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Abstract(s)
Esta dissertação baseia-se no estudo do escoamento de éster nos enrolamentos dos transformadores de potência do tipo CORE, por meio de simulações CFD (OpenFOAM) e desenvolvimento de um método, mais expedito que CFD, para previsão da distribuição do caudal ao longo de todo o enrolamento. O objetivo foi a obtenção de coeficientes de perda de carga locais para criar uma matriz de resistências capaz de prever o caudal do éster em qualquer zona do enrolamento em função da geometria do próprio e da velocidade média de entrada. O interesse desta matriz consiste na possibilidade de calibração de ferramentas mais simples que permitam calcular com mais rapidez comparativamente como CFD, não descorando a precisão essencial no projeto de transformadores de potência. O estudo paramétrico realizado foi construído variando três parâmetros geométricos e seis velocidades de entrada distintas. A cada parâmetro geométrico, foram atribuídos cinco valores, correspondendo, no total, a 750 simulações. Após análise e tratamento de dados foi estudada uma forma de prever as resistências hidráulicas ao longo do enrolamento com resultados com precisão de 3.89 %. Esta metodologia de aferição das resistências hidráulicas, foi aplicada num modelo de redes desenvolvido em Open Modelica, que no caso particular demonstrado nesta dissertação obteve-se um desvio médio do calculado com CFD de 4.8%. Concluiu-se que esta metodologia adotada é eficaz e cumpriu com o objetivo de reduzir os recursos temporais e computacionais para o projeto de enrolamentos do tipo
CORE.
This dissertation is based on the study of ester flow in the windings of CORE-type power transformers through CFD simulations (OpenFOAM) and the development of a method, faster than CFD, to predict the flow distribution throughout the winding. The objective wastoobtainlocal pressure loss coefficients to create a resistance matrix capable of predicting ester flow in any area of the winding based on its geometry and average inlet velocity. The significance of this matrix lies in its potential to calibrate simpler tools that allow for quicker calculations comparedtoCFD,withoutsacrificingtheessentialaccuracy in power transformer design. The parametric study conducted involved varying three geometric parameters and six different inlet velocities. Each geometric parameter was assigned five values, resulting in a total of 750 simulations. After data analysis and processing, a method was studied to predict the hydraulic resistances along the winding with a precision of 3.89%. This methodology for assessing hydraulic resistances was applied in a network model developed in OpenModelica, which, in the specific case demonstrated in this dissertation, achieved an average deviation of 4.8% compared to CFD. It was concluded that the adopted methodology is effective and met the objective of reducing the time and computational resources required for the design of CORE-type windings.
This dissertation is based on the study of ester flow in the windings of CORE-type power transformers through CFD simulations (OpenFOAM) and the development of a method, faster than CFD, to predict the flow distribution throughout the winding. The objective wastoobtainlocal pressure loss coefficients to create a resistance matrix capable of predicting ester flow in any area of the winding based on its geometry and average inlet velocity. The significance of this matrix lies in its potential to calibrate simpler tools that allow for quicker calculations comparedtoCFD,withoutsacrificingtheessentialaccuracy in power transformer design. The parametric study conducted involved varying three geometric parameters and six different inlet velocities. Each geometric parameter was assigned five values, resulting in a total of 750 simulations. After data analysis and processing, a method was studied to predict the hydraulic resistances along the winding with a precision of 3.89%. This methodology for assessing hydraulic resistances was applied in a network model developed in OpenModelica, which, in the specific case demonstrated in this dissertation, achieved an average deviation of 4.8% compared to CFD. It was concluded that the adopted methodology is effective and met the objective of reducing the time and computational resources required for the design of CORE-type windings.
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Keywords
Power Transformers CFD Parametric Study Pressure loss coefficients Transformadores de potência Parametrização Perda de carga