Showing 4 results for Nozzle
B. Jafari, D. Domiri Ganji,
Volume 3, Issue 2 (6-2013)
Abstract
Air pollution is one of the major issues about the diesel engines in todays' world. It is a special concern in
those areas that have difficulty meeting health-based outdoor air quality standards. Natural gas has low
emission and resource abundance and also conventional compression ignition engine can be easily
converted to a dual fuel mode to use natural gas as main fuel and diesel as pilot injection. The main object
of this work is to investigate the effect of number of injector nozzle hole on the combustion and exhaust
emission in a gas engine ignited with diesel fuel. We use one and three-dimensional simulation in parallel
way in order to analyze the performance and combustion process of a dual fuel engine. The experimental
results have also reported and compared with the simulated data.
A. Zandi, S. Sohrabi, M. Shams,
Volume 5, Issue 1 (3-2015)
Abstract
Cavitation and turbulence in a diesel injector nozzle has a great effect on the development and primary breakup of spray. However, the mechanism of the cavitation flow inside the nozzle and its influence on spray characteristics have not been clearly known yet because of the internal nozzle flow complexities. In this paper, a comprehensive numerical simulation is carried out to study the internal flow of nozzle and the cavitation phenomenon. The internal cavitation flow of the nozzle is simulated using the Eulerian-Eulerian two-fluid model. In this approach, the diesel liquid and the diesel vapor are considered as two continuous phases, and the governing equations of each phase are solved separately. Simulation method is validated by comparing the numerical results with experimental data and good correspondence is achieved. The effective parameters on the nozzle flow are investigated, including injection pressure, back pressure, inlet curvature radius of orifice, orifice iconicity and its length. Results clearly show the importance of nozzle geometrical characteristics and dynamic parameters on the internal nozzle flow. Discharge coefficient of nozzle and cavitation distribution in the nozzle are extremely dependent on these parameters, so the effect of cavitation on the primary breakup is not negligible.
S. Hassanzadeh Saraei, Sh. Khalilarya, S. Jafarmadar,
Volume 6, Issue 2 (6-2016)
Abstract
Modern diesel engines should have higher pollutant emissions standards with better performance and by using split injection strategies which could optimize the air – fuel mixture, this purpose could be achieved. After achieving the successful validation between modeling and experimental results for both single and double injection strategies, for the first time and in this paper, double injection strategies with new nozzle configuration were used in which number of nozzle holes were doubled and located below the previous holes and then double injection strategies were implemented in a case that for each pulse of injections upper or below holes were used, then this study focused on the effects of the new nozzle configuration holes angle in each pulse of injections. This study confirms that split injection could decrease Nox emission, because it has lower maximum in-cylinder temperature than single injection case due to its separate second stage of combustion, also results showed that using new nozzle configuration with two rows of holes could be more effective in decreasing pollutant emissions without any significant effects on engine performance.
Mr Mehran Nazemian, Mr Mehrdad Nazemian, Mr Mahdi Hosseini Bohloli, Mr Hadi Hosseini Bohloli, Mr Mohammad Reza Hosseinitazek,
Volume 14, Issue 3 (9-2024)
Abstract
This study investigates the influence of nozzle hole diameter (NHD) variations on spray dynamics, combustion efficiency, and emissions in a Reactivity-Controlled Compression Ignition (RCCI) engine using Computational Fluid Dynamics (CFD) simulations with the CONVERGE software. The study systematically examines NHDs ranging from 130 µm to 175 µm and evaluates their impact on key parameters such as injection pressure, droplet formation, Sauter Mean Diameter (SMD), and evaporation rates. The results demonstrate that reducing NHD to 130 µm significantly enhances fuel atomization by reducing SMD to 15.49 µm and increasing droplet number by 24%, which in turn accelerates evaporation and improves fuel-air mixing. These effects shorten ignition delays, accelerate combustion, and increase peak cylinder pressures and temperatures. Optimal NHDs (150–160 µm) achieve the highest combustion efficiency (92.04%) and gross indicated efficiency (38.58%). However, further reduction in NHD below this range causes premature ignition, energy dissipation, and higher NOx emissions (10.08 g/kWh) due to elevated combustion temperatures. Conversely, when the NHD increases to 175 µm, the larger droplets formed result in prolonged ignition delays, slower combustion, and lower peak pressures. These effects negatively impact combustion efficiency and promote incomplete combustion, leading to higher HC (15.27 gr/kWh) and CO (4.22 gr/kWh) emissions. Larger NHDs, however, lower NOx emissions to 2.66 gr/kWh due to reduced peak temperatures. This study clearly identifies an optimal NHD range (150–160 µm) that effectively balances droplet size, evaporation rate, combustion timing, and emission reduction, thereby enhancing both engine performance and environmental sustainability.
