Turbomachine Casing Cooling via Segmented Tubes and Grooves
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Solution Overview
Problem
Turbomachine casings experience premature damage due to inadequate cooling, particularly in areas where air flow is trapped, leading to severe thermal stress and clearance issues between blades and abradable material rings.
Innovation Solution
A cooling device featuring a collector housing with circumferentially extending cooling tubes and radial and axial grooves that allow for efficient air circulation and extraction, preventing air stagnation and reducing pressure losses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If cooling tubes are added to improve cooling efficiency, then the cooling effect is improved, but the device complexity increases
Solution Approach 1:
The cooling device is segmented into multiple cooling tubes distributed around the collector housing, with each tube serving a specific circumferential zone. This segmentation allows targeted cooling of different casing areas while maintaining manageable complexity through modular arrangement.
Solution Approach 2:
The cooling tubes are nested within the collector housing structure, with tubes positioned inside the annular space formed by the collector housing. This nesting integrates the cooling function into the existing housing geometry rather than adding external components.
2Temperature
If air ejection openings are increased to improve cooling, then the cooling efficiency is improved, but air flow stagnation occurs
Solution Approach 1:
Air ejection openings are strategically positioned at specific locations on the cooling tubes and collector housing to create localized high-velocity jets that target hot spots on the casing. This localized approach prevents uniform air distribution that could lead to stagnation while ensuring adequate cooling where needed.
Solution Approach 2:
The cooling system utilizes three-dimensional air flow paths with radial and axial components. Air is ejected both radially outward from the tubes and axially through the collector housing, creating multi-directional flow patterns that prevent stagnation by continuously refreshing the cooling air supply across different spatial dimensions.
3Temperature
If the number of cooling tubes is increased to improve cooling coverage, then the cooling effectiveness is improved, but pressure losses increase
Solution Approach 1:
Rather than uniformly distributing cooling across the entire casing, the system uses a limited number of strategically positioned cooling tubes that target the most critical thermal zones. This partial action approach achieves adequate cooling effectiveness while minimizing the total number of tubes and associated pressure losses.
Solution Approach 2:
The cooling system creates periodic high-velocity air jets through the cooling tubes, with air being pulsed or continuously ejected in directed streams. This periodic action maintains effective cooling through high momentum flows that reach deeper into casing crevices without requiring a continuous high-volume air supply that would increase pressure losses.
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
The solution effectively cools the turbomachine casing by ensuring better air circulation and preventing overheating, thereby extending the lifespan of the casing and maintaining turbomachine efficiency.
Implementation Method 1
Each tube 23 has an air inlet opening into the channel of the corresponding collector housing 22 and a closed distal end. Each tube 23 also has a cylindrical wall with air ejection openings facing casing 18, so that cooling air can enter the collector housing 22 and then the tubes 23 before opening through the openings facing casing 18 to cool it. This is known as impact cooling because the air impacts the casing 18.
Implementation Method 2
the collector housing also including an air passage formed by a radial groove extending radially from the radially inner end of the collector housing to the radially outer end of the housing, and an axial groove extending from a first axial end to a second axial end of the housing
Data Source
AI summary
A cooling device for an annular casing of a turbomachine includes a collector housing having ejection openings in a radially inner part of the collector housing facing the annular casing and at least two cooling tubes extending circumferentially from the collector housing and having election openings in a radially inner part of the tubes facing the annular casing. The collector housing having an air passage formed by a radial groove extending radially from a radially inner end of the collector housing to a radially outer end of the collector housing and an axial groove extending from a first axial end to a second axial end of the collector housing.