Sensor-Controlled Aircraft Intake Restrictor for Flow Distortion
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Solution Overview
Problem
The annular air inlet ducts in aircraft engines experience non-uniform air flow due to factors like Mach number, sideslip angle, and engine mass flow rate, leading to increased total pressure losses and air flow distortion, affecting the performance of the compressor section and downstream components.
Innovation Solution
A movable flow restrictor, or 'ski-jump', within the annular inlet duct is controlled by a system of sensors and actuators to adjust its position based on pressure differences, optimizing airflow distribution and reducing non-uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a fixed annular inlet duct is used, then the structure is simple, but non-uniform air flow causes increased total pressure losses and flow distortion
Solution Approach 1:
The flow restrictor is made movable rather than fixed, allowing it to dynamically adjust its position around the annular inlet duct circumference. This dynamic adjustment enables the system to adapt to varying flow conditions and minimize total pressure losses by optimally positioning the flow restrictor to counteract non-uniform flow patterns caused by different operating conditions such as Mach number, sideslip angle, and engine mass flow rate.
2Reliability
If a fixed annular inlet duct is used, then the device complexity is low, but air flow distortion at compressor inlet increases
Solution Approach 1:
The flow restrictor can dynamically reposition itself around the annular inlet duct to counteract flow distortion under different operating conditions. By adjusting its position based on detected flow patterns, the movable flow restrictor maintains more uniform flow distribution at the compressor inlet, thereby increasing stall margin and improving reliability.
Solution Approach 2:
The system incorporates sensors that detect flow conditions and provide feedback to the control system. Based on this feedback, the flow restrictor adjusts its position to optimize flow distribution. This closed-loop control ensures that the inlet duct adapts to changing conditions and maintains reliable compressor operation.
3Adaptability or versatility
If the flow restrictor position is fixed, then the system is simple, but it cannot adapt to different operating conditions
Solution Approach 1:
The flow restrictor is designed to move dynamically around the annular inlet duct, enabling the system to adapt to various operating conditions including different Mach numbers, sideslip angles, and engine mass flow rates. This dynamic capability allows optimal performance across a wide range of flight conditions.
Solution Approach 2:
Sensors detect flow conditions and provide feedback to the control system, which then adjusts the flow restrictor position accordingly. This feedback mechanism enables the system to automatically adapt to changing operating conditions without manual intervention.
Solution Approach 3:
The movable flow restrictor system serves multiple functions: it reduces total pressure losses, minimizes flow distortion, and adapts to various operating conditions. This multi-functional design enhances the versatility of the inlet duct system across different flight regimes.
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 solution reduces inlet air pressure losses, minimizes compressor inlet flow distortion, and increases the compressor stall margin by actively managing airflow through the duct.
Implementation Method 1
at least one sensor, two first sensors 32A, 32B disposed proximate or at the duct inlet 22A. The two first sensors 32A, 32B may each be located on a respective side of the center line CL; one of the two first sensors 32A, 32B located proximate the first section 22B whereas the other of the two first sensors 32A, 32B located proximate the second section 22C.
Data Source
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AI summary
An aircraft engine (10), has: an inlet (12) extending circumferentially around a central axis (A); an annular inlet duct (22) having a duct inlet (22A) fluidly connected to an environment outside of the aircraft engine (10) and a duct outlet (220) fluidly connected to the inlet (22A); a flow restrictor (26) extending across the annular inlet duct (22) and being movable within the annular inlet duct (22); an actuator (31) engaged to the flow restrictor (26) and operable to move the flow restrictor (26); and a controller (34) operatively connected to at least one sensor (32A, 328, 33A, 33B) and the actuator (31), the controller (34) having a processing unit (702) and a computer-readable medium (704) operatively connected to the processing unit (702) and containing instructions (706) for: receiving a signal indicative of a pressure difference between opposite sides of the flow restrictor (26); and powering the actuator (31) to move the flow restrictor (26) with the actuator (31) from a first position to a second position offset form the first position as a function of the pressure difference.