A combined method for calculating the trajectories of suspended particles

© 2016, Allerton Press, Inc.A combined method for calculating the trajectories of suspended particles in the hydrodynamic velocity fields is proposed. The method utilizes capabilities of existing CFD codes and parallel computing on a computer with a graphics card that supports CUDA technology. The software package that implements the method is described

A model for heating and evaporation of a droplet cloud and its implementation into ANSYS Fluent

© 2018 Elsevier Ltd A model for heating and evaporation of a cloud of monocomponent droplets in air, taking into account the evolution of droplet number densities, is developed and implemented into ANSYS Fluent. Functionality testing of the new customised version of ANSYS Fluent is based on its application to the analysis of a droplet cloud in a two-phase back-step flow. It is shown that the effect of the droplet cloud needs to be taken into account when estimating the heat and mass transfer rates from the carrier phase to the droplets

Modelling of the evolution of a droplet cloud in a turbulent flow

The effects of droplet inertia and turbulent mixing on the droplet number density distribution in a turbulent flow field are studied. A formulation of the turbulent convective diffusion equation for the droplet number density, based on the modified Fully Lagrangian Approach, is proposed. The Fully Lagrangian Approach for the dispersed phase is extended to account for the Hessian of transformation from Eulerian to Lagrangian variables. Droplets with moderate inertia are assumed to be transported and dispersed by large scale structures of a filtered field in the Large Eddy Simulation (LES) framework. Turbulent fluctuations, not visible in the filtered solution for the droplet velocity field, induce an additional diffusion mass flux and hence additional dispersion of the droplets. The Lagrangian formulation of the transport equation for the droplet number density and the modified Fully Lagrangian Approach (FLA) make it possible to resolve the flow regions with intersecting droplet trajectories in the filtered flow field. Thus, we can cope successfully with the problems of multivalued filtered droplet velocity regions and caustic formation. The spatial derivatives for the droplet number density are calculated by projecting the FLA solution on the Eulerian mesh, resulting in a hybrid Lagrangian–Eulerian approach to the problem. The main approximations for the method are supported by the calculation of droplet mixing in an unsteady one-dimensional flow field formed by large-scale oscillations with an imposed small-scale modulation. The results of the calculations for droplet mixing in decaying homogeneous and isotropic turbulence are validated by the results of Direct Numerical Simulations (DNS) for several values of the Stokes number

Study of correlation of oil flow properties with nuclear magnetic resonance and self-diffusion characteristics

© Copyright 2016.Correlation curves of viscosity, average spin-spin relaxation time, and average self-diffusion for crude oil samples from Tatarstan oil fields have been obtained. Two different averaging models were used to calculate mean values. It has been found that self-diffusion D and average spin-spin relaxation time R2 are best correlated in case reciprocal values 1/R and 1/D are averaged

ETHICAL PROBLEMS IN SOLVING TASK WITH ARTIFICIAL INTELLIGENCE

В статье дается краткий обзор современного уровня исследований в области этики использования технологий искусственно интеллекта. Проблема этичности применения искусственного интеллекта рассматривается с различных аспектов: морально-этического, этико-религиозного, правового и со стороны степени несения ответственности за принятое решение.In this article a brief overview of state-of-the-art ethics research of using artificial intelligence technologies is given. Problem of ethical applying AI come on different aspects: morally-ethical, religious-ethical, law aspect, and from the responsibility of decision making

An atomic force microscopy study of hybrid polymeric membranes: Surface topographical analysis and estimation of pore size distribution

© 2016, Pleiades Publishing, Ltd.The surface morphology of polymeric membranes as organic–inorganic block copolymers has been studied by atomic force microscopy (AFM). These hybrid block copolymers have been obtained by the polyaddition of toluene 2,4-diisocyanate to macroinitiators and the addition of oligomeric polyhedral оctaglycidyl silsesquioxane (Gl-POSS) as a bulky branching agent in a concentration range of 0.1–15 wt %. The AFM study of the morphology made it possible to determine the main roughness parameters and to perform topographical analysis of the surface of the polymers. The pore size distribution was evaluated by histogrammic approximation with the use of the Gauss distribution. The hypothesis of the normalcy of distribution of the experimental sample of pore diameters was confirmed by a combined criterion and Pearson’s chi-square goodness-of-fit test. The effect of the Gl-POSS concentration on the surface morphology and the microstructure of the organic–inorganic polymeric membranes was found to be nonmonotonic over the test concentration range

Paper estimability of heavy oil viscosity by nuclear magnetic resonances researchestitle

Copyright © 2014, Society of Petroleum Engineers. This paper presents the results of laboratory and nuclear magnetic resonances researches of seventy-seven crude oil samples from the Devonian, Carboniferous and Permian formations of Tatarstan oil fields with a wide range of viscosity varying from several cps to 60,000 cps. The results can be used to estimate the viscosity of the oil, including in situ viscosity. It has been found that the NMR relaxation characteristics of the tested samples presented in the form of T2 time distribution spectra confirm that crude oil is multicomponent. Numerical characteristics resulting from the analysis of the spectrum of spin-spin relaxation time T2 have been determined, which show good correlation with the viscosity of the hydrocarbon fluid. The paper presents the obtained experimental correlations between the rheological properties and NMR characteristics for oil samples studied

The fully Lagrangian approach to the analysis of particle/droplet dynamics: Implementation into ansys fluent and application to gasoline sprays

The fully Lagrangian approach (FLA) to the calculation of teh number density of inertial partucles in dilute gas-particles flows was incorporated into teh CFD code ANSYS Flunet. The new verion of ANSYS Fluent was applied to moedling dilute gas-particle flow around a cylinder and liquid droplets in a gasoline fuel spray. In a steady-state case, thre predictions of the FLA for the flow around a cylinder and those based on teh equilibrium Eulerian method (EE) are almost the same for small Stokes number (Stk) and small Reynolds number (Re). FLA predicts higher values of the gradients of particle number densities in front of the cylinder compared with the ones predicted by the EE for larger values of Stk and Re. Application of FLA to a direct injection gasoline fuel spray has concentrated on the computation of the number densities of droplets. Results revelaed good agreement between the numerical simulation and exeperimental data

Numerical adiabatic potentials of orthorhombic Jahn-Teller effects retrieved from ultrasound attenuation experiments. Application to the SrF2:Cr crystal

A methodology is worked out to retrieve the numerical values of all the main parameters of the six-dimensional adiabatic potential energy surface (APES) of a polyatomic system with a quadratic T-term Jahn-Teller effect (JTE) from ultrasound experiments. The method is based on a verified assumption that ultrasound attenuation and speed encounter anomalies when the direction of propa- gation and polarization of its wave of strain coincides with the characteristic directions of symmetry breaking in the JTE. For the SrF2:Cr crystal, employed as a basic example, we observed anomaly peaks in the temperature dependence of attenuation of ultrasound at frequencies of 50-160 MHz in the temperature interval of 40-60 K for the wave propagating along the [110] direction, for both the longitudinal and shear modes, the latter with two polarizations along the [001] and [110] axes, respectively. We show that these anomalies are due to the ultrasound relaxation by the system of non-interacting Cr2+ JT centers with orthorhombic local distortions. The interpretation of the ex- perimental findings is based on the T2g (eg +t2g) JTE problem including the linear and quadratic terms of vibronic interactions in the Hamiltonian and the same-symmetry modes reduced to one interaction mode. Combining the experimental results with a theoretical analysis we show that on the complicated six-dimensional APES of this system with three tetragonal, four trigonal, and six orthorhombic extrema points, the latter are global minima, while the former are saddle points, and we estimate numerically all the main parameters of this surface, including the linear and quadratic vibronic coupling constants, the primary force constants, the coordinates of all the extrema points and their energies, the energy barrier between the orthorhombic minima, and the tunneling splitting of the ground vibrational states.Comment: 8 pages, 3 figure