Safety and reliability criteria for modern aero engines require an efficient vent pipe system for the discharge of air/oil mictures from bearing chambers. Complex two-phase flow phenomena in various pipe geometries show locally enhanced heat transfer where oil coking or oil fire with the risk of flashback into the bearing chamber can occur. This paper deals with the experimental investigation of local heat transfer phenomena of air/oil mixtures generated under high rotational speeds along the internal wall of various vent pipe elements. In addition to a straight pipe and two knee pieces with inclination angles fo 30 deg and 45 deg, respectively, influences of a bend with a curvature angle of 45 deg on the downstream heat transfer are shown. The pipeline elements have been mounted in the vent system of a high speed bearing chamber test rig which is operated under engine relevant conditions. Local and mean heat transfer coefficients have been calculated out of the measured temperature distribution utilizing a stationary technique which is based on a two-dimension finite element procedure. Exemplary results giving a first insight are discussed as a function of operation conditions typical for high speed bearing chambers.


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    Title :

    Two-phase air/oil flow in the vent pipe system of aero engine bearing chambers - Determination of internal wall heat transfer


    Additional title:

    Zweiphasen-Luft/Öl-Strömung in der Entlüftungsrohrleitung der Lagergehäuse von Flugtriebwerken - Bestimmung des Innenwandwärmeüberganges


    Contributors:
    Busam, S. (author) / Wittig, S. (author)


    Publication date :

    1998


    Size :

    10 Seiten, 9 Bilder, 9 Quellen



    Type of media :

    Conference paper


    Type of material :

    Print


    Language :

    English