About this Research Topic
Low temperature combustion (LTC) and its association with cool flame kinetics have recently become leading research topics of interest due to their relevance to achieving high thermal efficiency, fuel flexibility, and low pollutant emissions for both advanced and legacy internal combustion engine applications. For all engines, the thermal efficiency is limited neither by the Carnot cycle nor the Otto cycle efficiency. Rather, the engine thermal efficiency is compromised by heat losses from the high temperature combustion/flames to engine walls and the exhaust gas. As an effort to improve engine efficiency and significantly reduce the thermal losses, various low temperature combustion technologies (e.g., homogeneous charge compression ignition (HCCI) engines, reactivity controlled compression ignition (RCCI) engines, etc.) have attracted attention. Despite promising demonstration of LTC technologies (e.g., HCCI and RCCI engines) a lack of fundamental understanding of the coupled physicochemical processes limits the implementation of these technologies and concepts.
Since 2010, significant progress has been made in experimental observation and computational modelling of premixed, non-premixed, and fuel-lean low temperature chemistry and cool flames. These studies have provided understanding of the overall dynamics, chemistry and burning limits. However, areas that require further research and advancement are immense. Large discrepancies between model predictions and experiments in the cool flame regime persists, limited LTC/cool flame experimental data are available for high pressure, spray, and turbulent combustion, especially involving multi-component and low carbon alternative fuels, minimum ignition energy and transport effect on cool flames are not well explored, understanding of the role of LTC/cool flame combustion in engine knock, deflagration to detonation, lean blow-off and possible flame stabilization is missing. The goal of this issue is to showcase the ongoing research activities on LTC/cool flame combustion.
This Research Topic calls for contributions in the following areas:
• Experimental measurements and diagnostics of low temperature/cool flame combustion at spray relevant conditions, non-premixed conditions;
• Simulation and modelling of transport coupled low temperature/cool flame dynamics;
• Development and assessment of low-intermediate temperature kinetic models in predicting low temperature/cool flame combustion under standard and near limit conditions;
• Premixed cool flames;
• Measurements and simulations of laminar cool flames.
Keywords: Cool flames, Low-intermediate temperature chemistry, Flame dynamics, Low temperature combustion, Thermal efficiency
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