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The effect of heat source position on the heat transfer in an aluminium tube was investigated experimentally and analytically. The experimental data were obtained by measuring the temperature distribution along the tube wall for two different heat source locations. A theoretical model of the tube was developed and validated with the experimental data. A finite element method simulation was performed to analyze the temperature profile and to endorse assumptions for theoretical model. The results showed that the heat transfer rate depend on the heat source position. [ABSTRACT FROM AUTHOR]

We present numerical simulations using Finite Elements Method (FEM) that test the validity of a quasi 1D analytical model for a winding in an oil-filled distribution transformer with partial cooling ducts. We do this by employing a 2D FEM model of the transformer winding. The winding in the analytical and simulation model is represented with homogeneously distributed heat source and anisotropic thermal conductivity. We show that the numerical results confirm the assumptions of the analytical model for typical values of the parameters of the winding, but for certain marginal situations the anisotropic conductivity and 2D FEM model may also lead to unphysical predictions. [ABSTRACT FROM AUTHOR]

We present a description of the heat transfer mechanism in an oil-filled transformer that incorporates two main bottlenecks for the heat flow. The first one, the transfer from its windings into the oil, is simulated using a realistic 3D model and a finite element method. The second, the transfer from the transformer’s wall into the environment is described with a robust analytical model. The combination of the two gives an accurate prediction of critical temperatures better than 2ºC. The study was done in collaboration with BEZ Transformatory, a.s. [ABSTRACT FROM AUTHOR]