Gas Turbine Vane Throat Area Calculation Method
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Solution Overview
Problem
Existing methods for calculating the throat area in gas turbine engines are inadequate as they assume axi-symmetric flow paths and ignore undulations or end wall contouring, leading to inaccurate calculations.
Innovation Solution
A method that involves outlining the boundary of the throat area using CAD models, selecting and measuring inspection points on the outer and inner diameter portions, and radially dividing the area into sections such as trapezoidal or triangular shapes to accurately calculate the throat area, while accounting for error values and adjusting based on the trailing edge location.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional gauge-based methods are used to calculate throat area, then the calculation process is simple, but the accuracy is poor due to ignoring undulations and end wall contouring
Solution Approach 1:
The throat area calculation is divided into multiple discrete measurement sections around the circumference. Inspection points are segmented into different radial positions (inner diameter, outer diameter, mid-span) and angular positions. This segmentation allows the method to capture local variations in the flow path geometry, including undulations and contouring, thereby improving measurement accuracy while maintaining a systematic and manageable measurement process.
Solution Approach 2:
The invention transitions from traditional two-dimensional gauge measurements to a three-dimensional measurement approach by incorporating radial depth information. Multiple inspection points are measured at different radial positions (inner diameter, mid-span, outer diameter) to capture the full three-dimensional geometry of the flow path. This dimensional expansion enables accurate representation of complex flow path features such as end wall contouring and platform undulations.
2Ease of manufacture
If axi-symmetric flow path assumptions are made, then the calculation is easier, but the results are inaccurate for engines with undulations and contouring
Solution Approach 1:
The invention explicitly accounts for asymmetric flow path geometries by measuring and calculating throat area based on actual inspection points rather than assuming axi-symmetric conditions. The method captures asymmetric features such as end wall contouring, platform undulations, and non-uniform gap distributions between vanes. This asymmetric approach maintains calculation feasibility while significantly improving accuracy for modern engine designs with complex flow path geometries.
3Measurement precision
If more inspection points are measured to account for undulations, then the accuracy improves, but the measurement time and complexity increase
Solution Approach 1:
The invention uses a selective measurement approach where inspection points are placed at critical locations that provide sufficient information for accurate throat area calculation without requiring complete circumferential measurement at every radial position. The method identifies key measurement locations (such as peak and trough locations of undulations, leading and trailing edges) and focuses measurement efforts there, achieving high accuracy with reduced measurement time compared to exhaustive full-circumference measurement.
Data Source
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AI summary
A method of calculating a throat area (66) of a section of a machinery includes outlining a boundary (68) of the throat area (66) of the section, selecting a plurality of inspection points (OD1-N, ID1-N, SS1-N, PS1-N) along the boundary (68) of the throat area (66), dividing the throat area (66) into a plurality of sections (S1-S8), calculating an individual area of each of the plurality of sections (S1-S8) and summing the individual areas of each of the plurality of sections (S1-S8) to calculate the throat area (66).