A shaft end self-sealing structure with high speed and high pressure difference

Abstract

The invention discloses a shaft end self-sealing structure with high rotational speed and high pressure difference, which includes a combined labyrinth seal group and an axial flow compression self-sealing group. The combined labyrinth seal group includes a plurality of side-by-side circumferential metal hard seal teeth, The outer end of the metal hard seal teeth is provided with an organic material soft seal head; the axial flow compression self-sealing group is arranged between two of the metal hard seal teeth, including the compression movable blades arranged on the rotating shaft, the set The diffuser static blades on the shell, the compression movable blades and the diffuser static blades are intersected along the axial direction of the rotating shaft, and the rotation direction of the compression movable blades is consistent with the rotation direction of the main impeller blades on the rotary machine. In the present invention, the combined labyrinth seal group can reduce the leakage gap and enhance the throttling effect; the axial flow compression self-sealing group raises the background pressure of the atmospheric environment to the background pressure of the leaked gas at the diffuser static vane after reverse flow and pressure boosting , reduce the pressure difference inside and outside the rotating machinery, and effectively prevent the shaft end leakage of the supercritical rotating machinery.

Description

technical field [0001] The invention relates to the technical field of rotating machinery, in particular to a shaft end self-sealing structure with high rotational speed and high pressure difference. Background technique [0002] In the field of power conversion technology, supercritical CO 2 With its high thermal efficiency and low operating cost, the Brayton cycle system will gradually replace the steam Rankine cycle as the mainstream form of energy conversion. There are a large number of rotating machines in this system, and they all operate under high pressure conditions above 8 MPa, and some rotating machines are under pressure or even Exceeded 20MPa. CO 2 After the leakage, it is not liquefied, but directly mixed into the environment, which not only leads to insufficient system working fluid, but also takes away part of the lubricating oil in the sliding bearing due to the leakage gas, resulting in an increase in the demand for lubricating oil replenishment, and the ...

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Problems solved by technology

[0005] The technical problem to be solved by the present invention is that the existing supercritical rotating mechanism has the problem of reducing the leakage of working fluid

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