Numerical investigation of the effect of nozzle hole diameter on the combustion, emission, and spray characteristics in a diesel engine

ABSTRACT

The present study aims to investigate the effect on combustion, emission, and spray characteristics with the variation of the nozzle hole diameters (NHD) in a diesel engine. For this a CFD 3D model is developed for a four-stroke diesel engine fueled with neat diesel and three different NHD, i.e., 0.20 mm, 0.26 mm, and,] 0.30 mm. The CFD 3D models were effectively able to predict the turbulence and turbulent-flame propagation interaction, chemistry involved in combustion processes, and the dissociation and reassociation of chemical species. For the model validation, the combustion characteristics of the CRDI-VCR engine are used. The validation results showed good compatibility having the relative error within the range. The analysis showed that increasing the nozzle hole diameter resulted in the decrease of the in-cylinder pressure by about 8.31% and 31.93%, respectively, for 0.26 mm and 0.30 mm diameter compared to 0.20 mm. The AHRR also showed a similar trend with a decrease of about 11.82% and 42.18%, respectively, for 0.26 mm and 0.30 mm diameter as compared to 0.20 mm. Subsequently, the increase in nozzle diameter showed an increase in HC and CO emissions but a decrease in NOx emissions. The CO emissions increase by about 0.65% and 5.08% and HC emissions increase by about 29.90% and 60.13% respectively for 0.26 mm and 0.30 mm diameter compared to 0.20 mm. While the NOx emission reduces by about 41.18% and 70.58% respectively for 0.26 mm and 0.30 mm diameter as compared to 0.20 mm. The effect of different nozzle diameters on spray characteristics is analyzed and verified from previous studies. The increase in nozzle diameter showed an increase in liquid penetration length, breakup length, and SMD. Also, the present study shows the possibilities of the CFD models for the simulation of engines employing different fuels and operative conditions.

KEYWORDS:

• Nozzle hole diameter
• diesel engine
• ansys forte
• spray characteristics
• nox emissions

Abbreviations

CO Carbon monoxide

HC Unburned Hydrocarbon

NOx Nitrogen Oxide

bTDC Before Top Dead Centre

CRDI Common Rail Distribution Injection

ASTM American Society for Testing and Materials

CFD Computational Fluid Dynamics

rev/min Revolution per minute

Additional information

Notes on contributors

Vaibhav Singh

Vaibhav Singh is working as a Research Scholar at the Centre for Advanced Studies and Research in Automotive Engineering, Dept. of Mechanical Engineering, Delhi Technological University. He did his M.Tech in Thermal Engineering from Delhi Technological University, Delhi, India. His research interests include; combustion, fluid mechanics, heat transfer, and computation fluid dynamics.

Naveen Kumar

Naveen Kumar was born in August 1967 in Uttar Pradesh, India; Prof. Naveen Kumar did the B.E. from Dayal Bagh Educational Institute, Agra, the M.Tech from IIT Delhi, and Ph.D. from the University of Delhi. He is a Fellow of Institution of Mechanical Engineers (FIMechE), UK; Fellow of Institution of Engineers (FIE), India and Charted Engineer, Engineering Council, UK. His research interests include; alternative fuels with special emphasis on biofuels, decentralized energy systems, renewable energy, waste recycling, and sustainable development. Presently working as Professor of Mechanical Engineering at Delhi College of Engineering since 1996, Prof. Kumar possesses 27 years of experience in academics, industry, and research. He has published more than 100 research papers in the International Journals of repute and more than 100 in Indian Journals and Conferences.