Turbomachine Inner Ring Indentations for Thermal Deformation Control
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Solution Overview
Problem
Turbomachines face efficiency issues due to thermally induced deformations and leaks caused by thermal stress in inner rings, leading to undesirable widening of gaps and stress peaks, which are not effectively addressed by existing designs.
Innovation Solution
An inner ring with reduced wall thickness indentations, particularly in the radial direction, is designed to improve temperature distribution and reduce thermally induced deformations, featuring a more favorable temperature profile and reduced 'cording effect, thereby enhancing sealing and operational efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the inner ring has uniform wall thickness, then the structural strength is maintained, but thermal stress causes deformations and gap widening
Solution Approach 1:
The patent applies local quality by creating indentations at specific locations on the inner ring where thermal stress concentration occurs. These localized modifications change the thermal and stress distribution only where needed, rather than altering the entire ring structure. The indentations allow for localized thermal expansion accommodation while preserving the overall structural integrity of the inner ring.
2Strength
If reinforcing ribs are added to the inner ring, then structural strength is improved, but thermal stress concentration and deformations increase
Solution Approach 1:
Instead of adding material (reinforcing ribs) to strengthen the inner ring, the patent inverts the approach by removing material through indentations. This negative design approach reduces thermal mass in critical areas, allowing for better thermal stress distribution and reduced concentration effects, while still maintaining adequate structural strength through the overall ring geometry.
3Shape
If slot-shaped recesses are introduced to influence stress distribution, then thermal deformation is reduced, but stress peaks occur at the base of slots
Solution Approach 1:
The patent employs asymmetric indentation designs that are specifically shaped and positioned to match the actual thermal stress distribution patterns in the inner ring. Rather than using symmetric slot-shaped recesses, the asymmetric indentations are tailored to the specific geometry and thermal loading conditions, allowing for more effective stress distribution without creating concentration peaks at recess bases.
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 inner ring design reduces thermally induced movements and deformations, minimizing leaks and improving turbomachine efficiency, fuel consumption, and surge limit, while also reducing weight and flexural rigidity, resulting in a more stable and efficient operation.
Implementation Method 1
the indentation(s) can influence, in particular reduce, a thermally induced movement and/or deformation of the inner ring during operation
Implementation Method 2
As a result of the thermal stress, undesirable, thermally induced deformations of the inner ring can occur, in particular the widening of gaps
Data Source
Figure 1~2
Figure 3~5
Figure 6~7
AI summary
Inner ring (120) for a guide vane ring for attachment to, in particular adjustable, guide vanes (10) of a turbomachine, in particular a compressor or turbine stage of a gas turbine, a guide vane ring for a turbomachine with an inner ring (120), a turbomachine with an inner ring (120) and a method for manufacturing an inner ring (120), wherein the inner ring (120) has several guide vane receptacles (124) arranged circumferentially spaced apart from one another, in particular recesses, each designed to receive a fastening element (11), in particular a fastening pin, of a guide vane (10), wherein the inner ring (120) has at least one recess (126) between at least two adjacent guide vane receptacles (124) with a wall thickness reduced in the radial direction (y) compared to an area adjacent to the recess (126) outside of the recess (126),and wherein the recess (126), with respect to a rotational axis of a turbomachine in a functional installation state of the inner ring (120) in a turbomachine, has a greater extent in the axial direction (x) than in the circumferential direction.