A sealing structure for impeller blade tip of impeller machinery

Abstract

The invention discloses a sealing structure for the top of a moving blade of a turbomachinery, which includes a turbine blade shroud, a sealing tooth and a casing, the first boss on the inlet side of the blade shroud is continuous in the circumferential direction without slots, and other high steps are provided with pumping grooves / hole, the notch is contracted from the exhaust side to the intake side, and forms a certain angle with the centerline of the rotating shaft, so that when the blade rotates, the gap airflow passes through the contracted pumping groove / hole to produce a "pumping effect", thereby Increase the pressure on the air outlet side of the long sealing teeth to reduce the pressure difference on both sides of the gap between the long sealing teeth and reduce leakage. In order to reduce the leakage of the blade tip clearance gas toward the blade tip when the gas is boosted countercurrently along the slot, the slot on the tip of the blade tip is contracted toward the tip of the blade, or an opening is provided on the boss instead of the slot, which can Play a better effect of preventing leakage. Through the application of the above-mentioned sealing structure, the leakage of the tip clearance can be made smaller, thereby reducing the leakage loss of the turbine, and improving the efficiency and economic benefits of the unit.

Description

technical field [0001] The invention relates to the seal structure of the moving blade top of the turbomachinery, specifically a combination sealing structure of a turbine blade top labyrinth and a spiral groove / hole. Top clearance leakage and flow loss, thereby improving the efficiency and economics of the turbine. Background technique [0002] There is a gap between the rotor and the casing of the labyrinth seal, no solid contact, no lubrication, simple maintenance, long service life, no need to use other sealing materials and allow thermal expansion, and can adapt to high temperature, high pressure, high speed frequency occasions, so This type of sealing is widely used in blade tip seals and shaft seals of steam turbines, gas turbines, compressors, blowers and other equipment. The leakage of the labyrinth seal increases with the increase of the gap value and the pressure difference before and after the seal. [0003] The biggest advantage of the spiral groove seal is th...

AI Technical Summary

Problems solved by technology

However, the spiral seal is greatly affected by the rotor speed, and when the design speed deviates to a certain extent, there is a problem of seal failure.

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