Delivered by Ingenta to: Guest User IP : 222.124.194.25 Sun, 02 Oct 2011 10:05:30 Copyright © 2011 American Scientific Publishers All rights reserved Printed in the United States of America RESEARCH ARTICLE Advanced Science Letters Vol. 4, 2807–2811, 2011 CFD Analysis for Merdeka 2 Solar Vehicle Zahari Taha 1 , Rossi Passarella 2 5 ∗ , Sugiyono 3 , Nasrudin Abd Rahim 2 , Jamali Md Sah 4 , and Aznijar Ahmad-Yazid 2 1 Faculty of Manufacturing Engineering and Technology Management, Universiti Malaysia Pahang, 26300, Malaysia 2 Faculty of Engineering, University of Malaya, Kuala Lumpur, 50603, Malaysia 3 Department of Mechanical and Industrial Engineering, Gadjah Mada University, Yogyakarta, 55281, Indonesia 4 School of Manufacturing Engineering, Universiti Malaysia Perlis, 02600, Malaysia 5 Department of Computer Engineering, University of Sriwijaya, Palembang, 30662, Indonesia Vehicle’s low drag force is critical to achieve higher speed and for efficient energy usage. Most solar vehicles that participated in the World Solar Challenge event adopted the ‘cockroach’ shape which has been considered as the best shape to achieve optimum speed and aerodynamics characteristics. However, the team from University of Malaya decided to design their entry vehicle based on the profile of a box fish, said to possess an even lower drag coefficient value. This paper describes the aerodynamics characteristics numerical study of the solar vehicle using a computational fluid dynamics (CFD) code called FLUENT. The numerical computation is based on the frontal area of the vehicle and the obtained results have shown reasonable values of drag and lift coefficients when compared to ordinary road vehicles. Keywords: Solar Vehicle, World Solar Challenge, Box Fish Shape, CFD. 1. INTRODUCTION In 2009, the Center for Product Design and Manufacturing (CPDM) University of Malaya again participated in the World Solar Challenge (WSC) event with a second version of solar vehi- cle, named Merdeka 2; shown in Figure 1. The concept of using off-the-shelf components previously adopted for the first entrant in 2007, Merdeka was maintained. The Merdeka 2 was designed to be as similar possible to an ordinary vehicle except for the presence of solar panels at the roof of the vehicle. The vehi- cle main body structure was fabricated using aluminium alloy. The solar vehicle used a 48 V permanent magnet DC motor rotating at 3000 r.p.m. maximum. 4 units of 12 V deep cycle batteries were used to store the generated electrical energy from the photovoltaic solar panels, which in turn powered the motor. Each of the 12 V batteries were individually charged by sep- arate solar panels. 4 units of Maximum Power Point Tracking (MPPT) acted as the solar panels charging controller. During the 2009 event, with the average speed of 45 km/h, Merdeka 2 managed to finish 590 km of the approximately 3020 km, the total race distance. This achievement is approximately a 100% improvement compared to the performance of the previous entrant, Merdeka. The total manufacturing cost was approxi- mated at RM 50,000.00 (US$ 15,000). In the future, with lim- ited funding, it is foreseen that the researchers at CPDM will face a huge task to continue developing of the next solar vehicle ∗ Author to whom correspondence should be addressed. with the aim of completing the race, or to overhaul Merdeka 2 achievement. 2. AERODYNAMICS ANALYSIS Initially, the design concept for Merdeka 2 was based on the profile of the box fish, similar to the Mercedes Benz minivan, shown in Figure 2. This shape is said to possess a low drag coefficient value, C d , of approximately 0.06, that can lead to a 20% reduction of fuel consumption. To analyze the aerodynamics of the solar vehicle, a numer- ical method using computational fluid dynamics (CFD) code called FLUENT 2 was performed. Generally, there are two steps involved when performing this, firstly preparing the computa- tional domain and then conducting the numerical analysis. The first step, preparing the computational domain was carried out using Gambit, an integrated pre-processor of FLUENT to cre- ate the geometry of the model, generating the grid system and assigning the boundary conditions. The second step was car- ried out using the FLUENT processor, where the numerical model was set up and the computation performed to achieve the solution. The geometry of the model is drawn using the existing dimen- sions of the solar vehicle. However, in order to obtain a numeri- cally acceptable model, a simplified geometry of the solar vehicle was drawn instead and is shown in Figure 3. The length, width and height of the solar vehicle model were 4620 mm, 1395 mm and 1375 mm, respectively. Adv. Sci. Lett. Vol. 4, No. 8/9/10, 2011 1936-6612/2011/4/2807/005 doi:10.1166/asl.2011.1632 2807