Critical speed prediction method of cryogenic liquid expander rotor considering influence of sealing force

Abstract

A critical speed prediction method of cryogenic liquid expander rotor considering the influence of sealing force is presented. Firstly, the parameters of rotor and bearing are obtained. Then, the flowfield of labyrinth seal is numerically simulated based on the vortex rotor model by combining the sealing thermophysical properties file with the solution of labyrinth seal flow field. The flow fieldof labyrinth seal is obtained. The radial and tangential components of the sealing force acting on the rotor are obtained by integrating the pressure area on the inner surface of the rotor. Then according to the linearized model of sealing force, the stiffness coefficient and damping coefficient are obtained. Finally, a finite element model is established to predict the critical speed of the rotor. The invention considers the influence of the sealing gas flow characteristic in the labyrinth seal of the cryogenic liquid expander on the rotor dynamic behavior under the real situation, so that the prediction of the critical speed is more scientific and reasonable and more practical. The prediction method provided by the invention is simple and clear, and provides an effective calculation method for predicting the critical speed of a liquid expander rotor under the conditions of different structures and different sealing gases.

Description

technical field [0001] The invention belongs to the technical fields of low-temperature air separation and liquefaction, and relates to the rotor dynamics problem of a low-temperature liquid expander, in particular to a method for predicting the critical speed of a low-temperature liquid expander rotor considering the influence of sealing force. Background technique [0002] Cryogenic liquid expander is a new type of energy-saving device for cryogenic air separation and cryogenic liquefaction plants. It is used to replace the traditional high-pressure liquid throttle valve. It can not only meet the pressure reduction requirements of the low-temperature process, but also reduce the energy loss of the process and generate significant energy savings consumption benefit. Similar to the conventional turbomachinery, the cryogenic liquid expander is a rotating machine, and its rotordynamic characteristics directly affect the stable operation of the expander unit and even the entire...

AI Technical Summary

Problems solved by technology

Taking the influence of the sealing force into account will help improve the prediction accuracy of the critical speed of the rotor of this type of liquid expander, thereby avoiding resonance more effectively, which is of great significance to the safe operation of the liquid expander. Patent documents at home and abroad There are no public reports in

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