Alternating Rotor Blade Stages for Gas Turbine Symmetry
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Solution Overview
Problem
Gas turbine engines with counter-rotating compressors and turbines face issues due to non-symmetric rotor blade configurations, leading to thermal expansion and centrifugal force-related problems.
Innovation Solution
A method for assembling gas turbine engines involves installing alternatingly spaced rotor blade stages with ring members and outer drum assemblies to ensure symmetrical shape and secure attachment, using a tongue and groove attachment interface and a rotating outer drum for clamping.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple stages of rotor blades are installed between adjacent stages of first speed rotor blades, then the gas turbine engine efficiency is increased, but the rotor blade configuration becomes non-symmetric leading to thermal expansion and centrifugal force issues
Solution Approach 1:
The patent applies asymmetry by installing an odd number of rotor blade stages (e.g., three stages) between adjacent first speed rotor blade stages. This intentional asymmetric configuration, combined with alternating circumferential directions of rotation, resolves the symmetry problem while maintaining the efficiency benefits of multiple rotor stages.
2Reliability
If rotor blade stages are assembled with attachment interfaces, then the rotor blades are securely fixed, but the assembly process becomes complex requiring precise fitting and pressing operations
Solution Approach 1:
The patent segments the rotor blade assembly into modular stages, each with standardized attachment interfaces. This segmentation allows for simplified assembly where each stage can be independently assembled and then connected to adjacent stages through standardized fitting and pressing operations, reducing overall assembly complexity while ensuring secure attachment.
3Object-affected harmful factors
If alternatingly spaced rotor blade stages are installed, then the thermal expansion and centrifugal force issues are reduced, but the assembly requires precise positioning and alternating circumferential directions
Solution Approach 1:
The patent applies inversion by alternating the circumferential directions of rotation for adjacent rotor blade stages. Instead of all stages rotating in the same direction, adjacent stages rotate in opposite circumferential directions. This inversion approach balances the thermal expansion and centrifugal force effects while providing clear manufacturing guidance for positioning.
Data Source
AI summary
A method includes installing a first stage assembly including a first ring member and a first stage of rotor blades, the first ring member defining a first end and the first stage of rotor blades defining a second end; installing a second stage assembly including a second ring member and a second stage of rotor blades, the second ring member defining a first end and the second stage of rotor blades defining a second end, wherein installing the second stage assembly includes fitting the first end of the second ring member to the second end of the first stage of rotor blades to form a first attachment interface; and pressing the second stage assembly against the first stage assembly to fix the first attachment interface.