Variable Rim Width Turbine Blade Root for Lighter Rotor Disks
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Solution Overview
Problem
Mechanically inefficient blade attachments in gas turbine engines increase rotor weight, limiting maximum rotational speed and work capacity, especially in compact rotor assemblies.
Innovation Solution
A rotor assembly with a disk and blade featuring a variable rim width profile, where the root and disk widths vary to optimize stress distribution, reducing excess weight and enhancing mechanical efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If blade attachment is made mechanically efficient, then rotor weight is reduced, but blade attachment strength must be maintained
Solution Approach 1:
The patent applies local quality by varying the rim width at different radial positions. The rim width is increased at the blade attachment region (near the root) to provide enhanced strength and stiffness where stresses are highest, while the rim width decreases toward the outer periphery to reduce weight where stresses are lower. This creates an optimized weight distribution that concentrates material where mechanically necessary.
Solution Approach 2:
The patent changes the geometric parameter of rim width from a constant value to a variable profile. Specifically, the rim width is defined as a function of radial position, with maximum width at the attachment region and minimum width at the outer periphery. This parameter variation allows the structure to achieve optimal strength-to-weight ratio throughout the rotor assembly.
2Power
If additional blade and disk weight is added to achieve target work capacity, then work capacity increases, but rotor assembly size increases radially
Solution Approach 1:
The variable rim width profile concentrates material locally at the blade attachment region where it is most needed for strength and work capacity, rather than uniformly distributing weight throughout the rotor. This allows the rotor to achieve target work capacity with reduced overall radial size, as material is optimized at critical stress locations rather than uniformly distributed.
Solution Approach 2:
By changing the rim width parameter from constant to variable, the design achieves higher work capacity for a given radial envelope. The optimized profile allows the rotor to maintain structural integrity and work capacity without requiring increased radial dimensions, thereby achieving compact design with sufficient power output.
Data Source
AI summary
A rotor assembly includes a disk and a blade. The disk is rotatable about an axis that includes a plurality of slots distributed circumferentially along an outer periphery of the disk. The blade includes an airfoil and a root extending radially inward from the airfoil that is received in one of the slots. The disk and the root have an axial widths that define a variable rim width profile. The variable rim width profile includes a minimum rim width disposed radially outward from a bottom lobe of the root.