Aerodynamic analysis and design of a solar powered vehicle using CFD

Abstract

The need for solar-powered vehicles is increasing as the threat of depletion of non-renewable energy sources, such as oil, increases. This gives reason for developing electric vehicles powered by renewable energy sources, such as solar power. An important aspect for the overall efficiency of such vehicles is the aerodynamic design. To improve the design, proper analysis is essential. A generically based methodology describes the design process applied to improve the aerodynamic performance of these vehicles using Computational Fluid Dynamics (CFD) as the design tool. CFD is a valuable tool as it accelerates the design process within a 3-D flow environment. The literature survey conducted during this study describes basic fluid properties relevant to the flow around a body. It also describes the different turbulence models used in CFD and the appropriate transition model to be used. Finally, the factors of the body of a solar-powered vehicle that can be optimised to improve the aerodynamics are also discussed. The methodology followed is an iterative process comprising of the improvement of the baseline design. It was found that this iterative method enables the designer to improve the design by analysing various vehicle revisions using CFD and adjusting certain aerodynamic factors described in the literature. The aim is to minimise the design parameters with each iteration; in other words the frontal area of the vehicle as well as the drag coefficient. Other factors greatly affecting the drag coefficient are the junction fillets of the different components as well as the positions of these components relative to each other. By varying these factors, the near optimum values could be correlated with the theoretical values and based on this the design could be improved. Proper airfoil designs should also be implemented when designing the components to improve the laminar flow. The results found illustrate that the process followed for the analysis and design of the vehicle provide a suitable method for related problems in future designs. CFD is also determined to be a suitable design tool. The end result can, however, be validated experimentally, as an assumption was made that the CFD simulations were adequate, as shown by the results of the validation process. Comparing the simulation results with experimental results will further prove the validity of the study.