Numerical Simulation for Cavitation around Horizontal-axis Counter-rotating Type Propellers in a Tidal Stream Power Unit (in Preparation for Suppressing Cavitation)

摘要

A counter-rotating type horizontal-axis tidal stream power unit has a number of attractive features, for instance, cavitation can be suppressed well owing to decrease the individual rotational speed in keeping the relative rotational speed same as the single propeller speed. A cavitation model based on a homogeneous multiphase flow method implemented in the Reynolds-Averaged Navier-Stokes (RANS) solver CFX14.0 was employed to carry out the cavitation simulations on a counter-rotating type horizontal-axis counter-rotating type impellers in a tidal stream power unit. The cavitation performance curve at a relative high tip speed ratio was obtained, and additional observations were made with regards to cavity size and shape as well as cavitation breakdown behavior.