Self-adaptive dynamic pressure gas film composite blade tip sealing device and sealing method thereof

Abstract

The invention discloses a self-adaptive dynamic pressure gas film composite blade tip sealing device. The sealing device comprises a rotating shaft, a movable blade arranged on the rotating shaft, a shroud arranged on the movable blade, a movable ring (comb sealing tooth) arranged on the shroud, a cylinder, and a static ring arranged in the cylinder, wherein the static ring is fixed on the inner wall of the cylinder through a spring; a sealing ring is arranged below the static ring to realize the gas film sealing with the inner wall of the cylinder; and the static ring and the movable ring are in clearance fit. If the rotating speed is higher and the pressure difference is greater, a gas film is easier to form; the sealing device is specifically suitable for impeller machinery in the environment with high pressure difference, high rotating speed and high temperature; a blade tip gap has self-adaptive axial disturbance change tracking capability; and an gas film gap is about 5-10% of a conventional comb sealing gap, so that the leakage quantity is low, and the efficiency and the stability of the impeller machinery can be improved.

Description

technical field [0001] The invention belongs to the field of mechanical sealing, and in particular relates to an adaptive dynamic pressure gas film composite blade tip sealing device and a sealing method thereof, which are suitable for impeller machinery such as turbomachinery and compressors, and are especially suitable for working under high pressure difference, high speed and high temperature. Turbomachinery in the environment. Background technique [0002] There is relative motion between the impeller and the cylinder wall of turbomachinery (steam / gas turbine, aero engine, compressor, etc.), and a certain gap must be left between them to avoid friction. When the medium flows in the blade passage, the pressure difference from the pressure surface to the suction surface causes a part of the fluid to flow into the blade tip clearance, forming a leakage flow. The jet vortex, the friction and mixing of the working medium at the blade tip and the end wall make the entropy of ...

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Problems solved by technology

[0003] In order to reduce the harm of leakage flow, people have proposed many new sealing types on the basis of traditional blade tip comb seals, such as: honeycomb, brush type, flexible sheet, fingertip seal, etc., and achieved certain results. , these sealing types generally have a contradiction between low leakage and high wear resistance, which cannot meet the demanding requirements of turbomachinery on aerodynamic performance, sealing component performance and life in an increasingly complex working environment

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