Development of an oxy-hydrogen engine for power generation application using simulation and experiment

Hydrogen is a zero-carbon fuel feasible for the de-carbonization of power generation and transport sectors. Hydrogen possesses excellent properties such as high calorific value, wide flammability limit, fast flame speed, and low ignition energy requirement which makes it suitable for spark ignition engine applications. Hydrogen fuelled spark ignition engines can operate at stoichiometric, lean and ultra-lean conditions. Stoichiometric combustion of hydrogen-air mixture leads to high NOx emission due to its high adiabatic flame temperature, whereas lean combustion decreases NOx emission significantly to low values. Oxy-hydrogen (H2-O2) is a renewable fuel which has the potential to increase engine power with near zero exhaust emission. Hydrogen and oxygen are generated onsite from the electrolyzer and fed to engine along with ambient air. Due to a higher concentration of oxygen, combustion is faster and more efficient. NOx emission are reduced to near-zero due to lesser mass fraction of nitrogen in oxyhydrogen-air mixture and lean combustion.In the present study, a 15 kVA two-cylinder genset was used. The retro fitted natural gas engine was used to operate on oxy-hydrogen and air without any modifications. A 50% engine load was achieved during the preliminary experiments. 1D simulations on GT-Power software were conducted to validate the experiment results and model the combustion of oxy-hydrogen-air. The power limiting factors were identified via simulation to further conduct the flow and power improvement analysis. Predictive simulations were carried out for combustion and power improvement of oxy-hydrogen-air engine. For higher altitude application, the ambient air pressure is lower which decreases the mass flow of air. Simulation results predict that supercharging technology can be used to boost the intake charge to achieve the target engine power along with near zero NOx emission. This study would be helpful in the development of oxy-hydrogen engines aiding in transition towards a zero carbon economy.