Influence of Reynolds Number and Heat Flux when Cooling an Array of Cylinders

Sammanfattning: When batteries are used, it is of interest to know how high the temperature will become and if the cooling is efficient enough. In this thesis project, the geometry used are batteries placed in an array shape, inside a box. This gives the possibility of assuming porosity conditions when looking at the box from the outside. With the use of the commercial program ANSYS CFX, simulations of convective cooling of cylinders was performed. The goal was to find how large influence the Reynolds number and heat flux  from the batteries have on the fluid flow and if there is a possibility to find a prediction equation to determine certain temperatures even before simulating. To determine the influence, the variables Reynolds number, heat flux and type of fluid was varied one at a time. The Reynolds number change the inlet velocity of the fluid and a higher Reynolds number will transport the heat away faster. The heat flux was changed to see the influence on how the temperature of the fluid changed and how the velocity profiles varied due to the amount of power generated by the batteries. Increasing the power output would increase the temperature of the fluid and change the velocity profile difference. Varying the fluid was done to see how the thermal conductivity influenced the fluids behaviour while heated up. The three fluids used in this thesis was water, engine oil and air. There was a clear difference between the three fluids with engine oil being the most efficient while air was considerably worse.