Gas Turbine Front Mount Layout for Core Bending Stiffness
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Solution Overview
Problem
Large gas turbine engines face structural challenges due to increased bending loads and stiffness issues, particularly with larger fan diameters, which can lead to deformation and efficiency losses.
Innovation Solution
The gas turbine engine design incorporates specific relative component positions and configurations, including a first flange connection downstream of the axial midpoint between compressor aerofoils, a gearbox-driven fan with a gear ratio between 3.1 and 4.0, and optimized fan blade and core casing geometries to manage bending loads and improve stiffness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the fan size of a gas turbine engine is increased, then the engine's thrust capability and efficiency are improved, but bending loads on the engine core are deleteriously increased
Solution Approach 1:
The engine core is divided into multiple sections with intermediate support structures, including a rear core support and front core support that are axially spaced apart. This segmentation distributes the bending loads from the large fan across multiple support points rather than concentrating them at a single location, thereby reducing the overall bending moment on the engine core while maintaining the large fan diameter for improved thrust capability.
2Productivity
If the fan diameter is increased, then the engine's propulsive efficiency is improved, but structural stiffness and deformation resistance are worsened
Solution Approach 1:
The engine core casing and support structures utilize composite material construction, combining materials with different mechanical properties to achieve both the necessary structural stiffness and the ability to accommodate thermal expansion. This allows the engine to maintain structural integrity and resist deformation under the increased loads from larger fan diameters while preserving propulsive efficiency.
Data Source
AI summary
A gas turbine engine includes an engine core including: a compressor system including first, lower pressure compressor, and second, higher pressure compressor; and an outer core casing. The engine includes a front mount arranged for connection to a pylon; and a fan located upstream of the engine core. The outer core casing includes a first flange connection that: is arranged to allow separation of the outer core casing at an axial position thereof, and is the first flange connection downstream of an axial position defined by the axial midpoint between the mid-span axial location on trailing edge of the most downstream aerofoil of first compressor and mid-span axial location on leading edge of the most upstream aerofoil of the second compressor. A front mount position ratio of:axialdistancebetweenthefirstflangeconnectionandthefrontmountfirstflangeradiusis equal to or less than 1.18.