Numerical Study On The Discharge Coefficient Of Rotating Orifices

Various forms of orifices are the important throttling components in aircraft engine air system,which are posted on the structures such as turbine disks, drums, shafts and so on. Accuratelygrasping the flow characteristic of all kinds of orifices is a key link of aircraft engine air systemdesign. This article adopts the method of numerical simulation to study the discharge coefficient ofrotating orifices systematically.In this paper, we study the change rules of discharge coefficient of axis and radial orificeswhich are rotating base on the factors such as rotating speed, pressure ratio, fillet, chamfering, dipangle and so on. Within the scope of this research, several main conclusions are obtained as below:1. As the speed number increases, discharge coefficient of orifices decreases, and it has nothingto do with the pressure ratio.2. As the ratio of length to diameter increases, discharge coefficient of static orifices increases;while orifices rotate at the same speed, discharge coefficient of orifices firstly decreases and thenincreases.3. As the ratio of fillet to diameter increases, discharge coefficient of static orifices increasesand tends to be stable, discharge coefficient of rotating orifices increases.4. As the ratio of chamfering to diameter increases, discharge coefficient of axial orifices whichare static increases and tends to be stable, discharge coefficient of radial orifices which are staticincreases; while orifices rotate at the same speed, discharge coefficient of orifices increases.5. As the dip angle increases, discharge coefficient of axial orifices which are static decreases,discharge coefficient of radial orifices remains unchanged in a small scope and then increases; whileorifices rotate at the same speed and the dip angle changes from negative angle to positive angle,discharge coefficient of axial orifices decreases slowly, discharge coefficient of radial orifices firstlydecreases and then increases.