Study On Spray Characteristics And Pyrolysis Characteristics For Methanol

In recent years, Chinese automotive industry develops rapidly, however Chineseoversea dependent ratio on oil continues to rise quickly, the internal combustionengine industry faces enormous opportunities and challenges. Searching for anefficient and clean and resourceful alternative fuel which is a main way to solve thedilemma.In China, methanol comes from a variety of sources and has lots of advantages,such as high octane, anti-knock, biodegradable easily, high oxygen content and themethanol combustion process requires less air, combustion is more efficient, flamespreads rapidly, and the duration is shorter, improve effectively the thermal efficiencyof internal combustion engine, and combustion products mainly are H2O and CO₂,lower pollution and improve emissions standards. So methanol has received extensiveattention as alternative fuel, many scientists and researchers devote their energies tocarrying out the application of methanol engine. Within this context, this research willstudy methanol spray characteristics and pyrolysis characteristics for applicationwidely of methanol engine in the future.Designing constant volume bomb and electric heating device, completedmethanol injector flow characteristics test with constant volume bomb, and thenanalyzed methanol spray characteristics with PIV laser testing technology and imageprocessing technology and AVL-Fire simulation technology, methanol was heated bythe electric heating device and then was pyrolyzed by two types of catalysts, thepyrolysis components were measured and analyzed by gas chromatography.The results show that the relationship between methanol injectors jet mass flowand ambient pressure complies with the trend of Bernoulli’s equation, as the ambientpressure is0.3MPa and is the same as the injection pressure, mass flow tends to aconstant number, and injection is not normal. Spray test and simulation results showthat ambient pressure affects significantly spray penetration distance, howevertemperature affects imperceptibly spray penetration distance. The effects of ambientpressure and temperature on methanol evaporation are complicated, as ambientpressure is0MPa and temperature variation has little effect on methanol evaporation,however as ambient pressure is0.2MPa or0.3MPa and methanol evaporation increases significantly when temperature increases. As temperature is20℃andmethanol evaporation reduces significantly when ambient pressure increases, howeveras temperature is60℃and methanol evaporation reduces imperceptibly whenambient pressure increases. The effects of ambient pressure and temperature on spraySMD are significant. Methanol pyrolysis characteristics test shows that methanol isheated and pyrolyzed, and then pyrolysis components are measured and analyzed bygas chromatography, the main components are H₂, CO, CH₄, water vapor andmethanol vapor as well, the peak of methanol pyrolysis rate shows different laws withcatalysts variation. Catalytic inlet temperature and catalytic outlet temperature aredifferent obviously when methanol is pyrolyzed by different catalysts.