Turbomachine Guide Vane Segment Detuning Vibrations
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Solution Overview
Problem
Turbomachines, particularly gas turbines, experience undesired vibrations due to resonant frequencies that existing technologies fail to effectively mitigate through frictional dissipation methods.
Innovation Solution
The implementation of guide vane segments with an inner ring segment and strategically placed impulse bodies in cavities near the trailing edges of guide vanes, allowing for impact contact and detuning of natural frequencies, reduces vibrations by concentrating pulse bodies in the detuning areas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If frictional dissipation methods are used to reduce vibrations, then energy is dissipated through friction, but the method fails to effectively mitigate resonant frequencies in turbomachines
Solution Approach 1:
The patent applies mechanical vibration through impulse bodies that impact the guide vanes to create detuning effects. The impulse bodies are arranged to make periodic impact contact with the guide vane surfaces, generating controlled vibrations that counteract the harmful resonant frequencies through frequency detuning rather than frictional dissipation.
Solution Approach 2:
The patent changes the physical parameters of the system by introducing impulse bodies with specific masses, materials, and positions. These parameter changes modify the natural frequencies and mode shapes of the guide vanes, effectively detuning them from resonant conditions and reducing vibration amplitudes without relying on frictional dissipation.
2Object-affected harmful factors
If impulse bodies are arranged on guide vanes for impact contact, then natural frequencies are detuned, but the arrangement must be optimized to concentrate pulse bodies in detuning areas
Solution Approach 1:
The patent applies local quality by concentrating impulse bodies in specific detuning areas on the guide vanes rather than uniform distribution. The impulse bodies are positioned in regions that maximize their detuning effect on the airfoil modes, such as near the leading edges or at specific spanwise locations where they most effectively alter the mode shapes and natural frequencies.
Solution Approach 2:
The patent segments the guide vane structure by dividing it into regions with and without impulse bodies. The detuning areas are identified and segmented as distinct zones where impulse bodies are concentrated, allowing for optimized vibration control while simplifying the overall arrangement by not requiring impulse bodies throughout the entire guide vane structure.
3Use of energy by moving object
If multiple guide vane segments are arranged to form a guide grid, then flow deflection and energy conversion are achieved, but sealing between segments is required to limit flow channels
Solution Approach 1:
The patent merges the sealing function with the inner ring segment structure itself. The inner ring segments are designed with integrated sealing features that combine the structural support function with the flow sealing function, eliminating the need for separate sealing components and simplifying the overall assembly while maintaining effective flow channel limitation.
Solution Approach 2:
The patent employs asymmetric sealing plate designs where the sealing plates have different geometries on opposite sides to accommodate the specific flow patterns and pressure distributions in the turbine stage. This asymmetric arrangement allows for effective sealing while optimizing the flow deflection and energy conversion characteristics of each guide vane segment.
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
This configuration significantly reduces airfoil modes and vibrations in turbomachines by effectively detuning natural frequencies through elastic impact contacts, enhancing the operational behavior of gas turbines.
Implementation Method 1
impulse bodies with movement clearance for impact contact... through elastic impact contacts
Data Source
Figure 1~2
AI summary
The present invention relates to a guide vane segment for a turbomachine stage, comprising an inner ring segment (10) and several guide vanes (20) arranged on the inner ring segment; wherein a detuning area (V) of the inner ring segment extends axially from an exit edge (21) of at least one guide vane (20), in particular from at least 50% of the guide vanes (50), towards an entry edge (22) of the guide vane (20) over a maximum of 50% of a width (B) of the inner ring segment (10) and/or a maximum of 5 mm and/or circumferentially on both sides over a maximum of 25% of a distance (A) between adjacent guide vanes (20), on and/or in which at least one cavity (112) is arranged, in which at least one impulse body (100) with clearance for impact contact is arranged.