To study the inlet flow field distribution of centrifugal compressor under strong pulsating backpressure

an automatic two-dimensional traversing system for unsteady flow field measurement was developed. The unsteady inlet flow field of the centrifugal compressor under different pulsating frequencies and time-averaged mass flow rate was measured by the traversing system with one-dimensional hot-wire anemometer. The results showed that: both circumferential and radial distributions of inlet velocity and flow angle experienced large periodic oscillations due to the pulsating backpressure. The fluctuation of flow angle was significantly higher at tip than that at the hub. The axial velocity in the circumferential angular region upstream the volute tongue was significantly lower than that in the downstream

and the distortion intensity further increased with the increase of frequency and time average mass flow rate. The maximum radial flow angle difference occurred at about 85% blade height: the maximum flow angle difference was 8 degrees at low mass flow rate and 12 degrees at high mass flow rate. The study proved the unsteady evolution of the inlet flow field of the centrifugal compressor at the conditions of pulsating backpressure

giving the experimental foundation for the theory of the optimal design of the compressor.