Influence on Transport Properties by Utilizing Unsteady Squeezed Magnetohydrodynamics Flow of Copper and Single Wall Carbon Nanotube Mineral Oil-Based Insulating Nanofluid in Traction Transformer of an Electric Train: A Numerical Study

Abstract

Mineral oil and synthetic ester are mainly used as the dielectric and insulating fluid for traction transformer in an electric train. Due to excessive heat caused by the high-power supply and frequent travel cycle, the traction transformer faces faster thermal aging. A lot of researches have been performed to improve the heat transfer and thermal conductivity of the current insulating fluid. Recent studies show that adding nanoparticles can enhance the transport properties of the existing fluid in the marketplace. The “try and error” experiment method in order to get the optimum nanofluid will be costly and will cause higher viscosity, making the fluid hard to circulate in the cooling system. In order to conduct a cleaner, low cost and sustainable experiment, mathematic modeling was chosen as the best option for behavior prediction prior to any experiment. The problem modeling is centered on the geometry and the interaction of nanoparticles namely: copper (Cu) and Single-Wall Carbon Nano Tube (SWCNT) with a homogeneous blend of mineral oil (MO). Unsteady squeezed Magnetohydrodynamics (MHD) flow was considered as the pump of the transformer will squeeze and force the fluid to circulate in the real cooling system. The main partial differential equations of momentum and energy are changed into Ordinary Differential Equation (ODE) and answered numerically and analytically using fourth or fifth order Runge Kutte Fehlberg method via shooting technique. Rate of heat transfer and thermal conductivity of insulating nanofluid were chosen as target factors. The volume concentration of 2%, 5% and 7%, different shapes of nanoparticles and the influence of the electric field were regarded as input factors. The comparison between solutions has been made and the influence of varying the input factors has been shown graphically. It was investigated that laminar shaped insulating nanofluids have a greater rate of heat transfer and higher thermal conductivity.