Abstract

Modeling of stator parts of power units of thermal and nuclear power plants is carried out according to several standard schemes. Common methods of modeling systems with non-uniform and non-stationary contact of stator elements lead to significant errors in calculating the amplitudes of forced vibration displacement at a given external load. The object of this paper is to analyze errors in calculating the displacement amplitudes of forced oscillations in different modeling schemes according to the standard approach and developing a method for constructing a quasi-dynamic model taking into account the time-varying contact of the system’s stator parts as well as other factors. To do this, the author has developed a series of models with different degrees of sampling and considering different system factors. Particular attention is paid to the impact of factors arising from the long operation of the power plant (subsidence of foundation). The modeling was carried out taking into account the calculation method. The finite element method was used to perform calculations. The results of the calculation of forced oscillation displacement amplitudes are available to show the areas of application of different types of three-dimensional models of the steam power unit. The results of research conducted on the developed models show the impossibility of using standard simulation schemes for systems with a variable contact between its stator elements, as shown by the example of a power unit with steam turbine. The efficiency of using the models taking into account the variable contact between the stator parts and other factors to calculate the displacement amplitudes of the forced oscillations with high accuracy is likewise presented. Every specialist should be aware of the factors that influence the research results. This paper is concerned with assessment of the influence of a number of factors on the results of calculating the vibrations of a complex mechanical system.

Highlights

  • Modern civilization exists due to the stable operation of power plants [1]

  • Many authors [16,17,18,19,20,21,22,23,24] are engaged in modeling and research of stator elements of power units

  • About stopping and starting the power unit in an emergency mode or outside the work schedule. All these difficulties can be avoided with the help of the new models and methods of vibration study of power units offered in this article

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Summary

Introduction

Modern civilization exists due to the stable operation of power plants [1]. The performance of power units depends on many factors. Many authors [16,17,18,19,20,21,22,23,24] are engaged in modeling and research of stator elements of power units. Their studies do not always provide reliable results or are sufficient to address issues of vibration and system reliability. About stopping and starting the power unit in an emergency mode or outside the work schedule All these difficulties can be avoided with the help of the new models and methods of vibration study of power units offered in this article. In discussion directions for increasing the accuracy of results and the realism of models are described

Mathematical model
Relationship between models
Simplified model
Consideration of soil stiffness
Consideration of generator stiffness
Considering hard contact
Consideration of alternating contact
Models without foundation subsidence
Models taking into account subsidence of foundation columns
Findings
Conclusions
Full Text
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