DESCRIPTION |
One of several wind tunnels operated by Arizona State University at the Planetary Aeolian Laboratory at NASA Ames Research
Laboratory, Moffett Field, CA, Building N242.
The tunnel is of open circuit design and is 12 meters long (40 ft.). It is constructed in five sections mounted on casters and
can be disassembled. The first three sections are 0.9 meters high by 1.2 meters wide in cross-section. The first section includes
the entry cone and is constructed of plywood and masonite. The next two sections have a plywood floor, plexiglas walls, and
plexiglas ceilings. These two sections comprise the test area. The last two sections are the tunnel diffuser. The vertical
dimension of these sections increases from 0.9 meters (3 ft.) to 1.6 meters (5.33 ft.). These sections are of plywood construction
and they contain the air ejector and fan drive systems.
During low pressure operation, tunnel flow is driven by the air ejector system. This system is powered by pressurized air supplied
by an Atlas Copco 75HP air compressor dedicated to building N242. This compressor produces air flow at a rate in excess of 260 CFM
with a maximum final pressure of 183 psi. The compressed air is stored in a 30,000 gallon tank located north of building N242.
Pressurized air is supplied to building N242 from this storage tank via a series of two and three inch pipe lines. The air supply
for the air ejecttor system arrives at a nominal pressure of 175 psi and is controlled by a two inch motor driven ball valve.
Maximum tunnel flow velocity with this system is 120 m/s (390 ft/sec) at 5.3 millibars (4 mm Hg). During operation at standard
atmospheric pressure, tunnel flow is generated by the fan drive system attached to the end of the tynnel. The maximum tunnel flow
velocity with this system is 10 m/s (33 ft/sec).
Tunnel instrumentation includes a static probe, a traversing boundary layer probe, and a temperature/humidity transmitter. The
probes are permanently attached in the test section of the tunnel and the temperature/humidity transmitter is suspended in the
tower adjacent to the tunnel. Data from these instruments are delivered to the control room computer for interpretation. A
removable flow straightening screen is currently in place to control boundary layer turbulence.
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