SIMULATION OF EMERGENCY MODES OF SEPARATOR UNIT

Предложена конструкция сепараторной установки, отличающаяся от существующих тем, что ее основание выполнено с кольцевыми канавками полукруглого сечения, посредством которых ротор-барабан установлен с возможностью вращения на неферромагнитные шарики. Кроме того, подогрев сепарируемого продукта в установке осуществлен с использованием неизбежного тепловыделения в обмотках установки путем пропускания сепарируемого продукта по трубкам, которыми обвиты лобовые части обмоток установки. Для исследования аварийных режимов этой установки (обрывов фаз, короткого замыкания) и получения ее динамических характеристик разработана математическая модель в виде системы дифференциальных уравнений, описывающей взаимосвязи между ее параметрами (сопротивления обмоток статора и ротора, число витков в них) и параметрами переходных процессов (ударные токи, длительность переходного процесса). Смоделирована работа сепараторной установки при обрыве одного фазного провода с помощью пакета прикладных программ Simulink – Simulation and model-based design (MATLAB). Разработанная модель позволила оценить влияние параметров статора и ротора установки на переходный процесс в аварийных режимах и учесть это влияние на этапе проектирования. Преимущества предлагаемой установки – повышенная надежность, улучшенные энергетические и массогабаритные показатели. The design of the separator unit is proposed, which differs from the existing ones in that its base is made with circular grooves of semicircular cross-section, through which the rotor-drum is mounted with the possibility of rotation on non-ferromagnetic balls. In addition, the heating of the separated product in the installation is carried out using the unavoidable heat generation in the windings of the installation by passing the separated product through the tubes that are wrapped around the front parts of the windings of the installation. A mathematical model in the form of a system of differential equations describing the relationship between its parameters (the resistance of the stator and rotor windings, the number of turns in them) and the parameters of transients (shock currents, the duration of the transient process) has been developed to study the emergency modes of this installation (phase breaks, short circuits) and to obtain its dynamic characteristics. The operation of the separator unit in the event of a single phase wire breakage is modeled using the Simulink is a Simulation and Model-Based Design (MATLAB) application software package. The developed model allowed us to estimate the influence of the stator and rotor parameters of the plant on the transient process in emergency modes and to take this influence into account at the design stage. The advantages of the proposed installation are increased reliability, improved energy and weight and size indicators.

Theory of Heat Exchange in Pipes With Turbulators With d/D = 0.95 ÷ 0.90 And t/D = 0.25 ÷ 1.00, and Also in Rough Pipes, by Air With Great Reynold’s Numbers Re = 106

Mathematical modeling of heat exchange in air in pipes with turbulators with d / D = 0.95 ÷ 0.90 and t / D = 0.25 ÷ 1.00, as well as in rough pipes, with large Reynolds numbers (Re = 106). The solution of the heat exchange problem for semicircular cross-section flow turbulizers based on multi-block computing technologies based on the factorized Reynolds equations (closed using the Menter shear stress transfer model) and the energy equation (on multi-scale intersecting structured grids) was considered. This method was previously successfully applied and verified by experiment in [1-4] for lower Reynolds numbers. The article continues the computational studies initiated in [1-4,25-27].

Design of Printed Circuit Heat Exchanger (PCHE) for LNG Re-Gasification System

In this paper, we present the ongoing process of the research and development of the Printed Circuit Heat Exchanger (PCHE) on Floating Storage Regasification Unit (FSRU). We performed a structural simulation work to find the optimal design of fluid channels on heat transfer plates, fabricated the heat transfer plates, and calculated the capacity of the PCHE using our analytical tool. In the simulation work, the plates having channels of 1 mm semicircular cross section were designed by varying the wall thickness between channels. At a temperature, 1373 K, compressing pressures were varied as 30, 85.7, and 500 bars. Based on the simulation results, we fabricated and bonded heat transfer plates using the diffusion bonding equipment which our department developed. Then, the sizing of PCHE was done with analytical calculation for the developing PCHE on FSRU.

Friction Force of the Sliding Surface with Pores Having a Semicircular Cross Section Form

A theoretical solution of the mathematical model is represented for obtaining the hydrodynamic pressure and friction force of the non-contacting sliding surfaces with pores having a semicircular cross section form. The expressions for the hydrodynamic pressure, shear stress, and friction force were obtained for a control cell that includes the inside and outside of the pore areas. The pore radii have been studied in the range from 0.5µm to about 18 µm. The parametric study of the pore performance is obtained with the specially written MATLAB program used the theoretically defined expressions. It is found that better performance in terms of positive hydrodynamic pressure and optimal friction forces can be achieved with proper selection of pore and outside of pore sizes. Better hydrodynamic pressures were observed at the gap-pore radii and cell-pore radii ratios range between 0.5 … 1 and 2.5 … 5, respectively. The maximal friction forces are achieved at pore radii values about 0.64 of the cell dimensions, which correspond to a r1 range of about 5 … 13 µm.

Stress Analysis of an Annular Sector Semicircular Cross Section Vessel

By using finite element software ANSYS, stress analysis was conducted to the annular sector semicircular cross section vessel which was made up of an annular sector plate, two semicircular plates and a semi-cylindrical with thicknesses of 20mm. The analysis results show that the maximum equivalent stress of the annular sector plate appears in the middle of the plate, and the maximum equivalent stress of the semicircular plate and the semi-cylindrical appear in the inner surface of the connections. The equivalent stress distribution trend of the annular sector plate, semicircular plates and the semi-cylindrical was obtained. Through these researches, the distribution trend of equivalent stress provided a reference for the design of the annular sector semicircular cross section vessel.