivity parameters. Furthermore, the Weissenberg number affects the velocity and temperature profiles differently in conditions n < 1 and n ≥ 1, respectively. The present results are essential in optimizing the pipe coating process.