The influence of frequency and clocking on stator wake in an axial-radial combined compressor

The unsteady flow in a combined compressor, which consists of axial flow and radial impellers, was simulated numerically at mass flow of 1.15 kg/s and speed of 60 kr/min (design point), and an in-depth analysis of the related factors caused stator wake flow variability was performed. This paper explored the major factors decided stator wake unsteady flow, as well as found out a method to control the stator wake unsteady flow. The research results indicated that: the blade passing frequencies of upstream and downstream moving blade rows decided the periodicity of stator wake unsteady flow; and when the upstream rotor had the same blade passing frequency as downstream rotor, the clocking could modify stator wake unsteady flow and the relative flow angle at inlet of radial rotor.