Technique for operational diagnosis of pipelines of energy systems and complexes

THE PURPOSE. To consider the problems of reliability of pipeline systems of housing and communal services. To analyze existing methods for assessing the technical condition of pipelines. To develop an improved technique that allows you to search for various types of defects in pipelines. To develop a device for inertial excitation of low-frequency diagnostic vibration vibrations. To develop software in the LabVIEW environment for collecting, storing and processing signals from a sensitive sensor (piezoelectric sensor) installed on a pipeline. To conduct a series of experimental studies to te st the proposed methodology. METHODS. The method of inertial excitation of vibrations was used to excite vibrations in the wall of the investigated pipeline. To search for the natural frequencies of vibrations of the pipeline under study, mathematical mode ling methods were used, implemented in the ANSYS software package. During the experiments, the fast Fourier transform method was used to process the signals coming from the piezoelectric sensor. RESULTS. The article presents a technique for assessing the t echnical condition of pipelines, as well as a device for inertial excitation of vibrations. The article presents the results of experimental studies on a fiberglass pipeline, the results showed that when an oscillatory wave passes through the wall of a defect-free pipeline, its amplitude changes insignificantly. If there is a defect in the wall of the investigated pipeline, the vibration amplitude will be much weaker due to the dissipation of vibrational energy in the place of the defect. Thereby, it is pos sible to determine not only the presence of a defect, but also its size by the degree of attenuation of the signal amplitude CONCLUSION. The proposed technique is the basis for the creation of a new measuring and diagnostic complex for vibration control of pipelines.

Dynamic response of vertical shaft Pelton turbine unit for forced vibration

This research work was carried out to model the excitation force imparted by water jet in the form of Fourier series and determine the forced response of Pelton turbine unite of Khulelhani-I hydropower analytically by developing mathematical mode. Amplitude of forced vibration form analytical was compared with simulation result. The mathematical model was developed by calculating the kinetic energy of disk and potential energy of both disk and shaft. Hamilton’s principle was used to determine equation of motion and then Galerkin method was used to determine response of the system. Fourier analysis was done to obtain the function in its exact form. The developed methodologies were followed to find the analytical solution of Kulekhani-I unit of 3100 kW rated at 600rpm. A rigid disk (runner and bucket assembly) was situated along end of flexible shaft with fixed support at the shaft. First five Fourier components are to be considered in analysis for meaningful representation of forcing function. The amplitude of vibration of Pelton turbine unit with single nozzle in Y-direction (the direction of water jet) obtained by analytical method was closed with that obtained from the ANSYS simulation.

Simulation of Transfer and Spread of Pollutants into the Marine Environment Using a Probabilistic Model of Turbulence

The paper describes the problem and specifies the key sources of marine pollution. A mathematical mode of particle transfer and settling as well as the parameters of environment turbulence are proposed. A 3D diffusion-advective model discussed in the paper was developed on the basis of “wandering particles” method with the use of random numbers generator for nondeterministic processes simulation. But it has a number of specific features as compared with similar models in practical setting of boundary conditions at water-air boundaries and water-bottom boundaries, description of turbulence of different scales, in taking into account the effects of the initial immersion of a heavy jet, in the effect of flocculation as well as taking into account non-conservatism of the impurity. Different simulation results are presented.

Análisis de la transferencia de calor de un sistema de refrigeración a partir de nanofluidos

In the last decade one of the main opportunity areas of the cooler systems is increase their efficiency; for this, it has been innovating in materials and working fluids mainly. In the last decade one of the main areas of opportunity in refrigeration systems is the reference to increase their efficiency. For this, it has been innovating in materials and fluids of work mainly. In this work, the analysis of the transfer of calories in liquid cooling systems is analyzed by adding nanoparticles. These systems have different industrial and refrigeration applications in electronic systems. In the present work a configuration of the refrigeration system to be used is proposed. The analysis consists of the mathematical mode from the design of the geometry and the trajectory of the flow in the pipeline, in addition to a simulation in Computational Fluid Dynamics (CFD) of the system. The conditions are presented in the results.

Особенности микрокристаллизации 50 % двухкомпонентных металлических расплавов в модели переходной двухфазной зоны в диффузионно-релаксационном режиме

В диффузионно-релаксационном режиме кристаллизации 50% двухкомпонентных металлических расплавов в модели переходной двухфазной зоны оценены термодинамические параметры, при которых возможно образование полностью разупорядоченной двухкомпонентной кристаллической фазы с простой кубической элементарной решеткой стехиометрического состава. Исследована область вблизи точки разупорядочения кристаллической фазы и установлен закон стремления параметра дальнего порядка к нулю при достижении критической температуры (переохлаждения) системы двухкомпонентный расплав-кристалл. Установлены кинетические особенности роста кристаллической фазы в точке разупорядочения. Установлен закон восстановления упорядоченной двухкомпонентной кристаллической фазы во времени. Оценены возможные значения времен релаксации при переходе из разупорядоченной двухкомпонентной кристаллической фазы с простой кубической элементарной ячейкой к полностью упорядоченной. Установлены кинетические особенности образования полностью упорядоченного двухкомпонентного кристалла. REFERENCES Sarkisov P. D., Baikov Yu. A., Meshalkin V. P. Matematicheskoe modelirovanie kristallizatsii odno- i dvukhkomponentnykh metallicheskikh rasplavov [The one- and binary metallic melts mathematical mode ling crystallization]. Moscow, Physmatlit Publ., 2003. 378 p. (in Russ.) Baikov Y. A., Petrov N. I. Structure of the Transitive Two-Phase Zone in Crystallization of Two-Component Metal Melts. Russian Physics Journal, 2014, v. 57(4), pp. 459–468. https://doi.org/10.1007/s11182-014-0262-2 Baikov Yu. A., Petrov N. I. Special Features of disordering in Crystallization of Two-Component Metal Melts in the Model of Two-Phase Transitive Zone. Russian Physics Journal, 2014, v. 57(5), pp. 598–614. https://doi.org/10.1007/s11182-014-0282-y Petrov N. I. The Crystal Disordering Study When Growing From the Binary Metallic Melts. National University of Science and Technology «MISiS» Dis. Cand. Phys.-Mat. Sci. Moscow, 2017, 180 p. URL: http:// misis.ru/fi les/6902/Petrov_AR.pdf (in Russ.) Sarkissov P. D., Baikov Yu. A., Meshalkin V. P. Order-disorder processes in crystals when crystallizing binary metallic melts. Doklady Physics, 2003, v. 48(6), pp. 290–295. https://doi.org/10.1134/1.1591316 Chistyakov Yu. D., Baikov Yu. A., Schneider H. G., Ruth V. The order-disorder transformation at supercooled melt/crystal transition region of binary melts (I) the master equation. Crystal Research and Technology, 1985, v. 20(8), pp. 1007–1014. https://doi.org/10.1002/crat.2170200802 Chistyakov Yu. D., Baikov Yu. A., Schneider H. G., Ruth V. The order-disorder transformation at supercooled melt/crystal transition region of binary melts (II) the steady state solution // Crystal Research and Technology, 1985, v. 20(9), pp. 1149–1156. https://doi.org/10.1002/crat.2170200903 Guinier A. J., Griffoul R. Compte Rendu, 1945, v. 221, pp. 121. Guinier A. J. Imperfections of crystal lattices as investigated by the study of X-ray diffuse scattering // Proceedings of the Physical Society, 1945, v. 57(4), pp. 310–324. https://doi.org/10.1088/0959-5309/57/4/306 Schneider H. G. Collection: Advances in Epitaxy and Endotaxy. Akademiai Kiado, Budapest, 1976, p. 23. Chistyakov Yu. D., Baikov Yu. A. Collection: Advances in Epitaxy and Endotaxy. Akademiai Kiado, Budapest, 1976, p. 159. Chistyakov Yu. D., Baikov Yu. A. Collection: Advances in Epitaxy and Endotaxy. Akademiai Kiado, Budapest, 1976, p. 257.

The Model of the Korla Fragrant Pear Mature Based on Effective Accumulated Temperature

In order to investigate the mature law of Korla fragrant pear with mathematics method, Korla pears in Aksu area be taken as the study object, and the fruit hardness and soluble solid content (SSC) be selected as the research index. The data of the two indices in the mature process are analyzed with Excel, SigmaPlot and Matlab. To draw the change rule of indices and establish the mathematical mode. The research shows that the effective accumulated temperature reaching up 3000°C to 3843°C is main mature stage of the Korla fragrant pear, and there is an accelerating stage in which. The change rule can be precise description by the established mathematical model that can provide reference for fruit maturity modeling.

Synthetical Evaluation Model Based on Integer Programming for Arranging Single Round Robin Schedule

In this paper, the synthetical evaluation model based on integer programming for arrangement of single round robin schedule is established through analyzing the major factors of matches. Following, as an example, we analysis and evaluate the schedule of NBA 08-09 season according to this mathematical mode. All results are obtained with the MATLAB software.

Grinding Wheel Dynamic Balance Weight Type System Based on the Self-Optimal Fuzzy Control

.Grinding wheel as the research object in this paper and aim at the vibration signal use the weight balance principle to balance the centrifugal force caused by the eccentric whee. Designed a kind of self-optimization fuzzy controller, through online optimization correction factor realized the control rules of self-adjustment and self-improvement. Not only solved the problem of relying on the Precise mathematical mode as the conventional control system,but also make the control system has automatic adaptation for the changes of the object properties.Experimental results show that:the effect of the correct balance amount and the grinding wheel unbalance correction offset is good, the vibration drop rate reached 93.2%, has played a good role in inhibition of unbalance, the grinder vibration quantity significantly reduced and improved the performance of the control system.

Proposed Model for Optimizing Production System Using CMS

Manufacturing cells are created by grouping the parts that are produced into families. This is based on the operation required by the parts. These cells which consist of machine or workstation are then physically grouped together and dedicated to producing these part families. In this paper a mathematical mode is presented to grouping the machine parts and machine cell. The objective of the proposed model is to minimize the mean flow time and maximize the throughput. This work presents a Genetic Algorithm for the cell formation and part family.Here, the implementation procedure of GA in the CMS problem has been discussed along with the detail of algorithmic parameters used in the algorithm