III。VIRTUAL PROTOTYPE TECHNOLOGY AND EDEMSOFTWARE 

Virtual  prototyping  technology  is  a  new  product  design and process  development method  appeared in  early  1990s。  It had  established  a  highly  visible  prototype  of  the  digital simulation  of  physical  prototypes  through  combining  virtual reality, computer simulation technology and CAD technology 

[3]。 EDEMTM is  the  first  multi-purpose  Discrete  Element Modeling  software  tool  in  the  world,  which  is  designed  for the simulation and analysis of industrial particle handling and manufacturing operations。  IV。ROTOR 

MODELING

 In this paper, the  rotor was modeled  by Solid Woks with the  Sandvik  RP109  as  prototype。  Without  affecting  the simulation  results,  the  rotor  three-dimensional  model  was Simplified  by  removing  and  merging  certain  parts,  and keeping the same parameters of rotor radius,  separating cone radius, runner plate installation angle, the size and installation angle of butt ends, total channel export spacing。 Respectively, the  rotor  was  modeled  with  3~8  channels  and  imported  into EDEM  through  the  IGES  format,  the  configuration distribution was showed in Fig。2。 A。  Global Settings The rotor model was imported into EDEM, in which the red  frame  was  the  computational  domain。  The  physical properties was set as the interaction between the particles and the  particles  to  geometry,  the  acceleration  of  gravity  g  along the z axis was -9。81m/s2。according to the documentation and the  survey  data,  the  material  of  rotor  was  steel,  the  material properties were:  Poisson’s ratio ν 0。28, the  shear modulus  G 7。1e+7Pa,density  ρ  7800Kg/m3。The  interaction  coefficient  of material was defined as follows, the restitution coefficient of particles  s1  0。1,the  static  friction  coefficient  f1 0。545,the 

rolling friction coefficient g1 0。01;the restitution coefficient of particles to rotor s2 0。2,the static friction coefficient f20。5,the rolling  friction  coefficient  g2 0。01[4],it  was  can  be  seen  inSet in the rotor speed for 1400r/min, in order to simulate the  practical  feeding  flow,  set  particles  factory  shape  for cylinder  of  the  radius:160mm,  high:100mm,  and  The  same axis  with  the  rotor,  produced  a  total  of  200kg  grain, generating  speed  for  140kg/s,  particle  generation  time  for initial 1e-12s,  generating position inside the  particles  factory random distribution。 D。  Simulator Settings To  ensure  the  simulation  accuracy  and  the  rotor  can throw all the particles, set total simulation time step of 1e-4s, simulation  time  is  2。5s;  cell  size  of  40mm,  a  total  of  9196 cells, set after completion of operations。 

VI。ANALYSIS OF SIMULATION RESULTS 

 In order to properly compare the rotors with different channels, respectively, the average speed-time graph was made with the average speed of particles thrown off the rotor as the vertical axis and the time as the horizontal axis, as shown in Fig。5。 Seen from Figure 5, speed of particles thrown off the rotor with 7,8channels is lowest with significant fluctuations in the average as time progresses。 Speed of particles thrown off rotor with 6 channels live in the middle, not the highest, however, the fluctuation is very small。 Although the speed of particles thrown off the rotor with 3~5 channels is slightly larger than that of rotor with 6 channels, their fluctuations are also great, as shown in Table 1。 TABLE I ARITHMETIC MEAN AND STANDARD DEVIATION OF PARTICLES EJECTED SPEED