نوع مقاله : مقاله پژوهشی
عنوان مقاله English
نویسندگان English
In this study, the effect of nozzle hole number on fuel injection, atomization, mixing quality, combustion characteristics, and exhaust emissions in an RCCI engine was investigated using three-dimensional simulations in CONVERGE software. The results revealed that increasing the number of nozzle holes leads to a reduction in fuel injection pressure and velocity, consequently cumulative the Sauter mean diameter. This reduction in kinetic energy and turbulence weakens both primary and secondary droplet breakup processes, significantly lowering fuel evaporation rates and mixing quality. With a 3-hole nozzle, the high kinetic energy of the spray resulted in finer droplets, faster evaporation, and improved fuel- air mixing, leading to a shorter ignition delay and enhanced combustion and gross indicated efficiency, which were 17.03 degrees, 92.1%, and 39.4%, respectively. Conversely, increasing the hole number to 6 (baseline) and 9 reduced spray kinetic energy and enlarged droplet sizes, which increased the mixing duration and combustion period, thereby deteriorating the atomization process. From an emissions perspective, a higher number of nozzle holes caused an increase in HC and CO emissions due to incomplete combustion, while NOx emissions decreased as a result of lower peak combustion temperatures. The findings demonstrate that nozzles with fewer holes significantly enhance combustion performance and thermal efficiency in RCCI engines by improving atomization, promoting efficient fuel- air mixing, and reducing ignition delay.
کلیدواژهها English
