A Analysis on Basic Combustion Theory and Issues of Droplets of Liquid Energy Sources |
Studies have been made of the combustion of droplets ofliquid bio fuels such as FAME and the alcohols, especially ethanol andn-butanol, and of pulverised solid biomass materials such as wood andMiscanthus which burn in an analogous fashion. Information is given on theburning rates of both the liquids and the solids and data given on sootformation yields for the different fuels. The mechanism of soot formation isdiscussed in relation to (1) volatile liquid fuels such as n-heptane, alcoholsand aviation fuels, (2) liquid fuels having higher aromatic levels such asdiesel fuels, and (3) biomass particle combustion. A new theoretical analysis based on heat transfer withinthe droplet is presented here. It shows that the condensed-phase unsteadinesslasts for about 20-25% of the total burning time. It is concluded that thediscrepancies between experimental observations and the predictions of theconstant-property quasi-steady analysis cannot be attributed either togas-phase or condensed-phase unsteadiness.