Multistage radial compressors are major components in plenty of industrial applications. Today, compressor downsizing for CAPEX reduction is of utmost importance. Accordingly, the pressure ratio must be increased, accommodated in a most compact design, accepting nearly no penalties in the performance level achieved so far.
In order to investigate the complex flow in stator parts of multistage centrifugal compressors and to increase the confidence level of numerical methods a new test rig is developed and taken into operation. This test rig allows to separate stationary flow effects from time variant effects leading to an in depth insight into the physical flow features. The aim is to investigate the flow in different stator designs in detail for varying flow coefficients. Additive manufacturing techniques are applied to achieve low costs simultaneously with short production time for the tested parts.
In this publucation, the measured flow field in the stator parts is discussed. The experimental results comprise velocity and pressure data from five-hole-probes and unsteady velocity data from single-film hot-film-probes. Using unsteady velocity data, turbulent statistics such as turbulence intensity and the turbulent kinetic energy will be determined. Subsequently, the experimental results are compared to numerical results. Therefore, (U)RANS simulations are performed using a commercial CFD-code. The simulation results are evaluated at planes appropriate to the measuring planes in the test rig to guarantee a directly comparable data base.