Variable Compressor Bleed Slot Walls for Lower Pressure Loss
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Solution Overview
Problem
Gas turbine engines experience excessive pressure losses in compressor bleed slots due to turbulent effects and vortex formation, particularly during low power conditions, which reduce the efficiency of extracted bleed air.
Innovation Solution
Implementing variable wall structures in compressor bleed slots that are passively controlled by ambient conditions, such as temperature and pressure, using shape memory alloys and bimetallic materials to adjust geometry and reduce turbulence, thereby minimizing pressure losses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If bleed slots are used to extract air from the compressor, then bleed air is obtained for various purposes, but excessive pressure losses occur due to turbulent effects and vortex formation
Solution Approach 1:
The patent employs movable walls that can change position between open and closed configurations. These walls are actuated based on operating conditions (such as power settings) to dynamically adjust the bleed slot geometry. By closing the walls during certain conditions, the patent reduces vortex formation and turbulent effects, thereby minimizing pressure losses while still enabling bleed air extraction when needed.
Solution Approach 2:
The patent changes geometric parameters of the bleed slots by moving walls to different positions. This alters the flow characteristics, reducing turbulence and vortex formation. The movable walls modify the slot width, depth, and orientation, thereby changing flow parameters to reduce pressure losses during bleed air extraction.
2Device complexity
If fixed geometry bleed slots are used, then the structure is simple, but pressure losses are excessive during low power conditions
Solution Approach 1:
The patent transitions from fixed geometry to dynamic geometry by incorporating movable walls. These walls can be positioned differently based on operating conditions, allowing the bleed slot to adapt its shape. This dynamic adjustment reduces pressure losses during low power conditions while maintaining relatively simple actuation mechanisms.
Solution Approach 2:
The movable walls can be actuated automatically based on sensor feedback regarding operating conditions (such as power settings or pressure differentials). This self-adjusting capability allows the system to optimize its geometry for current conditions without complex external control systems, balancing simplicity with performance.
3Quantity of substance
If larger bleed slots are used to increase bleed air flow, then more bleed air is available, but vortex formation and pressure losses increase
Solution Approach 1:
The patent uses movable walls to dynamically adjust the bleed slot geometry based on flow requirements. When large bleed air flow is needed, the walls open to provide sufficient area. When flow requirements are lower, the walls close to reduce the effective slot size, thereby minimizing vortex formation and pressure losses while still meeting the required bleed air flow.
Solution Approach 2:
The movable walls allow different sections of the bleed slot to have different openings or closures based on local flow requirements. This selective opening/closing capability enables optimization of each region to minimize vortices while maintaining adequate total flow area for required bleed air extraction.
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 variable wall structures effectively reduce vortex formation and pressure losses, enhancing the pressure recovery and usefulness of extracted bleed air, especially during low power conditions.
Implementation Method 1
variable wall structures that are passively controlled by ambient conditions, such as temperature and pressure, using shape memory alloys and bimetallic materials to adjust geometry
Implementation Method 2
variable wall structures that are passively controlled by ambient conditions, such as temperature and pressure, using shape memory alloys and bimetallic materials to adjust geometry
Data Source
AI summary
Compressor bleed slots with variable wall structures are disclosed herein. An example apparatus disclosed herein is to be coupled to a wall of a bleed slot of a compressor of a gas turbine engine, the bleed slot defining a flow path, the apparatus comprising a member to be coupled to the wall, and a plate coupled to the member, the plate having a first geometry at a first ambient condition at a first time, the flow path having a first area when the plate has the first geometry, and a second geometry at a second ambient condition at a second time, the flow path having a second area when the plate has the second geometry, the first area greater than the second area, the first time after the second time.