Parametric analysis of the inlet duct in the marine waterjet propulsor

YANG Fuqin, WANG Xuezhi, JIANG Jingwei, HE Yan

（College of  Electromechanical Engineering, Qingdao University of Science and Technology, Qingdao 266061, China）

Abstract: Aiming at the problem of how the waterjet propulsor affects the flow fields and velocities of the inlet ducts with different lengths and pipe diameters, the 3D models of the waterjet propulsors were established. The computational fluid mechanics (CFD) technology was used to simulate the flow fields of "boat+inlet channel +waterjet propulsor" with 1 time, 4times, 8times of the lengths and 1.6times, 2times of the diameters repectively. Then the velocity nephograms of non-uniformity of the outlet flow field in the inlet duct, the cavitation nephograms of the blade suction surface and the velocity nephograms of the nozzle were obtained. The results indicate that the non-uniformity of the outlet flow field, blade cavitation and nozzle velocity is affected little by the length of the inlet duct. However, it is affected more by the diameters of the inlet duct. To improve the adaptability of the inlet duct in working conditions, its diameter should be taken into consideration for its optimization.