Casing structure for stabilizing flow in a fluid-flow machine
AssigneeRolls-Royce Deutschland Ltd & Co KG
InventorsCarsten Clemen, Henner Schrapp
Life of this patent
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Abstract
A casing (2) includes at least one casing structure (casing treatment) for stabilizing a flow in an area of blade tips of rotor blades (4) in a fluid-flow machine, with the casing structure (casing treatment) being provided in at least one stage on an inner circumference of the casing (2). To provide a casing which improves compressor stability, is simply designed, features low weight and operates reliably without heating-up fluid in the fluid-flow machine, the casing structure is designed as a duct (20) which includes a first end (21) and a second end (22), with the first end (21) issuing into the interior of the casing (2) in the area of the blade tips of a rotor blade row and with the second end (22) being closed.
Claims18
A fluid-flow machine casing, comprising:
- at least one casing structure for stabilizing flow in an area of blade tips of rotor blades of the fluid-flow machine, the casing structure being provided in at least one stage on an inner circumference of the casing, wherein the casing structure is configured as a duct, which includes a first end and a second end, the first end issuing into an interior of the casing in the area of the blade tips of a rotor blade row and the second end being closed;
- a mechanism for speed-dependable adjusting a length l of the duct at the second end in a continuous range between a minimum length lmin and a maximum length lmax.
A method for stabilizing flow in an area of blade tips of rotor blades in a fluid-flow machine, comprising:
- providing a duct in a casing of the fluid-flow machine, the duct having a first end issuing from an inner circumference of the casing into an interior of the casing in the area of the blade tips of a rotor blade row and a second end being closed;
- moving a static pressure field forming on each rotor blade into the first end of the duct during rotation of the rotor blade and exciting vibrations of a fluid column in the duct;
- producing a standing wave in the duct to form a pulsating mass flow at the first end of the duct;
- adjusting a natural frequency of the fluid column to be speed-dependent by adjusting a length l of the duct.
Dependencies are inferred from the claim text.