The generation of radial gas flow by rotating a combination of parallel disks and screens has been investigated by Monte Carlo simulation.
  This time, the authors studied radial gas flow from a rotor with two different structures. The inner part of the rotor consisted of parallel disks, while the outer part was made up of parallel disks with screens. The rotor, which had an outer part with special off-center screens, was found to have both a pumping efficiency greater than 0.5 and a compression ratio greater than 10⁴ with a velocity ratio rω/<v> of 2, where <v> was the mean velocity of gas molecules and rω was the additional circumferential velocity due to rotation.