Adjustable Guide Vanes with Partial Slots for Rotating Stall Reduction
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Solution Overview
Problem
Rotating stall in turbomachine blades leads to vibrations and reduced service life, with potential thermal damage due to non-synchronous oscillations and resonance with periodic excitations matching blades' natural vibrations.
Innovation Solution
A blade wheel design with adjustable guide vanes featuring partial gaps adjacent to flow path boundaries, allowing for varying stagger angles and partial gap configurations across blocks of blades to alter aerodynamic load and reduce rotating separation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If guide vanes are made adjustable with partial gaps to vary aerodynamic load, then rotating stall is reduced and blade service life is extended, but device complexity increases
Solution Approach 1:
The guide vanes are divided into multiple segments along their axial length, with each segment capable of independent adjustment. This segmentation allows different axial positions to have different stagger angles, creating varying aerodynamic loads that disrupt rotating stall patterns while maintaining a manageable structural complexity through modular design
Solution Approach 2:
The guide vanes are designed with adjustable stagger angles that can be dynamically modified during operation. This dynamic capability allows the aerodynamic load distribution to be changed to prevent rotating stall, transforming a static structure into a dynamically adaptable one that responds to operational conditions
2Reliability
If partial gaps are formed in guide vanes to enable stagger angle adjustment, then rotating separation is reduced, but manufacturing precision requirements increase
Solution Approach 1:
By segmenting the guide vanes into multiple adjustable sections, the partial gaps are created in a controlled, modular manner. This segmentation makes the gap formation process more manageable and less prone to manufacturing errors compared to creating continuous gaps, as each segment can be precisely positioned independently
Solution Approach 2:
The partial gaps are formed locally at specific axial positions rather than uniformly across the entire guide vane. This local formation approach allows for precise control of gap dimensions and positions, reducing the overall manufacturing precision burden by concentrating precision requirements to specific critical areas rather than the entire structure
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 design effectively reduces vibrations and prevents rotating stall by introducing a changing aerodynamic load, thereby enhancing the service life and thermal resilience of turbomachine blades.
Implementation Method 1
The invention is based on the idea of preventing or reducing the occurrence of rotating separation by introducing a varying aerodynamic load acting on the blades. The flow in the individual blocks is varied by the blade blocks provided according to the invention, which form different partial gaps to define the flow path.
Data Source
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AI summary
The invention relates to a paddle wheel of a turbomachine, comprising a plurality of guide vanes (56-59, 76-77) forming a row of vanes and designed to extend in a flow path (8) of the axial turbomachine, which is bounded radially outside by an outer flow path boundary (410) and radially inside by an inner flow path boundary (950), wherein the guide vanes (56-59, 76-77) are adjustable in their staggered angle. The guide vanes (56-59, 76-77) have first partial slots (81, 811-816) facing the outer flow path boundary (410) and/or second partial slots (82) facing the inner flow path boundary (950).It is provided that the majority of guide vanes (56-59, 76-77) form N blocks (Bj, Bk) of vanes with N ≥ 2, wherein the guide vanes (56-59, 76-77) of a block (Bj, Bk) each have partial slots (81, 811-816, 82) of the same type, and the guide vanes (56-59, 76-77) of at least two adjacent blocks (Bj, Bk) have partial slots (81, 811-816, 82) of different types.