Radial Impeller Converging Blade Zeroed Internal Diameter
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Solution Overview
Problem
In gas turbine engines, maximizing the exducer area for flow is challenging due to limitations in the shroud outer diameter and minimum hub diameter, which can lead to unfavorable exducer angles and exducer chocking, especially at high rotor speeds.
Innovation Solution
A two-piece rotor impeller with a blade section and a forward section, where the blade section includes a converging blade that converges to a point with a minimized or zeroed internal diameter, directly attached to the rotor shaft, allowing for increased flow area without altering the outer shroud diameter.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the shroud outer diameter and hub diameter are kept within conventional limits, then the structural integrity and manufacturing feasibility are maintained, but the exducer area is limited leading to unfavorable exducer angles and chocking
Solution Approach 1:
The rotor impeller is divided into two separate pieces: a blade section and a forward section. The blade section contains the converging blade that forms the minimized internal diameter, while the forward section attaches to the rotor shaft. This segmentation allows the blade section to be optimized for aerodynamic performance with a zeroed internal diameter without compromising the manufacturability of the overall assembly, as each piece can be manufactured separately and then joined.
2Productivity
If the internal diameter is minimized to a point, then the flow area is maximized and exducer chocking is eliminated, but the structural complexity and manufacturing difficulty increase
Solution Approach 1:
By segmenting the impeller into blade section and forward section, the complex geometry of a zeroed internal diameter converging blade can be concentrated in the blade section, which is optimized for aerodynamic performance. The forward section maintains a simpler structure for easy attachment to the rotor shaft, thereby distributing the complexity rather than concentrating it throughout the entire impeller.
Solution Approach 2:
The complex converging blade geometry that creates the zeroed internal diameter is extracted as a separate blade section from the forward section. This allows the aerodynamic optimization to be isolated in the blade section while the forward section remains simpler and easier to manufacture and assemble.
3Reliability
If a two-piece impeller design is used with direct shaft attachment, then the exducer area is maximized and aerodynamic performance is improved, but the manufacturing processes and assembly requirements become more complex
Solution Approach 1:
The two-piece design segments the impeller into functionally distinct parts: the blade section optimized for aerodynamic performance with the converging blade, and the forward section for shaft attachment. This segmentation allows each part to be manufactured using optimal processes for its specific requirements, and the connection features are designed to facilitate reliable assembly.
Solution Approach 2:
The blade section and forward section are combined through various connection methods (threaded, bolted, brazed, welded, or adhesive connections) to form a complete impeller assembly that achieves the aerodynamic benefits of a zeroed internal diameter while maintaining manufacturing feasibility through modular construction.
Data Source
Figure 1
Figure 2
AI summary
A rotor assembly (201) is provided and includes a two-piece rotor impeller (210) and a rotor shaft (220). The two-piece rotor impeller (210) includes a blade section (211) and a forward section (212), which is connected to the blade section (211). The rotor shaft (220) includes an aft section (221) at which the rotor shaft (220) terminates. The aft section (221) is directly attached to the forward section (212) of the rotor impeller (210). The blade section (211) includes a converging blade (214) configured to converge to a point (P) with a minimized internal diameter (ID).