Annotation
Transportation of coolants, oil and oil products are associated with the flow of liquid medium through pipelines of circular cross-section. When the fluids move through the pipes, pressure losses arise on the friction of the flow against the pipe wall. Reduction of wall friction, and accordingly energy loss for pumping liquid can be achieved by pulsating flow in the pipeline. The pulsating mode has acceleration phases, which corresponds to a more complete velocity and deceleration profile, which is characterized by less filled velocity profile, in comparison with a stationary flow. The mathematical model is based on the theory of the boundary layer, using the Prandtl hypothesis on the length of the mixing path. As a result of the numerical experiment, qualitative and quantitative information on the effect of harmonic oscillations of the fluid flow on the hydrodynamic flow characteristics was obtained. The influence of frequency factors and the amplitude of flow oscillations is shown, as well as one of the main characteristics determining the economic effect of the process that is pressure loss on friction along the length of the channel. A method for creating harmonic and nonharmonic oscillations is proposed.
Аннотация:Постановка задачи. Выбор материалов и технологии изготовления неразъемных механических соединений трубопроводов (фитинга и трубы), формируемых методом холодной пластической деформации.Метод. Теоретический анализ выбора материалов контактирующих пар на основе упругого последействия материалов трубы и фитинга. Упругое последействие материала трубы должно превосходить упругое последействие материала фитинга.Результаты. Приведены рекомендации по материалам неразъемных соединений, формируемых при различных методах пластической деформации. Method. Theoretical analysis based on mechanical properties fitting and tubing materials. Springback tubing materials shall exceed springback tubing materials.Results. Describes recommendations for materials of contact connections, formed with various methods of plastic deformation.
The paper presents the results of testing the cooling capacity of a number of quenching oils using the device “IVF SMART QUENCH” of the company [[CHECK_DOUBLEQUOT_ENT]] IVF [[CHECK_DOUBLEQUOT_ENT]] (Sweden). The tests were carried out in order to expand the range of suppliers, to find alternative quenching media that match the cooling characteristics of traditionally used quenching oils. Both new and traditionally used quenching oils for volumetric quenching were tested. The cooling capacity characteristics of the Voltes 16 and Voltes 26 quenching oils were tested in comparison with the Thermo Oil 16 and Thermo Oil 26 oils used. The characteristics of Thermo Oil 16 and Thermo Oil 26 quenching oils in the “before operation” state (selected from storage tanks) were evaluated, and in the “during operation” state (selected directly from the quenching tanks). Based on the results obtained, the quenching media Thermo Oil 16 and Thermo Oil 26 produced by “TNK Lubricants” LLC in Ryazan are recommended for further practical use. The paper uses methods of statistical data processing to determine the characteristics of the stability of technological processes - the reliability and suitability indices.
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