Идентификация расчетной модели ротора газотурбинной установки в магнитных подшипниках по геометрическим и динамическим параметрам

Abstract

Описаны расчетные исследования по поиску по неполным данным расчетной конечно-элементной модели ротора газотурбинной установки в магнитных подшипниках, предназначенной для углубленного анализа его динамического поведения. Данные исследования выполнялись с помощью параметрического моделирования и проведения серии вариантных статических и динамических расчетов с целью определения параметров расчетной модели сопоставлением с известными данными. Результаты численных экспериментов свидетельствуют об адекватности найденной расчетной модели и ее пригодности для выполнения дальнейших исследований.

Computational studies on the search of a calculation finite-element model of a rotor of a gas turbine unit installed on magnetic bearings based on incomplete data is described. This model is intended for in-depth analysis of its dynamic behavior. These studies were performed using a parametric modeling and a series of variant static and dynamic calculations in order to determine parameters of the calculation model by comparison with the known data. Variable parameters were diameters of the rotor sections, as well as density and elastic modulus (Young's modulus) of the material of its components. Known data based on which model identification was performed were scheme of the rotor, overall dimensions and dimensions between supports, masses, transverse and equatorial moments of inertia and centers of gravity of the turbocharger, the generator and the drive shafting, as well as natural frequencies and forms of the rotor of the gas turbine unit. While performing variant calculations beam finite element model of the rotor, consisting of three-dimensional beam finite elements with circular and annular sections with different sizes for different parts of the rotor, was used. Modeling of active magnetic bearings was performed using special elastic-damper finite elements. Using this model, two types of analyzes were carried out. To search for a variant of the model with given masses, moments of inertia and mass centers series of static calculations with different densities and diameters of the sections was provided. After finding the values of these parametersa search of the model was made by selection of the elastic modules (Young) to match the natural frequencies with their reference values in a given range. Final checking of the model was performed by calculating of the natural frequencies depending on a rotational speed of the rotor, formation of Campbell diagram for finding the critical speeds and comparing it with the given diagram. Numerical results show an adequacy of the found calculation model and its suitability for further researches.