IN-CYLINDER FLOW ANALYSIS FOR A DIRECT INJECTION DIESEL ENGINE – A CFD APPROACH

2019 ◽  
Vol 14 (1) ◽  
Author(s):  
Ananthakumar S ◽  
Jayabal S ◽  
Thirumal P

A parametric study of the effect of piston bowl configuration on air motion of a direct injection diesel engine motored at 3000 rpm is investigated. Two piston bowl configurations (Mexican-hat and Re-entrant) are modeled for the computational flow analysis. The flow characteristics of these engine bowls are examined under transient conditions using STAR CD, a commercial computational fluid dynamics package. The predicted computational fluid dynamics results of mean swirl velocity of the engine at different locations inside the combustion chamber, at the end of compression stroke were compared with experimental results available in the literature. The results obtained showed very good agreement with the measured data given in the literature. This paper discusses the predicted flow structure inside the combustion chamber at top dead center, with different piston bowl shapes at 3000 rpm. It also compares the radial distribution of mean swirl velocity component in the piston bowl for the two cases. It is observed that the Re-entrant bowl provides a higher swirl ratio at almost all locations than the Mexican hat bowl.

2015 ◽  
Vol 18 (1) ◽  
pp. 102-111
Author(s):  
Khai Le Duy Nguyen ◽  
Hung Dac Khanh Nguyen

This paper presents a research on the influence of combustion chamber geometry on performance and emissions of direct injection diesel engine VIKYNO RV125-2 using threedimensional CFD code KIVA-3V. In this study, the piston bowl depth (pip-height), bottom bowl diameter and bowl diameter are changed while the engine compression ratio is still kept. Research results indicate that increased bowl diameter works best. Specifically, when the bowl diameter changes from 3.98cm to 4.7cm, the engine power is increased 22.6%, while the concentration of NOx is reduced 0.85%. However soot concentration will increase 45.83%.


2016 ◽  
Vol 20 (suppl. 4) ◽  
pp. 937-946 ◽  
Author(s):  
Venkadesan Gnanamoorthi ◽  
Navin Marudhan ◽  
Devaradjane Gobalakichenin

2002 ◽  
Vol 124 (4) ◽  
pp. 1042-1052 ◽  
Author(s):  
C. Hergart ◽  
N. Peters

Capturing the physics related to the processes occurring in the two-phase flow of a direct-injection diesel engine requires a highly sophisticated modeling approach. The representative interactive flamelet (RIF) model has gained widespread attention owing to its ability of correctly describing ignition, combustion, and pollutant formation phenomena. This is achieved by incorporating very detailed chemistry for the gas phase as well as for the soot particle growth and oxidation, without imposing any significant computational penalty. This study addresses the part load soot underprediction of the model, which has been observed in previous investigations. By assigning flamelets, which are exposed to the walls of the combustion chamber, with heat losses calculated in a computational fluid dynamics (CFD) code, predictions of the soot emissions in a small-bore direct-injection diesel engine are substationally improved. It is concluded that the experimentally observed emissions of soot may have their origin in flame quenching at the relatively cold combustion chamber walls.


2002 ◽  
Vol 125 (1) ◽  
pp. 351-357 ◽  
Author(s):  
Y. Kidoguchi ◽  
M. Sanda ◽  
K. Miwa

Effects of combustion chamber geometry and initial mixture distribution on the combustion process were investigated in a direct-injection diesel engine. In the engine experiment, a high squish combustion chamber with a squish lip could reduce both NOx and particulate emissions with retarded injection timing. According to the results of CFD computation and phenomenological modeling, the high squish combustion chamber with a central pip is effective to keep the combusting mixture under the squish lip until the end of combustion and the combustion region forms rich and highly turbulent atmosphere. This kind of mixture distribution tends to reduce initial burning, resulting in restraint of NOx emission while keeping low particulate emission.


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