Essam Abo-Serie

Influence of smoothing length and virtual particles on SPH accuracy

 Abstract—Using a well known 2-D transient heat conduction benchmark, a parametric study is conducted to identify the best values for the smoothing length (h) as function of particles spacing in order to minimize the error in the temperature distribution particularly at the center of the domain when applying the Smooth Particle Hydrodynamics (SPH) algorithm. Also the effect of the virtual particles on the numerical solution has been investigated. The results showed that the predefined smoothing length can have significant influence on the accuracy of the prediction and using the optimum value leads to minimum error in temperature prediction values. The results obtained with and without virtual particles has been presented and compared with the analytical solution.

Generation of robust and well-atomized swirl spray

The authors would like to thank for the financial support of the Combustion Engineering Research Center (CERC).

Gaseous fuel for lower emissions during the cold start and warming up of spark ignition engines

Gasoline engines during cold starting (cranking) and warming-up duration, particularly, at low environmental temperatures have negative impact on air pollutions, especially for sub-zero degrees. To achieve a stable engine operation at low environment temperatures, extra fuel has to be injected inside the combustion chamber and as a consequence more emissions particularly hydrocarbons are emitted. In this study, fuel consumption, emissions and engine-start conditions have been examined using different gaseous fuels during the period from the ignition time until the catalyst reaching its lighting off temperature at no load conditions. The results showed that gaseous fuels reduces fuel consumption and emissions due to achieving substantial reduction in the number of engine cranking in addition to the inherent low emission characteristics of gaseous fuel. Hydrogen, in particular, showed superior performance in comparison to other examined gaseous fuels. The significant number of engine-start using 200 g of gaseous fuel particularly hydrogen makes the gaseous fuel viable to be used together with conventional liquid gasoline fuel.

Least squares multi-level approach for centroid detection in active triangulation

Active triangulation has been successfully applied in numerous applications such as distance measurement, profile inspections and pose estimation in robotics. Its accuracy depends on many factors with locating laser centroid being one of them. The error generated in locating the laser centroid within the image is propagated to the system output with consequences in decreasing performance. In this paper, we propose an algorithm for reducing error and hence improving the measurement accuracy. The approach applies gamma square law as a preprocessing techniques to reduce effects of background noise and speckles from the laser. Pixels clusters are extracted from the image by searching for the pixels with intensity levels within a pre-defined value and then, the Region Of Interest (ROI) is located by looking for an object shape similar to an ellipse within the extracted clusters. Each row and column of the ROI is divided into three sub-pixels classes. Least-square method is used to fit linear regression into each subclass. The standard deviation computation from this method is used to locate the centroid of the laser spot with better accuracy. The experimental results obtained using this method show consistent and improved results with least error deviation.