Numerical investigation of in-cylinder swirl motion under cold start conditions in a diesel engine

Year 2025, Volume: 10 Issue: 1, 1185 - 1202, 18.03.2025

Fatih Aktaş , Zeynep Aytaç , Nuri Yücel

https://doi.org/10.58559/ijes.1632282

Abstract

The performance and efficiency of internal combustion engines, particularly diesel engines, are closely tied to the quality of air-fuel mixing and combustion processes. One of the critical factors influencing these processes is the in-cylinder airflow, specifically the swirl motion, which is the rotational movement of air around the cylinder axis. This swirl plays a pivotal role in enhancing the turbulence required for efficient fuel-air mixing, accelerating flame development, and improving overall combustion. This study shows a numerical analysis of the swirl movement within the cylinder of a diesel engine under cold starting conditions. Using computational fluid dynamics (CFD) analysis, the research evaluates the effects of various valve opening configurations on swirl intensity. The results indicate that increasing valve openings generally enhances swirl motion, improving combustion efficiency by promoting better air-fuel mixing. However, excessive swirl can negatively impact performance due to increased heat transfer and potential flame propagation issues. The study also assesses the impact of turbulence models and mesh density on the accuracy of the results, with the k-ε model providing predictions closest to experimental data. These findings contribute to optimizing engine design for improved combustion characteristics and reduced emissions.

Keywords

Cold flow, Swirl motion, Computational fluid dynamics

Ethical Statement

The author declares that this study complies with Research and Publication Ethics.

Supporting Institution

This study has been supported by the Scientific Research Projects Coordination Unit of Gazi University under code 06/2019-15.

Project Number

06/2019-15

Thanks

We would like to express our gratitude to AVL LIST GmbH for providing the AVL Boost software and to Türk Traktör Ziraat Makineleri A.Ş. for supplying the necessary information related to the engine. This study has been supported by the Scientific Research Projects Coordination Unit of Gazi University under code 06/2019-15.

Bir Dizel Motorunda Soğuk Başlatma Koşullarında Silindir İçi Girdap Hareketinin Sayısal Araştırması

Abstract

The performance and efficiency of internal combustion engines, particularly diesel engines, are closely tied to the quality of air-fuel mixing and combustion processes. One of the critical factors influencing these processes is the in-cylinder airflow, specifically the swirl motion, which is the rotational movement of air around the cylinder axis. This swirl plays a pivotal role in enhancing the turbulence required for efficient fuel-air mixing, accelerating flame development, and improving overall combustion. This study shows a numerical analysis of the swirl movement within the cylinder of a diesel engine under cold starting conditions. Using computational fluid dynamics (CFD) analysis, the research evaluates the effects of various valve opening configurations on swirl intensity. The results indicate that increasing valve openings generally enhances swirl motion, improving combustion efficiency by promoting better air-fuel mixing. However, excessive swirl can negatively impact performance due to increased heat transfer and potential flame propagation issues. The study also assesses the impact of turbulence models and mesh density on the accuracy of the results, with the k-ε model providing predictions closest to experimental data. These findings contribute to optimizing engine design for improved combustion characteristics and reduced emissions.

Keywords

Cold flow, Swirl motion, Computational fluid dynamics

Project Number

06/2019-15

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