Retractable Vortex Generator with Acute Pivot Axis
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Solution Overview
Problem
Existing retractable vortex generators for flow control surfaces require structural modifications and space for retraction, leading to drag penalties and ice accretion issues, and are not easily retrofittable to existing designs.
Innovation Solution
The use of vortex generators with a pivot axis forming an acute angle, capable of being positioned between an extended and retracted state using an actuator, such as a heater or electromagnetic motor, allowing them to lie adjacent to the flow control surface when retracted, eliminating the need for reserved space and reducing drag and ice accumulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If vortex generators are permanently installed on flow control surfaces, then they continuously mix low momentum boundary layer fluid with high momentum outer flow to improve maneuver effectiveness, but they produce continuous drag penalties and are susceptible to ice accretion
Solution Approach 1:
The vortex generators are made dynamically movable between an extended position (protruding from the flow control surface to generate vortices) and a retracted position (flush with the surface to minimize drag). This dynamic positioning allows the system to optimize between maneuver effectiveness and drag reduction based on operational conditions
Solution Approach 2:
The vortex generators can be retracted into a storage compartment when not needed, effectively removing them from the flow path to eliminate drag penalties and ice accretion risks, while being available for deployment when maneuver enhancement is required
2Loss of energy
If retractable vortex generators are designed with internal storage space within the flow control surface, then they can be retracted to reduce drag and ice accretion, but structural modifications are required that negatively influence wing design and complicate retrofitting
Solution Approach 1:
Instead of modifying the flow control surface structure to create internal storage space, the vortex generators are extracted outward to a separate mounting location on the upper surface of the wing. This eliminates the need for structural modifications while maintaining the retractable functionality for drag reduction
Solution Approach 2:
The vortex generators are mounted on the upper surface of the wing rather than being embedded within the flow control surface. This dimensional relocation allows the generators to be positioned in a different spatial plane, eliminating the need for internal storage space while maintaining aerodynamic functionality
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 design reduces drag and ice accumulation on flow control surfaces without requiring structural modifications, enabling easy retrofitting and efficient operation of retractable vortex generators on various flow control surfaces.
Implementation Method 1
the actuator may be a heater that actuates a shape memory material made from a nickel-titanium alloy
Implementation Method 2
a shape memory material made from a nickel-titanium alloy
Data Source
AI summary
A flow control device is disclosed including a flow control surface over which fluid is designed to flow in a predetermined direction. Vortex generators are associated with the flow control surface. Each respective vortex generator has a pivot axis that forms an acute angle with respect to the predetermined direction and is capable of being positioned in both of an extended state, in which the respective vortex generators function to create a swirling fluid flow, and a retracted state, in which the respective vortex generators are pivoted via the pivot axis so as to lie adjacent to the flow control surface. An actuator is associated with each of the vortex generators, each actuator adapted to position the associated vortex generator between the extended and retracted states. The flow control device is disclosed to be used in tiltrotor vehicles.