Turbine Intermediate Casing Radial Flange Coaxial Alignment
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Solution Overview
Problem
The existing attachment configuration of turbine casings in turbine engines, particularly the axial and radial offset between high-pressure and low-pressure turbine casings, leads to misalignment and air flow disturbances, impacting efficiency and causing additional issues due to heat-induced deformation.
Innovation Solution
An intermediate casing with a radial annular flange is introduced, allowing the high-pressure and low-pressure turbine casings to be fixed on the same flange, ensuring coaxiality and reducing the risk of air flow disturbances, while also serving as a structural support and attachment point for the turbine, thereby simplifying assembly and reducing mass.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If separate flanges are used for high-pressure and low-pressure turbine casings, then each casing can be independently positioned, but axial and radial offsets cause misalignment and air flow disturbances
Solution Approach 1:
The patent merges the positioning function into a single common flange structure that simultaneously supports both high-pressure and low-pressure turbine casings. This common flange provides unified axial and radial positioning references, ensuring precise coaxiality between the two casings while eliminating the misalignment issues caused by separate flanges.
Solution Approach 2:
The common flange acts as an intermediary element between the high-pressure and low-pressure turbine casings. It provides a stable reference frame that mediates the positioning relationship between the two casings, ensuring their relative axial and radial positions are precisely controlled through integrated positioning features.
2Manufacturing precision
If intermediate casing is removed to fix turbine casings together, then alignment is improved, but the turbine cannot be properly fixed to the aircraft structure
Solution Approach 1:
The common flange is designed with multi-functionality: it simultaneously serves as the attachment interface for both high-pressure and low-pressure turbine casings, provides precise alignment references for ensuring coaxiality, and offers mounting points for fixing the entire turbine assembly to the aircraft structure. This eliminates the need for the intermediate casing while maintaining all necessary functions.
3Manufacturing precision
If precise positioning features are added to ensure coaxiality, then alignment is improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The common flange creates an equipotential reference frame by providing unified axial and radial positioning surfaces that both turbine casings reference to the same geometric features. This ensures that both casings are positioned relative to the same datum surfaces, simplifying the positioning requirements compared to using separate flanges with multiple independent positioning features.
Data Source
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AI summary
The invention relates to a turbine comprising an intermediate casing (56) axially interposed between an upstream high-pressure turbine casing (36) and a downstream low-pressure turbine casing (38) and comprising an external annular ferrule (60) from which an annular flange (54) extends radially, characterized in that the downstream end (36a) of the high-pressure turbine casing (36) and the upstream end (38a) of the low-pressure turbine casing (38) are fixed to the radial annular flange (54) of the intermediate casing (56).