Numerical Research On Comples Oil-gas Separator Of Vehicles

The Oil-gas Separator is an important part of crankcase ventilation system of engine, and its separating performance directly affects economy performance, reliability performance and emission performance of internal combustion engine, along with increasingly strict exhaust gas legislation on automobile, which increasingly strict the performance of the separator. The Complex Oil-gas Separator has been developed and designed here, which is able to cope with the change of crankcase blow-by with the conditions and mileage and have high separation efficiency. So, it is more appropriate for the crankcase ventilation system. Therefore, the optimizing design of the Cyclone Oil-gas Separator becomes an important content of this paper studies. In this thesis, experimentation as well as numerical simulation is used to profoundly investigate the crankcase blow-by, the gas field in the Cyclone Oil-gas Separator and its performance. Whose goal is to offer a theoretical basis for the optimum design of the Cyclone Oil-gas Separator and lay solid foundation for the development and design of Complex Oil-gas Separator.The central contents of the thesis are followed.Firstly, by testing the engine of CA6SL2, crankcase blow-by changing along with the variety of the internal combustion engine speed and load is study and the efficiency of the original prototype model is tested, and the influencing factors to crankcase blow-by are studied carefully.Secondly, the software of CATIA is used for the establishment of a three-dimensional model, and the software of ANSA is also used to mesh this model in order to generate mesh, then the Computational Fluid Dynamics software of FLUENT is used to simulate the gas field in the Cyclone Oil-gas Separator model and its performance. By processing the results of simulation, the distribution of the velocity field, pressure field and Turbulent Kinetic Energy field and Turbulent Dissipation Rate field is obtained. Meanwhile, the ratio of the number of trapped oil droplets to the number of injected oil droplets is considered to be the numerical simulation separating efficiency, and by testing the prototype of the Cyclone Oil-gas Separator in the experiment, the result of numerical simulations coincides with the test, and the error is within 5%.Thirdly, the structure parameters of the Cyclone Oil-gas Separator and the entrance velocity of gas is the major factors of influencing the performance, it needs to carry out the further research. So, the performance of the Cyclone Oil-gas Separator is studied with numerical simulation by changing structure parameters one by one, and the content of numerical simulation research includes the pressure drop and efficiency, and then, by compromising the pressure drop and efficiency, the optimized size of the Cyclone Oil-gas Separator is determined, which provides a theoretical foundation for the further optimized design and lays solid foundation for the development and design of Complex Oil-gas Separator. Furthermore, the most important parameters to the efficiency and the pressure drop are the flow velocity (vj) and the diameter of air outlet (de) that is found, therefore, how the two parameters are determined should be seriously considered. At the same time, the optimal ratio of the size of the parts about Cyclone Oil-gas Separator to the diameter (Do) of its columnar part got in this paper is applicable to the design for all kinds of size of Cyclone Oil-gas Separators as a reference.