Study Of The Influence Of Spray Parameters On The Spray And Combustion Process Of Dual-opposed Engine

With the intensifying environmental pollution and the increasing depletion of oilresources, as well as increasingly stringent requirements on emissions in countries, it isindispensable to propose higher requirements on the power, economy and emissionperformance of engines. OPOC engine, for its light and high power density, has beenwidespread concern. The process improvement of cylinder spray combustion is the key factorto solve the above problems, while fuel injection system directly affects the atomizationquality of fuel oil and thereby affects the cylinder mixture formation and combustionprocess. Therefore, the influence rule study of fuel injection system parameters on enginespray and combustion process in OPOC engine has great significance.This article systematically discusses the three-dimension numerical simulationcalculation methods and numerical calculation model of the cylinder spray combustionprocess, and conducts specific theoretical analysis on the cylinder gas turbulence model, thespray model and the cylinder combustion and emissions model. Using FIRE, which is thethree-dimension CFD software, this article conducts the numerical simulation to cylinderspray combustion process and analysis the influence rule of the fuel injection advance angleand orifice diameter to mixture formation, combustion and emissions of the OPOC engine，focally on the influence to the ignition delay, heat release rate, fuel-air equivalence ratio, fuelevaporation rate, temperature and effluent quality scores, the results show that:(1) The influence of fuel injection advance angle: With the increase of the fuel injectionadvance angle, the ignition delay becomes longer, and the fuel evaporation rate of the ignitiontiming, before ignition of combustible pre-mixed gas, the peak of heat release rate, the highestcombustion temperature and the maximum cylinder pressure increases, which is conducive to the increase of the indicated power, but it can also cause the rapidly increase of the maximumexplosion pressure. As well as the increases of cylinder maximum temperature leads to anincrease in NOx emissions, due to the sufficient combustion, so soot emissions reduce.(2) The impact of the orifice diameter: orifice diameter has little impact on the ignitiondelay period. Under the same conditions as the amount of fuel injection, with the increase ofthe orifice diameter and the oil beam penetration distance, it is likely to cause the fuel to wall,make inadequate combustion and make soot emissions increased. With the decrease of orificediameter, SMD becomes smaller and unevaporated fuel quality reduces, but the fuelatomization quality and the indicated power improve, as well as the fuel consumption rateappropriately reduce. The effect of the decrease of the orifice diameter on soot emissionscontrol is more obvious, but at the same time the rise of cylinder temperature will lead to theincrease of NOx emissions.