Particle insertion

Hi,
my aim is to simulate the mixing process in which particles are inserted into the cylindrical box and impeller is rotated to mix the particles. I have two issues regarding this one is that some particles are suspended/stick with impeller and cylinder walls and second is if I use a large number of particles than many particles are lost suddenly during mixing.
following is the simple script of the multi-sphere particle mixing having a rod shape structure

### mixcer

### Initialization

# Preliminaries

units si
atom_style sphere
atom_modify map array sort 0 0
boundary f f f
newton off
communicate single vel yes

#processors 2 2 3

# Declare domain

region cyl cylinder z 0. 0. 0.075 0. 0.350 units box
create_box 1 cyl

# Neighbor listing

neighbor 0.003 bin
neigh_modify delay 0

### Setup

# Material and interaction properties required

fix m1 all property/global youngsModulus peratomtype 2.5e7
fix m2 all property/global poissonsRatio peratomtype 0.31
fix m3 all property/global coefficientRestitution peratomtypepair 1 0.5
fix m4 all property/global coefficientFriction peratomtypepair 1 0.4
fix m5 all property/global coefficientRollingFriction peratomtypepair 1 0.01

# Particle insertion

fix pts1 all particletemplate/multisphere 123457 atom_type 1 density constant 2456 nspheres 3 ntry 10000 spheres &
file data/rod1.test scale 1 type 1
fix pdd1 all particledistribution/discrete 63243 1 pts1 1.0

# Create cylindrical box:
fix zwalls1 all wall/gran model hertz tangential history primitive type 1 zplane 0.020
fix zwalls2 all wall/gran model hertz tangential history primitive type 1 zplane 0.33
fix cylwalls all wall/gran model hertz tangential history primitive type 1 zcylinder 0.072 0. 0.

# Import mesh from cad:
fix cad1 all mesh/surface file meshes/impeller.stl type 1 curvature 1e-5

# Use the imported mesh as granular wall:
fix mixer all wall/gran model hertz tangential history mesh n_meshes 1 meshes cad1

# Integrator:
fix integr all multisphere

#rregion in which particlesv are introduced:
region factory1 cylinder z 0. 0. 0.07 0. 0.30 units box

#particle insertion type1
fix ins1 all insert/rate/region seed 123481 distributiontemplate pdd1 nparticles 5000 &
particlerate 16000000 insert_every 1000 overlapcheck yes vel constant 0. 0. -1.0 region &
factory1 ntry_mc 10000

run 100000
unfix ins1

# Define the physics

pair_style gran model hertz tangential history #Hertzian without cohesion
pair_coeff * *

### Detailed settings

# Gravity

fix grav all gravity 9.81 vector 0.0 0.0 -1.0

# Time step

timestep 0.000025

# Thermodynamic output settings

thermo_style custom step atoms ke cpu
thermo 1000
thermo_modify norm no lost ignore
compute_modify thermo_temp dynamic yes

# Check time step and initialize dump file

fix ctg all check/timestep/gran 1 0.01 0.01
run 1
unfix ctg

# Create imaging information

dump dmp all custom 2000 post/dump*.mixer id type x y z ix iy iz vx vy vz &
fx fy fz omegax omegay omegaz radius
dump dumpstl all mesh/stl 2000 post/dump*.stl
dump dmpvtk all custom/vtk 2000 post/dump*.myforce.vtk id type x y z ix iy iz vx vy vz &
fx fy fz omegax omegay omegaz radius

#rotate central shaft
fix movecad2 all move/mesh mesh cad1 rotate origin 0. 0. 0. axis 0. 0. 1. period 2.0

### Execution and further settings

run 100000
unfix movecad2
run 10000