Inflatable Splitter Wall for Turbofan Airflow Split Control
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Solution Overview
Problem
Existing turbofan engine arrangements for aircraft propulsion systems lack the ability to dynamically adjust airflow split between the core and bypass flowpaths, leading to suboptimal performance across varying operating modes.
Innovation Solution
Incorporation of an inflatable bladder in the bypass flowpath wall to adjust the radial outer surface geometry, allowing for dynamic changes in the airflow split by inflating or deflating the bladder to accommodate different throttle settings and operating conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a fixed splitter geometry is used in turbofan engines, then the structure is simple and reliable, but the airflow split cannot be dynamically adjusted for varying operating modes
Solution Approach 1:
The patent applies the dynamics principle by replacing the fixed splitter geometry with an inflatable bladder that can dynamically change the flowpath wall geometry. The bladder transitions between inflated and deflated states to adjust the radial position of the flowpath wall, enabling dynamic airflow split adjustment for different operating modes while maintaining a relatively simple overall structure.
Solution Approach 2:
The patent applies parameter changes by using pressure-controlled inflation of the bladder to change the geometric parameters of the flowpath wall. By controlling the internal pressure of the bladder, the radial position and shape of the flowpath wall are modified, allowing optimization of airflow split for specific operating conditions without complex mechanical adjustments.
2Productivity
If the flowpath wall geometry is made adjustable, then airflow distribution can be optimized for different operating conditions, but the device complexity increases
Solution Approach 1:
The patent applies flexible shells and thin films by using an inflatable bladder made of flexible material to form the adjustable portion of the flowpath wall. The bladder's flexibility allows it to conform to different pressure conditions and generate the required geometric changes for optimizing airflow distribution across various operating modes.
Solution Approach 2:
The patent applies pneumatics by using pressurized gas (air) to inflate the bladder and change the flowpath wall geometry. The pneumatic system allows for smooth, controlled deformation of the flowpath wall without complex mechanical actuators, thereby optimizing engine performance while limiting the increase in device complexity.
3Power
If a deformable flowpath wall is used, then thrust output can be improved through optimized airflow, but the manufacturing precision requirements increase
Solution Approach 1:
The patent applies segmentation by dividing the flowpath wall into a rigid portion and a deformable bladder portion. This segmentation allows the majority of the flowpath wall to be manufactured with standard precision, while only the bladder interface requires specialized integration. The modular approach reduces overall manufacturing precision requirements compared to a fully deformable structure.
Solution Approach 2:
The patent applies composite materials by combining rigid flowpath wall materials with the inflatable bladder material to create a hybrid structure. This composite approach allows the rigid portion to provide structural integrity and standard manufacturing tolerances, while the bladder provides the necessary deformability for thrust optimization, thereby balancing manufacturing precision requirements with performance goals.
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
Enhances engine performance by optimizing airflow distribution between the core and bypass flowpaths, improving thrust output and efficiency across varying throttle settings.
Implementation Method 1
The inflatable bladder is configured to change a geometry of the radial outer surface... the inflatable bladder is configured to deform the radial outer surface such that, when viewed in a reference plane parallel with the axis: at least a portion of the radial outer surface is convex during a first mode; and at least the portion of the radial outer surface is concave during a second mode
Implementation Method 2
The air system may be configured to at least one of: direct air into the interior volume of the inflatable bladder to deform the radial outer surface in a radial outward direction; or direct air out of the interior of the inflatable bladder to deform the radial outer surface in a radial inward direction
Data Source
AI summary
An assembly is provided for an aircraft propulsion system. This assembly includes a bladed rotor, an inner flowpath, an outer flowpath, a splitter and a flowpath wall. The bladed rotor is rotatable about an axis. The inner flowpath includes an inner flowpath inlet downstream of the bladed rotor. The outer flowpath includes an outer flowpath inlet downstream of the bladed rotor. The outer flowpath inlet is radially outboard of the inner flowpath inlet. The splitter is disposed radially between and partially forms the inner flowpath inlet and the outer flowpath inlet. The flowpath wall is arranged with the splitter and forms a radial inner peripheral boundary of the outer flowpath. The flowpath wall includes an inflatable bladder and a radial outer surface. The inflatable bladder is configured to change a geometry of the radial outer surface.