Heat transfer and entrance flow characteristics of viscoplastic fluid in a circular cylinder using the Bingham-Papanastasiou model

Abstract

This study investigates the laminar flow of an incompressible viscoplastic fluid in the entrance region of a circular cylinder, with emphasis on heat transfer characteristics by considering two different thermal boundary conditions: constant wall temperature and constant wall heat flux. The fluid behavior is modeled using the regularized Bingham-Papanastasiou approach, and the analysis is conducted under the assumptions of Prandtl's boundary layer theory using the finite difference method. The study highlights the simultaneous development of the velocity and thermal boundary layers. It presents a detailed analysis of the heat transfer behavior of Bingham fluid flow in the cylindrical geometry. The impact of yield stress on the flow and thermal parameters is thoroughly examined. The presence of yield stress significantly affects flow characteristics such as velocity, pressure, and temperature distributions. It also influences heat transfer performance, particularly the Nusselt number. The effects of key dimensionless parameters, such as the Bingham and the Prandtl number, are also discussed. The obtained results are consistent with previously reported findings in certain limiting cases, validating the current approach.