How to calculate pipeline flow rate?
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1. It is known that the inner diameter of the pipe is 12 centimeters. If there is a gauge pressure of 60 kg/CM2 at the pipe inlet and atmospheric pressure at the outlet, how can the flow rate be calculated? 2. If the inlet pressure is not taken into account, what is the maximum flow rate that can pass through this pipe, and how can it be calculated? Thank you very much!
Calculated using Bernoulli’s equation, the pipe flow velocity is determined based on the pressure difference between the inlet and outlet, and thus the flow rate can be known. Of course, pipeline friction loss and the height difference between the inlet and outlet also need to be taken into account.
This post was last edited by arpcd on 2017-5-11 at 20:42; the original poster can now go work on small-diameter wind tunnels. . . With such a high pressure difference, the exit velocity is directly at the speed of sound. Both of your questions lead to this same result: the maximum flow velocity is the speed of sound, which is 1 M. The backpressure on your vent pipe is 1, while the pressure upstream is 60; thus the pressure ratio is 60. In fact, even a pressure ratio of 2 around the vent pipe is sufficient to result in velocities close to the speed of sound. With a ratio of 60, it’s definitely at the speed of sound. You can simply use 340 m/s for calculations – it’s pretty accurate. If you’re interested, attaching a Laval nozzle to the outlet will enable supersonic speeds, allowing for tests of fighter jet exhaust nozzles. :lol
I would like to ask the teacher: We have a pump with a capacity of 350 cubic meters per hour, operating at an outlet pressure of 5.5 kilograms per square centimeter. It uses DN200 pipes to transfer liquid to a storage tank located 35 meters high. It was found that, about 20 meters after the pump’s outlet, the pressure gauge showed 3 kilograms per square centimeter, and after 1000 meters, the pressure was 2.5 kilograms per square centimeter. The flow rate into the tank was only 80 cubic meters per hour. What’s wrong: L