Turboprop Blade Positioning Device for Wear Reduction
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Solution Overview
Problem
Existing turboprop blade orientation devices suffer from rapid degradation of rotary joints due to quasi-permanent stresses and risk of fluid coking caused by high temperatures, leading to reduced service life and maintenance challenges.
Innovation Solution
The blade orientation device is positioned between the external turbine surface and internal fixed nacelle, maintaining a temperature below 120°C, eliminating the need for rotary joints and ensuring the actuation components are not subjected to rotational movement, thus preventing premature wear and coking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the annular cylinder is fixed to the rotating housing with conduits passing through the turbine rotor, then the blade pitch can be adjusted, but the rotating joints are subjected to quasi-permanent stress leading to rapid degradation
Solution Approach 1:
The patent extracts the actuation system from the rotating environment by positioning the actuator and supply conduits in the stationary housing, separating the pitch adjustment function from the rotating propeller assembly. This eliminates the rotating joints that were previously necessary to connect the actuation system to the moving blades, thereby resolving the reliability issue while preserving adaptability.
Solution Approach 2:
Instead of fixing the actuator to the rotating housing as in prior art, the patent inverts the approach by fixing the actuator to the stationary housing and allowing the propeller to rotate independently. This fundamental repositioning of the actuation system eliminates the reference frame change problem and removes the need for rotary seals.
2Adaptability or versatility
If the conduits pass through the turbine rotor, then the actuation fluid can reach the rotating components, but the high-temperature environment causes coking of the fluid
Solution Approach 1:
The patent extracts the actuation fluid supply system from the high-temperature turbine environment by routing conduits through the stationary housing rather than through the rotating turbine rotor. This physical separation removes the actuation fluid from exposure to temperatures exceeding its thermal stability threshold, preventing coking while maintaining fluid delivery capability.
3Adaptability or versatility
If the orientation device is positioned inside the turbine, then it can control the blade pitch, but it becomes inaccessible for maintenance operations
Solution Approach 1:
The patent extracts the orientation device from the turbine interior by positioning it in the stationary housing, making it externally accessible for maintenance while preserving its blade pitch control function. This repositioning allows technicians to service the device without disassembling the turbine assembly.
Solution Approach 2:
The patent introduces the stationary housing as an intermediary space that houses the actuation system components. This intermediary structure provides both functional capability and maintenance accessibility, serving as a buffer zone between the high-temperature turbine environment and the actuation system.
4Device complexity
If rotary seals are used to seal the conduits passing from rotating to fixed reference frame, then the system can accommodate both rotating and stationary components, but the rotary seals are subject to rapid degradation
Solution Approach 1:
The patent extracts the actuation system from the rotating reference frame and positions it entirely in the stationary housing. This eliminates the need for rotary seals that would be required to connect rotating and stationary components, as the actuation fluid conduits now remain entirely within the stationary reference frame.
Solution Approach 2:
Instead of using rotary seals to connect rotating and stationary reference frames, the patent inverts the approach by keeping the actuation system in the stationary reference frame and allowing the propeller to rotate independently. This eliminates the reference frame transition problem that necessitates rotary seals.
Data Source
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AI summary
The invention relates to a turboprop provided with a blade-positioning device. The invention relates in particular to a turboprop (1) comprising: a stationary nacelle (2), a rotary nacelle (3a) comprising a plurality of blade (5) roots (4), a turbine (6), said stationary (2) and rotary nacelles (3) and said turbine (6) being coaxial on a longitudinal axis x, a blade (5) positioning device (7a) comprising for each blade (5) a means (8) for transforming movement suitable for transforming a translation movement into a rotation movement, each one of said means (8) for transforming movement being secured to said rotary nacelle (3) and being suitable for pivoting a blade (5). Said positioning device (7a) is placed between the inner surface (S2) of said stationary nacelle (2) and the outer surface (S6) of said turbine (6), said positioning device (7a) comprising at least one member (9) comprising a body (10) secured to said stationary nacelle (2) and a rod (11) suitable for sliding along an axis substantially parallel to said longitudinal axis x. The turboprop according to the invention can be used specifically in turboprops provided with two unshrouded counter-rotating propellers.