Mass and Heat Transfer Inside the Air Gap of a Discoidal and Unshrouded Rotor Stator System With a Jet Impingement

Mass and heat transfer are experimentally investigated in a discoidal and unshrouded rotor-stator cavity where an air jet passes through the stator and impinges on the rotor center. Using a jet impingement is a way to bring fresh air inside the air gap and to increase shear stresses and so heat transfer over the rotor. This study focuses on comparisons between heat transfer coefficients and velocity fields obtained inside the air gap for the case of a dimensionless spacing interval G = 0.02 and a low aspect ratio for the jet e/D = 0.25. Two jet Reynolds numbers ranging from 16000 to 42000 and three rotational Reynolds numbers between 30000 and 516000 are considered. Mass transfers are investigated by Particle Image Velocimetry technique while the radial distribution of heat transfer coefficients over the rotor is obtained using a thick wall method and temperature measurements by infrared thermography.