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-   -   How to get flow rate in litre/minute in fluent (https://www.cfd-online.com/Forums/fluent/180055-how-get-flow-rate-litre-minute-fluent.html)

rsaurabh November 15, 2016 15:46

How to get flow rate in litre/minute in fluent
 
Hi all,
i am doing a 2-D simulation where i wish to get flow rate in litre/minute but in fluent i have no such option. for now i am use following conversion-

litre/minute=10^(-3)m^3/60s
(m^3/s)*density(Kg/m^3)=Kg/s

i just want to know, is this way of doing it correct or not?
thanks in advance.

regards
saurabh

CFD-fellow November 16, 2016 00:02

Hi
Go to define-> units->volume flow rate
make a new unit by putting its factor in regard to m3/s.

rsaurabh November 16, 2016 06:04

Hi,
Thanks for your kind reply. i hope this will help.

rsaurabh November 16, 2016 07:00

Hi,
i have checked my results but still i can not see flow rate in m^3/s in solution reports. where can i check volume flow rate in reports instead of mass flow rate?

oozcan November 16, 2016 07:09

reports>volume integrals>

rsaurabh November 16, 2016 07:16

It is giving me only m^3. so should i consider it as m^3/s

oozcan November 16, 2016 07:22

reports>surface integrals>report type> volum flow rate,

or mass flow rate / density = it gives you ''volume flow rate''

rsaurabh November 16, 2016 07:28

Thanks, i get it.
but i have to define zero static pressure at outlet and some value for total pressure at inlet to get desired flow rate in m^3/s. so i am giving value 100 at inlet and zero at outlet and operating pressure is zero. are these BC's true or will give me wrong result?

oozcan November 16, 2016 07:34

So, let you re-correct me,

outlet is found in atmospheric field.Is it correct?. That's why you called it ''0'' (zero)

Operating pressure must not be 0, otherwise, that will be a ''vacuum''. Operating pressure is generally 1 atm.

rsaurabh November 16, 2016 07:37

The paper i am following states that zero static pressure at outlet, some value at inlet to get desired 5 litre/minute flow rate. in it there is no mention about operating pressure. but my geometry works for pressure range 80-120 mm Hg.

oozcan November 16, 2016 07:43

Well,

you need to define pressure_inlet BC. and gauge total pressure 100 bar( are you sure, watch out the unit!!), and supersonic/initial gauge pressure is 0,As for, outlet_pressure, gauge pressure is 0, target mass flow rate 5 lt/min (convert to kg/s)

rsaurabh November 16, 2016 07:57

i have done the simulation but the velocity contour has velocity very less velocity compare to original results. there maximum velocity is around 1m/s but mine maximum is coming 0.336m/s. so i am not able to figure out what is the problem here.

oozcan November 16, 2016 08:02

check scale your model in FLUENT. All dimensions are correct or not!,

Then, your fluid domain maybe should be extended if there is heat fluxed wall,

and which model have you defined?,turbulence or laminar, maybe you can need to change your model if you want to have correct result.

rsaurabh November 16, 2016 10:00

i have checked all dimensions are correct and using turbulence model. for your understanding i am attaching my case file here.

https://drive.google.com/file/d/0Byn...ew?usp=sharing

oozcan November 16, 2016 12:27

I have checked it, I am going to adjust ;)


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