OIL AERATION AND DEGASSING MEASUREMENTS FOR THE STUDY OF AERO-ENGINE OIL PUMP PERFORMANCE IN CAVITATION

Cavitation combined with degassing strongly affect the pump performance in low-pressure operation. The understanding of oil aeration and degassing mechanisms is of great interest to explain and model the pump performance. This paper presents the techniques used for the measurement of the degassing and aeration phenomena applied to turbine lubrication oil. The measurement principle is to cause oil to degas and measure the flow density, which indicates the volume of degassed air and the oil aeration. The density was experimentally measured with two devices, one based on Coriolis forces and one on X-ray transmission. The paper describes and discusses the results obtained for various operating conditions and cases, such as constant aeration, degassing transient (pressure decrease) and aeration transient (pressure increase). The transient results fit exponential laws which give the asymptotical values and the time constant of the phenomenon. The comparison of the two techniques is also discussed.