Turbulent impinging jet flow into an unshrouded rotor–stator system: Hydrodynamics and heat transfer

• Comparisons of two RANS models with velocity and temperature measurements for an impinging jet onto a rotating disk.
• Effect of the confinement stator disk on the fluid flow and heat transfer.
• Turbulence characteristics using an innovative RSM model.
• Empirical correlations for the Nusselt number along the rotor for a wide range of jet and rotational Reynolds numbers.

New calculations using an innovative Reynolds Stress Model are compared to velocity measurements performed by Particle Image Velocimetry technique and the predictions of a k–ω SST model in the case of an impinging jet flow onto a rotating disk in a discoidal and unshrouded rotor–stator system. The cavity is characterized by a dimensionless spacing interval G = 0.02 and a low aspect ratio for the jet e/D = 0.25. Jet Reynolds numbers ranging from 1.72 × 104 to 4.3 × 104 and rotational Reynolds numbers between 0.33 × 105 and 5.32 × 105 are considered. Three flow regions have been identified: a jet-dominated flow area at low radii characterized by a zero tangential velocity, a mixed region at intermediate radii and rotation-dominated flow region outwards. For all parameters, turbulence, which tends to the isotropic limit in the core, is much intense in a region located after the impingement zone. A relative good agreement between the PIV measurements and the predictions of the RSM has been obtained in terms of the radial distributions of the core-swirl ratio and of the turbulence intensities. The k–ω SST model overestimates these flow characteristics in the jet dominated area. For the thermal field, the heat transfers are enhanced in the jet dominated region and decreases towards the periphery of the cavity. The jet Reynolds number appears to have a preponderant effect compared to the rotational one on the heat transfer distribution. The two RANS modelings compare quite well with the heat transfer measurements for these ranges of parameters.