Gas Turbine Drum Venting via Axial Retaining Segments
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Solution Overview
Problem
In turbomachines, particularly in twin-spool gas turbine engines, there is a challenge in effectively ventilating the low-pressure turbine blades due to stress concentrations caused by drilling for air passage, which hinders the delivery of ventilation air to blade attachments in one-piece drum configurations.
Innovation Solution
Creating radial or annular passages through the shell ring and axial retaining segments allows communication between the internal drum volume and blade cavities, enabling air to reach and ventilate the blade roots without compromising the structural integrity of the disk.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If drilling is made in the shell ring to create air passage to blade cavities, then ventilation air can reach blade attachments, but stress concentrations are caused which compromise structural integrity
Solution Approach 1:
The axial retaining segments are designed with internal passages that segment the air flow path. Instead of drilling through the entire shell ring, the segments themselves contain channels that allow air to pass from the drum interior to the blade cavities, distributing the structural load and avoiding stress concentrations.
Solution Approach 2:
The axial retaining segments serve as intermediary elements between the shell ring and the blade cavities. These segments incorporate internal passages that mediate the air flow, allowing ventilation air to reach blade attachments without requiring direct drilling through the shell ring, thus preserving structural integrity.
2Weight of stationary object
If disks are grouped together to form one-piece drums, then mass is reduced and design is simplified, but conveying ventilation air to blade attachments becomes more difficult
Solution Approach 1:
The axial retaining segments perform multiple functions: they retain the blades axially, provide passages for ventilation air flow, and maintain structural integrity of the drum. This multi-functionality allows the one-piece drum configuration to be achieved without compromising ventilation capability.
Solution Approach 2:
The segmentation of the drum into modular disk units connected by shell rings, combined with internal passages in the retaining segments, allows ventilation air to be conveyed effectively throughout the one-piece drum structure while maintaining the mass and design benefits of the integrated configuration.
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 solution ensures effective ventilation of blade attachments while maintaining the strength and reducing mass costs, ensuring axial retention without loss of effectiveness.
Implementation Method 1
air bled from the high-pressure, HP, compressor to cool components located in a hotter environment
Data Source
AI summary
A device for supplying ventilation air to a turbine rotor of a gas turbine engine including a first turbine disk, a second turbine disk, and a downstream shell ring together forming a one-piece drum is disclosed. The second turbine disk includes cavities machined in the rim to house the turbine blades, where the blades are axially retained by axial retaining segments. The downstream shell ring has at least one aperture drilled therethrough, downstream of the rim, which places an internal volume of the drum in fluid communication with at least one of the cavities via a passage formed in the segments.