| 摘要 |
A multistage turbine is provided for driving a downhole motor, which is driven by the flow of a fluid therethrough. The turbine comprises a housing and a shaft positioned in the housing, the shaft rotating about the longitudinal axis thereof. A plurality of turbine stages are mounted on the shaft for rotation therewith, each turbine stage including a rim coaxial with the shaft and a plurality of turbine blades fixed to the rim. A plurality of flow directing stators are positioned between adjacent turbine stages, each of the stators having a wall portion and diverter portion, wherein the wall portions are perpendicular to the axis of the shaft and the diverter portions are at an angle of less than 90 DEG with respect to the axis of the shaft. At least one of the turbine blades and the diverter portions form a seal for preventing the flow from passing therebetween, such that flow through a turbine stage is perpendicular to the axis of the shaft in the space between adjacent wall portions and wherein the diverter portions are positioned with respect to said wall means for diverting flow from the turbine stage to an adjacent turbine stage. The turbine blades are positioned between adjacent stators such that flow between the wall portion of adjacent stators contacts the edges of the turbine blades, thereby imparting a drag force on the turbine blades and flow through adjacent diverter portions impinges upon the face surface of the turbine blades, thereby imparting a dynamic force on the turbine blades, whereby the turbine blades are rotated by the combination of the drag forces and dynamic forces thereon.
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