Compressor Stator Endwall Profile for Secondary Flow Reduction
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Solution Overview
Problem
Existing methods to reduce secondary flows in gas turbine engine compressor stages result in complex and expensive endwall geometries that are not optimally effective.
Innovation Solution
The use of modified axial cross-sectional profiles for endwalls, featuring concave and convex deviations, to influence fluid flow and achieve a more uniform velocity distribution between the leading and trailing edges of vanes, thereby reducing secondary flows and energy losses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If modified endwall geometries are used to reduce secondary flows, then energy losses are reduced, but the endwall geometry becomes complex and expensive to produce
Solution Approach 1:
The invention applies preliminary action by modifying the endwall geometry upstream of the vane leading edge to prevent secondary flow development before it can significantly impact performance. The convex and concave portions are positioned to proactively influence flow patterns, reducing the need for complex downstream modifications.
Solution Approach 2:
The invention applies local quality by introducing specific geometric features (convex portion upstream, concave portion downstream) at localized positions on the endwall rather than uniformly modifying the entire endwall surface. This targeted approach reduces secondary flows where they originate while maintaining simplicity in other areas.
2Reliability
If complex endwall geometries are used to reduce secondary flows, then flow characteristics are improved, but manufacturing cost increases
Solution Approach 1:
By positioning the convex portion upstream of the vane leading edge, the invention prepares the flow in advance, allowing simpler manufacturing approaches to achieve better flow characteristics. The preliminary geometric modification creates favorable flow conditions that reduce the need for complex downstream features.
Solution Approach 2:
The invention improves reliability through localized geometric modifications rather than comprehensive complex geometry. The convex and concave portions are strategically placed to address specific flow issues, achieving reliable flow characteristics while maintaining ease of manufacture in other endwall regions.
3Loss of energy
If existing endwall modification methods are applied, then some secondary flow reduction is achieved, but velocity distribution uniformity between leading and trailing edges is not optimized
Solution Approach 1:
The invention addresses velocity distribution uniformity by applying different geometric modifications at different locations: a convex portion upstream of the leading edge and a concave portion downstream of the trailing edge. This localized approach optimizes velocity distribution across the entire vane span, achieving manufacturing precision that existing uniform methods cannot provide.
Solution Approach 2:
The convex portion positioned upstream performs preliminary flow conditioning before the fluid reaches the vane leading edge. This preliminary action sets up more uniform velocity distribution from the start, which then maintains uniformity through the trailing edge, achieving better manufacturing precision than methods that only modify downstream regions.
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 approach simplifies the manufacturing process while improving flow characteristics, reducing secondary losses, and enhancing the performance and operability of compressor stages by minimizing secondary flow accumulation and flow separation.
Implementation Method 1
The use of modified axial cross-sectional profiles for endwalls, featuring concave and convex deviations, to influence fluid flow and achieve a more uniform velocity distribution between the leading and trailing edges of vanes
Implementation Method 2
During operation, secondary flows can develop on or near such endwalls and produce energy losses
Implementation Method 3
enhancing the performance and operability of compressor stages by minimizing secondary flow accumulation and flow separation
Data Source
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AI summary
A compressor stator (22) comprises a circumferential array of stator vanes (28) and a shroud (24, 26) for supporting the stator vanes (28). The shroud (24, 26) has a circumferentially extending inner endwall (30, 32) exposed to an annular gas path (20) of the compressor (14). The endwall (30, 32) has a circumferentially uniform axial cross-sectional profile (42). The axial cross-sectional profile (42) comprises at least one deviation (48, 50) from a nominal axial cross-sectional profile (44) defining an overall shape of the annular gas path (20). The at least one deviation may comprise a concave deviation (48) and a convex deviation (50).