Mixed convection study on the influence of low Prandtl numbers and buoyancy in turbulent heat transfer using DNS

• DNS of PRB flow for low Prandtl number fluid. The influence Pr in has been studied with varying Pr. Turbulence is enhanced decreasing number. Extensive results and temperature statistics are analyzed presented. Direct numerical simulation (DNS) performed to study turbulent heat transfer Poiseuille-Rayleigh-Bénard (PRB) flows numbers this article. mesh Cartesian a highly accurate finite difference sixth-order compact scheme chosen discretize the incompressible Navier–Stokes equations perform DNS. Liquids fixed Richardson 0.25 four different (Pr = 0.025, 0.05, 0.1, 0.71) simulated compared Poiseuille investigate buoyancy on –PRB flows. Constant fluid properties Boussinesq approximation assumed. obtained discussed analysed an extensive way study. Specifically, initiate large scale circulation shrinks increasing Velocity fluctuations become stronger which indicate that can strongly enhance intensity. Re ? increased cases Moreover, when decreases, distributions found be more homogeneous mixing fluids sufficient middle channel. Additionally, large-scale structures enlarged mixed convection forced convection. This observed field low-Prandtl-number fluids. It also Reynolds analogy cannot used predict thermal under or research R&D Gen IV nuclear fast reactors.