Investigation of the effect of using a swirl nozzle and increasing injection pressure on the output characteristics and pollution of the combustion chamber

In the present study, the effect of using a swirl nozzle and increasing the pressure of liquid fuel injection on the performance and emission of soot, nitrogen oxide and carbon monoxide combustion chamber of a propulsion system is investigated. The proposed solutions can change the intensity of cavitation and fuel spray characteristics.The effect of each of the proposed solutions with the help of a three-dimensional numerical model in EVL Fire software, which has been validated with experimental data in each section, on the performance of the diesel engine and its emissions has been investigated.The numerical results show that the creation of swirl inside the nozzle leads to a rotational flow of the fuel injector, an increase in the spray cone angle and the turbulence intensity inside the combustion chamber. Increasing the resulting spray cone angle improves the performance of the diesel engine by reducing fuel consumption and increasing power and torque, and the production of nitrogen oxide and carbon monoxide pollutants due to a better fuel-air mixture, increased turbulence intensity and average temperature inside the chamber.Combustion is reduced to an appropriate amount. Increasing the injection pressure can also improve the performance of the diesel engine.One of the negative points of increasing fuel injection pressure is the increase in nitrogen oxide production.By increasing the fuel injection pressure from 1350 bar to 2100 bar, fuel consumption decreases by 38% and its power and torque increase. Also in this case, carbon monoxide pollutants decrease by 65% and nitrogen oxide pollutants increase by 20%.