Hydrogen Addition to Natural Gas in Cogeneration Engines: Optimization of Performances Through Numerical Modeling

A numerical study of the energy conversion process occurring in a lean-charge cogenerative engine, designed to be powered by natural gas, is here conducted analyze its performances when fueled with mixtures gas and several percentages hydrogen. The suitability these blends ensure engine operations proven through zero–one-dimensional schematization, where an original combustion model employed account for different laminar propagation speeds deriving from hydrogen addition. Guidelines recalibration are traced thanks achieved results. Increasing fractions blend up propagation, achieving highest brake power 20% fraction considered. Further increase this last would reduce volumetric efficiency virtue lower mixture density. formation NOx pollutants also grows exponentially fraction. Oppositely, related exploitation exhaust gases’ enthalpy reduces as shorter durations lead temperatures at exhaust. If operative conditions shifted towards leaner air-to-fuel ratios, in-cylinder flame speed decreases because amount fuel trapped mixture, reducing efficiencies emitted nitrogen oxides link between spark timing highlighted: maximum reached ignition 21° before top dead center 10 20%. However, temperature diminishes retarded timings. Lastly, optimization algorithm implemented individuate optimal condition which characterized production minimum consumption environmental impact. As main result, addition 15% volume real cogeneration systems viable route only if avoid rapid pressure rise excessive pollutant emissions.