  Purpose - The purpose of this work is to determine dependence of the
separative power of the Iguassu gas centrifuge (GC) on the velocity of the
rotor.
  Design/methodology/approach - The dependence is determined by means of
computer simulation of the gas flow in the GC and numerical solution of the
diffusion equation for the light component of the binary mixture of uranium
isotopes. 2D axisymmetric model with the sources/sinks of the mass, angular
momentum and energy reproducing the scoops was explored for the computer
simulation. Parameters of the model correspond to the parameters of the
so-called Iguassu centrifuge. The separative power has been optimised in
relation to the pressure of the gas, temperature of the gas, the temperature
drop along the rotor, power of the source of angularmomentum and energy, feed
flow and geometry of the lower baffle.
  Findings - In the result, the optimised separative power depends only on the
velocity, length and diameter of the rotor. The dependence on the velocity is
described by the power law function with the power law index 2.6 which
demonstrate stronger dependence on the velocity than it follows from
experimental data. However, the separative power obtained with limitation on
the pressure growth with the velocity depends on the velocity on the power
similar to 2 which well agree with the experiments.
  Originality/value - For the first time, the optimised separative power of the
GCs have been calculated via numerical simulation of the gas flow and diffusion
of the binary mixture of isotope.
