hi，To set up the internal particle model, the momentum, mass, and energy equations will change, and where should the UDFs for heat and mass transfer be set?
Please provide more detail about exactly what you are trying to do.
1.If I want to obtain the temperature gradient inside the particles and use the finite difference method to solve it, which inlet should I use for the UDF processing
2. If assuming that cp changes over time, where should be modified for udf processing
Internal temperature can only be modeled with the glued sphere approach (GSP). You do not need to write UDFs for that.
If you define species, cp will be a function of temperature and will change if the temperature changes over time.
Thank you for your reply, but I want to calculate the thermal conductivity of single particles using DEM, so where should the UDF be modified? Additionally, if I want to couple the three-parameter model for particle shrinkage, where should the UDF be modified?
Please see
https://mfix.netl.doe.gov/doc/mfix/24.3/html/reference/user_defined_functions.html
You probably want to modify one of usr_properties.f, and one of the usr*_des.f files, depending on how and when you want to calculate these factors.