Particles problem
 

Hi All, I am simulating a centrifugal pump in which I want to track how fluid particles are flowing. For that I have introduced droplets of same properties as fluid in the fluid domain. The problem is transient and involves sliding rotor mesh. Now problem is that when I post process the results I see the droplets are not moving outside the sliding interface, instead they are bouncing back from that interface which is totally abnormal. In actual case there is no such interface so particles will move spirally outwards. Any idea how can I fix this issue?

Thanks