Problem Statement and Motivation

Key Achievements and Future GoalsTechnical Approach

Electrostatic Atomizers for Mineral & Biological Oil CombustionFarzad Mashayek, MIE/UIC; John Shrimpton, Imperial College London

Primary Grant Support: NSF

Bio-fuel combustion in direct injection engines and stationary gas turbines is now widely considered as a potential solution to the future energy crisis. Burning bio-fuels reduces CO2 production by naturally recycling this gas. It is also strategically favored because of reducing our dependence on foreign mineral oil. The main impediment to existing technology for combustion of bio-fuels, however, is the difficulty of atomization due to higher viscosity of these oils.

• Electrostatic spraying has already been successfully implemented for a range of mineral oils.

• A workable theory exists for predicting the size of the drops by assuming a negligible role of hydrodynamics.

• The main goal of this project is to extend this process to bio-fuels which are viscous than common diesel oil.

• The role of hydrodynamic and the physics behind the charge injection process will be investigated theoretically to improve the design of the atomizer.

We use an electrostatic process which has proven extremely efficient in improving atomization, dispersion, evaporation rate, and hence combustion mixture preparation. The novelty of this work lies in the implementation of this process for electrically insulating liquids such as bio-fuels. This is accomplished by injecting charge into the liquid prior to its flow through the orifice. The charging process is more efficient for more viscous fluids and requires a negligible (~ mW) electric power with a small (~ 3-4 bar) pressure. This makes these nozzles ideal for injection of highly viscous liquid fuels without any need for preheating.

The nozzleSpray without (left) and with (right) charge injection

Combustion of Diesel oil in open air