Variable-Pitch Turbine Distributor Blade Control
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Solution Overview
Problem
Current radial turbine solutions for aircraft air conditioning systems fail to efficiently modify the injection cross section over a wide range of flow rates while maintaining performance and reliability, leading to issues such as restricted air intake, secondary flows, and mechanical inefficiencies.
Innovation Solution
A distributor for a radial turbine with variable-pitch blades mounted on pivot shafts that can rotate and translate radially, allowing for simultaneous control of blade angle and position to modify the air stream passage cross section, optimizing the expansion stage efficiency across varying flow rates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the air passage cross section is modified by axial translational movement of the casing, then the injection cross section is increased, but restricted air intake occurs at the impeller inlet generating secondary flows and degrading performance
Solution Approach 1:
The distributor blades are made movable with variable pitch angles, allowing the air passage cross section to be modified dynamically. This dynamic adjustment enables optimization of the injection cross section without the detrimental effects of axial translational movement, maintaining reliable performance across different operating conditions.
Solution Approach 2:
The pitch angle of the distributor blades is changed as a parameter to modify the air passage cross section. By varying the blade pitch angle rather than translating the casing axially, the injection cross section can be increased without causing restricted air intake or secondary flows at the impeller inlet.
2Area of stationary object
If the blades of the distributor are pivoted to modify the air passage cross section, then the injection cross section is modified, but mechanical clearance at the distributor reduces efficiency and misalignment or blockage may occur at extreme positions
Solution Approach 1:
The distributor blades are designed with variable pitch capability through controlled pivoting. This dynamic design allows the air passage cross section to be modified while maintaining optimal alignment, reducing mechanical clearance losses and preventing misalignment or blockage at extreme positions compared to fixed-pitch designs.
3Area of stationary object
If the blades of the distributor are pivoted to modify the air passage cross section, then the injection cross section is modified, but misalignment of the impeller inlet occurs at extreme openings or closings
Solution Approach 1:
The variable-pitch blade mechanism is designed to maintain proper alignment of the air passage throughout the range of motion. This dynamic adjustment system ensures that even at extreme openings or closings, the impeller inlet remains properly aligned, avoiding misalignment issues that would occur with simpler pivoting mechanisms.
Data Source
AI summary
The invention relates to a distributor for a turbomachine radial turbine, comprising an annular grill (26) extending about a central axis (10) and comprising a plurality of variable-pitch blades (31), defining between them an air passage cross section, characterized in that each blade is rotatably mounted about a pivot shaft (32), itself moveable in a translation direction, comprising at least one radial component, such that said blade may, upon actuation of control means (40), be pivoted about the pivot shaft and/or moved in relation to the central axis in said translation direction so as to be able to modify the air passage cross section by respectively controlling the metal angle (α3) and the radial spacing (ΔR).