Compressor Bleed Air Channels with Vortex Generators
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Solution Overview
Problem
In turbofan engines, flow separation in compressor bleed air channels leads to reduced bleed air pressure recovery and pressure in the bleed cavity, limiting the availability of bleed air for cooling and powering aircraft systems.
Innovation Solution
The implementation of vortex generators on the surface of the first wall in the bleed channel, which create vortices and turbulence, reducing flow separation and enhancing airflow smoothness, thereby improving bleed air pressure recovery and pressure capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If bleed air channels are designed without vortex generators, then the channel structure remains simple, but flow separation occurs leading to reduced bleed air pressure recovery
Solution Approach 1:
Vortex generators are introduced as intermediary elements within the bleed air channel. These small protrusions act as mediators that modify the flow characteristics by generating controlled vortices, which in turn delay flow separation and improve pressure recovery without requiring major structural changes to the channel itself.
Solution Approach 2:
The vortex generators change the flow parameters by introducing controlled turbulence and vorticity. This parameter change transforms the laminar separated flow into a more energetic turbulent flow that adheres better to the channel walls, thereby improving pressure recovery while maintaining a relatively simple channel structure.
2Reliability
If vortex generators are added to the bleed channel, then bleed air pressure recovery improves, but the device complexity increases
Solution Approach 1:
The vortex generators are segmented into multiple small, discrete elements distributed along the channel surface. This segmentation allows the complexity to be distributed and managed in small units rather than requiring a single complex structure, making the system easier to manufacture and maintain while achieving the desired flow control effect.
Solution Approach 2:
Vortex generators are placed at specific locations where flow separation is most problematic, rather than uniformly across the entire channel. This local application of complexity focuses the flow control effect where it is most needed, improving pressure recovery without unnecessarily increasing complexity throughout the entire channel structure.
3Ease of manufacture
If conventional smooth channel surfaces are used, then manufacturing is simpler, but flow separation reduces pressure capacity
Solution Approach 1:
The vortex generators are designed to be self-formed or self-installed features on the channel surface. In many implementations, they are created directly during the manufacturing process (such as through injection molding or extrusion) without requiring separate assembly steps, thus maintaining ease of manufacture while providing the flow control function that increases pressure capacity.
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 use of vortex generators on the surface of the first wall in the bleed channel significantly improves bleed air pressure recovery and pressure capacity, ensuring a more efficient and reliable supply of bleed air to downstream systems, especially during nominal bleed conditions.
Implementation Method 1
vortex generators on the surface of the first wall in the bleed channel, which create vortices and turbulence
Implementation Method 2
vortex generators on the surface of the first wall in the bleed channel, which create vortices and turbulence, reducing flow separation
Data Source
AI summary
In one aspect, the present disclosure is directed a gas turbine engine including a compressor, a combustor, and a turbine in a serial flow arrangement. The compressor includes a casing having an inner wall and an outer wall. The inner wall defines a passageway for airflow through the compressor. The casing defines a bleed cavity between the inner wall and the outer wall. The inner wall has an opening. The casing defining a channel between the opening and the bleed cavity to direct airflow into the bleed cavity. The channel is defined by a first wall and a second wall of the casing. The second wall being downstream of the first wall. A surface of the first wall has a pattern to reduce flow separation in the channel.