Wind Tunnel Fan Drive Train With External Motor and VFD Control
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Solution Overview
Problem
Wind tunnel systems for skydiving are inefficient, costly, and hazardous due to high power requirements, inadequate safety mechanisms, and large nacelle size, leading to operational challenges and increased maintenance needs.
Innovation Solution
A system with a single fan and motor, where the motor is located outside the nacelle and connected via a ratio gearbox and jackshaft, reducing horsepower requirements and eliminating the need for supplemental cooling, while incorporating a variable frequency drive and lubrication system for enhanced control and safety features.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a motor is located inside the nacelle to directly drive the fan, then the power transmission is direct and simple, but the nacelle size increases and accessibility is reduced
Solution Approach 1:
The motor is extracted from the nacelle and relocated to an external position. The patent describes moving the motor outside the nacelle structure, connected to the fan through a ratio gearbox and jackshaft arrangement. This extraction reduces the nacelle footprint while maintaining the drive function through the intermediate mechanical transmission components.
2Productivity
If high horsepower motors are used to drive the fan at high speeds, then the fan can generate sufficient air flow, but the power consumption and energy requirements increase significantly
Solution Approach 1:
The system employs dynamic speed control through a variable frequency drive (VFD) that adjusts motor speed based on operational requirements. The patent describes controlling the motor within a defined speed range (e.g., 500-1915 RPM) to optimize air flow generation while minimizing power consumption, eliminating the need for supplemental cooling and reducing energy waste.
Solution Approach 2:
The patent changes the operational parameters of the motor by implementing a ratio gearbox that transforms high-speed low-torque motor output into low-speed high-torque fan rotation. This parameter transformation allows the use of a smaller, more energy-efficient motor while maintaining the required fan performance.
3Reliability
If multiple fans and motors are used within the wind tunnel, then redundancy is provided, but the system becomes more complex and requires more power
Solution Approach 1:
The single fan design is engineered to perform multiple functions: generating upward air flow for flight simulation, providing inertial support during power loss, and enabling safe flyer descent. The patent describes how the fan's mass and inertia serve as a safety mechanism, allowing it to maintain rotation and provide controlled descent during electrical failures without requiring backup systems.
4Productivity
If the motor operates at high speeds to drive the fan, then the fan performance is optimized, but supplemental cooling becomes necessary
Solution Approach 1:
The variable frequency drive dynamically adjusts the motor operating speed within an optimized range that balances fan performance with thermal management. The patent specifies operating the motor between 500-1915 RPM, where the lower bound ensures adequate cooling without supplemental systems while the upper bound maintains fan performance requirements.
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 power consumption, enhances reliability and safety, and decreases the nacelle size, allowing for more efficient operation and reduced maintenance costs while ensuring safe airspeed control during power loss, thus improving overall system performance and user safety.
Implementation Method 1
a ratio gear box directly connected to the fan; and a motor disposed remote from the nacelle for powering the fan via a jackshaft and the ratio gearbox
Implementation Method 2
the single fan has sufficient mass and inertia in relation to the wind tunnel such that the rotation rate is reduced at a sufficiently slow level to enable a flyer (person or user) to be lowered
Implementation Method 3
a variable frequency drive positioned remote from the wind tunnel and configured to regulate the speed of the motor within a range sufficient to negate supplemental external cooling of the motor
Data Source
AI summary
A flight simulator having a wind tunnel with a vertical flight chamber and a second vertical chamber communicatively coupled thereto via air flow conduits. A nacelle disposed within the second vertical chamber includes a fan and a ratio gearbox connected to the fan. A motor is disposed remote from the nacelle for powering the fan via a jackshaft and the ratio gearbox. A variable frequency drive responsive to a control signal from a programmable logic controller regulates the speed of the motor.