Seal dynamic property coefficient acquisition method based on least square method

Abstract

The invention provides a seal dynamic property coefficient acquisition method based on a least square method. The seal dynamic property coefficient acquisition method comprises the following steps: setting that force and displacement of a rotor is in a linear relation, ignoring influence of vortex motion higher derivative, and obtaining displacement model of the force through rigidity of the rotorseal dynamic property coefficient and a damping matrix; taking a rotor seal center O as an origin of a coordinate system for which x is taken as a horizonal axis and y is taken as a vertical axis tobuild a coordinate system; setting that the rotor performs vortex motion along an elliptical orbit at an eccentric position of a moment t, taking the eccentric position as a vortex motion center, andobtaining a parameter equation of the elliptical vortex motion orbit; obtaining a residual value of a direction x and a direction y according to the parameter equation, the displacement model and theleast square method; determining total residual square and function expression of S according to the residual value of the two directions; solving partial derivatives for eight seal dynamic property coefficients through the function expression of S, obtaining an equation set for solving partial derivatives for eight seal dynamic property coefficients, and solving the equation set to obtain the eight seal dynamic property coefficients.

Description

technical field [0001] The invention relates to a numerical value acquisition method of a turbomechanical seal dynamic characteristic coefficient, in particular to a method for obtaining a seal dynamic characteristic coefficient based on a least square method. Background technique [0002] Due to the gradual development of rotary turbomachinery towards ultra-large size, high pressure ratio, and high speed, the working conditions of the rotor are getting worse and worse, and the airflow excitation caused by the seal is becoming more and more prominent. have a greater impact on economic benefits. Studies have shown that fluid flow in the seal is one of the main sources of airflow excitation force, and people usually use eight stiffness and damping coefficients to represent the dynamic characteristics of the seal. [0003] At present, the identification of seal dynamic characteristic coefficient is mainly divided into three methods: experimental method, theoretical method and ...

AI Technical Summary

Problems solved by technology

However, some scholars have adopted unreasonable assumptions in order to simplify the calculation, such as: (1) ignoring the influence of the whirl trajectory on the dynamic characteristic coefficient; (2) directly assuming that the whirl trajectory is circular, etc.

The above two assumptions lead to the inability to identify the eight dynamic characteristic coefficients of the seal at the same time from the source, and the identification accuracy is low, and even lead to incorrect identification results

Images