Steam turbine seal method and structure

Abstract

The invention provides a steam seal method for a steam turbine. Steam seal teeth on a rotor are arranged to be threaded teeth, the spiral thrust direction of the threaded teeth is opposite to the steam leakage direction, steam seal teeth on a steam seal ring are arranged to be constant-depth teeth, and the interval of the constant-depth teeth is equal to the thread pitch of the trapezoidal threaded teeth, so that the steam seal teeth on the steam seal ring oppositely correspond to the steam seal teeth on the rotor one to one, each opposite gap serves as a steam leakage passage, and a steam retention space is formed between every two adjacent steam seal teeth; when the rotor rotates, the threaded teeth exert axial thrust on steam in the retention spaces, the direction of the axial thrust is opposite to the steam leakage direction, and therefore the purpose of steam seal is achieved. By means of the axial thrust of the threaded teeth, reverse damping is exerted on the steam to prevent the steam from leaking, the seal is of an active type, the traditional thinking habit of passive seal in the field is broken through, the steam seal method is daring liberation of the design ideas and has the remarkable effect, while an enough contact-rubbing gap reserved between a stator and the rotor is ensured, steam leakage is reduced substantially, and the unit efficiency is improved.

Description

Technical field: [0001] The invention relates to a steam turbine, in particular to a steam seal structure and method of the steam turbine. Background technique: [0002] With the development of the rotating machinery industry to this day, high efficiency is the unanimous pursuit of all major manufacturers, and as a means of improving efficiency, sealing the dynamic and static parts to prevent the leakage of working fluid has made R&D personnel rack their brains. The current structure using dynamic and static seals has very high requirements for the design of the stator part, but there is no special requirement for the other half of the rotor as a sealing pair, almost all of which are city wall teeth or directly optical axis structures. This sealing method has high requirements on the seal gap, and the smaller the required gap, the better, but in order to avoid dynamic and static friction, a sufficient gap must be reserved, which is a pair of contradictions. [0003] When th...

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Problems solved by technology

[0005] The principle of the above-mentioned steam seal structure is to minimize the flow area of ​​steam leakage or to make the steam leakage path tortuous and long, and the resistance is increased, thereby reducing the amount of steam leakage. As a result, being constrained by it, the above-mentioned contradictions have not been effectively resolved so far.

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