Numerical Simulation Of Combustion In Heavy Oil Direct Injection Internal-combustion Engine

UAVs are currently used on the battlefield with gasoline engine, while tanks and armoredvehicles are using heavy oil. The fuel supply at the front restricted circumstances needs to provide aseparate fuel, which will increase the burden of logistical supply, and also increase the storage costs.In addition, heave fuel energy has high efficiency and torque. The potential is more reliable and morewidely in the battlefield. The specific energy of heavy oil is higher than gasoline, and higher flashpoint, non-flammable, so more safety in transportation and storage. Though also belong to petroleumproducts, as substitute of light fuel such as gasoline which is more shortage, the heavy oil engine inpower system of UAVs can overcome the main defects of the gasoline engine.Using professional internal combustion engine simulation software AVL-FIRE, the inlet,compression, spray, evaporation and burning process were numerical simulated in aerial piston enginecombustion with kerosene. Select different injector locations along the center line between intakevalve and exhaust valve, analyze the2D and3D results. The influence on the evaporation, mixturedistribution and combustion processes of important parameters, as the injector location and Start ofInjection (SOI) were discussed and compared. The injector location and start time of injection wereoptimized according the results. The difference of fuel evaporation, mixture distribution andcombustion performance was analyzed when combustion with kerosene and gasoline. The simulationresults show that:(1) When injection position was in y=0.054, the mixture distributed harmoniously before ignition,burning pressure is higher. As military products, compared with NO, the Soot is more considered.Soot less is helpful for burning stability and avoids deflagration damages the engine. In addition, inthis position, heat load decreases, the injector can be cooled and cleaned using high-speed inlet flow.In addition, there is a large space, be helpful for processing injector installation holes, decorateconvenient.(2) When injection at480°CA, fuel evaporated earlier, the SI time can be regulated more freely.The harmonious mixture is suitable for the fire spread quickly. Combustion pressure and the fuelefficiency is higher, Soot produced less. The late intake stroke in cylinder temperature graduallyraised, injection decrease temperature to improve for filling quantity coefficient, increase the airinflow.(3) Compared with gasoline, kerosene evaporated slowly, but can be evaporated completely before spark ignition time. For kerosene, the combustion pressure is higher, the NO and Sootemissions reduced slightly.