Compressor Cavity Separator for Gas Turbine Bleed Optimization
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Solution Overview
Problem
Existing compressor designs for gas turbines face challenges in optimizing bleed cavity size and flow topology during start-up and normal operations, leading to high flow losses and potential structural issues due to mismatched flow and temperature conditions, which are not adequately addressed by current designs that compromise between aerodynamic and structural considerations.
Innovation Solution
The introduction of a separator element or membrane within the compressor cavity divides it into two sub-cavities, optimizing flange positioning and reducing heat transfer and vortices, while venting holes equalize pressure and temperature between sub-cavities, and thermally insulating materials minimize deformations and losses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a larger bleed cavity is used to accommodate required air extraction during start-up, then the functionality during transient operations is improved, but the axial length and manufacturing cost increase
Solution Approach 1:
The bleed cavity is divided into two separate cavities by a partition wall: a first cavity for receiving air during start-up transient operations and a second cavity for receiving air during normal operations. This segmentation allows each cavity to be optimized for its specific function, reducing the total volume and axial length required compared to a single large cavity that must accommodate both operational modes.
2Ease of manufacture
If a smaller bleed cavity is used to reduce cost and axial length, then manufacturing cost and space constraints are improved, but the ability to accommodate required air extraction during start-up deteriorates
Solution Approach 1:
The partition wall creates dedicated spaces for different operational requirements, allowing the overall cavity system to be more compact while maintaining adequate volume for start-up air extraction. The segmented design optimizes space utilization and reduces material requirements.
Solution Approach 2:
The partition wall extends in the circumferential direction rather than requiring increased axial length, allowing the cavity to accommodate more volume laterally. This dimensional approach reduces the axial footprint while maintaining the necessary capacity for air extraction during start-up.
3Loss of energy
If the bleed cavity geometry is optimized for low flow losses, then aerodynamic performance is improved, but the structural geometry constraints and manufacturing complexity increase
Solution Approach 1:
The partition wall features rounded corners and curved surfaces instead of sharp edges, which reduces flow separation and vortex formation. This curvature optimization minimizes flow losses and improves aerodynamic performance while the partition wall itself provides a manageable structural element for manufacturing.
4Loss of energy
If a partition wall is added to divide the cavity, then flow topology and heat transfer are optimized, but the device complexity increases
Solution Approach 1:
The partition wall divides the bleed cavity into two functionally distinct cavities, allowing independent optimization of flow paths for start-up and normal operations. This segmentation improves heat transfer characteristics and flow topology by preventing mixed flow patterns, while the partition wall remains a relatively simple structural addition.
Solution Approach 2:
Different regions of the bleed cavity are given different functions through the partition wall: the first cavity is optimized for start-up conditions with appropriate flow characteristics, while the second cavity is optimized for normal operations. This local differentiation improves overall system performance without requiring complete redesign of the entire cavity structure.
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 enhances the flexibility of compressor design, reduces flow losses, and minimizes heat transfer and pressure differences, ensuring stable operation by guiding flow effectively and maintaining structural integrity during transient and steady-state conditions.
Implementation Method 1
a separator element, or membrane, located in the cavity (6) and arranged therein such to divide the cavity (6)... The separator element is then used to guide the flow in an advantageous way, for example, reducing the number of vortices.
Implementation Method 2
venting holes equalize pressure and temperature between sub-cavities
Implementation Method 3
venting holes equalize pressure and temperature between sub-cavities
Implementation Method 4
thermally insulating materials minimize deformations and losses
Implementation Method 5
The consequence of this S-swirl is a flow in the upward direction in the cavity, which then breaks into two 90° flows moving away from each other... As the flows reach to the corner edges, they form a swirl
Data Source
AI summary
A compressor assembly, and more in general relates to a compressor for a gas turbine providing a solution that teaches to locate within a cavity formed by the outer casing of the compressor and the inner vane carrier a separator element, or membrane, such to divide the cavity into two sub-cavities. This advantageously results in a more flexible design with respect to the positioning of the flange blow-off extractor and to the cavity sizing, as the flange position is not necessarily the boundary for the flow anymore as it would be without the separator element.