Educational Wind Tunnels

SMART BLADE has considerable experience in industrial wind tunnel testing. Industrial or Research Wind Tunnels however are generally extremely expensive, bulky and very complicated to operate. For academic, educational and demonstration purposes, small, robust, reliable and low cost wind tunnels are required.

We can offer big and small solutions for this general tasks with our Big Visualization Wind Tunnel and a new, small and flat Mini Visualization Wind Tunnel.

CAD view of the big Visualization Wind Tunnel with its mounting frame

Visualization Wind Tunnel

In order to demonstrate some basic principles of wind tunnel testing, the research team of SMART BLADE designed and constructed the "Visualisation Wind Tunnel". It is an affordable, low turbulence, low noise, portable wind tunnel, ideal for flow mechanics' lectures as well as for general eye-catching demonstrations.

The visualization wind tunnel was designed based on the established closed-loop wind tunnel principle. The general design was based on analytical state of the art calculations while the final dimensions were decided after several numerical flow simulations with in-house CFD tools. The flow visualisation is generated with water particles (produced with an Ultrasonic Humidifier) and turned into streamlines with the hot-wire technique. The test models are built from laminated, precisely cut, foam blocks or are 3D printed and their angle is adjusted through a digital servo system.

Section view of the CAD model of the wind tunnel
Flow visualization (velocity contours) from the CFD simulations of the wind tunnel

Details: The Fan

The fan used in the SMART BLADE wind tunnel is an axial 100W - 24V (DC) unit. It has an efficient blade design which provides silent and smooth operation. The precise speed variability of the fan (0-2750 min-1) allow for a very fine flow velocity regulation inside the wind tunnel. At the standard wind tunnel version the velocity at the test section can be regulated between 1 - 12 m/s. The low free stream velocities are required for smooth and clear flow visualization while the higher velocities are necessary for aerodynamic force measurements.

Isometric section view of the axial fan and part of the divergent-convergent segment of the wind tunnel

Details: The Test Section

The test section of the wind tunnel comprises a measurement box which has a large opening on one side for easy access and unobstructed view. The measurement box is internally covered with non-reflecting material which provides a good contrast and a suitable background for flow visualization. The opening of the measurement box is covered by a glass, to remove any external flows that might influence the flow visualization results.

SMART BLADE can provide laminated test wings of some basic types of airfoils or CNC machined test wings of any airfoils type or any other desirable shape. The test wings are attached on a rotating mounting system which allows their easy replacement. The mounting system is driven by a digital servo which can vary the Angle of Attack (AoA) of the test wing. The digital servo be controlled manually, can operate is automatic loops or can be externally controlled through a computer (USB port) via the existing servo controller.

The test section is also equipped with a heated lateral grid which generates the necessary streamlines out of the uniform "fog" of water particles. The heating power of the grid can be regulated from the user thus regulating the thickness of the generated streamlines. Another flow fine tunning possibility is provided to the user in the form of a manually adjustable back-pressure flap. This device regulates the cross-section of the tunnel just before the axial fan thus allowing the user to fine-tune the free-stream velocity.

The test section of the SMART BLADE wind tunnel with the adjacent heated grid and some test wings

Flow Visualization & Other Experiments

The low turbulence levels of the SMART BLADE wind tunnel in combination with the effective flow visualization concept and the dynamic test wing control provide many interesting possibilities for experimental investigations. The manual precise AoA adjustment permits the demonstration of several flow phenomena such as:

- Upstream & Downstream streamline deflection

- Trailing edge stall

- Boundary layer flow reversal

- Leading edge stall & Vortex bursting

- Laminar separation

- Karman Vorticex Streets

- Wake roll-up

- Magnus effect

- Nozzle & Diffuser flow visualization

- Vehicle profile flow visualization

 


NACA 4412 airfoil at large negative AoA. Note the leading edge vortex at the pressure side (Top) and its bursting (Bottom). Note also the trailing edge wake roll-up
Visualization of Karman vortex streets behind test structures of different diameter

Available Versions

The tunnel is available in two versions: Baseline and FlowVis

The Baseline version provides the basic functions of a wind tunnel whereas the FlowVis version has an integrated system for generating streamlines for flow visualizations without any additional equipment (e.g. smoke machine). The flow visualization is generated by water vapour.

Baseline Version Specifications:

-Wind tunel with axial variable speed fan

-Electric control panel for fan speed regulation and switches for LED light sheet

-Closed Test section:

-Access through removable window made of safety glass with anti-reflection coating

-Pin for attachment of wings or test bodies, angle adjustable mechanically via knob

-Two test airfoils with different profiles

-Shut-off valve for manual flow regulation

-power supply

-four steering rollers (including two breaks)

-Flow straightener

-Flow screens

-User manual

FlowVis Version Specifications:

-Wind Tunnel with integrated flow visualization

-Axial variable speed fan

-Heat-grid assembly

-Electric control panel for fan speed regulation, and switches for fog, heating and light sheet

-Closed test section: 2 LED arrays for light sheet generation in test section (top and bottom)

-Access through removable window made of safety glass with anti-reflection coating

-Pin for attachment of wings or test bodies, angle adjustable mechanically via knob

-Two test airfoils with different profiles

-Shut-off valve for manual flow regulation

-Floating piezo-electric ultrasonic atomizer with water tank

-power supply

-Distilled water consumption (approx.): 400ml/h

-four steering rollers (including two breaks)

-Flow straightener, flow screens for low turbulence level

-User manual

FlowVis version of the Visualisation Wind Tunnel with integrated control cabinet

Technical Details

- Maximum free stream velocity: 9m/s (12m/s with High Speed Option)

- Free stream velocity for visualization: min. 1m/s

- Dimensions of wind tunnel: l=2.2m, h=1.2m, w=0.44m; h=1.7m total height including support frame & wheels

- Dimensions of test section (visible area): l=0.72m, h=0.37m, w=0.2m

- Wing model size: a=110mm, b=190mm

- Weight of wind tunnel and frame (depends on version): 150-300kg

- Power usage: max. 300 W

- Distilled water consumption (approx.): 400ml/h

Modules and Accessories

Further modules have been developed for different purposes:

With the High Speed Option, the speed in the test section can be increades up to 12 m/s.

With the Smartest option (Control and measurement package), the tunnel comes with a software and hardware package: Touchscreen, Mini PC with Windows(C) OS, Labview(R) with software for wind tunnel control. This is ideal in combination with a balance to measure forces and to plot polars.

Encasement for use e.g. in museums. Color and Material can be chosen.

2 component balance (lift and drag) with program showing polars during automated measurement. Includes servo.motor for automatic angle of attack variation.

3 component balance (lift, drag and pitch moment) with program showing polars during automated measurement. Includes servo.motor for automatic AoA variation.

Test bodies: custom made test bodies on demand.

Velocity measurement: Integrated pressure transducer and software module for velocity measurement.


Mini Visualization Wind Tunnel

We're about to prepare information on the new Mini Wind Tunnel we can offer. More comming soon... Please ask for information via email below!


More Information

For more technical information, custom design requests and pricing please
contact us at: info[at]smart-blade.com