Axial Fluid Machinery

Abstract

The invention provides an axial flow fluid machine capable of effectively reducing unstable fluid force caused by leakage flow and suppressing unstable vibration. The steam turbine has an annular shroud (6) connected to the outer peripheral portion of the moving blade row (4), and an annular recess (12) provided on the inner peripheral surface (8) of the casing (1) and accommodating the shroud (6). ). A gap flow path (15) is formed between the outer peripheral surface (13) of the cover (6) and the bottom surface (14) of the recess (12). A gap inlet flow path (18) is formed between the upstream side (17), and a gap outlet flow path is formed between the downstream side (19) of the cover (6) and the downstream side (20) of the recess (12). (twenty one). Furthermore, between the gap inlet flow path (18) and the gap flow path (15), a gap inlet expansion flow path (22) is provided, and the gap inlet expansion flow path (22) is substantially uniform throughout the entire circumferential direction with a ratio of the concave portion ( The bottom surface (20) of 12) is formed so as to expand toward the outer peripheral side and to expand toward the upstream side in the rotor axial direction than the upstream side surface (17) of the concave portion (12).

Description

technical field [0001] The present invention relates to an axial-flow fluid machine such as an axial-flow turbine, and more particularly, to an axial-flow fluid machine having a shroud on the outer peripheral portion of a rotor blade row and a concave portion on an inner peripheral surface of a case housing the shroud. Background technique [0002] An axial flow turbine (specifically, such as a steam turbine, a gas turbine, etc.), which is one of axial flow machines, generally includes a casing, a rotor rotatably provided in the casing, and stator blades provided on the inner peripheral side of the casing. row, and a moving blade row disposed on the outer peripheral side of the rotor and disposed on the downstream side of the rotor axial direction relative to the stationary blade row. Furthermore, the working fluid (specifically, steam, gas, etc.) flows in the order of the stationary blade row and the moving blade row, and the internal energy of the working fluid is converte...

AI Technical Summary

Problems solved by technology

In addition, due to the above-mentioned variation in the width dimension H of the gap flow path 104 and the swirling flow, an uneven pressure distribution P is generated in the circumferential direction of the gap flow path 102 .

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