PLIF Analysis And Research Of Biodiesel Combustion Flame Characteristics

A bio-fuel atomization evaporation combustion system of biomass liquid fuel was designed and built to produce biodiesel laminar premixed system,and using OH-PLIF technique to study the laminar premixed flame characteristics of biodiesel and its mixed fuel,the relationship between OH radical distribution and CO/CO₂ generation and NO emission of biodiesel,etc.At present,there are a few researches on the diagnosis of laminar premixed flame characteristics of biodiesel by PLIF technique,but it is important to study the combustion charateristics and products of biodiesel according to the distribution of OH radicals,and this paper focuses on this perspective to conduct research.Firstly,the physicochemical properties of the oils used in this study were detect and analyzed,and bio-fuel atomization evaporation combustion system of biomass liquid fuel was designed and built according to these physicochemical properties.In this paper,the detail of the system composition,operation flow and usage was described.Also,the composition of the OH-PLIF system used in the research and the experimental principle are introduced.The above is the prerequisite for the start of the experiment.Secondly,the OH-PLIF system was used to detect and analyze the laminar premixed flame characteristics of Jatropha curcas L.biodiesel and waste oil biodiesel,including flame height,flame front area,flame speed and OH-PLIF total signal intensity.When the equivalence ratio was increased,the height of the biodiesel laminar premixed flame increased,and the area of the laminar flame front first decreased and then increased,and the laminar flame speed first increased and then decreased,and the total OH-PLIF signal intensity increased.When equivalence ratios were identical,the laminar flame speed of waste oil biodiesel increased with an increase in the temperature of the premixed gas.Thirdly,the relationship between OH radical distribution and CO/CO₂ emissions of Jatropha curcas L.biodiesel and waste oil biodiesel was studied.When the OH-PLIF average signal intensity of combustion flame increased,[CO]/[CO₂]decreases.When the OH-PLIF average signal intensity of combustion flame decreased,[CO]/[CO₂]increased.And when the equivalence ratio was increased,the NO emissions of two kinds of biodiesel gradually decreased,and the NO emissions of waste oil biodiesel was less than Jatropha curcas L.biodiesel.Finally,the combustion characteristics of waste oil biodiesel/butanol blended fuel and waste biodiesel/ethanol blended fuel were studied,including flame height,flame front area and flame speed.Among them,the increase of the n-butanol addition ratio will increase the OH-PLIF total signal intensity of flame,and the increase of the ethanol addition ratio will reduce the OH-PLIF total signal intensity of flame.