Application Note...

DPG 2101 Digital Pressure Gauges

Application:

Wind Tunnel System Monitor

Challenge:

Typical of most wind tunnel applications, one system is used for the overall monitoring of actual wind conditions in the wind tunnel. Other systems are predominately used to take measurements on the test device. The system for calculating the airspeed must deal with the extreme non-linearity's of the pressure to airspeed equation. Slow air speeds generate very small changes in pressure. Larger air speeds generate more reasonable pressures. These two distinct pressure requirements (high resolution and wide dynamic range) are also compounded by the fact that the control rooms can be 100 feet or more from the actual wind tunnel. Either the pressure lines must be run from the wind tunnel into the control room or pressure sensing must be done in the tunnel and electrical signals sent back. Both situations present their own set of problems.

Solution:

Mensor supplied sets of two digital pressure gauges. These gauges were placed in the control room and connected using existing pressure lines to the wind tunnel. Pressure ranges varied based on the air speed capability of the wind tunnel. One unit was typically a barometric range device used to measure the static pressure and the other was a gauge, differential, or bi-directional device used to measure the impact pressure. The DPGs displayed the static pressure and the impact pressure in the control center. The digital outputs of the DPGs were also connected to a data acquisition system that calculated the actual airspeed and provided a permanent record of the data.