Numerical prediction of flow and heat transfer in the coolant passages of gas turbine rotor blade

Numerical prediction of three-dimensional flow and heat transfer was performed for four cases. (1) A rotating/non-rotating smooth square channel with 180° bend in which the rotation number was varied from 0 to 0.24, the inlet coolant-to-wall density ratio was varied from 0 to 0.22, while the Reynolds number was fixed at 25,000. The computation results were compared with experimental data of Wagner et al. (1991). (2) A non-rotating two-pass square channel with and without 90° parallel ribs. The rib height-to-hydraulic diameter ratio (e/Dh) was 0.125 and the rib pitch-to-height ratio (P/e) was 10. The Reynolds number (Re) was fixed at 30,000. The computation results were compared with Ekkad and Han (1997) data. (3) A non-rotating two-pass square channel with 60° angled parallel ribs in which the rib height-to-hydraulic diameter ratio (e/ Dh) was 0.125 and the rib pitch-to-height ratio ( P/e) was 10. The Reynolds number (Re) was fixed at 30,000. (4) A rotating/non-rotating square channel with 45° angled ribs in which the rib height-to-hydraulic diameter ratio ( e/Dh) was 0.1 and the rib pitch-to-height ratio (P/e) was 10. The computation results were compared with Johnson et al. (1994) data at a Reynolds number ( Re) of 25,000, inlet coolant-to-wall density ratio (Deltarho/rho) of 0.13 and three rotation numbers (Ro) of 0.0, 0.12, 0.24.;A multi-block numerical method was employed together with a chimera domain decomposition technique to calculate three-dimensional flow and heat transfer in a curvilinear, body-fitted coordinate system. The finite-analytic method solved the Reynolds-Averaged Navier-Stokes equation in conjunction with a two-layer kappa-epsilon isotropic eddy viscosity model and also a near-wall second-order Reynolds stress (second-moment) closure model.;The present near-wall second-moment closure model provided an improve and heat transfer prediction in comparison with the kappa-epsilon eddy viscosity model,...