Aerodynamic Effect of Composite Wheel Cover Use in Electric Vehicles

Summary

The rising trend in energy consumption is accelerating efforts focused on efficient use of existing energy sources and the application of renewable energy sources across different sectors. The use of renewable energy sources in transportation is significant due to its role in reducing emissions in urban areas and improving quality of life by lowering noise levels through the widespread adoption of electric vehicles. With the proliferation of electric vehicle use, numerous research areas in electronics and mechanics are gaining prominence, including electrical conversion that needs improvement to enhance efficiency, chemical storage efficiency of electricity, weight reduction of moving masses, and reduction of aerodynamic drag. In this study, the production of aluminium wheel hubs and polymer composite wheel covers produced using the VARTM method, designed and developed for improving the aerodynamic structure of the electric vehicle Demobil 09 of the Solaris Solar Car Team, was examined through computational fluid dynamics analysis for their effect on the aerodynamic structure.

1. Introduction

In this study, the effect of wheel covers produced using vacuum-assisted resin infusion (VARTM) on the aerodynamic structure of the Demobil 09 electric vehicle was examined. In the first part of the study, the application of the vacuum-assisted resin transfer method for the wheel cover produced in the research was described, and in the second part, the results obtained through computational fluid dynamics regarding the use of these covers on the wheels were presented.

2. Materials and Method 2.1. Polymer Composite Structure

Figure 1. Schematic representation of the vacuum-assisted resin infusion (VARTM) process [9]

Polymer composite structures, which have a polymeric matrix in their internal structure and fibres providing mechanical strength, have become increasingly widespread in the design of lightweight yet high-strength structures. Their application in vehicles is one such area. Fabrics of different orientations, weave structures and densities can be applied in different numbers of regional layers, with or without core material, according to results obtained from mechanical analyses. The vacuum-assisted resin infusion production method is a process that works on the principle of the resin forming the matrix in the composite structure advancing in a vacuumed environment. The use of the vacuum-assisted resin infusion production method has certain advantages over other production methods. These advantages can be listed as follows: [2] • Unlike the resin/fibre mixture ratio in the hand-lay-up method, the infusion method reverses this and allows for more durable and longer-lasting products with reduced resin consumption, • Use of inconsistent materials is prevented and homogeneity in the material structure is ensured, • A clean working environment is provided during production and gases generated during production are prevented from dispersing into the surroundings. The production process of the Demobil 09 EV wheel covers, planned to be manufactured using the vacuum-assisted resin infusion production method, begins with the design and manufacture of female moulds. (See Figure 2) In the second stage, the necessary composite material components are prepared. The arrangement of composite materials takes place as follows: (See Figure 1) [9] In the second stage, a liquid release film and a layer separation film are first applied to the mould surface. The liquid release film and layer separation film allow the manufacturer to remove the product from the mould without damage and easily. Then carbon fibre fabric is placed. A peel ply is placed over the carbon fibre fabric to facilitate easy removal of the film. At the final part of the production preparation stage, the vacuum bag is placed over the mould with double-sided tape. The technical properties of the carbon fibre fabric and epoxy resin used are found in Tables 1 and 2.

Figure 2. Female moulds designed for Demobil 09 EV wheel covers

 

Table 1. Technical Properties of Dowaksa 200 [g/m²] 3K-Plain Carbon Fibre Fabric Used

Table 2. Technical Properties of Epoxy Resin Used

Figure 3. Vacuum infusion production setup

It has been demonstrated in previous studies that products manufactured using the vacuum-assisted resin infusion production technique achieve structural homogeneity and produce lightweight, long-lasting products with reduced resin consumption. [2,9] Table 3 contains weight information for wheel covers produced using the vacuum infusion production technique.

Table 3. Product information resulting from manufacturing with the vacuum-assisted resin infusion method

Talha Batuhan Korkut Dokuz Eylül Üniversitesi Department of Mechanical Engineering Automatic Control and Robotics Laboratories   Dr. Aytaç Gören Dokuz Eylül Üniversitesi Department of Mechanical Engineering Automatic Control and Robotics Laboratories     Onur Özaydın R&D Engineer Cevher Jant Sanayii A.Ş.     Elvan Armakan R&D Engineer Cevher Jant Sanayii A.Ş.