Impeller Rear Sealing Assembly for Axial Thrust and Leakage Control
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Solution Overview
Problem
Turbomachines face efficiency reduction and thrust issues due to fluid leakage, which deteriorates impeller and housing durability and affects stable operation, as existing labyrinth seals fail to effectively prevent fluid discharge and reduce thrust.
Innovation Solution
A sealing assembly with a ring-shaped rotation body and extension portion is mounted at the impeller's rear end, forming a low-pressure inner space by sealingly coupling with the impeller and shaft, using a sealing member like an O-ring to minimize fluid leakage and reduce thrust.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a labyrinth seal is provided at the back of the impeller to reduce fluid leakage, then the amount of fluid flowing through the gap between impeller and housing is reduced, but the efficiency of the turbomachine is reduced due to loss of operating fluid
Solution Approach 1:
The sealing assembly divides the space at the back of the impeller into separate regions using a rotation body with extension portions. This segmentation creates distinct high-pressure and low-pressure zones, allowing controlled fluid management that prevents uncontrolled leakage while minimizing energy loss through strategic sealing locations.
Solution Approach 2:
The rotation body acts as an intermediary element between the impeller and the housing. It introduces a new component that actively manages the fluid flow and pressure distribution, serving as a mediator that reduces both fluid leakage and energy loss by controlling the interaction between the impeller and housing surfaces.
2Force
If air passage is formed along the rotary shaft to discharge air toward the inlet, then thrust is reduced, but the loss of operating fluid occurs which reduces efficiency
Solution Approach 1:
The sealing assembly applies local quality by creating different pressure conditions in different locations. The extension portions generate localized low-pressure zones at specific positions around the shaft, allowing thrust reduction through localized suction effects rather than requiring global air discharge that would cause fluid loss.
3Device complexity
If the joint between impeller and shaft is not sealed, then assembly is simple, but fluid leaks from the joint causing thrust increase and efficiency reduction
Solution Approach 1:
The sealing function is merged with the rotational support structure. The rotation body that surrounds and supports the shaft also performs the sealing function through its extension portions, combining structural support and sealing functions into a single integrated component rather than requiring separate sealing elements.
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 sealing assembly effectively reduces axial thrust on the impeller, prevents dry gas seal movement, and maintains low pressure within the inner space, enhancing turbomachine efficiency and stability.
Implementation Method 1
an extension portion extending from the rotation body to the rear end of the impeller to form an inner space between the rotation body and the rear end of the impeller, wherein the extension portion is sealingly coupled with the rear end of the impeller
Implementation Method 2
forming a low-pressure inner space at the back of the impeller, thereby preventing the reduction in efficiency of the turbomachine due to the leakage of an operating fluid while minimizing the thrust applied to the impeller
Data Source
AI summary
A sealing assembly, which is mounted at a rear end of an impeller, and a turbo machine including the sealing assembly is provided, the sealing assembly includes a rotation body having a ring shape that surrounds a shaft coupled with the impeller at the rear end of the impeller; and an extension portion extending from the rotation body to the rear end of the impeller, such that an inner space is formed between the rotation body and the rear end of the impeller, wherein the extension portion is sealingly coupled with the rear end of the impeller.