Study on the Effect of Impeller on the Air Supply Parameters of a Partial Intake Pre-Swirl System in an Aero-Engine

In order to reduce the specific fuel consumption of an aero-engine and improve its economy, a partial intake strategy in a pre-swirl system is adopted in the cruising condition to reduce the bleeding air flow from the compressor. The influence of partial intake air on the characteristic parameters such as air supply mass flow rate and air supply temperature of the pre-swirl system is studied. The simulation is conducted mainly for the presence of impellers in the cover-plate cavity under the operating conditions where partial nozzle flow paths are open (full admission/intake) and closed (partial admission/intake). The calculation results show that the decrease of the air supply mass flow rate is smaller than that of the nozzle geometric flow area. With full admission, the fluctuation of the mass flow rate of a single supply hole ranges from −5.0% to 5.3%. The air supply temperature fluctuates by about 0.9K, with temperature non-uniformity coefficient ranging from −0.27% to 0.28%. After partial intake, the fluctuation amplitude of the air supply hole mass flow rate increases approximately 36%, and that of air supply temperature increases 2.1 times. Compared with the system without impellers, the impellers will reduce the decrease of the air supply mass flow rate, reduce the average air supply temperature by more than 2K, increase the non-uniformity range of the air supply mass flow rate by 66.7% and the non-uniformity range of the air supply temperature by about 2.6 times.