A Numerical Simulation Of Medium-speed Marine Diesel Engine In-Cylinder Using KIVA-3V

With higher requirements for environment protection at home and abroad, people hopeto gain a power plant, which needs less energy but releases less pollution emissions. Fromthis point of view, more and more stringent requirements are put forward to the performanceof marine diesel engine, such as the greater output power, less fuel consumption rate, and atthe same time, the engine must conform to the present ever more stringent emissionregulations. The cylinder combustion affects the economic performance, the dynamicperformance and the main factors for emissions of diesel engines. Because the experimentalmethod of studying the diesel engine cylinder work process demands special equipments,and the experimental condition involves burning, apart from special laboratory can providethe test conditions, most experimental methods are hard to conduct. So using experimentalmethod to study the work of the diesel engine in cylinder has some limitations. Thereforelaunching a numerical simulation method research on the combustion process of dieselengine has been a hot topic in internal combustion engine industry.L21/31marine medium-speed diesel is taken as the research object and KIVA-3Vprogram is used to simulate the cylinder combustion progress in it. To generate the diesel’sgrid meshes, the K3PREP generator and ANSYS ICEM-CFD software are used respectively.By comparing the measured pressures and NOxemissions with two calculated results,ICEM-CFD model is chosen for the more reasonable model, meanwhile the accuracy of thismodel has also proved successful. On this basis, the main emphasis is placed on theinfluence of four factors including speed, load, fuel injection advance angle and inlet delayangle on how these parameters effect on the cylinder process, dynamic performance andspatial distribution of harmful emissions such as NOxand CO of the diesel engine.Aimed at NOxemissions limits of the second stage which implemented by IMO in2011, and that of the upcoming third stage in2016, this paper adds physical parameters ofliquid DME to fuel libery of KIVA-3V program. We chose liquid DME as a substitute fordiesel fuel, analysed the influence of DME on L21/31type of marine medium speedmachine NOxemissions. On the basis, reducing the load and delaying the fuel injectionadvance angle to research how these two parameters effect on the NOxemission value withDME fuel. Then we can forecast whether this type of engine can meet the standard of thethird stage NOxemissions after2016, and provide a theoretical basis for enterprise to retrofit the design of the model in this paper.