Prediction of Heat and Mass Transfer in a Rotating Ribbed Coolant Passage With a 180 Degree Turn

Abstract

Numerical results are presented for flow in a rotating internal passage with a 180 degree turn and ribbed walls. Reynolds numbers ranging from 5200 to 7900, and Rotation numbers of 0.0 and 0.24 were considered. The straight sections of the channel have a square cross section, with square ribs spaced one hydraulic diameter (D) apart on two opposite sides. The ribs have a height of 0.1D and are not staggered from one side to the other. The full three dimensional Reynolds Averaged Navier-Stokes equations are solved combined with the Wilcox k-ω turbulence model. By solving an additional equation for mass transfer, it is possible to isolate the effect of buoyancy in the presence of rotation. That is, heat transfer induced buoyancy effects can be eliminated as in naphthalene sublimation experiments. Heat transfer, mass transfer and flow field results are presented with favorable agreement with available experimental data. It is shown that numerically predicting the reattachment between ribs is essential to achieving an accurate prediction of heat/mass transfer. For the low Reynolds numbers considered, the standard turbulence model did not produce reattachment between ribs. By modifying the wall boundary condition on ω, the turbulent specific dissipation rate, much better agreement with the flow structure and heat/mass transfer was achieved. It is beyond the scope of the present work to make a general recommendation on the ω wall boundary condition. However, the present results suggest that the ω boundary condition should take into account the proximity to abrupt changes in geometry.

Effect of Coriolis and centrifugal forces on turbulence and transport at high rotation and density ratios in a rib-roughened channel

“…Shih and Sultanian [20], gave a review on computations of internal and film cooling in gas turbines. Rigby [21] used k-omega turbulence model with concentration on grid structure to describe heat transfer in a ribbed channel with 180 deg bend and showed reasonable agreement with experimental results of Park et al [22]. Prakash and Zerkle [23] performed a computation of rib-roughened rotating duct neglecting buoyancy-centrifugal effect.…”

Detached eddy simulation of turbulent flow and heat transfer in a two-pass internal cooling duct

“…Ooi et al (2002) present predictions using a v 2 -f model on orthogonal inline ribs and found that the model performs better than the k-e and S-A RANS models. Rigby (1998) studied the heat and mass transfer in a two pass ribbed channel with a 180°turn using a modified version of MenterÕs SST model (Menter, 1992(Menter, , 1993. Both stationary and rotating cases were studied.…”

Investigations on Nusselt Number Enhancement in Ribbed Rectangular Turbine Blade Cooling Channels of Different Aspect Ratios and Rotation Numbers

“…Other three-dimensional CFD studies with k-ω model have been made and the overall flow structure was predicted in good agreement to the experiments. However, the vortical structures and the heat flux were overestimated in the stationary case and in the rotating setup the simulations did underestimate the heat flux in comparison to experiments by Rigby [4].…”