SCO₂ 离心压气机非定常凝结特性及 DMD 分析

In this paper, unsteady numerical simulations of a centrifugal compressor were performed by employing the Reynolds-averaged Navier-Stoke equation to obtain the unsteady evolution of condensation in the impeller. The results show that a triangular distribution of the condensation region at the pressure surface of the leading edge of the blade appears during a rotation period due to the asymmetric structure of the volute. The high energy ratio modes associated with the condensation in the tip clearance are mainly: the averaged flow mode, and three modes (0.5BPF, 1.0BPF, 1.5BPF) associated with the blade passing frequency (BPF). The low static pressure strip LP1 causes local perturbation of these four modes, and the location of the mode perturbation zone corresponds to the condensation region. Thus, the effect of the low static pressure strip LP1 on the condensation in the tip clearance is revealed from the flow field.