The purpose of this thesis was to design a cooling system for the UQ Racing Formula to evaluate and potentially employ in the 2013 Formula SAE vehicle. Cooling system fundamental behaviours, current and previous designs were studied, major design principles investigated and vehicle specific conditions researched to establish a thorough understanding of how cooling systems operate during Formula SAE operation. This process identified that the heat exchanger, air flow (assisted by an electric fan, shroud and ducting) and water pump were the main components. Other components required include the surge tank, overflow tank, pressure cap and plumbing.
The radiator core geometry was optimised to receive hot fluid at a temperature of 85°C and cool it to 80°C, whilst minimising its size and weight. It was concluded that a core of cross section 300mm by 300mm with a depth of 42mm would supply the necessary cooling whilst minimising weight and size. Single row, dual pass, dimple tube and louvered fins further enhance the heat transfer by inducing turbulence on both the wetted and non wetted sides, promoting thorough mixing of hot and cold fluids.
The square radiator geometry was selected to enable even air flow distribution when assisted by an electric fan. A five flat bladed Spal VA03-AP70/LL-37A single fan housed within a shroud, mounted in the pulling configuration was identified as the best available option. Connecting the fans electric system to a Davies Craig Digital Controller initiates the fan as soon as radiator outlet temperatures of 83°C are reached, and then switched off when the temperature falls below 80°C.
The Davies Craig Digital Controller is designed to be utilised in conjunction with a single EWP80. This pump can be simply plumbed into the hose between the radiator outlet and the engine inlet without any hard mounting (the pump ‘floats’ between two sections of hose). This electric water pump used in conjunction with digit control renders the thermostat redundant and eliminates the power losses associated with factory mounted belt driven modules.
The side pod is proposed to compose of an undertray leading up to a short enclosure. The enclosure shall be positioned such that no turbulence from the wheels or suspension are captured. A diffuser angle of 5° shall slow the flow and increase the pressure prior to the radiator. The air stream will then pass through the heat exchanger prior to being expelled through a converging nozzle (shroud). This will effectively eliminates drag by increasing exit velocity to greater than atmospheric air relative to the vehicle.