Hi, thanks for your reply.Â

I have used the following formula to calculate the total mass flow rate (kg/s) = volume fraction/volume of particle multiplied by the area of the geometry (2D pipe) and by the particle velocity, and the calculated value 11 kg/s. However, the solver could not complete the calculation with the message ''reverse flow'' ''turbulent viscosity limited'' and ''floating point error'' when this value is set. Hence, I set the value to default (1e-20) and the simulation completed but the solver returns a value zero for particle radial distribuion even when it says some particles are trapped on the walls.Â Â

Some assistance with setting the mass flow rate and how many particles are injected when the surface type injection is set would be boost.Â

Many thanks,