Composite shafting supporting method for two-stage runner of vertical two-stage mixed-flow water turbine

Abstract

The invention discloses a composite shafting supporting method for a two-stage runner of a vertical two-stage mixed-flow water turbine. The method comprises the following steps that N bearing type fixed guide vanes arranged along the circumference are arranged at the horizontal section of an inlet of the second-stage mixed flow runner; a composite shafting supporting structure surrounding the main shaft is arranged at the upper end of the upper wall of the second-stage flow channel corresponding to the N bearing type fixed guide vanes and located in a water-free cavity of the second-stage flow channel; secondary runner seat rings are arranged at the lower ends of the N bearing type fixed guide vanes along the circumference; the thrust bearing is greatly moved to the position below the generator rotor from the position below the draft tube of the water turbine; and the length of the main shaft is shortened to the second-stage mixed flow rotating wheel. The length of the main shaft of the vertical two-stage mixed-flow water turbine can be greatly shortened, and the stability of a whole shaft system of the two-stage mixed-flow water turbine is greatly improved; and meanwhile, the disadvantage that a main shaft of a conventional vertical two-stage mixed-flow water turbine needs to extend to the draft tube in a flow channel to form a crossed shaft system with the draft tube is avoided.

Description

technical field [0001] The invention relates to the technical field of hydroelectric power generation, in particular to a composite shafting support method for a secondary flow channel of a vertical two-stage mixed flow water turbine. Background technique [0002] The existing Francis turbines all work in the underwater channel, have lower speed and larger unit capacity, and the current maximum unit capacity can reach 1000MW; in addition, compared with the impulse turbine, the Francis turbine has higher efficiency and is resistant Better resistance to sand and sand. The Francis turbine in the prior art includes a main shaft, a generator, a guide bearing, a thrust bearing and a single-stage Francis turbine. The upper and lower ends of the main shaft are respectively erected on the guide bearing and the thrust bearing. Top cover, bottom ring, draft tube, runner and its corresponding water guide mechanism; the water inlet pipe is composed of multi-section pressure steel pipes ...

AI Technical Summary

Problems solved by technology

[0005] However, the main shaft in the above-mentioned Chinese patent application needs to extend to the draft tube in a single common flow channel, and after forming a cross shafting system with the draft tube, a thrust bearing is installed at the bottom end of the cross shafting system. Insufficient stability

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