Transient Response of Floating Ring Liquid Seals

Abstract

The design and analysis of pressure balanced seals are important to the designers and users of turbomachinery which require floating element seals. The design objective for compressor seals differs from that of the engineered pump seal but the common factor includes the ability to predict the dynamic response of the floating ring seal relative to the rotor shaft. Steady-state calculations can be used to study possible operating conditions for compressor designs, but they do not include accurate account of rotor shaft response and ring spin torque. In addition, engineered pump seal applications are such that the ring is expected to track shaft movement during start-up and shut-down transients when reduced pressures and leakage produce laminar flow sealing conditions. The analysis presented in this paper gives the designer the ability to evaluate seal ring dynamic transient response, including friction stick-slip on the axial sealing face and the ring spin torque interaction with the antirotation element. The analysis results presented in this paper were obtained from a personal computer program written specifically for seal transient analysis.