Current Issue : October - December Volume : 2018 Issue Number : 4 Articles : 5 Articles
In this article the mathematical model of complex regulated electric system in\nmatrix form is developed. This mathematical model makes it possible to study\nthe steady-state stability of a complex electrical system by determining the eigenvalues\nof the dynamics matrix. The model of an electrical system that reflects\ntransient processes for small deviations is convenient, both algorithmically\nand computationally, in particular, in cases of their joint solution with\nsteady-state equationsââ?¬â?the equations of nodal voltages. The obtained results\nin the form of the eigenvalues of the matrix spectrum are qualitatively the\nsame as the results of classical studies, which is a consequence of the adequacy\nof the proposed model and the correct reflection of the dynamic processes\noccurring in a real electrical system. In addition, the equations obtained are of\nindependent importance for the analysis of various modes, including transient,\nelectrical systems of any complexity....
In order to improve the quality of the project, we adopt the intelligent compaction\ncontrol system and collect CMV values through experiments. In the\nexperiment using finite element simulation software to simulate and analyze.\nFrom the simulation results to analyze the road surface displacement and\nstress trends, derived from the displacement of the pressed material in the\nfifth pass, the sixth pass is almost the same, the rate of change close to 0, can\nbe considered pressed material has the desired pressure. The actual degree is\nin good agreement with the actual compaction of sand filling, indicating that\nthe compaction state of the pressed material can also be verified from the\nstress angle of the pressed material. The stress change from the weak vibration\nto the strong vibration load increases first and then decreases rapidly, and the\nreduction of strong vibration is more obvious. Therefore, the simulation result\nalso shows that the strong vibration has the better compaction effect than the\nweak vibration....
It�s very useful to put the virtual prototype technology into hydraulic ripper,\njust for improving the product research and development efforts. A certain\ntype of hydraulic ripper was simulated and calculated using CATIA and\nADAMS software, the simulation system is set up, and the relevant parameters\nof hydraulic ripper are gotten; on this basis, a prototype model is compared\nwith the reality. At the same time, a comparative analysis of simulation\nresults and real results under certain conditions is used to verify the rationality\nof the prototype model, and the reference value of its products must build a\ngood development platform for hydraulic ripper....
This study simulates the behavior of a jet issuing into a two-layer density-\nstratified fluid in a cylindrical tank and the resulting mixing phenomena.\nThe upper and lower fluids are water and an aqueous solution of sodium\nchloride (NaCl), respectively, with the lower fluid issuing diagonally upward\nfrom a nozzle on the bottom of the tank. The angle between the centerline of\nthe jet and the tank bottom is 60�š. The phenomena when the Reynolds number\nRe of the jet is 475, 1426, and 2614 are simulated. The mass concentration\nof the aqueous solution of NaCl is 0.02. The simulation successfully grasps the\njet behavior and the resulting mixing, which agree with the authorsâ�� experimental\nresults at the corresponding Re value. The secondary flows that appear\nin the horizontal cross-sections consist of a pair of vortices and flows along\nthe tank wall. The secondary flow at the density interface represents the intrusion\nof an internal density current, which gives rise to mixing along the interface....
Polymer solutions are used in chemical EOR processes to achieve incremental\noil recoveries through obtaining favorable mobility ratios. In the process, the\nin-situ viscosity is a key parameter for the polymer flood design, as well as the\nchanges in permeability due to the retention or adsorption (e.g.: plugging).\nUnderstanding the major causes of the plugging effects allows predicting injectivity\nproblems as well as optimizing project design. The objective of this\nwork is to use glass-silicon-glass micromodels in combination with tracer particlesââ?¬â?\nattached to the flooded fluidsââ?¬â?to qualitatively and quantitatively describe\nthe extent of permeability changes after polymer injection. Laboratory\nwork is performed in order to determine the physical properties of the polymer\nsolutions when they flow through porous media, such as the presence of\npermeability reduction/plugging of the micromodel. A statistical analysis of\nthe distribution and extent of plugged areas is performed and a study of the\npressure response during various injection stages will complement the study.\nA biopolymer (Scleroglucan) was tested and compared to a commonly used\npolymer, giving a direct insight into their pros and cons. Five different concentrations\nof polymers were tested and put into relation with their quantitative\nand qualitative amount of sort of called retention. The amount of adsorption\nwas determined experimentally in one case in order to draw the significance.\nBy exploiting the potential of GSG-micromodels in combination with\ntracer particles, it was possible to visualize the reduction of flow paths and its\nincrease during various injections for the first time. Expanding the working\nprinciple proposed in this work could provide further understanding of the\nbehavior of any polymers. The results obtained and workflow presented in\nthis work allow for additional understanding of polymer solutions behavior in\nflooding applications. Furthermore, the definition of optimized workflows to\nassess any kind of solutions in porous media and permeability changes is\nsupported....
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