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Compression-Ignition Engine Combustion
Published in Kenneth M. Bryden, Kenneth W. Ragland, Song-Charng Kong, Combustion Engineering, 2022
Kenneth M. Bryden, Kenneth W. Ragland, Song-Charng Kong
In the following sections of this chapter, combustion chamber geometry and flow patterns, fuel injection, ignition delay, combustion performance, and emissions are discussed. Ways to improve diesel engine combustion, including the low-temperature combustion concept and dual-fuel partially premixed combustion, are also presented.
Effect of intake port design modifications on diesel engine characteristics fuelled by pine oil-diesel blends
Published in Energy Sources, Part A: Recovery, Utilization, and Environmental Effects, 2022
Vikneswaran Malaiperumal, Chidambaram Ganapathy Saravanan, Vallinayagam Raman, Raj Kiran Kirubagaran, Premkumar Pandiarajan, Ankit Sonthalia, Edwin Geo Varuvel
The impact of intake port modification on engine performance for various blends of pine oil is investigated. Figure 10 shows the trends of different pine biofuel diesel blends on the engine brake thermal efficiency (BTE) for different single-pass intake port configurations at low, medium, and high load operation of the engine. Clearly, the 60° single-pass configuration shows increased BTE when compared to other design configurations. The BTE shows an increasing trend with an increase in the percentage of pine biofuel in the blend regardless of the engine load. Besides the swirl enhancement introduced by the modified port design as identified in the numerical study, the inherent oxygen present in the molecular structure of a component present in the pine oil biofuel improves the combustion and subsequently the BTE of the engine. Furthermore, the prolonged ignition delay due to a lower cetane number of pine oil increases the premixing effect and thereby the efficiency. Past results on partially premixed combustion using gasoline and alcohol fuels report enhanced premixing effects and increased engine efficiency (Noh and No 2017; Yanzhao et al. 2018a), which justifies the results of the current study.
Lean Flame Root Dynamics in a Gas Turbine Model Combustor
Published in Combustion Science and Technology, 2019
James C. Massey, Zhi X. Chen, Nedunchezhian Swaminathan
Modern gas turbine engines have to comply with stringent environmental regulations for pollutants emission. Lean combustion can provide improved efficiency, while lowering flame temperatures and thereby a reduction in pollutants emission (Driscoll, 2011). However, operating under lean conditions make such combustion systems prone to risks that may hinder successful ignition and flame stability (Gicquel et al., 2012). Feikema et al. (1991) demonstrated that the effect of swirl can provide increased stability for gas turbines operating under lean combustion and extend the lean flammability limit. In addition, swirling flows allow gas turbine combustors to be more compact, since swirling flow causes intense mixing and hence, the reactant mixture is either premixed or partially premixed prior to ignition (Syred, 2006). Partially premixed combustion is present for swirling flows where the flames are lifted, which is due to the fuel and air entering the combustion chamber through separate inlet streams (Masri, 2015). The potential for flame blow-off is also inevitable in lean combustion and thus, the physical mechanisms behind this phenomenon should be investigated thoroughly.
Evaluation of partially premixed turbulent flame stability from mixture fraction statistics in a slot burner
Published in Combustion Science and Technology, 2023
Stephan Kruse, Mohy S. Mansour, Ayman M. Elbaz, Emilien Varea, Gerd Grünefeld, Joachim Beeckmann, Heinz Pitsch
While the premixed and non-premixed flame types are highly relevant for fundamental combustion research, partially premixed combustion is prevalent in many practical combustion systems. Partially premixed combustion is found in diesel engines, direct injection stratified charge engines (Aleiferis et al., 2004; Dec, 2009), and gas turbines (Huang and Yang, 2009) where mixture fraction gradients enhance efficiency and lower emissions (Masri, 2015). Partially premixed flames are characterized by large fluctuations of the local mixture fraction covering ranges inside and outside the flammability limits (Masri, 2015). Thus, modeling of partially premixed flames is highly complex.