Laminar burning velocity in hydrogen-oxygen-nitrogen mixtures
Abstract
As today’s world is demanding a greener environment where greenhouse gas emission and global warming are much reduced, hydrogen has become the most promising element among others from periodic table. As today’s world is demanding a greener environment where greenhouse gas emission and global warming are much reduced, hydrogen has become the most promising element among others from the periodic table. Combustion of hydrogen has been observed as a renewable and efficient green method to replace the burning of hydrocarbon fuels with higher efficiency in the combustion systems. Even though hydrogen can be efficient in some ways, there are different factors that can be hazardous to the environment as well as to human beings. Due to the safety reasons for hydrogen utilization in the combustion systems, the required studies have been done to investigate the behaviors of hydrogen while mitigating the problems for safety purposes. In order to replace energy sources from fossil fuels, a required predictive and reliable modeling such as the laminar premixed burning velocity of the mixture is mainly used. In the method, the chemical reactions during the combustion process are based on and studied to proceed with the evaluation of the laminar burning velocity of the hydrogen-oxygen- nitrogen mixture. For numerical computations of chemical reactions and laminar burning flame speed, the chemical kinetics model and the tool Cantera are used. In the present study, the laminar burning velocity of the hydrogen-oxygen-nitrogen mixture is evaluated to find how hydrogen explosion in a confined space can be mitigated by varying the oxygen concentration. The concept that reducing oxygen concentration in the cloud can decrease the heat release and laminar burning velocity of the premixed gas is proposed. The study aims to find the burning velocity in hydrogen-oxygen-nitrogen mixtures by performing experiments in a 20-liter explosion vessel. The evaluation of laminar burning velocity is done on different concentrations of the mixture and different ignition energy. The literature study is first done, and the experiments are performed to investigate the laminar flame speed, Markstein length, stretch rate, and laminar burning velocity. Besides, the simulation tool Cantera is used to calculate the laminar burning velocity of the mixture and to validate the mechanisms and methods used in this study.