ME 391 Instrumentation LAB #6 Volume Flow Rate and Centerline Speed in a Tube Wind Tunnel Performed: 03/05/2004 Soma: I believe I performed 50% of this lab. (Participation: __/50) Sinan Ozcan: I believe I performed 50% of this lab. (Participation: __/50)

Abstract The volumetric flow rate and centerline speed of air in a tube wind tunnel were measured for a range of blower speeds. As a consistency check, the centerline speed for each flow rate was compared to the centerlines speed based on slug and parabolic velocity profiles. The volume flow rate and centerline speed were determined by measuring the pressure from a venturi tube and a Pitot probe using pressure transmitters. The maximum volume flow rate was m 3 /s. The measured centerline speed was bracketed by the values predicted for slug and parabolic velocity for all blower speeds.

Table 1 Atmospheric Pressure and Temperature Readings This table presents the atmospheric temperature and pressure during the experiment. It also presents the pipe and tube inner diameters and areas, and the flow coefficient for the venturi tube. The manufacture stated uncertainties of the pressure transmitters are also included.

Table 2 Measurement Readings and Calculated Values This table presents the transmitter current and pressure differences for the venturi tube, Pitot probe and gage pressure for different flow conditions. The uncertainty of the pressures is also included. The calculated tube absolute pressure, density, volume flow rate and centerline speed are also presented. The uncertainty of the volume flow rate and speed are based on the uncertainties of the venturi tube flow coefficient and pressure measurements.

Figure 1 Measured and Predicted Centerline Velocities Versus Volume Flow Rate The measured centerline velocity is between the values predicted for slug and parabolic velocity.