Engine Strut Flow Control to Mitigate Separation
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Solution Overview
Problem
The proximity of stators and struts in turbofan engines leads to flow separation and back pressure effects, which are amplified by downstream components, affecting the performance of the engine components and creating a self-feeding feedback loop.
Innovation Solution
The implementation of extraction inlets and injection outlets on the strut to manage airflow, mitigating flow separation by either extracting air from or injecting air into the separation zone, using passive doors to regulate airflow based on pressure differences.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If stators are placed closely followed by struts in the bypass area, then the structural support function is achieved, but flow separation occurs on the strut due to back pressure from downstream components
Solution Approach 1:
The patent extracts the harmful separated flow from the system by providing an extraction inlet that allows the separated flow to be removed from the strut surface, preventing the harmful feedback loop between the strut and upstream stators
Solution Approach 2:
The patent introduces an intermediary flow control system consisting of extraction inlets, internal conduits, and injection outlets that mediate between the back pressure from downstream components and the upstream stator flow, converting the harmful back pressure into a controlled flow management mechanism
2Object-affected harmful factors
If extraction inlets and injection outlets are added to the strut, then flow separation is mitigated, but device complexity increases
Solution Approach 1:
The patent merges the flow control functionality into the existing strut structure by integrating extraction inlets, internal conduits, and injection outlets within the strut body, combining structural support and flow control functions in a single component
Solution Approach 2:
The system uses passive doors that automatically open based on pressure differences to allow flow extraction, and uses the engine's own bypass flow to provide the injection fluid, eliminating the need for external power sources or complex control systems
3Ease of operation
If passive doors are used to regulate airflow, then ease of operation is improved, but manufacturing precision requirements increase
Solution Approach 1:
The passive doors are designed to automatically open and close based on pressure differences across the door, using the engine's own operating conditions to control the flow extraction without requiring external actuators or complex control systems
Solution Approach 2:
The system exploits changes in pressure parameters during engine operation to automatically control the passive doors, allowing the flow extraction to adapt to different operating conditions through natural pressure variations rather than mechanical control
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
Reduces or eliminates flow separation around the struts, improving airflow stability and promoting even cooling, thereby enhancing engine performance and range with minimal cost and weight impact.
Implementation Method 1
each of the first and second extraction inlets includes a respective passive door configured to open and allow flow therethrough depending on pressures outside the respective passive door and in the internal conduit
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
A gas turbine engine strut (100) includes a strut body extending in a radial direction and defining an airfoil shape in cross-section perpendicular to the radial direction. The airfoil shape includes a leading edge and a trailing edge. An extraction inlet is defined through an exterior surface of the strut body, in fluid communication with an internal conduit of the strut body. An injection outlet is defined through the exterior surface of the strut body, in fluid communication with the internal conduit for fluid communication through the internal conduit from the extraction inlet to the injection outlet.