Eventos Anais de eventos
COBEM 2021
26th International Congress of Mechanical Engineering
PERFORMANCE EVALUATION OF AN ELLIPTICAL CROSS SECTION TUBE POWER TRANSFORMER RADIATOR USING A CFD MODEL
Submission Author:
João Marcos Oliveira Condé , MG
Co-Authors:
Guilherme Ladeira Pinho, João Marcos Oliveira Condé, MARA NILZA ESTANISLAU REIS, Gustavo Fonseca de Freitas Maia
Presenter: Guilherme Ladeira Pinho
doi://10.26678/ABCM.COBEM2021.COB2021-0804
Abstract
Power transformers are mainly used in electrical energy generation and distribution systems. Radiators are attached to its structure for the purpose of promoting a cooling procedure of the electrical equipment, ensuring that it can function properly with a minimum energy loss caused by heat interference. Recent studies showed that, at the exit flange of the equipment, the temperature of the fluid, which flows internally, could present a significant variation on its value, depending on the radiator cross section area. One of the studies presented three main subjects: a geometric modeling of an elliptical cross section tube radiator, the calculation procedure of convection coefficient for external fluid flow and the execution of a fluid dynamic simulation of the model, using Siemens Star CCM+ software. The fluid inlet temperature, outlet temperature and mass flow were obtained through experimental observation of a commercial model, manufactured by a renowned company from the industry, with similar design characteristics. These data could be used as boundary conditions for the setting configuration in simulation process. With these parameters, the simulation resulted in the obtention of radiator internal fluid flow velocity and temperature gradients, which could be used to validate the model, in comparison with the experimental results. The mean fluid outlet temperature obtained from simulation was 4.7 ºC higher, if compared to the experimental method. From this result, it could be concluded that the final value for outlet fluid temperature, obtained from computational fluid dynamic simulation, was a good approximation to the experimental result. This paper proposed an improvement of the radiator design, which involved the reduction of the number of vertical plates, from 30 to 28 and 28 to 26, in order to reduce manufacturing costs, without causing a negative impact to the heat exchange process. Another proposal was made to modify the position of the radiator outlet flange, in order to improve fluid internal circulation. The fluid outlet temperatures obtained from simulation, considering the proposed modifications, were similar if compared to the previous study results, indicating the viability of the improvement. Although the temperature did not decrease with the fluid outlet position change, but an enhancement of the fluid flow distribution at the inlet tube could be observed.
Keywords
Power Transformer, Radiator, Elliptical cross section, StarCCM+
