چكيده به لاتين
Due to the leakage and pressure differences in between combustion chamber and the crankcase of an engine, some combustion products enter the crankcase. The release of these gases into the environment is a source of pollution. Separators are used to reduce oil consumption (mixed with blow-by gases) and reduce air pollution. In this research, numerical simulation of a single-channel variable cross-sectional collision separator, a cross-sectional variable separator with vertical barrier and an impact-separator with a cross-section with variable oblique barriers have been investigated. Using the experimental data available in the papers, related to the Separator of the Ford Ecobost engine (a simple variable cross-section separator), the geometry and similar boundary conditions were used to validate the models used in the simulation. To verify the accuracy of the simulation, the pressure drop in experimental results and the simulated model for the Ford Ecobost collision separator are compared. According to results, it is found that experimental and numerical results are adequately matched. By choosing a proper turbulence model and solving algorithm, Euler-Lagrangian method was used to track particles. The results of the separator with simple variable cross-section showed that most particles with diameter between 0.3 and 0.7 μm follow the path of the fluid flow. A number of these two diameters are separated by a flexible plate and some by the wall of the outlet channel. For a diameter of 1 micron, more than 80 percent of the droplets are separated by the flexible plate and the wall of the outlet channel. The particles with diameter of 2 microns and larger droplets are completely separated from the fluid by the flexible sheet at the beginning. In the next step, the tracking of particles for variable separators was studied with a vertical and oblique barrier with a distance of 5 mm and separator with variable cross-sectional area with a vertical barrier of 1 mm with a flexible plate. The collision efficiency and oil vapor separation efficiency for different separators for different flow rates, and the effect of vertical displacement on the oil seperation and collision efficiency were investigated. The results showed that the addition of a vertical barrier and oblique, reducing the barrier distance and indenting on the flexible sheet would increase the efficiency of the separation. Finally, the highest separation efficiency, which was calculated to be 93%, was observed in a separable flexible plate with a reflection and obstruction of 1 mm.
Keywords: Sequential separator with variable cross-section, Euler-Lagrange, particle tracking, collision efficiency
