Application of a multi-step soot model in a thermodynamic diesel engine model

The formation of a suitable air and fuel mixture in diesel engines is one of the most important factors in quality of combustion and engine exhaust emissions. The mixture formation depends on mass transfer phenomenon inside the combustion chamber. This study presents a new thermodynamic model to simulate the mass transfer phenomenon in diesel engines. Diesel engine is simulated utilizing a thermodynamic multi zone model coupled to a semi‐detailed chemical kinetics mechanism. Heat and mass transfer submodels are linked to the multi zone model. Bulk flow and diffusion mass transfer between zones are considered in the mass transfer submodel. Bulk mass transfer simulates fluid motion between different zones caused by piston speed and difference in zonal temperature and pressure. Diffusion mass transfer occurs due only to difference in composition of different zones. The results indicate diesel engine performance and exhaust emissions can be predicted accurately applying mass transfer submodels. Bulk mass transfer mechanism has more significant effects on engine performance and emission compared to diffusion mechanism. Neglecting mass transfer submodels, calculated in‐cylinder peak pressure is under predicted and both of exhaust NOx and soot are over predicted. The rates of soot oxidation reactions decrease and rates of NOx important reactions increase when mass transfer submodels are ignored. © 2019 American Institute of Chemical Engineers Environ Prog, 38:e13146, 2019

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“…Table shows the engine characteristics. More details about the engine specifications can be found in previous papers .…”

Section: Resultsmentioning

confidence: 99%

Thermodynamic modeling and validation of in‐cylinder flow in diesel engines

Neshat

Nazemian

Honnery

2019

Env Prog and Sustain Energy

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“…The SAGE solver was adopted to simulate the combustion process. 50 The extended Zeldovich model 51 and Hiroyasu soot model 52 were used to simulate the NOx and soot emissions, respectively. To validate whether the inflow boundary can be used for high-pressure gas injection, the evolution of the methane concentration in terms of mass fraction from CFD is compared with the experimental results 53 in Figure 4.…”

Section: Sootmentioning

confidence: 99%

Effects of injection strategies on low‐speed marine engines using the dual fuel of high‐pressure direct‐injection natural gas and diesel

Liu

Wang

et al. 2019

Energy Science & Engineering

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Pilot‐ignited high‐pressure direct‐injection (HPDI) natural gas engines have drawn much attention since being proposed, as these engines can maintain high performance and lead to clean combustion compared with conventional diesel engines. This prospective concept is not only used in vehicle engines but also used in large‐scale marine engines. In this study, the effects of injection strategies of dual fuels on combustion characteristics and emissions were investigated using the computational fluid dynamics (CFD) code CONVERGE coupled with a reduced n‐heptane/methane mechanism. The results showed that the effects of absolute injection timing (AIT) on the combustion characteristics and emissions are similar to those of traditional diesel engines. As the AIT varies from advanced by 4°CA to retarded by 4°CA, the peak values of the in‐cylinder pressure and temperature decrease gradually. However, a conventional trade‐off between NOx and soot/CO/HC/ISFC emissions can also be observed as the AIT is retarded. In contrast, relative injection timing (RIT) has more complicated impacts on the combustion and emissions characteristics. The in‐cylinder temperature distribution and concentration stratification change as the gas jet initially interacts with the pilot flame. The effects of the gas injection timing on the combustion characteristics and indicated specific fuel consumption are also similar to those of the AIT, but the emissions are quite different. The pilot injection timing shows minimal influence on the main combustion process. Better performance can be obtained with partially premixed combustion with a slightly late injection timing compared with that of the original (ORG) base case.

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“…The engine was coupled to a Heenan & Froude eddy-current dynamometer and a Froude-Hofmann V4 dynamometer controller, and the engine specifications are shown in Table 1. The experimental setup has been described in detail in previous papers [17,35].…”

Section: Experimental Set-upmentioning

confidence: 99%