Unsteady conjugated heat transfer in turbulent channel flows with convection from the ambient

Abstract

A numerical study is carried out to investigate the transient conjugated heat transfer in turbulent channel flows with convection from the ambient. The solutions take wall conduction and heat capacity effects into consideration. Major nondimensional groups identified in this work are the wall-to-fluid conductivity ratio K, the wall-to-fluid thermal diffusivity ratio A, the dimensionless wall thickness β, the Reynolds number Re, the Prandtl number Pr, the outside Nusselt number Nu o and the dimensionless cooling length L. The influences of wall material, β, Pr, Re and Nu o on the interfacial heat flux, outer wall temperature and interfacial temperature are examined in detail. Results show that wall conduction plays a significant role in the transient conjugated heat transfer problem. In addition, the time required for heat transfer to reach the steady state condition is longer for systems with a larger β or smaller A, Re and Nu o.