Numerical study of parameters affecting the temperature distribution in a disc-type transformer winding

In this paper, the effect of the numerical model, mass flow rate and inlet boundary conditions on the flow and temperature distributions in a disc-type transformer winding is investigated using a commercial CFD code. For the winding under investigation, it was found that the results obtained with simplified models are quite different from those computed with a complete Conjugate Heat Transfer model that considers the individual copper conductors forming the disc. The temperature profile (uniform or non-uniform) specified at the inlet of the winding is another parameter having a significant influence on the hot-spot temperature prediction and the paper stresses that a refined model is needed to capture this effect. The numerical results also indicate that a higher flow rate gives a more efficient cooling of the winding since the temperature distribution is more uniform and the hot-spot factor is reduced.