Description of Problem 505: You are given the flow rate through an orifice plate flow meter and are asked to calculate the corresponding pressure drop. Analysis of Problem 505: The relationship between pressure drop and flow rate for an orifice meter is a simple equation available in any Fluid Mechanics textbook. There is a solved example in the ME Review Manual by Lindeburg that is virtually the same as this problem. Here is a problem we've crafted dealing with a venturi flow meter to test your understanding of the equations that apply to these flow metering devices. 
Thermal and Fluid Systems Depth (PM) Exam Sample Problem #5 A venturi meter is installed in a 2in diameter, schedule 40 steel pipe (ID = 2.067 in). The fluid in the pipe is ambient temperature No. 4 fuel oil with a specific gravity SG=0.85. The meter is provided with a Utube manometer. From past experience with this meter, it is known that for a manometer fluid height, h, of 8 inches, the oil flow rate is 400 gallons per minute. 
The average fluid velocity (ft/min) in the pipe just upstream of the meter when the height h=4 inches, is most nearly: (A) 27 (B) 200 (C) 1,225 (D) 1,623 Have questions? Need help? Then leave a comment below. You may download the solution here:
