Turbomachine Sealing System Static Tip Vortex Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In axial flow machines, leakage flows through sealing gaps between rotating blading and housing lead to mixing losses due to different orientations and speeds of main and leakage flows, reducing efficiency, as existing sealing systems often form vortices with opposite rotation direction to the main flow, causing high-loss mixing.
Innovation Solution
A sealing system incorporating a static sealing tip that influences the flow through the gap, reducing flow losses and forming vortices with the same rotation direction as the main flow, thereby minimizing disruption and enhancing efficiency by reducing low-loss mixing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a conventional sealing system without a static sealing tip is used, then the structure is simpler, but vortices with opposite rotation direction to the main flow are formed, causing high-loss mixing and reducing efficiency
Solution Approach 1:
A static sealing tip is introduced as an intermediary element between the rotating blading and the housing. This sealing tip acts as a mediator that modifies the flow characteristics at the seal interface, generating vortices with rotation direction aligned to the main flow, thereby reducing mixing losses without requiring complete redesign of the sealing system
Solution Approach 2:
The invention converts the harmful effect of vortex formation (which normally causes high-loss mixing) into a beneficial effect. By carefully designing the static sealing tip geometry, the vortices generated at the seal interface are made to rotate in the same direction as the main flow, transforming what would be a loss mechanism into a low-loss mixing scenario that maintains or improves efficiency
2Loss of substance
If the radial gap above the sealing fins is minimized, then leakage flows through the cavities are reduced, but the sealing system becomes more sensitive to manufacturing tolerances and wear
Solution Approach 1:
The invention changes the geometric parameters of the sealing interface by introducing a static sealing tip with specific profile characteristics. This modifies the flow path and pressure distribution in the sealing gap, enabling effective leakage control with more relaxed gap dimensions compared to conventional systems
3Loss of energy
If a static sealing tip is added to the sealing system, then flow losses are reduced and vortex rotation is aligned with main flow, but the device complexity increases
Solution Approach 1:
Instead of modifying the entire sealing system, the invention applies a localized solution by adding a static sealing tip only at the critical seal interface where the rotating blading meets the housing. This localized modification achieves flow loss reduction and vortex control without requiring complex changes throughout the entire sealing system
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 proposed sealing system effectively reduces leakage and mixing losses, improving the efficiency of axial flow machines by aligning the vortex rotation with the main flow direction, resulting in low-loss mixing and increased turbomachine performance.
Implementation Method 1
a possible formation of vortices downstream of the static sealing tip can be influenced by the static sealing tip. The gap flow between the static sealing tip and the shroud can cause a vortex or vortex area downstream, the direction of rotation of which has primarily the same flow direction as the adjacent main flow.
Data Source
Figure 1
Figure 2
Figure 3~5b
AI summary
The present invention relates to a sealing system (100) for an axial turbomachine, in particular for a gas turbine, comprising an impeller (3) with a radially outwardly arranged shroud (4) and a housing (30) surrounding the impeller (3), wherein a gap (6) is arranged between the shroud (4) and the housing (30), and wherein the gap (6) is limited by a seal (12) connected to the housing (30) and at least one sealing tip (5) arranged on the shroud (4), opposite the seal (12), to reduce flow losses through the gap (6). At the downstream end region of the seal (12), a further static sealing tip (20) connected to the housing (30) is arranged to influence the flow through the gap and/or to influence the flow downstream of the static sealing tip (20).Furthermore, the present invention relates to an axial turbomachine, in particular a gas turbine, with at least one low-pressure turbine stage, wherein the low-pressure turbine stage comprises a sealing system (100) according to the invention.