Abstract: Marine current turbine (MCT) is a new mechanical device for marine current energy utilization, and cavitation performance of it is important for the safe and stable operation. Based on two phase homogeneous mixture model, numerical simulation of the cavitating flow is performed on a horizontal axis marine current turbine (HMCT). Cavity shapes and performance of the HMCT in variable cavitation numbers are obtained. Numerical results show that the numerical method can be used to predict the cavitation performance of marine current turbine; the incipient cavitation number is predicted, and the cavity shape is similar with the experiment; cavitation usually appears in the suction surface of the blade and locates in the area near the blade tip, and becomes longer in the span and chord direction with lower cavitation number; when the cavitation number is relatively higher, cavitating region locates in the middle area of the blade in chord direction, and develops to the trailing edge of the blade when cavitation number becomes lower; when the cavitation number equals to the incipient cavitation number, performance of the HMCT has no change almost, only when cavitation number reduces to some extent, the output power decreases and thrust increase, which means the marine current turbine operates in a bad condition and this condition should be avoided in the practical operation.

Key words: Cavitation, Cavitation inception, Forizontal axis marine current turbine, Numerical simulation