Turbomachine Fan Blade Optimization
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Solution Overview
Problem
Current jet engine designs face inefficiencies due to excessive fan blades, which increase costs and weight without significant benefits, and reducing blade count compromises aeromechanical stability and propulsion efficiency.
Innovation Solution
Optimizing fan blade count and chord width based on specific relationships between fan diameter, pressure ratio, and corrected fan tip Mach number to enhance aerodynamic and fuel efficiency, while using polymer matrix composite materials with metal leading edges for durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If fan blade count is increased, then propulsion efficiency is improved, but weight and cost increase
Solution Approach 1:
The patent applies parameter changes by optimizing the chord width of fan blades based on specific relationships between fan diameter, pressure ratio, and corrected fan tip Mach number. By adjusting the chord width parameter within defined ranges rather than increasing blade count, the design achieves improved propulsion efficiency while reducing fan weight and cost.
Solution Approach 2:
The patent employs composite materials by using polymer matrix composite materials with metal leading edges for the fan blades. This composite construction provides the necessary structural strength and aerodynamic performance while reducing overall blade weight compared to traditional metal construction, thereby resolving the contradiction between propulsion efficiency and weight reduction.
2Weight of moving object
If fan blade count is reduced, then weight and cost decrease, but aeromechanical stability is compromised
Solution Approach 1:
The patent resolves this contradiction by changing the chord width parameter of individual blades rather than reducing the number of blades. By optimizing chord width within specific ranges derived from fan diameter, pressure ratio, and corrected fan tip Mach number, the design maintains aeromechanical stability while achieving weight reduction through more efficient blade geometry.
Solution Approach 2:
The patent applies local quality by optimizing the chord width of fan blades at specific locations and conditions. Instead of uniform blade design, the chord width is locally optimized based on the specific relationships between fan diameter, pressure ratio, and corrected fan tip Mach number, thereby maintaining stability while reducing overall weight.
3Productivity
If chord width is increased, then aerodynamic efficiency is improved, but manufacturing complexity increases
Solution Approach 1:
The patent resolves this contradiction by establishing specific parameter ranges for chord width based on fan diameter, pressure ratio, and corrected fan tip Mach number. By keeping chord width within these defined ranges rather than maximizing it indefinitely, the design achieves improved aerodynamic efficiency while maintaining manufacturing feasibility and avoiding excessive complexity.
Data Source
AI summary
A gas turbine engine includes an annular casing, a fan disposed inside the annular casing and mounted for rotation about an axial centerline, a core turbine engine drivingly coupled to the fan and comprising a compressor section, a combustion section, and a turbine section arranged in serial flow order, and a variable bleed assembly comprising a variable bleed duct extending between a VB inlet and a VB outlet. The fan includes fan blades that extend radially outwardly toward the annular casing. The fan has an average chord fan width according to a first performance factor. The fan has a quantity of fan blades according to a second performance factor.