<p>The demanding emission requirements must be satisfied by the modern aero-engines which led the researchers into exploration and development of environment-friendly, and sustainable aviation fuels. Water emulsification in fuels is a proven mechanism to reduce nitrogen oxide (NO<sub>X</sub>) and pollutant emissions. Furthermore, water addition in liquid fuel can improve the combustion performance and fuel economy by microexplosions and puffing phenomenon due to the volatility difference between liquid fuels and water. These microexplosions and puffing result in the breaking of fuel droplets into smaller droplets which promotes secondary atomization of the liquid fuels. The secondary atomization contributes to a higher combustion rate, improves fuel-air mixing, and, thus improves fuel economy. Also, with the depletion of fossil-fuel sources, the scientific community is exploring renewable sources which can be both reliable and better substitutes for conventional fossil fuels. Blending biofuel with fossil fuel is an interesting way to a sustainable solution for green energy production and carbon footprint reduction of conventional aviation fuels. In these contexts, this study reports an experimental investigation on the combustion characteristics of water emulsified Jet-A and water emulsified ethanol-blended Jet-A fuels. The Ultrasonication method is used to prepare homogenized fuel emulsions with two different water concentrations (5% &amp; 10% by weight) for both Jet-A and ethanol-blended Jet-A fuels. A mixture of Sorbitan monooleate (Span 80) and Polyoxyethylene sorbitan monooleate (Tween 80) is used as an emulsifier to increase the stability of the fuel emulsions. Blended Jet-A fuels are prepared for different ethanol concentrations (5%,10%,15% &amp; 20% by weight). Droplet combustion is carried out by suspending a sub-millimeter spherical droplet of different fuel emulsions on three 16µm silicon carbide wires. The suspended sub-millimeter spherical droplet is ignited using two hot wire loops which are positioned on either side of the droplet for uniform heating. The combustion process is captured with a high-speed CCD (charge-coupled device) camera and a high-speed CMOS (complementary metal-oxide-semiconductor) camera. The resulting high-speed images are post-processed to analyze the combustion behaviors of the different emulsified fuels. Combustion characteristics such as ignition delay, combustion rate, total combustion time, and flame stand-off ratio (FSR) data are generated for each emulsified fuel. The results are compared for both Jet-A and ethanol-blended Jet-A fuel emulsions. It is hoped that the outcome of the present study will increase further interest in combustion characteristics modification of conventional aviation fuels by emulsification. In addition, the findings of the present study will provide experimental data which can be applied for future computational modeling of the combustion process of emulsified fuel.</p>

Experimental Investigation of the Combustion Behavior of Jet-A/Water Emulsified Fuel and Ethanol-Blended Jet-A/Water Emulsified Fuel Droplets

Paper Proceedings: https://asmedigitalcollection.asme.org/IMECE/IMECE2021/volume/85543

ASME 2021 International Mechanical Engineering Congress and Exposition (IMECE2021)

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