Author Topic: How do I get contour plot of D32 (Sauter Mean diameter) over a plane in Fluent  (Read 5598 times)

Offline infocfd

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I want to plot contours of D32 (sauter mean diameter) in Fluent? I am modelling spray simulation.

Thank you.

Offline william

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Attached is a udf to calculate particles mean diameter (including D10, D20, D30 and D32) for each cell. After this udf is hooked up, you can draw the contour of any of the above mean diameters on the graphics window just like any flow variable.

To use this udf, you need to follow the following procedures:

(1) copy this udf "spray_sample.c" to your working directory where Fluent case/data files of a converged spay simulation are saved.

(2) compile that udf and create a udf library: launch Fluent and read in your case/data file; go to the Define/User-Defined/Functions/Compiled panel, add "spray-sample.c" to the source list, and hit "Build" to generate a udf library. After the library is built, click "Load" button to load in the udf.

(3) Hook up the udf:
a) Go to the Define/User-Defined/Memory panel and set 10 UDMs.
b) Go to the Define/User-Defined/Function Hooks/Adjust and hook up "adjust_spray"
c) Go to the Define/Discrete Phase Model panel to hook up "body_force_spray" to Body Force under User-Defined Functions, and also set Number of Scalars to be "1" in that panel.

(4) Run more iteration. The more iterations you run, more particles will be used to get those statistics.

(5) Draw contour of those mean diameters.

The above procedures give you particles mean diameters at each cell. If you want to know particles mean diameters across a particle cut plane,
Let¿s say D32, you can use the following procedures:

(1) Go to the Report/Surface Integrals to calculate Sum_(n_k*d_k**3): choose "Integral" under Report Type and "User Defined Memory" and
"udf-3" user Field variable, and pick up a cut-plane in the Surface list. Click "Compute" will give you Sum_(n_k*d_k**3).

(2) Calculate Sum_(n_k*d_k**2) in the same panel: choose "User Defined Memory" and "udf-2" user Field variable and click "Compute" to obtain

(3) D32=Sum_(n_k*d_k**3)/Sum_(n_k*d_k**2).