关键词: 预旋系统;预旋喷嘴;预旋孔;流量系数;预旋效率

Abstract: Experimental measurements and numerical simulations on the discharge coefficient of pre-swirl nozzles with pre-swirl angles 30°, 25°, 20° and 15°,respectively, were carried out under pressure ratio range 1.1~1.9. The effects of pressure ratio and pre-swirl angle on the velocity and flow angle at the nozzle inlet and outlet, discharge coefficient and pre-swirl effectiveness were investigated via CFD work. Experiment and CFD results of discharge coefficient coincide well with each other. Data show that the discharge coefficient and pre-swirl effectiveness increase with the increase of pressure ratio. It is observed that the decrease of pre-swirl angle will lead to an almost unchanged discharge coefficient,while the pre-swirl effectiveness raises remarkably because of decreasing flow exit angle, with a maximal increase of 10%. 

Key words: Pre-swirl system; Pre-swirl nozzle; Pre-swirl hole; Discharge coefficient; Pre-swirl effectiveness