Etude numérique des gains de performances et de capacité d'aspiration apportés par un étage axial contra-rotatif par rapport à une pompe mono-rotor.

This study deals with the development of an efficient method of design for subsonic conter-rotating axial flow turbomachineries. From specifications of a reference axial pump with only one rotor, two configurations of counter-rotating systems are studied : a system with a lower specific speed, and a system with a smaller specific radius. The numerical study is conducted in stationary regime, with a RANS-type turbulence model. Numerical simulations of the flow in stationary cavitating conditions use an homogeneous model at the thermodynamic equilibrium state. Results obtained for the two counter-rotating systems increase the yield of 12% for the same operating point. The first configuration decreases the size of 25%, which is a favorable for the manufacturing cost and the use in the system. The second configuration allows to obtain a lower speed of rotation (35%) which is beneficial for the increase of the suction capacity