A comprehensive investigation of early pilot (e-pilot) mode split injection variations for improving NG-diesel dual-fuel combustion in a medium-speed marine engine: Experiments and CFD study

IF 6.4 2区工程技术 Q1 THERMODYNAMICS

Case Studies in Thermal Engineering Pub Date : 2025-02-14 DOI:10.1016/j.csite.2025.105881

Mustafa Deniz Altinkurt , Gokhan Coskun , Martin Tunér , Ali Turkcan

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引用次数: 0

Abstract

Natural gas/diesel dual-fuel combustion is a novel technique that offers high thermal efficiency and reduced emissions without requiring extensive hardware changes or complex aftertreatment systems. Previous study conducted on the same setup has shown that increasing the diesel mass split ratio (SR) between two injections and advancing the start of first injection (SOI₁) improved NO_x, HC emissions, and combustion efficiency. In this study, in-cylinder flow, spray and combustion was simulated in computational fluid dynamics (CFD) software to reveal the effects of variable SR and early SOI₁, enabling e-pilot combustion. First, experiments at 50 % and 70 % SR were validated, and additional cases (85 and 92.5 %) with higher SR were analyzed via CFD simulations. Low and high temperature reactions are investigated using formaldehyde (CH₂O) and OH radicals, respectively.

Increasing SR delays low and high-temperature reaction phases. Initial OH formation occurs near the cylinder wall at SR = 50 % and shift toward the center as SR increases. Higher SR and advanced SOI₁ result in decreased P_max and retarded combustion. CFD results show that unburned HCs effectively decrease with increasing SR. Advancing SOI₁ results in a greater decrease in NO_x emissions than an increase in HC emissions. Increasing SR decreases both NO_x and HC emissions, increases gross indicated power by up to 3.9 %, and reduces specific fuel consumption by 2.5 %. The early pilot (e-pilot) strategy used in this work effectively controls fuel-temperature stratification and emissions by controlling low and high-temperature reactions.

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来源期刊

Case Studies in Thermal Engineering Chemical Engineering-Fluid Flow and Transfer Processes

CiteScore

8.60

自引率

11.80%

发文量

812

审稿时长

76 days

期刊介绍： Case Studies in Thermal Engineering provides a forum for the rapid publication of short, structured Case Studies in Thermal Engineering and related Short Communications. It provides an essential compendium of case studies for researchers and practitioners in the field of thermal engineering and others who are interested in aspects of thermal engineering cases that could affect other engineering processes. The journal not only publishes new and novel case studies, but also provides a forum for the publication of high quality descriptions of classic thermal engineering problems. The scope of the journal includes case studies of thermal engineering problems in components, devices and systems using existing experimental and numerical techniques in the areas of mechanical, aerospace, chemical, medical, thermal management for electronics, heat exchangers, regeneration, solar thermal energy, thermal storage, building energy conservation, and power generation. Case studies of thermal problems in other areas will also be considered.