Learning Forum

[kashiraman99]

Hi all:

Can we use a population balance model to have particles with different diameters in my Fluidised bed? If so how?

Is there a better way?

[DrAmine]

Yes. Might be combined with granular model. You might require your own user defined kernels. Other way using DDPM .

[kashiraman99]

Thank you for your reply,

I am trying to find bed height as a function of time, to do this I have written an UDF, which returns the height where the double derivative of the volume fraction is zero(Change of volume fraction is maximum at the interface).

When I tried to compile it showed me these errors

"Copied 1Projects#4FluidisedBed_filescomputational_project_new_filesdp0FFFFluent/1Projects#4FluidisedBed_filescomputational_project_new_filesdp0FFFFluentdifferential_udf.c to libudfsrc

udf_names.c and user_nt.udf files in 2ddp_host are upto date.

(system "copy "C:PROGRA~1ANSYSI~1ANSYSS~1v194fluent"fluent19.4.0srcudfmakefile_nt.udf "libudfwin642ddp_hostmakefile" ")

1 file(s) copied.

(chdir "libudf")(chdir "win642ddp_host")# Generating ud_io1.h

differential_udf.c

C:PROGRA~1ANSYSI~1ANSYSS~1v194fluentfluent19.4.0srcmainglobal.h(9): fatal error C1083: Cannot open include file: 'stdio.h': No such file or directory

udf_names.c and user_nt.udf files in 2ddp_node are upto date.

(system "copy "C:PROGRA~1ANSYSI~1ANSYSS~1v194fluent"fluent19.4.0srcudfmakefile_nt.udf "libudfwin642ddp_nodemakefile" ")

1 file(s) copied.

(chdir "libudf")(chdir "win642ddp_node")# Generating ud_io1.h

differential_udf.c

C:PROGRA~1ANSYSI~1ANSYSS~1v194fluentfluent19.4.0srcmainglobal.h(9): fatal error C1083: Cannot open include file: 'stdio.h': No such file or directory "

The error messages have been highlighted in bold.

I did not type or mention stdio.h in my UDF.

How do I run my udf?

Also, can interfaces be tracked and height plotted without a different way?

Thank you for your time

[DrAmine]

What about using the curvature register directly? Or iso surface of volume fraction. I cannot commend on your error message as it requires looking into the udf.

[kashiraman99]

Thank you for your answers,

I want to get a plot of height of interface vs time step/time, how to achieve that using curvature registers?

 

 

 

[DrAmine]

You can say that the surface height is where the volume fraction of the particulate phase tends to zero or based on average volume fraction in the whole domain. You take that value and create an iso-surface of it. You then report the max. coordinate of it.

 

Check: doi:10.1155/2012/956975