Three-dimensional Simulation Calculation Of Gas Oil Chamber Optimization For Marine Diesel

In recent years, with the rapid development of shipping, ship emissions impact onatmospheric pollution is more and more serious, with energy conservation and environmentalprotection arousing people’s more and more attentions, the emissions regulations related todiesel engine become increasingly stringent, In particular, the 《MARPOL73/78》corrected byinternational maritime organization (IMO) especially rules the emissions limits of NOxmadeby marine diesel engine. Therefore, how to reduce the emissions of diesel engine, especiallyreduce the emissions of nitrogen oxides has become one of the important research topics inthis industry. In this paper, take a new diesel engine as the research object and adopt thethree-dimensional simulation software FIRE to establish the burning in cylinder simulationmodel of diesel engine, Mainly by changing the diesel engine combustion related parametersof gas, oil and chamber to study the influence on diesel engine combustion and emissions.First of all, in order to guarantee the accuracy of the simulation calculation, with theFIRE software making the simulation of the air-inlet system so that have more intuitiveunderstand of the diesel engine intake process. The calculations of vortex ratio and flowcoefficient provide a theoretical basis for the simulation calculation of the combustionchamber; With GT-power software establishing the one-dimensional simulation of singlecylinder diesel engine model, the pressure and temperature in cylinder on intake valve closingtime obtained from the pressure and temperature curve provide the initial conditions to thesimulation calculation of the combustion chamber with the FIRE software.Secondly, according to the diesel engine combustion chamber geometry to establish asimulation model of combustion in cylinder and divide the mesh of the model to establishthree-dimensional dynamic meshing simulation model. According to the actual data of thediesel engine, use the simulation results of inlet and single cylinder model to set calculationparameters accurately. Select the inlet turbulence, combustion and emission model in cylinderreasonably according to the diesel engine working process and then make the simulationcalculation. What’s more, make the simulation results compared with the diesel engine designtarget value to verify the accuracy of the simulation model.Finally, in order to improve combustion and reduce emissions of the diesel engine, takethe relevant parameters of air intake, fuel injection and combustion chamber as the research variables, use the FIRE software to make three dimensional simulation of combustion processfor the diesel engine. Through the comparison and analysis of simulation results, according tothe results of the various parameters on the influence of combustion emissions, Come to theconclusion that appropriately and reasonably increase intake pressure, adjust vortex ratio,nozzle diameter and nozzle number, increase beam Angle and combustion chamber throatdiameter are beneficial to improve the combustion and emission performance of the dieselengine. The comprehensive optimization simulation results of gas oil chamber verify theconclusion. The conclusions provide predictive reference of improving engine structure andoptimizing diesel engine combustion and emissions performance.