Performance Analysis Of Triangular Pyramid Longitudinal Vortex Generators To Strengthen The Oil-immersed Transformer Heat Dissipation

To ensure electric transformers operate safely and reliable, the transformer iron core and windings temperature must be controlled within a certain range. The most widely used heat radiator of the oil-immersed transformer is the panel type. The transformer oil absorbs heat from the core and windings, and then flows through the radiator to dissipate the heat to the environment. The main thermal resistance of the heat transfer process is the convective heat resistance at the air side of the heat radiator panels. Thus increasing the air convection heat transfer coefficient can effectively improve the heat dissipation amount of oil-immersed transformer.Using Longitudinal Vortex Generators (LVG) is an effective passive heat transfer enhancement method. With the advantages of having simple structure, easy to be produced and requiring no external power, LVGs are used widely. LVGs can be divided into two categories: airfoil vortex generator and spoiler columnar vortex generator. But these two kinds of LVGs are not easy to be applied to oil-immersed transformers.This paper has proposed a kind of Triangular Pyramidal LVG(TPLVG) which can obtained by punching or pressing. To get the best structure and arrangement of the TPLVGs, the influence on heat transfer of TPLVGs arrangement parameters such as attack angle, height and spacing had been analyzed analyzed by numerical method, and the heat transfer mechanism had also been probed into.The study showed that the TPLVGs can significantly improve the radiators convection heat transfer coefficient even with no fan. By analyzing the influence of attack angle and height of the TPLVGs for oil-immersed transformer heat sink thermal performance concluded that in natural convection conditions the best angle of attack is45°, the optimum height is10mm. By studying the staggered arrangement and in-line arrangement TPLVGs in diffenent H and L, concluded that panel radiators with staggered arrangement TPLVGs release more heat than those with in-line arrangement ones. In this paper physical model the best H and the best L were35mm and80mm. Relative to the not using longitudinal vortex generators oil-immersed transformer heat sink, can increase the convective heat transfer coefficient of11.548%This paper has also proposed several other kinds of longitudinal vortex generators which can be applied to the oil-immersed transformer to improve the heat dissipation efficiency. They can also improve the air side convective heat transfer coefficient of oil-immersed transformer radiators in natural convection conditions, and can reduce the need of fan.