Numerical study of periodically fully developed flow and heat transfer in cross-corrugated triangular channels in transitional flow regime

Cross-corrugated triangular ducts provide high heat transfer capabilities with strong mechanical strength. Flows in such geometries are usually transitional, with typical Reynolds numbers varying from 100 to 6,000. In this study, periodic fully developed fluid flow and heat transfer in a cross-corrugated triangular duct is studied numerically. Periodicity is used to reduce the complexity of the channel geometry and enables the smallest possible segment of the flow channel to be modeled. To model the transitional flow in the topology, a validated low Reynolds number k-omega (LKW) turbulence model is employed to account for the turbulence in the flow. The temperature, velocity, and turbulence contours are obtained in the three-dimensional complex domain. The friction factors and the segment mean Nusselt numbers are calculated and correlated with Reynolds numbers, for both uniform temperature and uniform heat flux boundary conditions. The results are compared with the available experimental data for cross-corrugated sinusoidal ducts. The turbulence center intensifies and moves from the upper wall corrugation to the lower wall corrugation with increasing Reynolds numbers.