Gas Turbine Seal Runner with Internal Cooling
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Solution Overview
Problem
Existing contact seals in gas turbine engines, particularly in high-speed and high-temperature applications, tend to leak during certain operating conditions such as aircraft engine motoring, necessitating an improved sealing solution.
Innovation Solution
A contact seal assembly comprising a carbon seal mounted in a fixed position within a seal housing and an annular seal runner that rotates relative to the carbon seal, featuring a coolant scoop, slingers, and a coolant collector groove to form a fluid-tight seal, with internal cooling passages and oil scoops to manage heat and prevent leakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If prior art contact seals are used in high-speed rotating shafts, then the seal structure is simple, but the seal leaks during certain operating conditions such as aircraft engine motoring
Solution Approach 1:
The seal runner is divided into multiple segments with individual cooling channels, allowing each segment to be independently cooled and sealed. This segmentation enables better control over sealing performance while managing thermal effects that cause leakage.
Solution Approach 2:
Cooling channels are nested within the seal runner structure itself, with coolant passages integrated into the runner body. This nested design provides internal cooling without adding external components, maintaining seal tightness while avoiding increased overall complexity.
2Temperature
If external cooling nozzles are used to cool the seal runner, then the cooling effect is strong, but the device complexity and potential for leakage increase
Solution Approach 1:
The cooling function is merged with the seal runner structure by integrating cooling channels directly into the runner body. This combination eliminates the need for separate external cooling nozzles and their associated mounting hardware, reducing overall system complexity while maintaining effective cooling.
Solution Approach 2:
The seal runner cools itself through internally integrated cooling channels that circulate coolant through the runner structure. This self-cooling mechanism eliminates dependence on external cooling systems and their complex control mechanisms.
3Reliability
If the seal runner is not cooled, then the structure is simpler, but the seal leaks due to heat generation during high-speed rotation
Solution Approach 1:
The cooling channels are designed to continuously circulate coolant through the seal runner during operation, maintaining constant thermal management. This continuous cooling action prevents heat buildup that would compromise sealing performance without requiring intermittent or complex cooling cycles.
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
The solution provides a substantially fluid-tight seal and effective cooling of the seal runner, reducing the risk of leakage and enhancing the reliability of gas turbine engines by maintaining a tight seal and managing heat internally without external cooling nozzles.
Implementation Method 1
slinging at least some of the coolant contacting the portion of the outer surface radially away from the outer surface by all of: a first slinger disposed between a coolant scoop of the seal runner and the contact interface
Implementation Method 2
the fluid passage defining a tortuous fluid flow path through the fluid passage and receiving cooling fluid therein for cooling the seal runner from within
Data Source
AI summary
The contact seal assembly for a shaft of a gas turbine engine includes a carbon seal mounted in a fixed position within a seal housing, and an annular seal runner adapted to be connected to the shaft of the gas turbine engine and rotatable relative to the carbon ring segments. The seal runner is disposed adjacent to and radially inwardly from the carbon ring segments to form a contact interface between the seal runner and the carbon ring segments which forms a substantially fluid tight seal. The seal runner includes a coolant scoop disposed in a cavity defined by the seal housing, a first slinger disposed between the coolant scoop and the contact interface, a second slinger disposed between the first slinger and the contact interface, and a coolant collector groove disposed between the first slinger and the second slinger.