Axial Compressor Vane with Spanwise Varying Leading Edge Angles
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Solution Overview
Problem
Three-dimensional losses in axial flow compressors limit pressure rise capability and compromise efficiency and stall margin, as existing designs often require a trade-off between increasing efficiency and maintaining stall margins.
Innovation Solution
The compressor vane or blade features airfoil sections with varying leading and trailing edge angles, where angles are increased near the hub and casing to reduce flow separation and tip leakage, and customized using 3D CFD code to minimize losses and improve flow ranges, with the leading edge angles being up to 10° and 18° larger near the hub and casing respectively compared to mid-span sections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If conventional compressor blades with uniform leading edge angles are used, then manufacturing is simpler, but three-dimensional losses increase and efficiency decreases
Solution Approach 1:
The patent applies local quality by varying the leading edge blade angles along the span of the airfoil. Specifically, the leading edge blade angle is increased for airfoil sections close to the hub and close to the casing compared to mid-span sections. This localized geometric modification addresses three-dimensional losses in endwall regions without requiring complete redesign of the entire blade, thereby reducing energy losses while maintaining manageable manufacturing complexity.
Solution Approach 2:
The patent implements parameter changes by modifying the leading edge blade angle parameter along the spanwise direction. The leading edge blade angles are made larger for hub-proximal and casing-proximal airfoil sections compared to mid-span sections. This parameter variation optimizes flow attachment and reduces three-dimensional losses, directly addressing the energy loss issue while the changes remain within manufacturable limits.
2Loss of energy
If efficiency is increased through conventional means, then energy loss reduces, but stall margin decreases
Solution Approach 1:
The patent applies local quality by implementing different leading edge blade angles in different spanwise regions. The increased leading edge angles near the hub and casing specifically address flow separation in these problematic regions, reducing aerodynamic losses locally without adversely affecting the overall stall characteristics of the blade. This localized approach allows efficiency improvement while maintaining adequate stall margin.
Solution Approach 2:
The patent segments the blade into different spanwise zones (hub region, mid-span region, casing region) and applies different leading edge blade angle configurations to each zone. This segmentation allows optimization of each region's flow characteristics independently, reducing overall aerodynamic losses while preserving the blade's stall behavior through careful mid-span angle selection.
3Loss of energy
If leading edge angles are increased near hub and casing, then flow separation and tip leakage are reduced, but manufacturing precision requirements increase
Solution Approach 1:
The patent applies local quality by concentrating geometric modifications in specific spanwise regions where flow separation and tip leakage are most problematic (near hub and casing). By localizing the leading edge angle variations to these endwall regions rather than applying uniform changes across the entire blade, the design addresses tip leakage and flow separation effectively while limiting the overall manufacturing complexity to manageable levels.
Solution Approach 2:
The patent applies partial action by modifying only the leading edge blade angles in the hub and casing regions rather than redesigning the entire blade geometry. This partial modification approach targets the specific problem areas (endwall flow separation and tip leakage) without requiring extreme manufacturing precision across the whole blade, thereby reducing energy losses while maintaining reasonable manufacturing requirements.
Data Source
AI summary
A compressor vane or compressor blade is provided. The axial flow compressor includes an axial direction, a radial direction, a compressor hub and a compressor casing. The vane or blade includes an airfoil with airfoil sections having a span, a chamber line and a leading edge at which the chamber line includes a leading edge blade angle with the axial direction of the compressor and a trailing edge at which the chamber line includes a trailing edge blade angle with the axial direction of the compressor. The airfoil sections are stacked at the leading edge on a straight line extending along a radial direction of the compressor from the compressor hub towards a compressor casing and in that the leading edge angles of the airfoil sections vary along the span and are larger for airfoil sections close to the hub and close to the wall than for mid-span airfoil sections.