• State Resolved
  • Replies 5 replies
  • Subscribers 78 subscribers
  • Views 138 views
  • Users 0 members are here
Support feedback
Options
Options
Similar topics

Original question:

EVM430-FR6043: How to calculate Volume Flow Rate

EVM430-FR6043: EVM430-FR6043: How to calculate Volume Flow Rate (2)

Igor Man
Prodigy 30 points
Part Number: EVM430-FR6043

Tool/software:

Hi! I have EVM430-FR6043 Evaluation board.
My tube configuration is shown in the picture below.

The length L is not much larger than the radius of the pipe r (L is 8 cm and r is 2.5 cm) so I have to take r into account.

I want to calculate the Volume Flow Rate for gas (not for water). I already asked this question and I know that there is a formula how to calculate v (velocity of gas flow). This formula doesn't contain r (radius of the pipe) but this formula contains c (the velocity of the ultrasound in the gas). I don't know c and don't know how to calculate it. I think c depends on the temperature, gas composition, pressure. I can measure the temperature of the gas, but I don't know the gas composition. I saw a formula and a figure "Temperature vs. Sound velocity in water", but I didn't see it for gas.

So my question is how to calculate the Volume Flow Rate for gas? Should I calculate c (the velocity of the ultrasound in the gas) or maybe there is a formula how to take into account the radius r ?

  • 0
    TI__Mastermind 30625 points

    Hi,

    In theory, the volume flow rate(VFR) is calculated by Meter Constant * dTOF / (absTOF1*absTOF2). The dTOF and absTOF is calculated by the USS library. The Meter Constant is getting from flow test with a reference meter. 

    In flow test, assume you read from the reference meter, it is 100LPH now. Then you read out the dTOF and absTOF from the USS library. Then you can get the meter constant value now. No need to know the c to calculate the VFR

    Best regards,

    Cash Hao

  • 0 in reply to Cash Hao11
    Prodigy 30 points

    Am I right that I have to calculate the Meter Constant many times for different values of temperature and gas composition ? And then I have to use the proper value of the Meter Constant ?

  • 0 in reply to Igor Man
    TI__Mastermind 30625 points

    Hi,

    Yes, you need to calculate Meter Constant many times under different conditions. 

    Best regards,

    Cash Hao

  • 0 in reply to Cash Hao11
    Prodigy 30 points

    It is easy to measure the gas temperature, but I'm not sure I can measure the gas composition :-(   So am I right that this configuration

    is not suitable for gas measurung? (Because I need to know the gas composition or the velocity of the ultrasound in the gas for correct measuring).

    And for gas measuring I have to use one of these configurations :

  • +1 in reply to Igor Man
    TI__Mastermind 30625 points

    HI,

    Yes. Usually, the gas meter uses those two kind of pipe design. 

    Best regards,

    Cash Hao

**Attention** This is a public forum