Automatic control of rotary pump using measurements of oil-well liquid by on-line proton magnetic resonance analyzer

In the paper described system of automotive control of installation of rotary pump of oil-mining using parameters of oil-well liquid, measured by on-line proton magnetic resonance analyzer. Described theoretical basis of the system and its practical use. Mathematically modeled system tooling tuning) at changing moment of strength from features of oil-well liquid

Implementation of Flux Limiters in Simulation of External Aerodynamic Problems on Unstructured Meshes

The study is dedicated to the peculiarities of implementing the flux limiter of the flow quantity gradient when solving 3D aerodynamic problems using the system of Navier–Stokes equations on unstructured meshes. The paper describes discretisation of the system of Navier–Stokes equations on a finite-volume method and a mathematical model including Spalart–Allmaras turbulence model and the Advection Upstream Splitting Method (AUSM+) computational scheme for convective fluxes that use a second-order approximation scheme for reconstruction of the solution on a facet. A solution of problems with shock wave structures is considered, where, to prevent oscillations at discontinuous solutions, the order of accuracy is reduced due to the implementation of the limiter function of the gradient. In particular, the Venkatakrishnan limiter was chosen. The study analyses this limiter as it impacts the accuracy of the results and monotonicity of the solution. It is shown that, when the limiter is used in a classical formulation, when the operation threshold is based on the characteristic size of the cell of the mesh, it facilitates suppression of non-physical oscillations in the solution and the upgrade of its monotonicity. However, when computing on unstructured meshes, the Venkatakrishnan limiter in this setup can result in the occurrence of the areas of its accidental activation, and that influences the accuracy of the produced result. The Venkatakrishnan limiter is proposed for unstructured meshes, where the formulation of the operation threshold is proposed based on the gas dynamics parameters of the flow. The proposed option of the function is characterized by the absence of parasite regions of accidental activation and ensures its operation only in the region of high gradients. Monotonicity properties, as compared to the classical formulation, are preserved. Constants of operation thresholds are compared for both options using the example of numerical solution of the problem with shock wave processes on different meshes. Recommendations regarding optimum values of these quantities are provided. Problems with a supersonic flow in a channel with a wedge and transonic flow over NACA0012 airfoil were selected for the examination of the limiter functions applicability. The computation was carried out using unstructured meshes consisting of tetrahedrons, truncated hexahedrons, and polyhedrons. The region of accidental activation of the Venkatakrishnan limiter in a classical formulation, and the absence of such regions in case a modified option of the limiter function, is implemented. The analysis of the flow field around a NACA0012 indicates that the proposed improved implementation of the Venkatakrishnan limiter enables an increase in the accuracy of the solution

Simulation of Turbulent Convection at High Rayleigh Numbers

The paper considers the possibility of using different approaches to modeling turbulence under conditions of highly developed convection at high Rayleigh numbers. A number of industrially oriented problems with experimental data have been chosen for the study. It is shown that, at Rayleigh numbers from 109 to 1017, the application of the eddy-resolving LES model makes it possible to substantially increase the accuracy of modeling natural convection in comparison with the linear vortex viscosity model SST. This advantage is most pronounced for cases of a vertical temperature difference with the formation of a large zone of convection of strong intensity. The use of the Reynolds stress model EARSM is shown for cases of natural convective flow in domains with dihedral angles in the simulated region and the predominance of secondary currents. When simulating a less intense convective flow, when the temperature difference is reached at one boundary, the differences in the approaches used to model turbulence are less significant. It is shown that, with increasing values of Rayleigh numbers, errors in the determination of thermohydraulic characteristics increase and, for more accurate determination of them, it is expedient to use eddy-resolving approaches to the modeling of turbulence. © 2018 Sergey Dmitriev et al

INSTRUMENTS AND METHODS OF CONTROL OF THE CONCENTRATION OF PARAFIN IN OIL

Made ananalysis of contemporary laboratory devices and methods of control and analysis of paraffin ’s concentration in oils and oil products. Obtined NMR-spectra of standard and natural oil samples. Made an analysis of spectra line parameters. Established correlations between paraffin ’s concentrations, densities and relaxation times. Suggested for aim of of express-analysis to use method of nuclear magnetic resonance relaxometry (NMRR) and Portable relaxometer NMR-NP1

Simulation of Turbulent Convection at High Rayleigh Numbers

The paper considers the possibility of using different approaches to modeling turbulence under conditions of highly developed convection at high Rayleigh numbers. A number of industrially oriented problems with experimental data have been chosen for the study. It is shown that, at Rayleigh numbers from 109 to 1017, the application of the eddy-resolving LES model makes it possible to substantially increase the accuracy of modeling natural convection in comparison with the linear vortex viscosity model SST. This advantage is most pronounced for cases of a vertical temperature difference with the formation of a large zone of convection of strong intensity. The use of the Reynolds stress model EARSM is shown for cases of natural convective flow in domains with dihedral angles in the simulated region and the predominance of secondary currents. When simulating a less intense convective flow, when the temperature difference is reached at one boundary, the differences in the approaches used to model turbulence are less significant. It is shown that, with increasing values of Rayleigh numbers, errors in the determination of thermohydraulic characteristics increase and, for more accurate determination of them, it is expedient to use eddy-resolving approaches to the modeling of turbulence. © 2018 Sergey Dmitriev et al

Development of method of the trajectory measurings for the ballistics-navigation providing of management by the spaces vehicles of middle and distant space

Предлагается метод траекторных измерений для баллистико-навигационного обеспечения управления космическими аппаратами среднего и дальнего космоса на основе использования радиоинтерферометрической системы.Пропонується метод траєкторних вимірювань для балістико-навігаційного забезпечення управління космічними апаратами середнього і дальнього космосу на основі використання радіоінтерферометричної системи.The method of the trajectory measurings is offered for the ballistics-navigation providing of management by the spaces vehicles of middle and distant space on the basis of the use of the radiointerferometric system