喷水推进作为一种新型的推进方式显著提高了新型高速水面船舶的快速性、机动性与操纵性，国外已将此推进方式从水面应用拓展至水下，提升了水下航行体的动力性能，而国内相关研究处于起步状态。针对我国水下航行体对收缩型前置导叶喷水推进泵的需求，开展收缩型泵壳与前置导叶水动力机理研究，解决泵壳收缩引起的离心力做负功以及水动力原理的数学描述等科学问题，形成基于三元可控速度法的水下航行体推进泵水动力数学模型，为该泵型的研制提供理论与方法指导。本项目研究成果可以为我国新型高速水下航行体提供先进的推进方式，对提高我国水下航行体喷水推进技术有重要意义。

Waterjet propulsion as a new type of propulsive application has significantly increased the speedability and maneuverability. While related research has only started domestically, overseas, water jet propulsion has expanded its scope of application to underwater vehicles and boosted their power performance. To meet the national demand from underwater vehicles for contractive pre-guide-vane water jet pump, this research, taking full advantage of MARIC's water jet technology accumulated through years of research, intends to study the hydrodynamic mechanisms of contractive shrouds and pre-guide-vanes. Scientific issues such as the influence of the negative centrifugal work done by impeller inside a contractive shroud to hydrodynamic performance, and the strategy of establishing mathematic models for this pump type will be addressed in this research. Three dimensional mathematic models based on the 3D Controllable Velocity Moment Theory will be formulated for this pump type to better serve the underwater water jet technology.