Numerical analysis of centrifugal compressor operating in near-surge conditions

In order to reproduce the near-surge operation of centrifugal compressor a series of numerical simulations in ANSYS CFX have been conducted. Different settings of boundary conditions have been investigated in purpose of providing a combination allowing to model surge without non-physical flow constraints. This, in turn, would be a step towards modelling of anti-surge system. As the conclusions, it was observed that there is no possibility of simulating near-surge working regime without mass flow rate definition as a boundary condition. However, it is achievable to determine a throttle characteristic, which can be used as a function defining the outlet pressure and indirectly the mass flow rate. In case of transient simulations, it would allow to analyse both steady and unsteady regimes of the flow in a centrifugal compressor.