5
Operation 2
Operation
2.1 Setting Up the Mini Wind Tunnel - Precautions
A wind tunnel’s performance can be severely diminished if not used properly.
Please follow the following tips:
• Do not use the wind tunnel in small rooms. The air flow creates currents that
undermine the wind tunnel’s accuracy.
• Avoid locating the intake and exhaust toward open windows, door ways or
corridors where people are walking. The effect of air current changes across
the intake has a severe affect on the flow rate changing in the wind tunnel.
• There should be at least 1.5 m (5 feet) clear space in front of and behind the
wind tunnel. No obstacles, moving objects, or open doors or windows.
• Locate the exhaust towards the largest open area of the room to minimize
room air currents. The higher the flow rate, the more chance of creating currents.
• Air Probe geometry affects the readings. There is a correction factor table for
different types of air probes (Hot wire & Vane type).
• The air flow rate of the wind tunnel depends on the air temperature and
barometric pressure. Adjust it accordingly.
• This instrument should only be used for its intended purpose in accordance to
the instruction manual.
2.2 Operating the Wind Tunnel
Before operating the wind tunnel, please follow all the precautions stated in the
previous section and then proceed as follows:
1- Connect the cable from the DC Fan to the back of the Control unit
box labeled 'Fan Control'. Make sure the power switch in the back of the control
unit is off.
2- Connect the AC input of the Control unit to a line voltage (90 to 250 VAC @
50/60 Hz) with the Power cord provided. Please refer to the accessory table for
power cords for other countries.
3- Set the air speed selector switch on the front of the control unit to Zero
position (Meaning Zero air velocity). Turn on the Power switch in the back. You
will see the power LED indicator on the front of the control box turns on.
The air speed selector switch can be set to four fixed air speeds. The wind tunnel
has been calibrated at these four air speeds. The standard conditions are at
70ºF (21.1ºC) ambient temperature and 29.92 inches of Hg of Barometric
pressure. There are four plugs in front of the control unit box. Removing the
plugs, you will have access to potentiometers that will allow you to adjust the air
speed at the four settings.
For Hot wire anemometers:
1- Use the Chamber Door (Solid) to cover the test chamber.
2- Insert the air probe into Port #1 as shown in Fig 1. Port #2 is used to insert a
reference air probe if desired.
3- Align the air probe sensor to the center of the chamber using the scribed line on
the outside of the chamber.
4- Use the Teflon Ferrules and “hand-tighten” the probe in place. Do not use tools or
wrenches.
