Variable volume offset pump turbine

Abstract

The invention discloses a volume-changing offset distance type pump turbine. The volume-changing offset distance type pump turbine comprises a volute casing, a rotor arranged in the volute casing in a penetrating manner, a driving device for causing the volute casing to move back and forth in an in axial direction relative to the rotor, a water outlet pipe and an external water inlet pipe. The volume-changing offset distance type pump turbine can directly transform potential energy pressure into the rotation kinetic energy of the rotor; the energy transformation is direct and high-efficiency; and especially, when the water velocity of a water outlet is extremely low, the energy transformation efficiency is extremely high.

Description

technical field [0001] The present invention relates to a water turbine, in particular to a variable volume offset distance pump water turbine. Background technique [0002] The main conventional power generation technologies in the world today include thermal power generation, hydropower generation, atomic power generation and so on. Thermal power generation consumes a large amount of coal, a non-renewable resource, and the cost increases with the reduction of coal storage, and it pollutes the environment. The operating cost of nuclear power units is low, but once a nuclear fuel leakage accident occurs, it will cause serious consequences, and the post-processing of burning waste is difficult. The stability and continuity of wind power generation are poor, which affects the balance, safety and stability of the power system after grid connection. Hydroelectric power generation has the characteristics of flexible start, fast climbing speed, improved coordination of power gri...

AI Technical Summary

Problems solved by technology

However, its water turbine has two significant disadvantages: 1. It cannot be adjusted in speed, so it is not convenient for synchronous grid connection; 2. It can only be used as the prime mover of the generator and cannot also be used as a pump to pump water and store energy

High cost of four-machine separated and three-machine direct-connected pumped storage

But there are still two shortcomings: 1. The output is unstable and has periodic changes

During the rotation of the runner, the area of ​​the part of the web subjected to high water head pressure changes with the rotation angle of the runner, resulting in fluctuations in output

2. The radial force of the runner is large

However, there are still deficiencies: low utilization rate of blade radial net section, poor ability to adapt to low water head: blade expansion and contraction radius difference in the volute depends on the inner diameter of the volute and rotor outer diameter, and the net radius difference determines the flow of water. The cross-sectional area of ​​the cavity is related to the water passing capacity, but because there is a certain relationship between the maximum radius D, the outer diameter of the rotor d, and the radial dimension a of the rectangular blade, the limit value satisfies D=3d=3a, and d / D cannot be too small. This results in a large and narrow average radius of the water chamber, low volume availability, limited water flow capacity, and poor adaptability to micro-water with low water head; d / D should be reduced to improve the low volume availability and reduce the radial diameter of the turbine. Radius, stronger adaptability to low water head; therefore, it is necessary to develop a pump turbine with a more reasonable structure

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