How to plot gas void fraction distribution along pipe depth at different time steps
 

Hi,

I have a vertical upward multiphase flow problem where while diesel is flowing upwards, it is desorbing gas with time and depth (desorption happening due to pressure reduction while going up).


I have specified constant mass transfer coefficient in the setup. Now I want to see the gas (methane) void fraction at different depths at different time steps. So, my plot will be void fraction vs depth (or vice versa) where the it will contain different distribution curves for for different time steps.

Hope someone can help. I am using ANSYS 2020 version FYI.

Thanks.

Voidage Plot
 

Fluent does not maintain data for each time-step. Hence, you will have to extract data at a preset frequency, say, every 5 or 10 or, if you want, every time-step. Since you want a single graph, you can either create multiple lines passing through the domain and have multiple graphs at each time-step or you can use plot commands. There are two options within plot command (this can be done only via commands), caa and car, implying circumferentially-averaged-axial and circumferentially-averaged-radial. What you need to use is caa. You have to ensure proper definition of axis in the cell zone conditions. Default axis direction is (0 0 1). If yours is different, do change it before using the command. You will also have to specify how many sections you want to use along the axis. The maximum possible is the number of cells in the axial direction. You can use a very high number and Fluent will automatically limit it to the maximum. With caa, Fluent determines a single value at one axial location, which is average of all the cells located at that axial location.