Circumferential Seal Assembly With Adjustable Seating Forces
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Solution Overview
Problem
Turbine engines face challenges in maintaining effective sealing between compartments at higher shaft speeds and pressures, leading to increased leakage, wear, and heating issues.
Innovation Solution
A circumferential seal assembly comprising a primary sealing ring, a ring-shaped insert, a second sealing ring, and a third sealing ring, which work together to minimize leakage and reduce seating forces across face and radial sealing surfaces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If higher shaft speeds and pressures are used to enhance turbine engine performance, then power and efficiency are improved, but leakage across sealing surfaces increases and wear/heating problems worsen
Solution Approach 1:
The seal ring is divided into multiple segments that can independently move and adjust. Each segment contains channels that allow fluid communication between the high-pressure and low-pressure sides, enabling the segments to self-adjust their position and sealing force based on operating conditions, thereby maintaining effective sealing at higher speeds and pressures.
Solution Approach 2:
The seal segments are designed to be dynamically adjustable rather than fixed. The segments can move radially and rotate to adapt to changing operating conditions, allowing the sealing configuration to optimize itself for different shaft speeds and pressure differentials, thus maintaining reliability under varying high-performance conditions.
2Power
If higher shaft speeds and pressures are used to enhance turbine engine performance, then power and efficiency are improved, but wear and heating along sealing surfaces increase
Solution Approach 1:
The seal incorporates channels that utilize fluid pressure from both the high-pressure and low-pressure sides to create hydrodynamic lifting forces. These forces reduce the contact pressure between seal segments and the rotor surface, minimizing wear and heating while maintaining effective sealing at higher operating speeds and pressures.
Solution Approach 2:
The seal design allows parameters such as contact pressure, fluid flow rate, and segment position to dynamically change in response to operating conditions. By adjusting these parameters, the seal maintains optimal performance across a range of high-speed, high-pressure conditions while minimizing harmful wear and heating effects.
3Device complexity
If traditional seal designs are used, then结构简单性 is maintained, but leakage increases and coolant requirements increase at higher pressures
Solution Approach 1:
The seal is segmented into multiple independent units with integrated channels. This segmentation allows each unit to function autonomously in controlling fluid flow, reducing overall leakage without requiring a complex external coolant system. The segments work together to maintain sealing effectiveness while simplifying the overall structure.
Solution Approach 2:
The seal segments perform multiple functions simultaneously: they provide the primary sealing barrier, control fluid flow through integrated channels, and generate hydrodynamic lifting forces. This multi-functionality reduces leakage effectively while avoiding the need for additional complex coolant delivery systems.
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 effectively minimizes wear and heating along sealing surfaces, reduces contact forces, and eliminates the need for coolant, thereby enhancing the performance and efficiency of turbine engines.
Implementation Method 1
A garter spring is disposed within a groove about an outer circumference of the primary sealing ring and urges the primary sealing ring in a direction of the radial sealing surface
Implementation Method 2
The third sealing ring is biased toward the primary sealing ring via a compression spring
Implementation Method 3
The outward flange and the second sealing ring cooperate to separate the first cavity from the second cavity
Implementation Method 4
The primary sealing ring sealingly engages both a face sealing surface of the housing and a radial sealing surface of the rotatable element
Data Source
Figure 1
Figure 2
Figure 3a~3b
AI summary
A circumferential seal assembly (30) for use between a higher pressure side (36) and a lower pressure side (37) is presented. The seal assembly (30) includes a primary sealing ring (31), a second sealing ring (32), a third sealing ring (33), and an insert (34). The segmented primary sealing ring (31) sealingly engages both a face sealing surface (46) along a housing (35) and a radial sealing surface (45) along a rotatable element (52). The insert (34) is disposed within and directly contacts the housing (35). The second sealing ring (32) is adjacent to the primary sealing ring (31) and sealingly engages both the primary sealing ring (31) and the insert (34). The segmented third sealing ring (33) contacts and sealingly engages the primary sealing ring (31) opposite the housing (35). The insert (34), the second sealing ring (32), and the third sealing ring (33) cooperate to form a first cavity (53) adjacent to the second sealing ring (32) and the third sealing ring (33). The primary sealing ring (31), the second sealing ring (32), the insert (34), and the housing (35) cooperate to form a second cavity (54) adjacent to the primary sealing ring (31). The insert (34) and the second sealing ring (32) separate the first cavity (53) from the second cavity (54).