Low Radius Ratio Fan Blade for Gas Turbine Engine
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Solution Overview
Problem
Existing gas turbine engines face challenges in reducing the radius ratio of fan blades to increase thrust while maintaining performance and reducing mass, complexity, and fuel utilization.
Innovation Solution
Implementing fan blades with a shortened dovetail length and a leading edge hub point radially inward of the attachment pressure face, which reduces the axial dovetail length and rotor disk diameter, thereby decreasing the radius ratio.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If the radius ratio of fan blades is reduced to increase thrust, then thrust increases, but blade root length decreases which may compromise structural integrity
Solution Approach 1:
The patent changes the geometric parameters of the fan blade by reducing the axial dovetail length and repositioning the leading edge hub point radially inward of the attachment pressure face. This parameter modification allows the blade root to be shorter while maintaining structural integrity through optimized stress distribution in the composite material construction.
Solution Approach 2:
The fan blade is constructed using composite materials that provide high strength-to-weight ratio, enabling the blade to maintain structural integrity with a shortened root length. The composite construction allows for tailored fiber orientation and material distribution to handle the reduced blade root geometry while withstanding centrifugal and aerodynamic loads.
2Force
If the axial dovetail length is shortened to reduce radius ratio, then radius ratio decreases and thrust increases, but manufacturing complexity may increase
Solution Approach 1:
The fan blade is manufactured as an integral component with the airfoil, axial dovetail, and leading edge hub point formed as a unified structure. This segmentation approach during manufacturing (forming the entire blade root assembly in one piece) reduces assembly complexity despite the unconventional geometry, as the complex shape is created in a single molding or fabrication process rather than assembled from multiple parts.
3Weight of stationary object
If the rotor disk diameter is reduced to decrease radius ratio, then engine weight and complexity reduce, but blade attachment area decreases
Solution Approach 1:
The patent optimizes the attachment geometry by repositioning the leading edge hub point radially inward of the attachment pressure face and reducing axial dovetail length. This creates a more efficient stress distribution pattern that allows adequate attachment area in a reduced diameter rotor disk, maintaining connection strength despite the smaller overall size.
Data Source
AI summary
Methods, apparatus, systems, and articles of manufacture are disclosed to implement a low radius ratio fan blade for a gas turbine engine. A fan blade for a gas turbine engine includes an airfoil including a leading edge and a trailing edge extending between a root and a tip of the airfoil, a distance between the leading edge and the trailing edge defining a flow path length, a leading edge hub point defined by a radially innermost point of the leading edge, and an axial dovetail including a pair of opposed pressure faces, an axial length of the axial dovetail less than the flow path length, a top edge of the axial dovetail separating the pressure faces from the airfoil, the top edge of the axial dovetail radially outward of the leading edge hub point.