EXPERIMENTAL INVESTIGATION INTO THE EFFICIENCY OF AN AERO ENGINE OIL JET SUPPLY SYSTEM

This paper presents results of investigations on the interaction between a targeted oil jet and a rotating shaft in an aero engine typical bearing chamber. Measurements were performed at atmospheric temperature and pressure in order to study the influence of the operating conditions, nozzle diameters and impingement angles on the efficiency of such an oil supply system. The flow phenomena of the jet-shaft interaction were visualised. A qualitative analysis of the jet-shaft interaction revealed massive droplet generation due to the jet break-up In the air crossflow and its impact on the shaft. The latter could be reduced with shallower impingement angles. Measurements showed that the oil inflow rate, the shaft speed and the nozzle diameter have a strong influence on the collected oil quantity, which is expressed as catch efficiency, i.e. the ratio of collected and supplied oil. The impingement angle was also identified to have a strong influence on the catch efficiency. The ratio of the momentum fluxes of supplied oil and chamber air flow is proposed as a parameter to correlate the catch efficiency to the operating conditions.