Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Fluctuations in flow measurement

  1. Sep 28, 2010 #1

    I am having trouble to measure the volume flow of a rebound valve with a venturi flow meter. The valve itself starts to open at a certain pressure. But it doesn’t open completely at this point. In the beginning it is more like a flapping which in turn causes fluctuations. With rising pressure it begins to settles to more steady values.

    [0.5 inch ]---- > pressure regulator ----[ 0,5 inch ]---> flow meter –---[0.5 inch ]--> valve

    The inlet of the valve is about 0.8 mm in diameter. My venturi nozzle is 0.5 inches in diameter. I added 100 cm before and 30 cm behind the nozzle to get a laminar flow. I alter the pressure with a pressure regulator by hand and plot a pressure / flow diagram. The date gets recorded automatically.

    My Problem is that I am not able to record any reasonable measuring date! It gets all messed up by the fluctuations. Is there any way how I can reduce the fluctuations?

    I tried a few alternations in the setup of my measurement section. The only thing that really did improve my measurement was when I added a narrow pipe, 6 mm, between the venturi flow meter and my valve. But that functioned more like a lowpass and reduced the flow speed to much.

    The flow speeds are between 0 – 800 l/min. Pressure regulator and flow meter are able to handle this flow speed.

    How can I improve my measurement?

    Thanks in Advance.
  2. jcsd
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook

Can you offer guidance or do you also need help?
Draft saved Draft deleted