# Volumetric flow rate

1. Mar 14, 2005

### Ehsans

hi ,
I have a question that if you answer it I would be so thankfull, Q is:
"Can we calculate volumetric flow rate without knowing cross-sectional area?
If,yes,How?"

I have this Q because I see a portable Thermometer,volumetric flow rate meter ,which show it without giving any area size!!

Thanks lot,
Ehsan

2. Mar 14, 2005

### FredGarvin

What flowmeter do you have?

3. Mar 15, 2005

### Artman

Collect what is flowing in a measured container and time it.

Is this a theoretical question, or an aplication for which you need a calculation or measuring method?

4. Mar 20, 2005

### Ehsans

Hi artman,
I want to know how it works,maybe Theoretical or aplication :)

thanks ,
Ehsan.

5. Mar 20, 2005

### Ehsans

Hi Fred ,
I haven't it , just saw it in university.

thanks,
Ehsan.

6. Mar 20, 2005

### Integral

Staff Emeritus
You really do not provide enough information to enable a meaningful answer. What kind of flow meter are you talking about?

I am currently working with ftp://ftp.captor.com/docs/Datasheet_4311-30-US.pdf[/URL] it is a calorimetric mass flow meter, that is it measures the amount of heat carried off by the flow. The output is a 4-20ma signal which is proportional to the flow rate. Internal electronics "know" the physical parameters about the flow meter, so I do not need to.

Last edited by a moderator: Apr 21, 2017
7. Mar 20, 2005

### FredGarvin

The whole point of the flow meter is to give you the flow rate. Granted, proper calibration is a must, but that is the point of the instrument. Rephrase your question so we can better understand what it is you are looking for.

8. May 2, 2005

### quark

I am a bit late. Actually true mass flowmeters can directly measure mass glowrate and then it will be converted to volume flowrate. Thermal flowmeters based on calorimetric principle, as suggested by Integral, measure mass flowrate by sensing increase in temperature as heat flows from a resistor to the flowing fluid. The simple equation used is Q = mxCpxdT. Q is the constant heat flowrate supplied by the resistor, m is mass flowrate of fluid, Cp is its specific heat and dT is temperature difference.

Corriolis mass flowmeters measure the force exerted upon a sensor(based on the mass flowrate). These two devices don't require pipe size input. However, for better accuracy and lower pressure drops, a velocity range is specified.