Three-Dimensional Numerical Simulation Of In-Cylinder Working Process On ZH1105W Diesel

In order to study the influence of combustion chamber shape on the power and economy performance of diesel, the in-cylinder turbulence and vortex movement of ZH1105W diesel engine were deeply analyzed, therefore compared with flower shape combustion chamber bowl shape combustion chamber was thought to be able to make better use of the energy of vortex, decrease resistance, mix fuel and air more quickly, improve combustion situation. So an improved scheme of a flat-head piston with a bowl combustion chamber was brought forward. In addition, by reducing the clearance the relative heat transfer area of combustion chamber was decreased, squish swirl was increased which would do good to mixture formation and combustion.In this thesis, the mathematics methods and numerical methods for three dimensional in-cylinder process simulations were introduced. Simulation works were carried out both on an improved ZH1105W diesel engine and its original one. The in-cylinder gas fluid, spray and combustion process were predicted. The detail of in-cylinder gas fluid and spray development and temperature field and pressure field were showed on. On the emphasis, the regular rule of in-cylinder fluid and the features of turbulence and eddy and the features of the nitrous oxide formation were analyzed.Some tests on the improved ZH1105W diesel engine were done. Because of the difficulty in measuring micro-parameters and some other limit conditions, there were only some parameters could be measured on a certain speed such as in-cylinder temperature and pressure, power and fuel consumption ratio. The accuracy of numerical simulation was justified by comparing the results of simulation with experimental data. The simulation and experimental results show that the power of the improved ZH1105W diesel engine was increased highly, and its fuel consumption was decreased. The better power performance and economy performance were obtained. It was proved that the computer simulation with high speed and accuracy was of benefit to reducing the product's development cycle and cost, which was an effective research and design method.