Numerical study on hydrodynamic characteristics of hybrid contra-rotating propeller

  Objectives  In order to study the propulsion performance of the hybrid contra-rotating propeller,

  Methods  the hydrodynamic characteristics of the propeller, the podded propeller and the hybrid contra-rotating propeller(CRP) are numerically simulated by using sliding mesh method respectively, the differences in the hydrodynamic characteristics of each propulsion component in the hybrid CRP compared to those of the entire hybrid CRP are analyzed in detail, and the interaction between various parts of the hybrid CRP is studied.

  Results  The results show that the thrusting coefficient, the torque coefficient and the open water efficiency of the forward propeller decrease as the speed coefficient decreases due to the suction effect of the rear propeller on the forward propeller in the hybrid CRP, in which the trend is different from that in the single propeller. The thrusting coefficient, the torque coefficient and the open water efficiency of the rear propeller are different from those of the single podded propeller due to the blocking effect of pod and hub and the interference effect of unsteady wake of the forward propeller on the rear propeller. The calculated efficiency of the hybrid CRP is lower than that of the single propeller, and the energy absorption effect of the rear propeller on the forward propeller wake is not reflected. Therefore, the matching of the geometry parameters of the forward and rear propellers should be further considered in the design and study of the hybrid CRP.

  Conclusions  This study results can provide reference for the optimal design and engineering application of the hybrid CRP.