Thanks for your reply

In my case i want to perform multi-phase flow using DDPM model

I want to calculate the efficiency by giving mass flow rate as input at DPM injection tab

from the given mass flow rate i want to find the number of particles trapped and escaped,so that i can calculate my collection efficiency  

To be clear I want to find the collection efficiency of a cyclone separator

Maximum skewness for mesh was 0.93

Minimum orthogonality was 0.14

I have given mass flow rate at the particles as 0.25(i do not think this is something close to zero)