Arcuate Flow Sleeve for Turbine Shell Thermal Control
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Solution Overview
Problem
Existing systems for maintaining radial and axial clearances in gas turbine engines, particularly in double-shell configurations, are inadequate for efficient air distribution and temperature modulation on the inner surface of the outer shell, leading to suboptimal performance and efficiency.
Innovation Solution
A flow sleeve with arcuate segments is secured to the inner surface of the outer shell, forming circumferentially-extending flow channels and radial flow openings to direct air in targeted directions, enhancing air distribution and heat transfer within the turbine casing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If conventional air distribution systems are used in double-shell turbine configurations, then the system structure is simple, but the heat transfer efficiency is insufficient and cooling air requirements are high
Solution Approach 1:
The flow sleeve is divided into multiple arcuate segments (typically three) that are distributed around the inner surface of the outer shell. Each segment contains flow channels and openings positioned to target specific surfaces, allowing localized and efficient heat transfer without requiring a complex comprehensive system
Solution Approach 2:
The flow channels and openings in each arcuate segment are strategically positioned to direct air flow to specific target surfaces that require cooling or heating. This localized air distribution optimizes heat transfer efficiency where needed most, rather than uniformly distributing air throughout the entire cavity
2Productivity
If air is distributed uniformly throughout the cavity, then the system is simple to implement, but the cooling air requirements increase and performance is suboptimal
Solution Approach 1:
The flow sleeve segments direct air flow locally to specific target surfaces within the cavity rather than uniform distribution. The arcuate segments with strategically positioned openings ensure cooling air is delivered precisely where heat transfer is needed, reducing overall cooling air requirements while maintaining or improving engine performance
Solution Approach 2:
The flow channels extend in multiple directions (circumferential, radial, and axial) from each arcuate segment, creating a three-dimensional air distribution pattern that efficiently reaches target surfaces from multiple angles, thereby reducing the total quantity of cooling air needed compared to conventional single-direction distribution
3Productivity
If clearances between rotating and stationary components are minimized for efficiency, then engine efficiency improves, but clearance control becomes difficult due to thermal expansion and speed changes
Solution Approach 1:
The flow sleeve system modifies temperature parameters of the outer shell and adjacent components by directing heated or cooled air to specific surfaces. By controlling the thermal state of these components, the system compensates for thermal expansion effects and maintains optimal clearances between rotating and stationary components across varying operating conditions
Solution Approach 2:
The air distribution system allows dynamic adjustment of thermal conditions on the outer shell and stator components during operation. By modulating air flow to different regions, the system can adapt clearance dimensions in response to changing speeds and thermal loads, maintaining efficiency while accommodating expansion and contraction
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 flow sleeve effectively directs air to enhance heat transfer coefficients, reduce cooling air requirements, and maintain optimal clearances by targeting specific surfaces within the turbine casing, thereby improving the efficiency and performance of the gas turbine engine.
Implementation Method 1
the flow channel adapted to flow air in opposite circumferential and axial directions along the inside surface
Implementation Method 2
plural flow openings in the base for directing some of the air in the flow channel radially into the cavity
Implementation Method 3
the rotor and stator components will radially expand as temperature increases
Implementation Method 4
enhance heat transfer coefficients
Data Source
AI summary
A turbine casing includes at least one shell adapted to enclose one or more turbine stages in a gas turbine engine; an air inlet in the at least one shell; a flow sleeve secured to an inside surface of the at least one shell, the flow sleeve comprising at least two arcuate segments. Each arcuate segment includes an arcuate base, a pair of sidewalls extending radially outwardly of the base thereby forming a circumferentially-extending flow channel defined by the base, the sidewalls and the inside surface. The air inlet is aligned with the flow channel and the sleeve is configured to distribute air flowing in the channel into spaces proximate the one or more turbine stages in circumferential, radial and axial directions, including along the inside surface of the at least one shell.