Variable-Geometry Coanda Thruster for Low-Flow Thrust Stability
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Solution Overview
Problem
Fixed-geometry thrusters experience significant performance degradation at lower fluid flow rates due to inefficient primary fluid injection in the straight portion, leading to reduced thrust efficiency and entrainment, whereas the rounded ends maintain performance by facilitating rapid mixing with ambient air.
Innovation Solution
A variable-geometry Coanda-type thruster with a flow controller using shims and an actuating apparatus that adjusts the cross-sectional area of primary fluid passages to optimize fluid flow and velocity, ensuring high entrainment and thrust even at non-ideal flow conditions, by actively constricting or expanding the passages to match changing fluid conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a fixed-geometry thruster is used, then the structure is simple and easy to manufacture, but the thrust efficiency degrades significantly at lower primary fluid flow rates
Solution Approach 1:
The patent applies variable geometry to the thruster passages, allowing the passage cross-sectional area to change dynamically based on operating conditions. This is achieved through movable walls or adjustable components that can modify the passage geometry in real-time, enabling the thruster to adapt to varying primary fluid flow rates and maintain optimal performance across different operating regimes.
Solution Approach 2:
The patent changes the geometric parameters of the thruster passages, specifically the cross-sectional area, to optimize performance. By adjusting the passage area parameter in response to changing flow conditions, the thruster maintains efficient fluid dynamics and thrust generation across a wide range of operating conditions, resolving the contradiction between structural simplicity and adaptive performance.
2Use of energy by moving object
If the thruster operates at lower primary fluid flow rates, then energy consumption is reduced, but thrust efficiency and mixing performance degrade rapidly
Solution Approach 1:
The variable geometry thruster dynamically adjusts its passage cross-sectional area in response to changing flow rates. At lower flow rates, the passages are constricted to maintain optimal fluid velocity and mixing characteristics, while at higher flow rates, the passages expand to accommodate the increased flow. This dynamic adaptation allows the system to maintain high thrust efficiency across the entire operating range without excessive energy consumption.
Solution Approach 2:
The patent modifies the geometric parameters of the thruster passages based on operating conditions. By changing the passage area parameter in response to flow rate variations, the system optimizes the balance between energy consumption and thrust efficiency, preventing the rapid performance degradation that occurs in fixed-geometry thrusters at lower flows.
3Productivity
If variable geometry components are added to optimize thrust, then thrust efficiency increases, but device complexity increases
Solution Approach 1:
The patent implements variable geometry through carefully designed movable components that can alter the passage cross-sectional area. These dynamic elements are integrated into the thruster structure in a way that provides significant performance benefits while keeping the overall design as simple as possible, addressing the trade-off between complexity and performance.
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 variable-geometry thruster maintains high performance and increases thrust by up to 20% by enhancing primary fluid velocity and entrainment ratio, overcoming the limitations of fixed-geometry thrusters at varying flow rates, pressures, and temperatures.
Implementation Method 1
A variable geometry Coanda-type thruster with a flow controller using shims and an actuating apparatus
Implementation Method 2
optimizing fluid flow and velocity, enhancing entrainment and thrust
Data Source
AI summary
A propulsion system coupled to a vehicle. The system includes a diffusing structure and a conduit portion configured to introduce to the diffusing structure through a passage a primary fluid produced by the vehicle. The passage is defined by a wall, and the diffusing structure comprises a terminal end configured to provide egress from the system for the introduced primary fluid. A constricting element is disposed adjacent the wall. An actuating apparatus is coupled to the constricting element and is configured to urge the constricting element toward the wall, thereby reducing the cross-sectional area of the passage.