Twisted Rib Casting Core for Gas Turbine Blades
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Solution Overview
Problem
The existing casting processes for gas turbine engine blades with twisted airfoils are limited in designing ribs that remain in optimal orientation for strength and cooling, as they must be parallel to the die separation line, leading to suboptimal structural strength and cooling efficiency due to the parallel nature of formed ribs.
Innovation Solution
A casting core with twisted rib-voids is developed, allowing ribs to be oriented optimally for strength and heat exchange by using a flexible silicone mold or fugitive core die with a twist, enabling ribs to be non-parallel and follow the airfoil's twist, thus improving structural integrity and cooling efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a rigid die set with straight separation line is used for casting, then the manufacturing process is simple and cost-effective, but the ribs must be parallel to the separation line which limits structural optimization for twisted airfoils
Solution Approach 1:
The patent applies the dynamics principle by transitioning from a rigid die set with fixed straight separation line to a flexible silicone mold that can be twisted into the desired airfoil configuration. This allows the separation line to dynamically follow the twisted geometry of the airfoil, enabling ribs to be oriented optimally for strength while maintaining the simplicity of the casting process. The flexible mold captures the complex twisted geometry without requiring complex die sets.
Solution Approach 2:
The patent applies parameter changes by altering the geometry parameter of the separation line from straight to twisted, matching the airfoil's twist. By changing the orientation parameter of the ribs relative to the separation line, the design allows ribs to be non-parallel, enabling optimal structural orientation for twisted airfoils while maintaining cost-effective manufacturing through the flexible mold approach.
2Ease of manufacture
If ribs are made parallel to the separation line for ease of casting, then the manufacturing process is simplified, but cooling efficiency is reduced due to suboptimal rib orientation for heat exchange
Solution Approach 1:
The flexible silicone mold allows the separation line to dynamically follow the twisted geometry of the airfoil, enabling ribs to be oriented optimally for heat exchange. The dynamic twisting of the mold during casting creates non-parallel ribs that align with the airfoil's twist, improving cooling efficiency while maintaining manufacturing simplicity.
Solution Approach 2:
The patent applies local quality by optimizing the rib orientation locally at each radial cross-section to match the airfoil's twist at that specific location. Instead of uniform parallel ribs throughout, each rib segment is oriented according to the local twist requirement, maximizing heat exchange efficiency at each position while using the same flexible mold process.
3Ease of manufacture
If parallel ribs are used in twisted airfoils, then the casting process remains simple, but the rib length increases leading to higher weight and reduced centrifugal force resistance
Solution Approach 1:
The flexible silicone mold enables the separation line to dynamically follow the twisted airfoil geometry, creating shorter non-parallel ribs that reduce weight. The dynamic twisting allows ribs to be oriented more efficiently, reducing the length required to provide structural support while maintaining manufacturing simplicity.
Solution Approach 2:
The patent applies asymmetry by using non-parallel ribs that are oriented asymmetrically relative to the airfoil chord line at different radial positions. This asymmetric orientation allows for more efficient structural use, reducing rib length and weight while maintaining strength, all achieved through the flexible mold casting process.
Data Source
AI summary
A casting core (200) for a twisted gas turbine engine blade, including: an airfoil portion (202) having: an airfoil base end (208), an airfoil tip end (210), a concave side exterior surface (212), a convex side exterior surface (214), a leading edge (204), and a trailing edge (206). The airfoil portion is twisted in a radial direction from the airfoil base end to the airfoil tip end. The airfoil portion includes a first void (220) between the concave side exterior surface and the convex side exterior surface and extending radially to define the shape of a rib of an airfoil to be cast around the core. A first leading edge surface and a first trailing edge surface of the void are twisted from the airfoil base end to the airfoil tip end.