Papers by Keyword: Math Model

Abstract: In order to have more accurate analysis about the eruption period of gas eruption under a coal mine system, fractal geometry theory was introduced. Based on field test data, a novel R / S analysis method was used to calculate the Hurst parameter, which determined the persistence correlation of the gas system, and eruption period was calculated subsequently. The period was used by the coal mine factory to arrange the manufacturing process and for three years no accident about gas eruption under the coal mine was reported.

Abstract: The flow coupled secondary hydraulic lifting system of the excavator bucket was presented, also its structure, working principle, and performances. The math model of the lifting system is established, using the math mode to control the hydraulic accumulator, and then realize process controlling of the energy recycling and reusing. Further, the system pressure range was expanded, the energy reusing effect and efficiency were improved.

Abstract: Aiming at the low efficiency and precision of nowadays domestic auto-straightening machine of shafts, a new kind of shafts straightness detection system is researched and developed. The supporting part of the measuring mechanism adopts the mechanical structure of auto-going-down of straightening points supporting pedestal. The whole convolute measuring system fixes on the machine tool orbit sliding table, whose movement can change the position for the straightening point and make positioning faster and more accurate. In addition, this detection system bases on applications math and builds math model by Fourier transform which can separate the elliptical error signal, straightness error signal and impulse error signal and then gained ideal straightness error of shafts.

Abstract: In order to analysis the temperature rising rules of vehicle, road conditions and vehicle running state were considered. Process of friction heat generation, radiation heat and convection current exchange during drum brake working process was researched, and temperature rising model of drum brake was established. Under the guidance of similarity theory and dimension analysis theory, convection current heat exchange test of drum brake was carried out, and the solution equation of convection current heat exchange was obtained. Real road test results shows that the temperature rising curves between calculations and test are basically identical and the maximum inaccuracy variables approximately 20%.

Abstract: Bi-level coupling algorithm which is based on the improved genetic algorithm was proposed in this paper. Its upper-level module was designed to solve the load optimal distributing problem among the cascade hydropower plants and its lower-level module was designed to solve the generator group optimal-uniting problem among the generators in a hydropower system. This algorithm has advantages in getting the optimal operation schemes of the load distribution, as well as the generator group unitization at the same time. By using a practical basin cascade plants as an example, the results show that the software can carry on rational and optimal decision to the producing operation schemes. The Bi-level coupling algorithm has higher practical value in hydropower system management.

Abstract: The paper describes multi-section round bloom casting using external MEMS, equipped with max section D600mm and min D280mm mold, the center line of D280mm mold not coincident with the axis of stirrer coils. it is exist eccentric electromagnetic stirring of mold which section less than max D600mm, a mathematical model of MEMS has been established, the index of central segregation of D280mm macrostructure had decreased less than 1.12 by optimized parameters of electromagnetic stirring and SEN immerse depth, in the end, the quality of round bloom had improved.

Abstract: According to the photovoltaic working principle,the math model is established, because some parameters of the model are difficultly obtained in actual work, its application is limited. Considering that in pactice certain paramaters may be not obtained, the photovoltaic math model is properly simplified, thus the applied model is educed. For the exporting power of photovoltaic cell, the control model is established based dq coordinates. Calculating of simulation shows the model can be used in practice, it has practicability.

Abstract: This article dissertated the status of classification to desulfurization agent CaCO₃, designed a kind of new-type whirlpool grader, dissertated the principle and excellence of its impeller, at last we established its math model.

Abstract: This article presented a method to amend the model of magnetic levitation system by adding a current fixed link. It improved the accuracy of math model of magnetic levitation system with current controlled. Finally, simulation and experimental results showed effectiveness of the new model.

Abstract: Magnetic-electrochemical compound polishing is applied in difficult-to-process materials little by little. The influence of the magnetic field to electrochemical process is very complicated. In the paper, using Coulomb laws and Lorentz force, the two kinds of math model of the movement of the charged particles are established according to the different magnetic field whose direction is vertical or parallel to the electrical field. The velocity equations and loci equations of three typical particles are concluded in two kinds of magnetic field’s directions. To be compared and analyzed carefully, the influence of the magnetic field’s direction to polishing is concluded. This study can guide how to determine the magnetic field’s direction in magnetic-electrochemical compound polishing, and build the theoretical basis to study the mechanism of magnetic-electrochemical compound polishing.