MECH 322 Instrumentation Lab 6 Fluid Speed and Volume Flow Rate Performed: February 27, 2007 Group 0 Miles Greiner Lab Instructors: Mithun Gudipati, Venkata Venigalla

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 measured centerline speed was compared to the centerline speeds calculated from the volume flow rate 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 Conditions, Dimensions and Parameters for Experiment This table presents the atmospheric temperature and pressure during the experiment. It also presents the pipe and tube inner diameters and areas, and the Venturi tube flow coefficient. The manufacturer stated uncertainties of the pressure transmitters are also included.

Table 2 Measured Pressure Transmitter Currents

Table 3 Measurement Reading and Calculated Values This table presents the transmitter 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 uncertainties of the Venturi tube flow coefficient and pressure measurements. When the blower was on, the pipe Reynolds number is within or close to the prescribed range for the Venturi tube calibration, 54,000 < P < 137,000 Blower Condition P V [Pa] P P [Pa] P G [Pa] P [kPa]  [kg/m 3 ] W   kg/m   Q [m 3 /s] W Q [m 3 /s] V C [m/s] W Vc [m/s] V P [m/s] V S [m/s] Re P Blower off , , , , , , , , , , ,491 Blower off ,489 Uncertainty

Figure 1 Measured and Predicted Centerline Velocities Versus Volume Flow Rate When the blower was on, the measured centerline speed was between the values predicted for slug and parabolic velocity profiles. The uncertainty in Q was more significant than that for V C