Abstract
To reduce vibration and noise level, the impeller and
diffuser blade numbers inside an industrial compressor are
typically chosen without common divisors. The shapes of volutes or
collectors in these compressors are also not axis-symmetric. When
impeller blades pass these asymmetric structures, the flow field
in the compressor is time-dependent and three-dimensional. To
obtain a fundamental physical understanding of these
three-dimensional unsteady flow fields and assess their impact on
the compressor performance, the flow field inside the compressors
needs to be studied as a whole to include asymmetric and unsteady
interaction between the compressor components. In the current
study, a unified three-dimensional numerical model was built for a
transonic centrifugal compressor including impeller, diffusers,
and volute. HFC 134a was used as the working fluid. The
thermodynamic and transport properties of the refrigerant gas were
modeled by the Martin-Hou equation of state and power laws,
respectively. The three-dimensional unsteady flow field was
simulated with a Navier-Stokes solver using the