Hollow Profile Sealing Element for Turbomachine Gap Cooling
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Solution Overview
Problem
In fluid-flow machines, component gaps allow bleed or leakage flows, which are undesirable as they lead to energy loss and can cause overheating due to hot working fluid penetration, and existing sealing methods may fail to prevent fluid ingress during local pressure waves.
Innovation Solution
A sealing element with a hollow profile and spaced inlet and outlet openings is used, creating a pressure gradient that prevents main flow fluid from entering the component gap, even during temporary pressure waves, by ensuring the cooling fluid flow maintains a stable pressure gradient within the sealing element.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If component gaps are made smaller to minimize bleed or leakage flows, then energy loss is reduced, but temperature-induced expansion compensation becomes difficult
Solution Approach 1:
The sealing element is divided into multiple sealing sections along its length, with each section capable of independent deformation. This segmentation allows different portions of the seal to adapt to thermal expansion at various locations while maintaining overall sealing effectiveness, resolving the contradiction between minimizing gaps and accommodating expansion.
Solution Approach 2:
The sealing element incorporates resilient or flexible materials that enable dynamic adaptation to thermal expansion. The seal can deform and adjust its shape in response to temperature changes, maintaining contact with mating surfaces despite expansion, thus preserving both small gap dimensions and expansion compensation capability.
2Reliability
If cooling or sealing fluid is blown out with sufficient positive pressure to prevent working fluid penetration, then sealing effectiveness is improved, but the complexity of pressure control increases
Solution Approach 1:
The sealing element utilizes the existing pressure gradient of the cooling or sealing fluid flow through the component gap to generate the necessary positive pressure for sealing. The fluid dynamics itself creates the sealing action without requiring additional active pressure control mechanisms, maintaining high reliability while minimizing system complexity.
3Reliability
If strip seals are added to assist sealing effect and minimize cooling fluid requirement, then sealing performance is improved, but the device complexity increases
Solution Approach 1:
The sealing element performs multiple functions simultaneously: it provides mechanical sealing through its contact with mating surfaces, maintains pressure gradient through its structure, and guides the cooling or sealing fluid flow. This multi-functionality achieves improved sealing performance without requiring separate dedicated components for each function, thereby limiting the increase in device complexity.
4Temperature
If openings are provided in strip seals for cooling fluid throughput, then cooling effectiveness is improved, but the risk of hot working fluid forced into component gap increases
Solution Approach 1:
The sealing element is positioned and configured to establish the pressure gradient and sealing action before the cooling fluid passes through the component gap. This preliminary sealing action prevents hot working fluid from being forced into the gap during pressure waves, while still allowing cooling fluid to flow through openings for effective cooling.
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
Effectively seals component gaps in fluid-flow machines, preventing fluid ingress and reducing the risk of overheating by maintaining a stable cooling fluid flow and pressure gradient, thus minimizing energy loss and thermal damage.
Implementation Method 1
creating a pressure gradient that prevents main flow fluid from entering the component gap, even during temporary pressure waves, by ensuring the cooling fluid flow maintains a stable pressure gradient within the sealing element
Implementation Method 2
In order to be able to cool the sealing element internally by means of a cooling fluid flow
Data Source
AI summary
A sealing element for sealing a component gap with respect to a flow, in particular for use in a fluid-flow machine, specifically in a turbomachine is provided. In addition a fluid-flow machine is provided including such a sealing element for sealing a component gap. The sealing element includes a hollow profile enclosing a cavity. Arranged in the hollow profile are a first opening and a second opening, which are spaced apart from each other in the longitudinal direction of the hollow profile. The first opening is formed as an inlet opening for a cooling fluid into the cavity of the hollow profile, the second opening is formed as an outlet opening for the cooling fluid from the cavity of the hollow profile. With the sealing element arranged in a fluid-flow machine, the sealing element can consequently be internally cooled by means of the cooling fluid. Furthermore, the sealing element uses the pressure gradient occurring in the flow in the direction of flow to form a stable cooling fluid flow.