Analytical study of fluid flow entropy generation over a stretching sheet with variable thickness

Hot rolling is one of the most important processes in the industry that can be modeled with a series of flat plate assumptions with specific boundary conditions. Lowering the workpiece temperature is one of the important parameters in the hot rolling process. In this study, hot rolling is simulated as a boundary layer on a sheet of variable thickness, without pressure gradient and nonlinear tensile concerning the similarity solution and the definition of the similarity variable. For the validation of the present solution, the simulation results are compared with published research results. The continuity, momentum, and energy equations were transformed into nonlinear ordinary differential equations by similarity variables. Also Entropy analysis has also been used to examine more precisely the hot-rolling process with variable thickness. In the following, the effect of plate thickness change on thermal and frictional Bejan dimensional numbers was investigated. The results show that increasing the parameter of plate thickness decreased the heat transfer rate. Also, the entropy changes are mostly due to the thermal boundary layer changes. The results of this study can be used for more efficient cooling in the hot rolling industry.