Stator Vane Gap Layout for Turbine Rotor Vibration Balance
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Solution Overview
Problem
Turbine engines experience unbalanced forces and moments due to zero or one nodal diameter system responses in rotor-stator assemblies, leading to vibrations that propagate through the stator assembly, turbine engine frame, and aircraft structures, compromising aerodynamic and acoustic performance.
Innovation Solution
Implementing a stator assembly with at least one pair of opposing non-uniform gaps between adjacent stator vanes, separated by 180°, to eliminate or prevent unbalanced forces and moments by balancing the vibrational response.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If uniform spacing between stator vanes is used, then manufacturing is simplified, but unbalanced forces and moments occur due to zero or one nodal diameter system responses
Solution Approach 1:
The patent applies asymmetry by introducing non-uniform spacing between stator vanes, specifically creating different gap sizes at opposing locations around the stator assembly. This asymmetric configuration disrupts the periodicity that causes nodal diameter system responses, thereby eliminating unbalanced forces and moments while maintaining manufacturing feasibility through standardized gap adjustment techniques
2Object-affected harmful factors
If non-uniform gaps are introduced to balance vibrational response, then unbalanced forces are reduced, but stator assembly complexity increases
Solution Approach 1:
The patent applies local quality by introducing non-uniform gaps only at specific opposing locations around the stator assembly rather than throughout the entire structure. This localized modification allows targeted correction of unbalanced forces at critical locations while maintaining uniform spacing elsewhere, thereby reducing overall system complexity compared to complete non-uniform spacing
3Device complexity
If stator vanes are spaced uniformly, then structural simplicity is maintained, but aerodynamic and acoustic performance deteriorate due to vibrations
Solution Approach 1:
The patent introduces asymmetric non-uniform spacing at opposing stator vane locations to disrupt the periodic wake structures that cause harmful vibrations. This asymmetric configuration eliminates resonant interactions between rotor blades and stator vanes, thereby improving aerodynamic efficiency and acoustic characteristics while preserving overall structural simplicity
Data Source
AI summary
A rotor system for a turbine engine. The rotor system includes a rotor assembly and a stator assembly. The rotor assembly includes a plurality of rotor blades that rotate. The stator assembly includes a plurality of stator vanes arranged circumferentially about the stator assembly and includes at least one pair of non-uniform gaps between adjacent stator vanes. The plurality of stator vanes includes a first group of stator vanes having a first non-uniform gap between adjacent stator vanes, a second group of stator vanes having a second non-uniform gap between adjacent stator vanes, and a third group of stator vanes having a uniform spacing between adjacent stator vanes. The first non-uniform gap is positioned 180° from the second non-uniform gap. The plurality of rotor blades directs air through the plurality of stator vanes.