CFD investigation on the offset ratio effect on thermal characteristics of a combined wall and offset jets flow

Abstract

The present paper deals with CFD simulation of a two-dimensional, steady, incompressible and turbulent flow combining a wall jet and an offset jet (this combination will be denoted wall offset jet) in order to study the heat transfer phenomenon in this type of flow. Several turbulence models were tested including standard k–ω, SST k–ω, standard k–e, RNG k–e and realizable k–e models. A parametric study was also presented to investigate the offset ratio H and the Reynolds number Re effect on the local (Nu) and average \( \left( {\overline{{\text{Nu}}} } \right) \) Nusselt number evolution along the wall. Constant wall heat flux boundary condition is considered. The Reynolds number and the offset ratio have been varied respectively from 10,000 to 40,000 and from 5 to 20 and Pr = 0.7 is adopted for all computation. Correlations that predict the average Nusselt number as a function of both the offset ratio H and the Reynolds number Re are also provided. This study has allowed us to conclude that the heat transfer exchanged between the flow and the wall is intensified when decreasing the offset ratio H and increasing the Reynolds number Re.