DE-OILER SYSTEM FOR IMPROVED OIL CONTAINMENT

摘要

Oil containment is a critical design requirement that affects overall system safety and reliability of gas turbine engines. This paper examines a new method to enhance oil containment by use of an improved de-oiler that creates a favorable bearing compartment differential pressure environment even at low power settings. Typically gas turbine engines require seals to contain oil within the bearing compartment. These seals, both contacting and non-contacting configuration styles, rely on secondary airflow to buffer the sealing interface and force oil mist and droplets back into the compartment. This is not difficult to achieve at high or moderate power conditions since there is generally sufficient air flow and pressure available to meet the sealing requirements. However, at idle conditions, the engine low-pressure compressor (LPC) may not turn fast enough to produce sufficient airflow to buffer the seals. To address these concerns the authors propose a method where the de-oiler creates a vacuum at idle speed, which results in favorable compartment seal differential pressures and also acts as a restrictor at higher speeds, where limiting the contact pressure and increasing the service life of mechanical seals become desirable design goals. The paper will examine a specific case study with both analytical and experimental results.