Compressor Stator Vane Camber Profile Endwall Flow
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Solution Overview
Problem
Conventional compressor stator vane designs experience inefficiencies due to weak flow near endwalls, leading to tip blockage and potential stall, as the pressure and velocity profiles are weak in these regions, and the existing camber designs do not adequately address these issues.
Innovation Solution
The compressor stator vane features a normalized camber profile that increases beyond 1.4 in the outer span region and includes a leading edge with dihedral angles between −20 and +25 degrees, enhancing endwall flow speed and pressure to reduce tip blockage and increase throttle margin.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional stator vane designs with moderate camber increases (≤1.4) are used, then manufacturing simplicity is maintained, but endwall flow remains weak causing tip blockage and reduced throttle margin
Solution Approach 1:
The patent applies local quality by implementing different camber profiles at different span locations. The endwall regions (inner and outer) have enhanced camber (≥1.4) to strengthen flow, while the midspan region maintains moderate camber (≤1.2). This localized differentiation addresses the specific problem of weak endwall flow without unnecessarily complicating the entire vane design.
Solution Approach 2:
The vane span is segmented into three distinct regions: inner endwall region, midspan region, and outer endwall region. Each region has its own camber characteristics optimized for local flow conditions. This segmentation allows independent optimization of each zone to address the specific flow problems in endwall regions while maintaining simplicity in midspan areas.
2Speed
If increased camber (≥1.4) is applied throughout the entire span, then endwall flow strength is maximized, but manufacturing complexity and cost increase
Solution Approach 1:
Instead of applying high camber uniformly across the entire span, the patent applies enhanced camber (≥1.4) only to the endwall regions (inner and outer) where flow strengthening is most needed. The midspan region maintains moderate camber (≤1.2), reducing manufacturing complexity while still achieving the primary objective of strengthening endwall flow.
3Reliability
If weak flow conditions exist near endwalls, then tip blockage occurs and stall margin decreases, but the root cause is complex three-dimensional flow interaction
Solution Approach 1:
The patent changes the geometric parameters (camber angle and dihedral angle) of the stator vane airfoil to modify the flow field characteristics. By adjusting these parameters, the design strengthens endwall flow and reduces tip blockage, thereby increasing stall margin. This parameter-based approach addresses the complex flow interaction problem through controlled geometric modifications.
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 design improves the stall margin and extends the throttle range by strengthening endwall flow and reducing blockage, with analyses indicating over 5% improvement in throttle margin without compromising design point efficiency.
Implementation Method 1
The compressor rotor blades carry a lift on the body of the airfoil that manifests itself as a higher static pressure on the pressure surface of the airfoil and a lower static pressure on the suction surface of the airfoil
Implementation Method 2
The pressure difference between pressure side and suction side of the airfoil drives flow through the tip gap of the compressor rotor
Implementation Method 3
This tip flow can roll up into a vortex, which tends to collect on the pressure side surface of the circumferentially adjacent blade
Implementation Method 4
The stator vanes must efficiently diffuse the flow and deliver it with proper velocities to the downstream rotors
Implementation Method 5
Flow in the end wall region is complex where boundary layers on the vane and flowpath surfaces come together
Data Source
AI summary
A stator vane for a compressor is described. The stator vane has an airfoil root, an airfoil tip, a leading edge, a trailing edge, an inner span region, a midspan region and an outer span region, wherein the stator vane has a normalized camber profile that increases in the outer span region in a spanwise direction towards the tip and is more than 1.4 in the outer span region.