<p class="MsoBodyTextIndent" style="text-indent: 17.85pt">The labyrinth seal is widely applied in the turbomachinery to control the leakage flow across the clearance between the stationary and rotating components. The fluid excitation of the labyrinth seal would increase the instability of turbomachinery shaft. It is very important to develop accurate and quick predicition approach for analysis of the fluid exciation rotrodynamics of labyrinth seal. The objective of this study is to analyze the applicability of leakage models using Bulk-Flow method and investigate the factors affecting the rotordynamic characteristics of the labyrinth seal. An elliptical orbit for rotor whirling was assumed in the one-control-volume Bulk-Flow model considering an isentropic process to predict the frequency-dependent rotordynamic coefficients of the labyrinth seal. The best leakage model selection scheme was determined by comprehensively analyzing the applicability of 72 leakage models. Employing the best leakage model in the Bulk-Flow method, the effects of sealing clearance, pressure ratio, preswirl ratio and rotational speed on the rotordynamic characteristics of the labyrinth seal were investigated. The conclusions show that the best leakage model has an average prediction error of about 10% for cross-coupled stiffness and direct damping. Increasing preswirl ratio has a significantly destabilizing effect on the rotor stability, while the influence of increasing rotational speed is strongly related to preswirl direction. The effective damping of the labyrinth seal is sensitive to the inlet pressure, but insensitive to the outlet pressure and sealing clearance. The crossover frequency is hardly affected by the inlet pressure, outlet pressure and sealing clearance.</p>

Rotordynamic Characteristics of the Straight-Through Labyrinth Seal Based on the Applicability Analysis of Leakage Models Using Bulk-Flow Method

Paper Proceedings: https://asmedigitalcollection.asme.org/GT/GT2021/volume/84898

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