Numerical investigation of in-cylinder air flow characteristic improvement for Emulsified biofuel (EB) application

摘要

Emulsified biofuel (EB) has a relatively higher viscosity compared to conventional diesel; which affects the spray injection and restricts the maximum evaporation. The modification is necessary to standard engines in order to realize its application. This paper presents the effects of three dissimilar designs of piston-bowl geometry in the compression ignition (CI) engine to in-cylinder airflow characteristics improvement of the EB during injection. The three piston bowl geometry designs; open cylinder bowl (OCB), shallow depth re-entrance combustion chamber (SCC) and omega combustion chamber (OCC). ANSYS FLUENT 15 is utilized to run a three dimensional (3D) cold flow internal combustion (IC) engine simulation. The main parameters of this investigation; swirl, tumble and cross tumble ratios, as well as turbulence kinetic energy (TKE), with respect to crank angle. It shows that the SCC piston bowl design is the best due to significant effect on swirl, tumble, cross tumble ratios and TKE in the injection fuel region. It breaks up the length penetration of injection to mix with the surrounding air and capable to organize the distribution of the heavier molecules of the EB during the compression stage. (C) 2018 Elsevier Ltd. All rights reserved.