Numerical Analysis on Natural Convection Heat Transfer in an Enclosure of the Transformer Model

전기 변압기 형상 내부의 밀폐공간 내에서 층류 자연대류 열전달 현상의 수치해석

Numerical analysis of the laminar natural convection in an enclosure of the 20KVA oil-immeresed transformer is presented. The core in the transformer is modelled as a rectangular cylinder and calculation is carried out for $Ra=10^3-10^6$. The correlating equation between the inner cylinder mean Nusselt numbers and Rayleigh numbers can be obtained. The conduction and convection regimes for the variation of Rayleigh numbers are well represented in the temperature distributions along the side wall of the inner cylinder. For high Rayleigh numbers, it is found that the recirculating flow in the enclosure above the inner cylinder is divided into two recirculation regions.