| One of the major environmental challenges facing our planet and living beings is the global warming. This phenomena, known as the gradual increase in the overall temperature of earth's atmosphere is mostly caused by the greenhouse eect which is a result of increased levels of greenhouse gases. Major constitutes of these gases are Carbon Dioxide (CO2) and Nitrogen Oxides (NOx). Transportation sector is responsible for releasing a signicant portion of these gases into the atmosphere. In recent decades, many endeavors such as using alternative fuels and modications in engine cycles have been made to control the amount of pollutants emitted from internal combustion engines.;In this work, the impact of adding humidity to the input Oxidizer stream on reduction of NOx and Carbone Dioxide ( CO2) of a CNG engine has been studied. With the addition of the humidity, the combustion temperature will be reduced which improves the engines lifespan. Non-Premixed combustion process in a single cylinder is simulated using the STAR CCM+ software from CD-Adapco company, using the Presumed Probability Density Function (PPDF) combustion model which is an accurate model for combustion. Simulation results indicate with 10% humid air, signicant reductions in NOx and CO2 are obtained, with a moderate increase in CO output.;Adding humidity results in total emission reduction. |
