Dynamic Labyrinth Seal Gap Control in Shrouded Compressors
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Solution Overview
Problem
Existing electrical power generation systems, such as those used in unmanned aerial vehicles (UAVs), face challenges with short mission times due to low energy density batteries and inefficient internal combustion engines at low power levels. Additionally, conventional labyrinth seals in shrouded compressors experience leakage issues due to fixed radial gaps.
Innovation Solution
A dynamic sealing labyrinth seal is introduced, featuring a compression ring with a radially inner surface that mates flush with the shroud, a labyrinth seal on the radially outer surface, a groove within the radially inner surface, and a load ring within the groove. The load ring generates centrifugal force as the compressor rotates, reducing the radial gap between the labyrinth seal and the stationary frame, thereby enhancing sealing efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a fixed radial gap is used in conventional labyrinth seals, then the seal structure is simple and easy to manufacture, but leakage occurs due to the fixed gap unable to adapt to rotational speed changes
Solution Approach 1:
The patent applies the dynamics principle by making the labyrinth seal gap variable rather than fixed. The seal gap changes dynamically with rotational speed, allowing the seal to adapt to different operating conditions. This is achieved through the interaction between the compression ring, load ring, and centrifugal force, which automatically adjusts the radial gap size based on the rotational speed of the compressor assembly.
2Reliability
If a dynamic sealing mechanism is introduced to reduce leakage, then sealing efficiency improves, but the device complexity increases due to additional components
Solution Approach 1:
The patent applies the self-service principle by designing a seal mechanism that automatically adjusts itself based on operating conditions without external control. The centrifugal force generated during rotation automatically acts on the load ring, which in turn adjusts the seal gap size. This self-regulating mechanism eliminates the need for external actuators, sensors, or control systems, thereby reducing overall system complexity while improving sealing efficiency.
3Reliability
If the radial gap is reduced to minimize leakage, then sealing efficiency improves, but compressor efficiency decreases due to increased friction and heat
Solution Approach 1:
The patent applies the parameter changes principle by dynamically varying the seal gap size based on rotational speed. At different operating speeds, the optimal gap size changes, and this mechanism automatically adjusts the gap parameter to match the current operating condition. This prevents energy loss from both excessive leakage (at high speeds) and excessive friction/heat (at low speeds), thereby optimizing compressor efficiency across the entire operating range.
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 dynamic sealing labyrinth seal effectively reduces radial leakage by adjusting the radial gap based on rotational speed, improving the efficiency and reliability of the compressor and extending the mission time of UAVs by providing a more efficient power generation system.
Implementation Method 1
The load ring generates centrifugal force as the compressor rotates, reducing the radial gap between the labyrinth seal and the stationary frame
Data Source
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AI summary
A compression ring (400) for a shrouded compressor including a radially inner surface (424) having one or more areas configured to mate flush with one or more portions of a radially outward surface (222) of a shroud (220) of the shrouded compressor, a radially outer surface (422) located opposite the radially inner surface (424), a labyrinth seal (450) located on the radially outer surface (222), a groove (460) located within the radially inner surface (424), and a load ring (500) located within the groove (460).