Dual Thrust Streamtube Assembly for Low-Speed Fluid Efficiency
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Solution Overview
Problem
Existing fluid interaction apparatuses, such as helicopters and wind turbines, face inefficiencies in power consumption and thrust production at low free stream flow velocities, with conventional methods failing to effectively mitigate these issues due to constraints like flow separation and increased drag forces.
Innovation Solution
A fluid manipulation apparatus configuration that includes an upstream and downstream thrust apparatus assembly, where the downstream apparatus is placed in the streamtube of the upstream apparatus, allowing for a vector component of thrust parallel to the induced velocity vector, and optionally includes intentional momentum carrying apparatuses to reduce drag and enhance power extraction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a duct is employed to increase the local free stream flow velocity, then the thrust production efficiency is improved, but the wetted area and weight increase prohibitively
Solution Approach 1:
The invention extracts the flow acceleration function from a traditional duct structure and implements it through a vortex generator system. The vortex generators create localized vortices that accelerate flow without requiring a large enclosing duct structure, thereby achieving thrust enhancement without the prohibitive weight penalty of a full duct.
Solution Approach 2:
The vortex generators act as intermediary elements between the free stream flow and the propeller. They mediate the flow by creating vortices that increase local velocity and energy, serving as a lightweight alternative to a heavy duct while still achieving the desired flow modification.
2Speed
If a large diffuser duct is used to achieve large effect on local free stream flow, then the flow velocity increase is improved, but the wetted area becomes prohibitively large
Solution Approach 1:
Instead of using a large diffuser that modifies flow over a large area, the invention employs vortex generators that create localized flow acceleration at specific positions. The flow velocity increase is concentrated in localized regions where vortices are generated, achieving significant velocity enhancement without expanding the overall wetted area.
Solution Approach 2:
The invention transitions from a two-dimensional diffuser approach to a three-dimensional vortex-based approach. By creating vortices that extend in the spanwise direction, the system achieves flow acceleration through a different spatial dimension, avoiding the need for a large planar diffuser area.
3Object-affected harmful factors
If the wetted surface is made smooth to favor laminar flow, then the viscous drag force is reduced, but the drag force remains substantial
Solution Approach 1:
The vortex generators create controlled flow disturbances that, while appearing turbulent, actually enhance momentum transfer and reduce pressure drag. The periodic vortex shedding creates a dynamic flow pattern that prevents boundary layer separation and reduces overall drag, counterintuitively improving thrust efficiency through what appears to be turbulent rather than laminar flow.
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 configuration reduces power consumption and increases hovering endurance for helicopters and enhances thrust production or power extraction efficiency in fluid interaction apparatuses by modifying local free stream velocities, thereby minimizing drag and optimizing energy use.
Implementation Method 1
an upstream thrust apparatus configured to impart a rate of change of momentum to a fluid in a first direction
Implementation Method 2
a downstream thrust apparatus configured to impart a rate of change of momentum on the fluid in the streamtube of the upstream thrust apparatus, where a direction of this rate of change of momentum has at least a component in an opposite direction of the effect of the first rate of change of momentum
Data Source
AI summary
An intentional fluid manipulation apparatus (IFMA) assembly with a first thrust apparatus that imparts a first induced velocity to a local free stream flow during a nominal operation requirement. The first thrust apparatus creates a streamtube. A second thrust apparatus is located in a downstream portion of the streamtube. The second thrust apparatus imparts a second induced velocity to the local free stream flow. The second induced velocity at the location of the second thrust apparatus has a component in a direction opposite to the direction of the first induced velocity at the location of the second thrust apparatus.