| Currently, the increasing car numbers and the constantly worse environment have rasied stricter demand on the combustion and emission control of internal combustion engine, and the quality of spray atomizing effect directly affects the combustion efficiency and gas emission of the engine. Studying on the spray characteristics is a main method to improve spray atomization quality. Gas emission can be reduced by optimizing the atomization process of the fuel injection in order to optimize the engineer combustion.Currently, the fundamental studies of spraying and the mixture establishment are accomplished in the constant volume chamber.The comparison research of the spray characteristics between diesel and diesel/bio-diesel mixed liquid, BD0(Diesel liquid quality accounted for 100 percent), BD24(Biodiesel liquid quality accounted for 24 percent of the diesel/bio-diesel mixed liquid), BD100(Biodiesel liquid quality accounted for 100 percent)was analyzed by using high-speed viedo imaging machine and Malvern Spraytec spray particle size analyzer in this paper.Firstly,use high-speed viedo imaging machine to take photos of spray macrography form namely spray cone angle of different fuels in different backpressure and injection pressure. The conclusion is that in the same injection pressure and fuel,with the backpressure increases,the spray cone angle increases; in the same backpressure and fuel,with the injection pressure increases, the spray cone angle have a little decreasing trend, but the injection pressure have an unconspicuous effcet on the spray cone angle; in the same backpressure and injection pressure,with bio-diesel mixed ratio increases, the spray cone angle decreases.The spray cone angle of BD0 is obviously larger than BD100.Secondly, use Malvern method test the average diameter, characterized in diameter, divergence and distribution curve of pure diesel fuel BD0,24% mixed ratio bio-diesel BD24,pure bio-diesel BD100.The experiment study conclusion: in the same injection pressure and fuel, with the backpressure increases, the Sauter mean diameter, characterized in diameter, divergence decrease,the PDF distribution curve and cumulation volume distribution curve offset to the left and the atomization quality get better; in the same backpressure and fuel, with the injection pressure increases,the Sauter mean diameter, characterized in diameter, divergence decrease, the PDF distribution curve and cumulation volume distribution curve offset to the left and the atomization quality get better in the same backpressure and injection pressure with bio-diesel mixed ratio increases, the Sauter mean diameter, characterized in diameter, divergence decrease, the PDF distribution curve and cumulation volume distribution curve offset to the right and the atomization quality get worse. |
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