Eventos Anais de eventos
ENCIT 2022
19th Brazilian Congress of Thermal Sciences and Engineering
NUMERICAL INVESTIGATION ON THE THERMAL BEHAVIOR OF A TURBOGENERATOR
Submission Author:
Felipe Augusto Menon , SC
Co-Authors:
Felipe Augusto Menon, Guilherme Schneider Porepp
Presenter: Felipe Augusto Menon
doi://10.26678/ABCM.ENCIT2022.CIT22-0073
Abstract
A turbo generator (or alternator) is an electric device designed to be connected to the shaft of a gas or steam turbine for the generation of electric power through the principle of electromagnetic induction. This technology is widely used in the energy industry. Most of the world electricity is, in fact, produced in such equipment. When in operation, heat is generated inside the alternator as a result of electromagnetic losses, causing its temperature to rise. Continuously high temperatures on generator windings could cause the degradation of its electrical insulation materials, shortening the product life cycle. It is therefore important to control the heating of these machines. In synchronous generators, this is mostly done by means of convective heat transfer. Although essential to the integrity of the equipment, convective cooling introduces air flow losses that may account for up to 30% of the total power loss of an alternator. Thus, in order to obtain a low and uniform temperature distribution while trying to keep mechanical losses at a minimum, careful analysis is imperative at the design stage of the machine. Conventionally, temperatures in electric generators are evaluated through analytical calculation, with the structuring and solution of proper hydraulic and thermal circuits. Despite being long established, this methodology has certain limitations when more detailed results are needed. Furthermore, it relies greatly on empirical correlations to estimate important parameters, such as pressure drop and convective heat transfer coefficients. More recently, Computational Fluid Dynamics (CFD) proved to be an important tool in the design and development of alternators. The finite volume method allows for the computation of pressure, velocity and temperature fields in the whole domain, facilitating the prediction of windage and frictional losses. That being said, the authors intend to present a numerical study on the thermal behavior of a turbo generator designed to operate along with a steam turbine. Interesting results were obtained with commercial software Ansys CFX and are to be presented in comparison with experimental data of the actual manufactured equipment.
Keywords
Computational fluid dynamics (CFD), Thermal Analysis, Electricity generation, Turbogenerator
