Gas Turbine Purge Opening Radial Placement
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Solution Overview
Problem
The design of gas turbine engines faces challenges with hot gases ingesting into inner cavities, leading to increased corrosion and reduced efficiency due to the need for large amounts of purge air, which increases fuel consumption and can shorten turbine component life.
Innovation Solution
The method involves strategically placing purge openings in the gas turbine engine to direct bleed air into specific cavities, creating an air barrier that reduces the amount of purge air required to prevent hot gas ingestion, with varying radial locations optimizing sealing effectiveness between radially inner and outer portions of the cavity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If large amounts of purge air are directed into the inner cavity to resist hot gas ingestion, then the sealing effectiveness against hot gas ingestion is improved, but the fuel consumption increases and component efficiency decreases
Solution Approach 1:
The patent applies local quality by differentiating the purge air requirements for different radial portions of the cavity. The radially inner portion and radially outer portion are treated separately with different purge opening configurations, allowing optimized purge air distribution that reduces overall fuel consumption while maintaining sealing effectiveness in both regions
Solution Approach 2:
The patent segments the cavity protection system into multiple purge openings with different radial locations. By dividing the purge air distribution into multiple zones (radially inner and radially outer portions with different purge opening configurations), the system achieves better sealing effectiveness with reduced total purge air requirements compared to a single uniform purge system
2Object-affected harmful factors
If large amounts of purge air are used to prevent hot gas ingestion, then the corrosion of components in the inner cavity is reduced, but the thrust specific fuel consumption increases
Solution Approach 1:
Different radial locations of purge openings provide localized protection against corrosion in specific cavity regions. The radially inner purge openings protect inner components while radially outer purge openings protect outer components, allowing corrosion protection without requiring excessive purge air that would increase fuel consumption
Solution Approach 2:
The segmented purge opening configuration targets corrosion protection to specific areas where hot gas ingestion is most problematic. By segmenting the protection zones, the system reduces total purge air requirements and thereby reduces thrust specific fuel consumption while still providing adequate corrosion resistance
3Device complexity
If uncaptured purge air is allowed to escape, then the device complexity is reduced, but the combustion exit temperatures increase and turbine component life is reduced
Solution Approach 1:
The purge opening configurations are strategically located at specific radial positions to naturally capture and redirect purge air flow paths. This localized positioning creates effective flow patterns that capture purge air without requiring complex additional capture mechanisms, while still preventing temperature increases that would reduce turbine component life
Solution Approach 2:
Multiple purge openings segmented at different radial locations work together to create a distributed purge air capture system. This segmentation allows the system to capture purge air effectively through the distributed opening configuration rather than requiring a single complex capture device, thereby extending turbine component life through improved temperature control
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach reduces the mass flow rate of bleed air needed, enhancing engine efficiency by minimizing fuel consumption and extending turbine component life by effectively sealing hot gases within the cavities.
Implementation Method 1
Purge air is directed into the inner cavity at an interface between the turbine rotor and an associated transition housing to resist this flow of hot gas
Data Source
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AI summary
A method of designing a gas turbine engine (20) includes locating purge openings (118) in fluid communication with a first stage cavity (110). At least one of a cover plate (114) or a rotor disk (68) is positioned adjacent the first stage cavity (110) and radially inward from the purge openings (118). A portion of a rotor blade (64) is positioned radially outward from the purge openings (118). A mass flow rate of cooling air through the purge openings (118) is selected based on a radial location of the purge openings (118) to create an air barrier between a radially inner side of the purge openings (118) and a radially outer side of the purge openings (118).