Connect the high pressure hose of the 5 inch dp cell

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Connect the high-pressure hose of the 5-inch DP cell to the static pressure port of the UPSTREAM Pitot-static probe. Connect the low- pressure hose to the static pressure port of the DOWNSTREAM Pitot-static probe. The DP cell will now indicate the pressure difference between the probes. b. Make sure to record two channels (the pressure drop across the orifice and the pressure difference between the static pressure upstream and downstream). Turn the fan ON and sample the output of the DP cell connected to the static probes as well as the DP cell connected to the orifice meter. Make sure the static probes are properly aligned with the flow. Record the mean values and standard deviations for each DP cell by exporting the data to a file. From the data we can compare the duct non-recoverable pressure drop (the difference between the static probes) with the total duct flowrate measured by the orifice meter. c. Obstruct the duct outlet, using the gate valve, to reduce the duct flowrate and then repeat the two readings from step 2b. Repeat the measurements for five flowrates with orifice DPs of approximately 2.2, 1.8, 1.5, 1.0, 0.7 and 0.3 inches of water. You don't have to match these values, just use similar spacing between them, and record the values . Note that these values appear unevenly spaced because pressure drop across the orifice plate, your reference
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ME 4600:483 Lab Notes Revised 11/16/2015 Flow Measurement Page 10 of 18 measurement of duct flowrate, is related to the square of the flowrate rather than linearly related. 3. Repeat the room temperature, barometric pressure and humidity measurements for use in the error analysis. Clean up and leave the equipment in an orderly state . V. Required Data Analysis 1 a. Find the volumetric flow in the duct using the mean orifice pressure drop measurement. You must iterate on the orifice coefficient K 0 (from Figure 2) and Re for the duct (which is based on the duct diameter and velocity, not the orifice parameters). Evaluate the volumetric flow rate, average velocity and Reynolds number in the duct. Is the flow laminar or turbulent? b. Evaluate the precision and bias uncertainty in the measured value based on the standard deviation (precision) and manufacturer's uncertainty (bias) on the pressure measurement, variations in the room conditions and the accuracy of the orifice coefficient lookup. 2 a. Make two plots of the duct velocity as a function of duct diameter (using zero as the center of the duct), calculated from the dynamic pressure measured with the pitot-static tube during the two vertical traverses. Assume V=0 at the pipe wall. Do the velocity profiles look symmetric about the center? Do the measured profiles appear to be laminar or turbulent in nature? Can you determine if the flow is fully developed at any of the traverses?
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