Drag reduction in a class 8 truck - scaled down model

R Vishwa Krishna,M Venkatesan,R Suwathy,M Pragadeesh,V Jayakumar,S Sridevi,D Devika,S Ranganathan

doi:10.1051/matecconf/201817201003

R Vishwa Krishna, M Venkatesan + Show 6 more

Open Access

https://doi.org/10.1051/matecconf/201817201003

Copy DOI

Abstract

Trucks are heavy load vehicles used mainly for commercial transport operations. There are several classes of heavy duty commercial vehicles classified based on the weight loaded. More than 50% of the engine output power in such trucks is utilized to overcome the drag. Drag force in automobiles is the resistance offered by air on vehicles at higher speeds. Class 8 trucks suffer higher drag when compared to other classes. In the present work, a numerical model is developed using a commercial code ANSYS FLUENT to predict the drag coefficient value. The effects of gap width and cab front radius with a constant fairing is analysed using the numerical model developed. A Class 8 model truck with minimal drag coefficient having constant fairing and optimized gap width between the trailer and cab is proposed.

Highlights

Heavy trucks which contain a cab and trailer come across more drag than conventional vehicles because of the vortex formation in the gap
Three models among these considered models showed minimal drag. Flow analysis of these three models is done with variations in gap width and modifications of the cab radius
It is found that vortex formation in the gap width resulted in increase in drag

Summary

Introduction

Heavy trucks which contain a cab and trailer come across more drag than conventional vehicles because of the vortex formation in the gap. The conventionally used class 8 truck is found to have bluffed and unstreamlined profile by design This profile results in increased drag due to flow separation phenomenon. With proper design of geometry of the front cab of a given truck, the drag coefficient can be optimized. Such optimized geometries will result in decreased fuel consumption. The cab front edge was rounded and the effect of it on drag was studied. Such experimental methods cannot be implemented for all possible design variations or such an implementation is not economical. Hu et al [4] made inferences from

Size of the domain

Governing equations

Results and discussions

Model 2 - Sharp cab front surface with smaller gap width

Conclusions