Gas Turbine Seal Runner Cooling via Nested Fluid Passage
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Solution Overview
Problem
Existing gas turbine engine contact seals generate significant heat due to friction, which is challenging to dissipate efficiently, especially at high rotational speeds, and current cooling methods may not effectively manage this heat in compact designs.
Innovation Solution
A seal and bearing assembly with an internally cooled runner assembly featuring a concentric sleeve portion and cooling fluid passage that directs cooling fluid from an inlet along the radially-inner surface of the sleeve portion to a distal end, where it forms a film that travels back towards the bearing inner ring, utilizing integrated oil scoops and nozzles to efficiently distribute and collect cooling fluid, reducing the need for external cooling and allowing for a compact design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If external cooling methods are used for seal runners, then cooling effectiveness is improved, but device complexity and radial thickness increase
Solution Approach 1:
The cooling fluid passage is nested within the runner assembly structure itself, with the passage routed through the runner body and along its radially-inner surface. This integrates the cooling function directly into the seal runner component, eliminating the need for separate external cooling systems while maintaining effective heat dissipation.
Solution Approach 2:
The cooling fluid passage extends into the radial dimension of the runner assembly, routing coolant along the radially-inner surface and through the runner body thickness. This three-dimensional routing allows efficient heat removal from the friction interface without increasing the axial or circumferential dimensions of the seal system.
2Temperature
If cooling fluid passages terminate in outlet apertures, then cooling fluid can exit, but blockage risk increases and cooling efficiency decreases
Solution Approach 1:
The cooling fluid passage is configured as a continuous routed path that extends along the radially-inner surface of the runner and returns toward the bearing inner ring, rather than terminating in discrete apertures. This continuous routing maintains unobstructed fluid flow, preventing blockage accumulation and ensuring consistent cooling performance throughout operation.
3Volume of moving object
If radial thickness of seal runner is reduced, then compact design is achieved, but heat dissipation capability is reduced
Solution Approach 1:
The cooling fluid passage is segmented into multiple sections: an incoming segment, an outgoing segment extending along the radially-inner surface, and a returning segment. This segmentation allows the cooling fluid to traverse the full radial thickness of the runner assembly, maximizing heat extraction from the friction interface despite the compact overall dimensions of the seal runner.
4Productivity
If high rotational speeds are used, then productivity is improved, but heat generation from friction increases
Solution Approach 1:
Cooling fluid acts as an intermediary heat transfer medium, circulating through the routed passage within the runner assembly to absorb heat generated at the friction interface. The fluid continuously removes thermal energy from the seal runner, enabling high rotational speeds to be maintained without excessive temperature rise that would compromise seal performance or component integrity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration effectively manages heat dissipation within the seal runner, maintaining a fluid tight seal and reducing the likelihood of blockages, while allowing for a compact and efficient cooling system that maintains contact with the hot surfaces, thereby enhancing the operational performance of gas turbine engines.
Implementation Method 1
This heat dissipation is most often accomplished using fluid cooling, for example oil from the engine's recirculating oil system which is sprayed onto exposed surfaces of the seal runner and/or the ring.
Implementation Method 2
a cooling fluid passage having an incoming segment, an outgoing segment extending from the incoming segment and axially along the radially-inner surface of the sleeve portion... to cool the radially-inner surface of the seal runner
Data Source
AI summary
A seal and bearing assembly of a gas turbine engine having an engine case with a cooling fluid nozzle located between a bearing outer ring and ring segments, and a rotary shaft for rotation in the engine case around a main axis, the seal and bearing assembly can be assembled by positioning the engine case and the rotary shaft in axial alignment, and axially moving the engine case relative to the rotary shaft including moving the bearing outer ring across the axial location of the runner portion and into an assembled condition. The rotary shaft having mounted thereon a bearing inner ring and a runner assembly having a runner portion, a sleeve portion being concentric and radially internal to the runner portion, and a cooling fluid passage having a radial segment leading from an outgoing segment to a returning segment extending in a direction leading back toward the bearing inner ring.