INFLUENCE OF GAP FORM IN NON-CONTACT SEAL OF HIGH-SPEED TURBOMACHINE UPON ITS PARAMETERS

Consolidation is one of the most significant elements in any turbomachine defining both economy and capacity for work of a unit. In high-speed pumps and turbines which belong turbo-pump units (TPU) of liquid-propellant engines (LPE) to, one uses mainly non-contact seals and in the first place groove seals. A radial seal gap its value and a form is a basic factor defining parameters and characteristics of sealing. In the paper there is shown the influence of geometrical characteristics of a non-contact seal gap in a high-speed turbomachine upon its characteristics. The influ-ence of the form of a sealing gap upon carrying capacity in it is analyzed that is particularly significant at the definition of seal influence upon critical frequencies of rotor rotation. The mutual misalignments in rotor and stator elements of a seal result in rotor stability reduction, the occurrence of additional radial loads upon bearings. Deviations in a surface form and deformations of sealing elements result in the pressure redistribution in a seal gap that, in its turn, changes forces character affecting a rotor from the side of a seal and, hence, its dynamic characteristics. The analysis of the influence upon carrying capacity in a seal gap of such factors as ellipse, obliquity, barreling, saddling is carried out. The results shown in the paper allow defining the tolerances influence upon manufacturing and deformations of sealing elements upon dynamic characteristics of a high-speed turbomachine rotor at the stage of designing a “rotor-bearings-seals” system.