Compressor Rotor Blade Thickening for Resonance Shift
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Solution Overview
Problem
Compressor rotor blades in the second phase face challenges in achieving high aerodynamic efficiency while minimizing resonance problems and extending their useful life, as existing designs often lead to instability and vibrations due to natural frequency stimulation.
Innovation Solution
The blade design features a concave and convex surface profile with a thickening portion midway along its length, shifting resonance frequencies outside the operational range, and an aerodynamic profile defined by closed curves in a Cartesian coordinate system, ensuring reduced friction and increased reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the blade is designed with conventional aerodynamic profile, then high aerodynamic efficiency is achieved, but resonance problems and vibrations occur due to natural frequency stimulation
Solution Approach 1:
The patent applies parameter changes by modifying the blade's geometric parameters, specifically introducing a thickening portion with defined thickness ratios (0.1-0.3 of the blade chord) at specific locations (30-70% from the leading edge). This changes the mass distribution and moment of inertia parameters of the blade, shifting its natural frequencies away from the operating range while preserving the aerodynamic profile's efficiency characteristics.
Solution Approach 2:
The patent introduces a new dimensional feature - the thickening portion - that extends in the radial direction (thickness dimension) while maintaining the aerodynamic shape in the chordwise and spanwise directions. This adds a third dimension to the blade geometry, creating a complex three-dimensional structure that simultaneously achieves aerodynamic efficiency and resonance avoidance.
2Reliability
If the blade geometry is modified to avoid resonance, then reliability is improved, but aerodynamic efficiency may be compromised
Solution Approach 1:
The patent applies local quality by concentrating the mass addition in a specific local region - the thickening portion located at 30-70% of the blade chord from the leading edge. This localized modification affects the blade's natural frequencies without significantly altering the overall aerodynamic profile, allowing the rest of the blade to maintain its optimized shape for high aerodynamic efficiency.
Solution Approach 2:
The patent employs composite construction by combining the original aerodynamic blade profile with an additional thickening portion made of the same or different material. This composite structure allows the blade to have different density and stiffness characteristics in different regions, enabling independent optimization of aerodynamic performance and dynamic characteristics.
3Reliability
If the thickening portion is added to shift resonance frequencies, then vibrations are reduced, but the blade complexity increases
Solution Approach 1:
The patent applies segmentation by dividing the blade into distinct functional zones: the aerodynamic profile portion and the thickening portion. This segmentation allows each zone to be optimized independently - the aerodynamic profile for efficiency and the thickening portion for dynamic stabilization - while simplifying the manufacturing process by treating them as separate features that can be manufactured and assembled or molded as one piece.
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 enhances the compressor's performance and extends the life of its components by preventing resonance issues, allowing for optimized clearances and maintaining high aerodynamic efficiency, thus increasing the turbine's power and compressor reliability.
Implementation Method 1
shifting the resonance frequencies of said blade (10) outside the functioning frequency range of the rotor itself
Implementation Method 2
the geometric characteristics of the blade cause a distribution of the relative velocities in the fluid, consequently influencing the distribution of the limit layers along the walls and, ultimately, losses due to friction
Data Source
Figure 1~2
Figure 3
AI summary
The invention relates to a blade (10) of a rotor of a second phase of a compressor, which can be defined by coordinates of a discreet combination of points, in a Cartesian reference system (X, Y, Z), wherein the axis (Z) is a radial axis intersecting the central axis of the compressor, said blade (10) having a profile which can be identified by means of a series of closed intersection curves between the profile itself and planes (X, Y) lying at distances (Z) from the central axis, said blade (10) also comprising a thickening (30), substantially parallel to a base portion (12) of the blade (10) itself, fixable to said rotor, said thickening (30) being substantially situated midway up the blade (10) and being suitable for shifting the natural resonance frequencies of the blade (10) itself outside a functioning velocity range of said rotor.