Koji Muramatsu

Visualization of Coolant Flow inside Transformer Coil

From the view point of safety and maintenance simplicity, the development of high performance gas cooled gas insulated transformer has been desirable. In this type of transformer, the coolant gas is circulated in the gap between the coils to cool it. The flow pattern of coolant in the flow path strongly depend on its configuration formed by the coil. Therefore, in order to achieve high cooling efficiency of coils and at the same time to reduce the pressure loss, it is important to have sufficient knowledge about the flow behavior in the coil flow path. In the present work, in order to decide appropriate flow path configuration formed by the coil foi its efficient cooling, flow visualization study based on numerical simulation was performed. This study led to the understanding that for the standard coil flow path configuration there occurred recirculating flow covering a region of stagnation which caused increase in coil surface temperature and in efficient for cooling. In order to prevent the occu ?? ence of recirculating flow, a modified flow path configuration is proposed to have efficient cooling.