Numerical Investigation On Effects Of Varied De-swirl Nozzle Configurations In The Internal Air System

Aeroengine is a kind of high-speed rotating machine operating under high temperature and pressure.High-performance aero-engines inevitably require efficient cooling and sealing systems,all of which ultimately depend on high-quality cooling air.As an important part of the air bleed system,the performance of the de-swirl system has an important influence on the quality of cooling air.In order to explore the influence of the structure change of the de-swirl nozzle on the pressure loss of cooling air in the radial inflow process in the co-rotating disc cavity,numerical studies on the de-rotating disc cavity system under different conditions and with nozzle structures were carried out.The main research contents are as follows:(1)Analyzed the common structural changes of the nozzle structure,summarized several typical structural changes,and designed a numerical simulation study of the de-swirl nozzle which has only a single structural change;(2)Aiming at the de-swirl nozzle whose nozzle cross section is rectangular,the influence of the non-dimensional width of nozzle cross section on the performance of the de-swirl system was studied.The results show that the use of de-swirl nozzles is valid for putting off the increase of pressure loss.The effects of the nozzles with square cross section and circular cross section on reducing the pressure loss is very close.Reducing the angle between the entrance direction of de-swirl nozzles and the direction of airflow is effective on reducing the pressure loss caused by the de-swirl nozzles themselves.When the total flow area is constant,the increase of the de-swirl nozzle amount along the axial direction under the same circumferential position is profitless for reducing the pressure loss.With the cross-sectional non-dimensional width of the de-swirl nozzle with a rectangular section increasing,the pressure loss in the disk cavity first decreases and then increases,and the non-dimension width corresponding to the minimum pressure loss increases with the increase of the rotational speed.