Composite Fan Blades for Larger Geared Turbine Fans
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Solution Overview
Problem
Conventional gas turbine engines face limitations in fan blade size due to mechanical properties of metal materials, leading to inefficiencies in thrust output and fan pressure ratio, and the transition to composite materials is hindered by high manufacturing costs and complexity.
Innovation Solution
Designing gas turbine engines with composite fan blades that allow for increased fan size and reduced fan blade count, utilizing a reduction gearbox to optimize efficiency, and employing relationships like FLTCF and FLTOR to balance aerodynamics and weight, thereby overcoming manufacturing challenges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If metal materials are used for fan blades, then manufacturing cost and complexity are reduced, but fan blade size is limited and aerodynamic efficiency deteriorates
Solution Approach 1:
The patent applies composite materials (carbon fiber reinforced polymer) to replace traditional metal materials for fan blades. This enables increased fan blade size and improved aerodynamic efficiency while managing manufacturing complexity through specialized composite construction techniques
2Productivity
If fan blade count is reduced, then aerodynamic efficiency and thrust output improve, but structural reliability deteriorates
Solution Approach 1:
The patent changes the material parameters by using composite materials with superior strength-to-weight ratios, enabling reduced fan blade count while maintaining or improving structural reliability. The composite construction allows for optimized blade geometry and reduced weight, improving thrust output
3Stress or pressure
If hub radius is reduced, then fan pressure ratio and aerodynamic efficiency improve, but manufacturing precision requirements increase
Solution Approach 1:
The patent utilizes composite material properties to achieve reduced hub radius while managing manufacturing precision requirements. The composite construction allows for tailored material distribution and structural optimization that facilitates smaller hub radii with controlled manufacturing tolerances
Data Source
AI summary
A gas turbine engine includes: a turbomachine comprising a drive turbine and defining a working gas flowpath and an inlet to the working gas flowpath; a fan having a fan blade formed of a composite material, the fan blade defining a leading edge fan radius RFan_LE and a trailing edge fan radius RFan_TE, and the fan defining a leading edge hub radius RHub_LE and a trailing edge hub radius RHub_TE, the gas turbine engine defining a bypass ratio during operation of the gas turbine engine in a cruise operating mode; and a reduction gearbox mechanically coupling the drive turbine of the turbomachine to the fan; wherein the gas turbine engine defines a Fan Leading Edge to Trailing Edge Compression Factor (FLTCF) greater than or equal to 1.05 and less than or equal to 1.8.