Hole-pattern or honeycomb seals have been commonly used for many years in the Oil & Gas industry as damper seals for turbo-machinery. The main motivation has been to introduce additional damping to improve the shaft rotordynamic stability operating under high pressure conditions. Experience has shown that the dynamic and even static characteristics of those seals are very sensitive to the operating clearance profile as well as the installation tolerances. Rotordynamic stability is related not only to the seal effective damping but to the effective stiffness as well. In fact, for this kind of seal, the effective stiffness can be high enough to alter the rotor system's natural frequency. The seal stiffness is strictly related to the tapering contour: if the clearance profile changes from divergent to convergent, the effective stiffness may change from a strong negative to a strong positive magnitude, thus avoiding the rotor natural frequency drop as it is detrimental for the stability. Unfortunately the effective damping is reduced at the same time but this can be improved using proper devices to keep the pre-swirl low or even negative. This paper presents the results from an extended test campaign performed in a high-speed rotor test rig equipped with active magnetic bearings working under high pressure (14krpm, 200bar gas inlet pressure), with the aim to validate the rotordynamic characteristics of a negative pre-swirl, convergent honeycomb seal and demonstrate its ability to effectively act as a gas bearing as well as a seal.


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    Title :

    ROTORDYNAMIC COMPUTATIONAL AND EXPERIMENTAL CHARACTERIZATION OF A CONVERGENT HONEYCOMB SEAL TESTED WITH NEGATIVE PRE-SWIRL, HIGH PRESSURE WITH STATIC ECCENTRICITY AND ANGULAR MISALIGNMENT




    Publication date :

    2016




    Type of media :

    Article (Journal)


    Type of material :

    Print


    Language :

    English



    Classification :

    BKL:    52.52 Thermische Energieerzeugung, Wärmetechnik / 52.30 Strömungskraftmaschinen, Turbomaschinen / 52.52 / 52.30