How to avoid parcels being deleted in DPM with Droplet breakup model
When the particle collision-breakup model is used, streams with insignificant mass or numbers in parcel are deleted. It is possible to decrease the minimum mass or number of particles in parcel.
Use the text user interface commands,
(rpsetvar 'dpm/minimum-parcel-mass 1e-25)
(rpsetvar 'dpm/minimum-parcel-number 2)
I have checked these for Fluent 6.1.22 in Linux platform. Copy and paste these commands as they are in the main Fluent console. You might change the values that I have specified.