Axial-flow type water turbine inner skirt blade rotary wheel

Abstract

The invention relates to an axial-flow type water turbine inner skirt blade rotary wheel. The axial-flow type water turbine inner skirt blade rotary wheel comprises a curved blade and a ball-shaped pivot which connects the curved blade and the hub body, and a small gap is arranged between the hub body and the curved blade. A backpressure face of the curved blade is closed to the hub body, and a skirt with a small gap exists between the curved blade and the hub body. An effect of inhibiting gap cavitation from appearing on the surface of the blade can be achieved by increasing the skirt of one side of the blade backpressure face hub body. The axial-flow type water turbine inner skirt blade rotary wheel can prevent the blade from being damaged by gap caviation on the portion of the blade, and the portion of the blade is close to the hub body. The axial-flow type water turbine inner skirt blade rotary wheel can reduce cavitation abrasion of the blade surface, improves anti-cavitation ability of the blade and improves security and stability of operation.

Description

Technical field: [0001] The invention relates to an inner skirt blade runner of an axial flow water turbine. technical background: [0002] The liquid flow with water as the medium flows through a local area at a certain temperature. When the pressure is lower than a certain critical value, the small bubbles originally contained in the water body will expand rapidly, forming obvious bubbles containing water vapor or other gases in the water. This process of water vaporization due to pressure reduction is called "cavitation". When the cavitation bubbles carried by the water flow pass through the downstream area with higher pressure, the cavitation bubbles will expand and eventually collapse, causing cavitation in the turbine. Phenomena can cause cavitation damage of flow-passing components, and its consequences are mainly the deterioration of hydraulic performance parameters of the turbine, mechanical vibration and noise, and then affect the safe operation of the turbine. ...

AI Technical Summary

Problems solved by technology

[0002] The liquid flow with water as the medium flows through a local area at a certain temperature. When the pressure is lower than a certain critical value, the small bubbles originally contained in the water body will expand rapidly, forming obvious bubbles containing water vapor or other gases in the water. This process of water vaporization due to pressure reduction is called "cavitation". When the cavitation bubbles carried by the water flow pass through the downstream area with higher pressure, the cavitation bubbles will expand and eventually collapse, and cavitation occurs in the turbine. Phenomena can cause cavitation damage of flow-passing components, and its consequences are mainly the deterioration of hydraulic performance parameters of the turbine, mechanical vibration and noise, and then affect the safe operation of the turbine

[0003] The cavitation phenomenon of hydraulic turbines can be divided into airfoil cavitation, gap cavitation, cavity cavitation and local cavitation according to the location where cavitation occurs. For the cavitation phenomenon that occurs near the blade near the hub body, it may be The airfoil cavitation caused by the geometry of the blade airfoil may also be the gap cavitation caused by the water flow passing through the narrow gap between the inner edge of the blade and the hub body. Secondary adjustment of the blade airfoil can reduce or even eliminate the possibility of its occurrence, but the gap between the inner edge of the blade and the hub body is an inherent feature of the axial flow turbine, and the gap cavitation caused by it will not only appear in the On the runner body, it may also develop to the blade and cause damage to the blade

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