INFLUENCES OF LIQUID-SEAL INLET SWIRL RATIO ON THE DYNAMIC PROPERTIES OF A ROTOR SYSTEM

The dynamic coefficients of a given liquid annular seal under different inlet swirl ratios are obtained by numerically solving the governing equations based on a bulk-flow model. Equations of motion of the system are established with the consideration of seal’s dynamic properties. This is achieved by integrating the fluid dynamic reaction-force model of the liquid annular seal into the dynamic model of the system. The analytical expressions of modal damping and frequency, logarithmic decrement and dynamic magnification factor, which represent the dynamic properties of the system, are obtained by theoretical analyses. The influences of a seal inlet swirl ratio on the dynamic properties of the rotor system are discussed with figures. Conclusions are reached, which could be used for guiding the dynamic designs and diagnostics of rotor systems with liquid annular seals.