Bio-Alcohol Electrosprays for Practical Propulsion Systems

  • Ohood A. Al Nuaimi

Student thesis: Master's Thesis

Abstract

This study examined the electrosprays of ethanol, 1-propanol and 1-butanol at voltages ranging from 3 to 6 kV, and flow rates ranging from 5 to 25 ml/hr, sprayed along and against the direction of gravity. The possibility of coupling the electrostatic spraying with combustion was examined by performing burning experiments of the three fuels at 4 kV and 10 ml/hr. High-speed movies were taken of the light scattered by the spray from a planar laser sheet that included the spray axis to study the general spray and flame phenomenology, and to provide measurements of the size and the velocity of the droplets. A multiplexed distributor with 10 sprays were designed and manufactures for future experiments. When spraying along the direction of gravity, four modes of spraying were obtained which were droplet dripping, steady cone-jet spray, intermittent cone-jet spray and oscillating spray. Spraying opposite to the gravity produced cone-jet with a side spray, steady cone-jet spray, core cone-jet with a broader spray, multi-jet spray and oscillating spray. The obtained velocities corresponded to low Reynols numbers, low Nusselt numbers but high convective heat coeffecients. Electric conductivity played the major role in bioalcohol electrospraying, whereas the viscosity had a negligible effect. The bio-alcohol flames operated in two distinct modes. First in a large diffusion flame, and then a flat flame near the ground plate. Group combustion number calculation showed that the flame burnt in a group combustion mode.
Date of AwardJun 2017
Original languageAmerican English
SupervisorDimitrios Kyritsis (Supervisor)

Keywords

  • Electrospray
  • Combustion
  • Bio-Alcohols
  • Flame
  • Propulsion system.

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