Multi-dimensional Numerical Simulation Of Heavy Diesel Spray Charactristics

As the aggravation of the energy crisis, the oil price grows constantly nowadays, the fuel cost has already taken over 50% of the ship transportation cost. Therefore, the use of the cost-effective heavy-diesel becomes the urgent issue for the ship companies. Since the formation of mix gas is influenced by the spray characteristics, which determine the process of combustion. The study and the improvement for the spray characteristics of the heavy-diesel will be related to the use of heavy-diesel as well as the guarantee of dynamic property, economic efficiency and emission performance in the medium and high-speed diesel engine.The CFD software is used to build up the single-hole spray model, and then the model is tested and verified. The light and heavy diesel are simulated independently, and then analyze their differences with the help of their properties. The injection pressure, environmental pressure, orifice diameter, orifice length, fuel's temperature, and the different mixing ration with light diesel are made to optimize the spray characteristic of the heavy-diesel. And learn their influences for the heavy-diesel's spray characteristic. In order to close to the real condition of spray inside the diesel engine, base on the single-hole spray model, the multi-hole spray model is set up. Compareing their differences and analyze the causes, And then optimizeing the characteristics of the heavy-diesel.Results show that increasing the injection pressure and environmental pressure simultaneously, and heating while mixing with the light diesel can both improve the heavy-diesel's spray characteristics. However, comparing to the former, the latter is much easier to achieve, and it's spray characteristics is nearer to the light diesel's. For this reason, the project of heating while mixing the light and heavy diesel has its practical value.