Turbomachine Stator Pre-Curved Connecting Surface
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Solution Overview
Problem
In turbomachines, the connecting elements of stator devices can become de-arched or de-curved in hot states, leading to insufficient contact between receiving and connecting surfaces, which compromises sealing and stiffness.
Innovation Solution
A stator device with a rearward connecting surface pre-curved eccentrically in the cold state, which de-arches to a concentric curvature in the hot state, ensuring full contact with the receiving surface and enhanced sealing and stiffness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If circumferentially wide stator devices are used, then the device complexity is reduced, but the connecting surfaces become de-arched in hot states leading to insufficient sealing and stiffness
Solution Approach 1:
The connecting surface is pre-curved in the cold state with a specific curvature that is intentionally different from the final desired curvature in the hot state. This preliminary shaping allows the surface to automatically deform into the correct concentric curvature when heated, ensuring full contact with the receiving surface without requiring active control or adjustment mechanisms.
Solution Approach 2:
The patent exploits the thermal expansion and deformation properties of the connecting element materials. When the stator device is in the hot state, the connecting surfaces undergo thermal deformation that transforms the pre-curved eccentric shape into a concentric curvature, ensuring optimal contact with the receiving surfaces. This thermal effect is deliberately designed to achieve the desired sealing geometry under operating conditions.
2Device complexity
If circumferentially wide stator devices are used, then the device complexity is reduced, but the stiffness with respect to coupled vibration is reduced
Solution Approach 1:
The connecting surfaces are pre-shaped with a specific curvature in the cold state that anticipates the thermal deformation that will occur during operation. This preliminary curvature design ensures that when the stator device is installed and heated, the surfaces automatically transform into a concentric configuration that provides optimal contact area and stiffness for vibration resistance.
Solution Approach 2:
The patent utilizes thermal expansion effects to transform the connecting surface geometry from a pre-curved eccentric shape in the cold state to a concentric shape in the hot state. This thermal transformation ensures full surface contact between connecting and receiving surfaces, maximizing the contact area and thereby increasing the stiffness and vibration resistance of the connection.
3Reliability
If circumferentially narrow stator devices are used, then the sealing effect is improved, but more individual parts are needed increasing device complexity
Solution Approach 1:
The connecting surface is pre-curved in the cold state with a specific curvature that is intentionally different from the final desired curvature in the hot state. This preliminary shaping allows the surface to automatically deform into the correct concentric curvature when heated, ensuring full contact with the receiving surface without requiring active control or adjustment mechanisms.
Solution Approach 2:
The patent exploits the thermal expansion and deformation properties of the connecting element materials. When the stator device is in the hot state, the connecting surfaces undergo thermal deformation that transforms the pre-curved eccentric shape into a concentric curvature, ensuring optimal contact with the receiving surfaces. This thermal effect is deliberately designed to achieve the desired sealing geometry under operating conditions.
4Reliability
If more individual parts are used, then the sealing effect is improved, but the manufacturing efficiency is reduced
Solution Approach 1:
The connecting surface is pre-curved in the cold state with a specific curvature that is intentionally different from the final desired curvature in the hot state. This preliminary shaping allows the surface to automatically deform into the correct concentric curvature when heated, ensuring full contact with the receiving surface without requiring active control or adjustment mechanisms.
Solution Approach 2:
The patent exploits the thermal expansion and deformation properties of the connecting element materials. When the stator device is in the hot state, the connecting surfaces undergo thermal deformation that transforms the pre-curved eccentric shape into a concentric curvature, ensuring optimal contact with the receiving surfaces. This thermal effect is deliberately designed to achieve the desired sealing geometry under operating conditions.
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 achieves a significant improvement in sealing and stiffness of the connection system in hot states, ensuring a robust and low-maintenance connection between the turbine casing and the stator device.
Implementation Method 1
the connecting elements, in particular their connecting surfaces for connection to the receiving surfaces, may happen to become de-arched or de-curved when the turbomachine is in a hot state
Implementation Method 2
the rearward connecting surface being pre-curved in the circumferential direction eccentrically with respect to the rearward receiving surface
Data Source
AI summary
A stator device for disposition within a given turbine casing of a turbomachine, the stator device being provided on its radially outer side with an axially forward connecting element having a radially inward facing forward connecting surface for connection to a forward receiving surface of the turbine casing and an axially rearward connecting element having a radially outward facing rearward connecting surface for connection to a rearward receiving surface of the turbine casing, the rearward connecting surface being pre-curved in the circumferential direction eccentrically with respect to the rearward receiving surface; the rearward connecting element having a rearward rib portion extending substantially linearly away from a platform of the stator device and providing the rearward connecting surface at its radially outer end; and the rib portion being provided at its radially outer end with axially extending projections distributed along the circumferential direction for radially retaining the stator device to the turbine casing.