Enhancing heat transfer in power transformer radiators via thermo-fluid dynamic analysis with periodic thermal boundary conditions

Abstract

The efficient dissipation of energy losses in electrical power transformers is crucial to prevent overheating of their windings and ensure proper functioning. In this study, we investigate the thermal design of a 30 [MVA], 132/34.5/13.8 [kV] power transformer radiator operating in Oil Natural-Air Natural mode by using Computational Fluid Dynamics (CFD) simulations. We introduce artificial body forces in the momentum Navier-Stokes equation to analyze the thermo-fluid dynamic performance of secondary transverse flows. Additionally, we propose a numerical scheme to solve the thermal equation with periodic boundary conditions using a reduced length of the oil channel, allowing for the decoupling of the thermal and fluid dynamic problems. To enhance the heat transfer, we propose the use of turbulators and wall indentation arrangements. Through our simulations, we analyze the effects of these enhancements on the cooling capacity of the transformer radiator. Our results demonstrate that these modifications increase the heat transfer coefficient and improve the cooling capacity of the radiator. Furthermore, we propose manufacturing considerations for the turbulators and wall indentation arrangements to ensure their practicality. Our findings provide valuable insights into the thermal design of power transformer radiators and demonstrate the effectiveness of turbulators and wall indentation arrangements in enhancing their cooling capacity.