Low-specific-speed mixed-flow water turbine with double-inlet volute

Abstract

The invention discloses a low-specific-speed mixed-flow water turbine with a double-inlet volute. An annular opening in the inner side of the double-inlet volute is provided with a connecting base ring; the inner periphery of the connecting base ring is provided with a circle of fixed guide vanes; the outer periphery of the connecting base ring is provided with a circle of movable guide vanes; aninner ring of the connecting base ring is sleeved with a rotating wheel; the lower portion of the connecting base ring is connected with the front end of a tail water pipe; the vanes in the rotating wheel are configured as X-type unequal-thickness distortional vanes; and the front surfaces and back surfaces of the vanes are smoothly connected from top to bottom by virtue of different-curvature curved surfaces. Two water inlets of the low-specific-speed mixed-flow water turbine disclosed by the invention are the uniformity of water flow in the circumferential direction of the volute is improvedand the velocity component of the water flow in the circumferential direction is enhanced, thereby effectively increasing the circular rector of the coming water flow, improving the condition of thewater flow entering a water guide mechanism, reducing hydraulic loss of the water guide mechanism and thus achieving good hydraulic performance and running efficiency of the low-specific-speed mixed-flow water turbine.

Description

technical field [0001] The invention relates to a low specific speed Francis water turbine with a double-inlet volute, belonging to the technical field of water turbines. Background technique [0002] The Francis turbine is currently the most widely used type of turbine, and its main components include a water diversion chamber, a seat ring, a water guide mechanism, a runner and a draft tube. As the water diversion part of the turbine, from the hydraulic point of view, its function is to make the water flow form a circulation, so as to ensure that the water flow can enter the seat ring and the movable guide vane at a small angle of attack, and reduce the hydraulic loss of the water guide mechanism. [0003] A water turbine in the prior art sets all cross-sections of the spiral structure section of the volute to be elliptical to effectively increase the diameter of the runner to increase the output of the unit. However, it only changes the cross-sectional shape of the volute...

AI Technical Summary

Problems solved by technology

However, it only changes the cross-sectional shape of the volute, and does not optimize the water inlet conditions

[0004] In addition, the existing volutes are designed with one-way water inlet, and the section of the volute structure section gradually decreases to form the necessary circulation in front of the water guiding mechanism.

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