Synthetic Pulsator for Aircraft Flow Separation Control
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Solution Overview
Problem
Adverse pressure gradient fluid flows over aerodynamic surfaces cause buffeting, fatigue, and performance losses in aircraft, leading to increased drag, structural stress, and engine stalling, with existing solutions either increasing weight or limiting design options.
Innovation Solution
The use of synthetic pulsators that combine steady fluid flows with oscillatory flows from synthetic jets to manipulate primary fluid flows, reducing flow separation and vortex impact, by embedding these pulsators within surfaces and controlling their amplitude and frequency to create high-frequency eddies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If active control flows are used to mitigate adverse flow fields, then flow separation is reduced and performance is improved, but structural weight increases due to compressed air supply systems and piping
Solution Approach 1:
The synthetic jet actuator uses the primary fluid flow itself to drive the oscillatory motion through interaction with the aerodynamic surface, eliminating the need for external compressed air supply systems. The device generates control flows autonomously by exploiting the energy already present in the mainstream flow.
Solution Approach 2:
The invention uses fluid dynamic principles where the synthetic jet actuator creates oscillatory flows that interact with the boundary layer to control separation. The actuator generates pulsed jets that manipulate the fluid flow field without requiring mechanical compressors or pneumatic infrastructure.
2Reliability
If components are structurally hardened to withstand adverse flow stresses, then structural reliability is improved, but vehicle performance is reduced due to increased weight
Solution Approach 1:
The synthetic jet actuator applies preliminary control actions to the fluid flow field that prevent the development of strong adverse pressure gradients and flow separation before they can occur. By actively manipulating the boundary layer, the system prevents the harmful flow conditions that would otherwise require structural reinforcement.
3Reliability
If control jets are used to manipulate boundary layer, then flow separation is reduced, but mixing losses increase due to induced mixing between primary and secondary flows
Solution Approach 1:
The synthetic jet actuator employs periodic oscillatory flows rather than continuous injection. The pulsed nature of the actuator creates time-varying control flows that manipulate the boundary layer more efficiently, reducing the total amount of fluid required and minimizing energy losses associated with continuous mixing.
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
This approach enhances mixing and penetration of primary flows, reduces structural weight, and improves aircraft performance by minimizing flow separation and vortex-induced stresses, allowing for more efficient and lightweight fluid flow control.
Implementation Method 1
A mechanism in or about the housing periodically changes the volume within the internal chamber so that a series of fluid vortices are generated and projected into an external environment beyond the orifice of the housing
Implementation Method 2
The flexible diaphragm is typically actuated by a piezoelectric actuator or other appropriate means
Implementation Method 3
As the diaphragm moves outward with respect to the chamber, increasing the chamber volume, ambient fluid is drawn from large distances from the orifice into the chamber
Data Source
AI summary
A system and method for actively manipulating fluid flow over a surface using synthetic pulsators. Synthetic pulsators produce pulsed jet operable to manipulate the primary fluid flow proximate to the synthetic pulsator. The synthetic pulsator includes a dual diaphragm synthetic jet coupled to high performance dual actuator solenoids, wherein the synthetic jet is operable to produce an oscillatory flow. The oscillatory flow of the synthetic jet(s) produces the pulsed jet operable to manipulate the primary fluid flow. These synthetic pulsators may then be actively manipulated to control the flow behavior of the ducted fluid flow, influence the inception point and trajectory of flow field vortices within the fluid flow, and reduce flow separation within the primary fluid flow.