Large eddy simulation of turbulent heat transfer in curved pipe flow

In the current investigation, turbulent heat transfer in fully-developed curved pipe flow has been studied by Large Eddy Simulation (LES). We consider a fully-developed turbulent curved pipe flow with axially uniform wall heat flux. The Reynolds number under consideration is Re_τ=1, 000 based on the mean friction velocity and the pipe radius, and the Prandtl number (Pr) is 0.71. To investigate the effects of wall curvature on turbulent flow and heat transfer, we vary the curvature (κ) from 0.01 to 0.1. Dynamic subgrid-scale (SGS) models for turbulent SGS stresses and heat fluxes are employed to close the governing equations. The mean velocity, turbulent intensities and heat transfer rates obtained from the present LES are in good agreement with the previous numerical and experimental results currently available. To elucidate the secondary flow structures due to the pipe curvature, the mean quantities and various turbulence statistics of the flow and temperature fields are presented on the pipe cross-sections, and compared with those of the straight pipe flow. The friction factor and the mean Nusselt number are also compared with the previous experimental results. Based on our results, we attempt to clarify the effects of the pipe curvature on turbulent heat transfer. Our LES provides researchers and engineers with useful data to understand the heat transfer mechanisms in turbulent curved pipe flow which has numerous applications in engineering.