Numerical predictions of three -dimensional flow and heat transfer are presented for a rotating square channel with 45° angled ribs as tested by Johnson et al. (1994). The rib height-to-hydraulic diameter ratio (e/Dh) is 0.1 and the rib pitch-to-height ratio (P/e) is 10. The cross-section of the ribs has rounded edges and corners. The computation results are compared with Johnson’s et al. (1994) experimental data at a Reynolds number (Re) of 25,000, inlet coolant-to-wall density ratio (Δρ/ρ) of 0.13, and three rotation numbers (Ro) of 0.0, 0.12, 0.24.
A multi-block numerical method has been employed with a near-wall second-moment turbulence closure model. In the present method, the convective transport equations for momentum, energy, and turbulence quantities are solved in curvilinear, body-fitted coordinates using the finite-analytic method. Pressure is computed using a hybrid SIMPLER/PISO approach, which satisfies the continuity of mass and momentum simultaneously at every time step. The second-moment solutions show that the secondary flows induced by the angled ribs, rotating buoyancy, and Coriolis forces produced strong non-isotropic turbulent stresses and heat fluxes that significantly affected flow fields and surface heat transfer coefficients. The present near-wall second-moment closure model provided an improved flow and heat transfer prediction.
