3. A square edged orifice meter with corner taps (as shown in Figure 3) in a nominal 4-in- pipe (4.026 in ID) is to be used to measure the flow of air. At the upstream section, the temperature is 320°K and the pressure is 100 psia. The maximum flow is expected to be about 72 Ibm/min. Determine the throat diameter of the orifice plate if a maximum pressure drop of 28 inches of water column at 320 °K is obtained from the corner taps (For air, y=1.4 and R=287.0 J/kg-K). (Answer must match to 3 decimal places.) Figure 3 Orifice meter used in Q3. [30 marks]