The compressibility of the ventilation in the orifice should be considered in the calculation process.A representative bearing chamber for throttling vent lubrication system was studied

and gas flowing characteristics of bearing chamber of aero-engine throttling vent system was analyzed.The calculation method of bearing chamber pressure was concluded and validated by a real case.Compared with experimental data

the calculation result shows a low absolute error which can meet the requirements of the engineering.This calculation method can be used as a reference for further calculation of the pressure of aeroengine bearing chamber by throttling.