Generator Seal Assembly Leading Edge Leakage Prevention
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Solution Overview
Problem
Generator seal assemblies face coolant leakage due to reduced seal fluid pressure at the leading edge of coolant side seal ring segments caused by rotor shaft rotation, creating a leak path for coolant.
Innovation Solution
The seal assembly includes a coolant side seal ring with additional radial holes circumferentially distributed near the leading edge, allowing additional seal fluid to enter and increase pressure, preventing coolant leakage by maintaining a higher seal fluid pressure than coolant pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If seal fluid channels extend only partially around the rotor shaft, then the seal assembly is simpler to manufacture, but coolant leaks past the leading edge where seal fluid pressure is depleted
Solution Approach 1:
The seal fluid channel is segmented into multiple independent channels distributed around the rotor shaft circumference. Each channel operates autonomously to provide seal fluid at different locations, ensuring complete coverage including the critical leading edge region where pressure depletion occurs during rotation.
Solution Approach 2:
Additional seal fluid channels are strategically positioned at the leading edge region where seal fluid pressure is most depleted due to rotor shaft rotation. This local enhancement ensures adequate seal fluid pressure is maintained precisely where coolant leakage risk is highest, without requiring increased pressure system-wide.
2Reliability
If seal fluid pressure is increased system-wide to prevent leading edge leakage, then coolant leakage is prevented, but the cost and complexity of the pressure system increases
Solution Approach 1:
Instead of increasing seal fluid pressure system-wide, additional seal fluid channels are localized specifically at the leading edge region where pressure depletion occurs. This targeted approach maintains adequate seal fluid pressure only where needed, avoiding the cost and complexity of modifying the entire pressure system.
Solution Approach 2:
Additional seal fluid channels replicate the function of existing channels but are positioned specifically at the leading edge. These copied channels provide redundant seal fluid supply precisely where the original channels fail to maintain adequate pressure during rotor rotation.
3Stress or pressure
If seal fluid pressure drops below coolant pressure at the leading edge, then the seal assembly operates with lower pressure requirements, but coolant leaks through the seal ring
Solution Approach 1:
The seal fluid channel is divided into multiple segments around the rotor shaft, with additional segments positioned at the leading edge. This segmentation ensures that at least some channels maintain positive pressure relative to coolant at all rotational positions, preventing leakage without requiring the entire system to operate at higher pressure.
Solution Approach 2:
Additional seal fluid channels are positioned upstream at the leading edge to provide seal fluid before the rotor shaft rotation depletes pressure in the main channels. This preliminary action ensures seal fluid pressure is maintained at the critical leakage point before the harmful pressure drop occurs.
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 modified seal assembly effectively prevents coolant leakage without increasing seal fluid pressure, preserving coolant purity and reducing the need for costly modifications, offering a cost-effective and efficient design for generators and other electric machines.
Implementation Method 1
A pressure of the seal fluid is higher than a pressure of the coolant to prevent leakage of the coolant from the frame
Implementation Method 2
a plurality of radial holes circumferentially distributed along the seal fluid channel from the leading edge to the trailing edge through which a seal fluid enters the seal fluid channel
Data Source
AI summary
A generator seal assembly for preventing leakage of coolant in a generator is presented. The seal assembly includes a coolant side seal ring having a plurality of coolant side seal ring segments. The coolant side seal ring segment includes a seal fluid channel and radial holes circumferentially distributed along the seal fluid channel from leading edge to trailing edge through which seal fluid enters the seal fluid channel. Additional radial holes are circumferentially distributed along the seal fluid channel in a region near leading edge. Additional seal fluid enters the seal fluid channel in the region near leading edge through the additional radial holes such that pressure of seal fluid in the region is increased higher than pressure of the coolant to prevent leakage of the coolant in the region near leading edge due to ration of generator shaft.