Variable Mass Flow Rates
 

Good afternoon fellow Star CCMers!

I am having a problem. I want to have the mass flow rate at the mass flow inlet be varying...building up to a certain number. What is the best way to go about this?

I believe there is a tutorial or a article on the CD-adapco Steve Portal on how to do this. I would do this by having a table that has mass flow rate at each time step and have that imported on the inlet surface of the computational domain. There is definitely a way to do this, but you might have to dig a bit to find it! Good luck!

Like Icarasik mentioned, you could use a table to change the mass flow rate.
You can also do this via a field function, but for that you need to know the relation between the time (or iteration) and the mass flow rate.
If it is changing arbitrarily, then table would be the way to go.

Thanks guys. The mass flow is starting at 0 and increasing to a certain value. So I think the best way to go is the table perhaps then?

that's what i use to vary my inlet velocity. table(time) with two columns

time velocity
.00001 1 (take over after inital conditions)
1 1.5 (ramp up)
5 1.5 (end)
6 5 (ramp up)
....
etc

gotta make sure the table loads properly, if it's unsteady time i prefer to use so i can vary my timestep/inner iterations w/o recaclualating the iteration count and reloading the table.
load table in tools-> tables

i also, to make sure i'm ramping properly will monitor a report for an inlet mass flow rate, i would suggest doing the same.

SB123 Thanks for the advice! I will certainly try this!!

Im trying to import a .csv file into the simulation but I get an error message

"Time table profile method: No time column found in table"

you have to have a column titles 'time' or 'Time' i can't remember, same if you were do do an iteration table

Thanks...its time.

Hi nygrenm, I am getting the same error message even when my column is titles as: time. Did you take any other steps to resolve the issue?

have you figure it out?
it is weird. seems like the software can not read "time"

Had litteraly the same problem as explained aboth. In my case the error was solved by writing the "time" in the .csv file with Big Letter "T" --> Time :confused: