Increase Fuel Efficiency and Decrease Emissions with Atomization and Spray Technology
Legislation in the US, Europe and Asia demands progressive increases in energy efficiency, coupled with reductions in emissions of pollutants in gasoline, diesel and gas turbine engines for vehicles, aircraft and power plants. Combustion reaction, temperature and formation of pollutants are directly related to the distribution of air/fuel mixtures ratios throughout combustion chambers. The local mixture ratios are determined by vaporization of droplets in liquid fuel sprays. Evaporated fuel distribution is governed by drop diameter, velocity and trajectory as individual droplets traverse through airflow fields and deposit fuel in individual droplet wakes.
The design of atomizer nozzles, liquid fuel and atomizing air pressures and flow rates are important tools for controlling and changing breakup of liquid jets, spray angle droplet size and velocity distributions, The most efficient and energy saving combustion is with stoichiometric (perfect) air fuel mixture ratios where all fuel is consumed. However, these conditions create elevated temperatures that generate high formation of oxides of nitrogen – a major pollutant. The ideal fuel injection system requires pre-determined local air/fuel ratio distribution for maximum combustion and energy efficiency and minimum generation of pollutants. Spray characteristics, individual drop size and momentum are the most important factors for achieving the required local air/fuel ratio distributions.
Many years of research and development in spray science and technology have provided greater insight, knowledge and understanding of the physical mechanisms of breakup of liquid jets, formation of drops and spray characteristics. Atomizer designs include co-axial air assist, liquid and air swirl, pizo-electric induced fluctuations, effervescent bubble atomization, rotating cup and disk. Electrostatic charging of droplets allows deflection of droplets in flight and avoidance of deposition on surfaces. Sprays used in combustion and industrial systems have not been sufficiently optimized. By increased knowledge, understanding and control, optimum conditions can be prescribed to allow designs of atomizers, liquid and air flows that will result in significant increases in fuel and energy efficient as well as significant reductions in formation and emission of pollutants.