Volume I - Section IV - Experimental Work and Verification of CFD Methodology 
Page IV - 7 
Procedure to Set an Approach Velocity 
The wind tunnel air velocity was determined by a calibrated thermal anemometer (LAT model 
AVS-94A-10X). The anemometer was placed in front of the cage, centered on the cage. Air 
velocity within the cage wind tunnel was adjusted using a voltage regulator (Variac Auto 
Transformer) to adjust fan speed, a bypass door, and for lower velocities, a pressure restriction. 
Velocities were adjusted until the desired approach air velocities (15, 20, 30, 40, 50, 60, 70 or 80 
fpm (0.076, 0.10, 0.15, 0.20, 0.25, 0.30, 0.35 or 0.40 m/s respectively)) were read from the 
anemometer, in the form of a corresponding voltage. Air velocities were controlled by a 
centrifugal fan (0.15m (approx. 6") diameter inlet) and exhaust was vented through a flexible 
conduit (0.20m (approx. 8" diameter)) to the outside. 
Anemometer Calibration 
The LAT AVS-94A was calibrated prior to each test in a wind tunnel calibrator (TSI model 
8390). Velocities within the calibrator were precisely calculated by the manufacturer and 
presented in a table that related pressure differences to chamber velocities. To sense pressure 
differences within the chamber, a Dwyer Micro Detector micromanometer was used. As a safety 
check the micromanometer values were compared to pressure readings displayed by a digital 
pressure transducer (TSI model 8910). Calibrating the anemometer used to determine the 
approach air velocities required taking data at the desired approach air velocity (15, 20, 30, 40, 
50, 60, 70 or 80 fpm (0.076, 0.10, 0.15, 0.20, 0.25, 0.30, 0.35 or 0.40 m/s respectively). For each 
calibration temperature, sensor voltage, transducer reading, and micromanometer data were 
taken for the desired approach air velocity. Temperatures were taken near the calibrator using a 
SAMA mercury thermometer. The date and time of calibration was recorded. Calibrator 
pressures were regulated by adjusting the wind tunnel fan speed with a voltage regulator (Dart 
250). Pressures were adjusted until they matched the pressures corresponding to the desired 
approach velocity. When the desired pressure was reached the sensor voltage was noted and the 
sensor was placed into the wind tunnel. 
4.1.1 .4.2 Specific Series Procedures 
Siting of Sampling Tubes 
The question of locating the sampling tubes was considered prior to the series set base 
experimental measurements. The cage air exchange rates were measured with the tracer gas 
method using CCF as the tracer gas. When tunnel air approaches a cage, air is drawn from one 
part of the cage and fresh air enters the cage at another location. Therefore, air has to be sampled 
at both the entering and exiting locations of the cage. Smoke sticks (titanium tetrachloride) were 
placed into the cage to visually determine the locations where air entered and exited the cage in 
order to determine the locations for the sampling locations. Refer to figures 4.05 through 4. 10 for 
the placement of the air sampling tubes. 
