Learning Forum

[sapkotadpak]

Hi I couldn't understand the headings of DPM file

   x           y            z            u            v            w     diameter            t    mass-flow         mass    frequency         time         name)

what is the difference between mass flow and mass? Is it of particle or fluid? What is frequency?

I wanna compare the mass exiting the outlet wrt inlet where I have selected flow rate of 0.001kg/sec. which value should I use for the comparison?

[Rob]

Flow rate on the injection (inlet) is the total mass. I find the DPM Report for Escaped Mass to be useful.   The mass / mass flow will be for the particle or parcel and not the fluid. 

[Rob]

OK, the sum of mass-flow equals the injected mass in my test, so is the parcel mass. Mass is the particle mass (density * particle volume).  

[sapkotadpak]

How do I find the number of particles exiting from that outlet ? Can I compute with this mass flow rate?

I have different injections and it seems mass flow rate is same for every injections which is surprising to me

[Rob]

Where is the injection file taken from? Did you create a file for all injections? 

Note, parcels (not particles) are what is reported in the TUI summary, and not all parcels are the same mass. 

[sapkotadpak]

I didn't create it. I took it from the DPM sample for the region Outflow_2

(outflow_2minor

12)

(          x

y

z

u

v

w

diameter

t

mass-flow

mass

frequency

time

name)

(( 8.0408e-04

2.63E-02

-4.81E-02

1.68E-02

9.21E-03

-1.65E+00

1.00E-07

3.00E+02

9.80E-06

5.24E-19

1.87E+13

2.4197e-02)

injection100nm:34)

(( 8.6895e-04

2.46E-02

-4.81E-02

1.63E-02

-1.73E-02

-1.67E+00

2.50E-06

3.00E+02

9.80E-06

8.18E-15

1.20E+09

2.3722e-02)

injection25mum:14)

((-5.9798e-04

2.68E-02

-4.81E-02

4.85E-03

2.14E-02

-1.41E+00

2.50E-06

3.00E+02

9.80E-06

8.18E-15

1.20E+09

2.8561e-02)

injection25mum:16)

[Rob]

So each parcel has the same mass flow rate. What is the mass flow for each injection? What are the injection settings? 

[sapkotadpak]

So the mass flow rate for each injection is 0.001kg/s

surface option - inject using face normal direction

Discrete random wak model -on

particle type -inert

 

[sapkotadpak]

What should I do to find out the particle information?

[Rob]

OK, so each injection is adding the same total mass, that'll explain why (assuming it all leaves through the monitor plane) that you see the same total mass. 

I use the DPM reports in the monitors, there's a change coming with 2023R1 to significantly improve their functionality. 

[DrAmine]

Please do not confuse between DPM Reports and DPM Sample File and Injection File. The latter two are quite similar and DPM sample file can be "usually" used as injection file.

Tha mass flow appearing in the header is the mass flow rate associated with that line as each line is referring to a stream / parcel.

Please refer to Point Properties for File Injections in the Fluent User's Guide to check different injection file options.

 

[sapkotadpak]

Hi I still got some confusions about the particle numbers passing through that specific outlet. I tried looking into Reports>> Discrete Phase>>Summary-unavailable. Could you please provide me more insights about this topic?

[Rob]

You need to create the sample, and then that should read in as a Histogram. Or use the Report option, double click on Report then New as the DPM option is greyed out sometimes. 

[sapkotadpak]

Thank you for the clarification. While clicking on the report, I now have the information on escaped mass in kg/sec. How to get this value for different injections?

[DrAmine]

With Text User Interface Command (TUI), you can enable output per injection (under /report).

[sapkotadpak]

I dont know about the command. Could you please help me with this one? Is there any tutorial /video for this?

[Rob]

I doubt there's a tutorial on this, I did write it up as a solution but that's not public domain at present. 

 

[DrAmine]

The Quick Search Tool (Upper right near Ansys Logo): is useful.