Integrated Balancing Flange and Retention Ring for Turbine Engine
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Solution Overview
Problem
The existing balancing systems for turbojet engines, which use annular balancing flanges with mass fixing holes that open into the airflow, result in mass penalties and aerodynamic inefficiencies due to the need for numerous screws, leading to performance losses and drag.
Innovation Solution
The annular balancing flange is positioned inside the inlet cone, isolating the mass fixing holes from the airflow, and is integrated with the blade retention ring to form a single, mass-reduced component that optimizes aerodynamics by eliminating recesses and allowing optional partial balancing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If through-holes are provided in the balancing flange to accommodate balancing masses, then the turbojet engine can be optimally balanced, but the number of balancing screws increases significantly, resulting in mass penalty and aerodynamic inefficiency
Solution Approach 1:
The blade retention ring and balancing flange are merged into a single integrated component. The retention ring, which already exists to secure blades, is designed to also serve as the balancing flange with recesses for balancing masses. This eliminates the need for a separate balancing flange and reduces the number of balancing screws required, as masses can be positioned in the integrated structure without requiring through-holes that penetrate the aerodynamic surface.
Solution Approach 2:
The balancing masses are nested within recesses formed in the retention ring structure itself, rather than requiring through-holes that extend through the entire component. The recesses are strategically positioned to accommodate balancing masses while maintaining the aerodynamic integrity of the outer surface, allowing masses to be contained within the structure without compromising airflow.
2Stability of the object's composition
If balancing screws are installed in through-holes opening into the airflow, then balancing masses can be secured, but aerodynamic profile is degraded due to recesses and drag increases
Solution Approach 1:
The retention ring is designed with differentiated zones: an outer aerodynamic surface that maintains a smooth conical profile for optimal airflow, and inner recesses that provide accommodation for balancing masses. The recesses are positioned such that they do not protrude into the external airflow path, allowing the aerodynamic surface to maintain its intended quality while locally providing mass accommodation where needed for balancing.
Solution Approach 2:
The balancing mass accommodation function is extracted from the aerodynamic surface by creating internal or side recesses in the retention ring structure. This separates the balancing function from the aerodynamic surface, allowing the outer surface to remain smooth and aerodynamically efficient while still providing the necessary mass positioning capability through the extracted recesses.
Data Source
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AI summary
The fan (1) has an annular balancing flange (34) coupled in rotation with a fan disk (4) along a longitudinal rotational axis (2), and including weight fixation holes (24) spaced circumferentially from one another. Balancing weights i.e. balancing screws (26), are fixed on the flange by the holes. The flange is arranged inside an inlet cone (20) in a manner that the holes are isolated from a jet (22) of a turbomachine i.e. jet engine, of an aircraft. A blade retaining ring (16) axially retains fan blades (6) with respect to the disk. The ring and the flange are formed of a single piece.