Numerical Simulation of Two-Phase Water-Oil Flow in a Horizontal Pipe Using the Smoothed Particle Hydrodynamics Method

In this work, the numerical code DualPhysics, based on the Lagrangian particle and mesh free method Smoothed Particle Hydrodynamics, has been employed to solve the slightly compressible isothermal two-phase water-oil flow. The continuity and momentum equations are solved, and we used the modified Tait equation of state to determine the pressure. To validate the numerical code, we solved the modified Couette flow of two fluids. As a practical case, we solved the isothermal and two-dimensional two-phase water-oil flow. The mixing of the fluids occurs after passing through a 45 degree Y junction placed at the entrance of the horizontal pipeline. Results showed the potential for using the numerical code, although some modifications and alterations are still necessary to solve practical problems.

Predicted Mutual Solubilities in Water + C5-C12 Hydrocarbon Systems. Results at 298 K

Mutual solubilities of water with n-alkanes, cycloalkanes, iso-alkanes (branched alkanes), alkenes, alkynes, alkadienes, and alkylbenzenes were calculated at 298 K for 153 systems not yet measured. Recommended data for 64 systems reported in the literature were compared with the predicted values. The solubility of the hydrocarbons in water was calculated with a thermodynamically based equation, which depends on specific properties of the hydrocarbon. The concentration in the second coexisting liquid phase (water in hydrocarbon) was calculated using liquid-liquid equilibrium with an equation of state, which takes into account the self-association of water and co-association of water with π-bonds of the hydrocarbons.

Experimental investigation of water-nitrogen flow in microchannel with high aspect ratio (with the 20 µm gap)

This study is devoted to the experimental investigation of two-phase water-nitrogen flow in the slit microchannel with a gap of 20 µm and a width of 10 mm. The technology of microchannel fabrication has been developed and described in detail. Experiments were conducted in adiabatic conditions. Using a modified schlieren system, four flow patterns have been observed and described: jet, bubble, churn, and annular. Flow pattern map was plotted according to obtained patterns. Moreover, a two-phase pressure drop was measured. Dependencies between two-phase pressure drop and superficial liquid and gas velocities have been investigated.

Testing the Modified Subchannel TEMPA-SC Code in Comparison with Experiments and Other Computer Codes

The paper describes a modified version of the TEMPA-SC computer program designed to calculate temperature fields in bundles of rods cooled by a supercritical pressure medium. This version of the program is based on the subchannel method that was used in the TEMPA-1F program, developed earlier in the OKB "GIDROPRESS" for calculating heat and mass transfer in the core of VVER-type reactors cooled by single-phase water at subcritical pressure. As the relations that close the system of equations of mass, momentum, and energy conservation, the new version of the program includes correlations for calculating heat transfer and friction resistance, taking into account the strong dependence of the properties of the coolant on temperature and pressure. In particular, the use of the universal calculation model of heat transfer, developed by the authors of this paper, allows us to perform calculations in a wide range of flow parameters of various media, including the modes of normal, improved and deteriorated heat transfer. The results of tests of the TEMPA-SC program are presented in comparison with the available experimental data for water and modeling media (carbon dioxide, freons R-12 and R-134a) at supercritical pressures, as well as with the published data of calculations by using similar subchannel programs (COBRA-SC, ASSERT-PV) and CFD codes. A satisfactory agreement between the calculated and experimental data is shown.

A new technological approach to the granulation of slag melts of ferrous metallurgy: obtaining glassy fine-grained granules of improved quality

The technological factors required to improve the operational properties of granulated metallurgical slags demanded in the building industry have been analyzed. In order to satisfy these factors, a new technology for hydro-vacuum granulation of slag melts (HVG) has been developed. It is shown that the main advantage of the proposed HVG process is the provision of forced high-speed vortex convection of water, with the effect of vertical suction, crushing, and degassing of the three-phase (water–slag granules–water vapor) heterogeneous medium formed during the overcooling and solidification of slag. It is proved that the high-speed volumetric disintegration and overcooling with the degassing effect sharply reduces a degree of aggressive gas/vapor impact on the being cooled particles of slag, which, in turn, leads to the reduction of the perforation degree of the granules. The obtained granules are distinguished by stable fractionation and improved, well-defined dense amorphous glassy structure, the water-holding capacity of which has reduced from 45–50% to 25–13%, the actual moisture content from 24–20% to 6–4%, while the hydraulic activity in terms of CaO-uptake increased from the conventional 320–360 mg/g to 610–650 mg/g. Pilot scale research demonstrated that the designed equipment for the HVG technology allows sustainable control of the quality of granules, and it has the potential for further development and implementation.

Energy Performance Analysis of B1-3.5mm Burner Model of Fasobio-15 Biodigester Biogas Cookstoves

In Burkina Faso, finding wood for cooking is still a headache for rural households due to the advancing desert. Here, we try to bring a new way for farmers who already have a biodigester and convince those who are reluctant to adopt this work to reduce their dependence on wood. For this purpose, a characterization of the energy performance of biogas stoves is carried out based on the three-phase water heating test protocol called Water Boiling Test (WBT). The fuel used in the study is the biogas produced by a batch biodigester fed with pig manure. The analysis of the produced biogas shows a methane content of 60% and maximum hydrogen sulfide of 400ppm. The heat balance shows a loss of 11% in the walls of the cookstove and about 36% in the flue gas. Thus the energy performance of the furnace is estimated at 53%, a combustion rate of 6.4 L /min and the average boiling time is 50 minutes. Given these results, we suggest that households use biogas fuel and the B1-3.5mm burner in the cookstove as a replacement for the other burners. We intend to carry out a controlled cooking test on this stove, a modeling of the biogas production and its consumption in this type of burner.

Development and Validation of new RP-HPLC Method for simultaneous Estimation of Methylcobalamin, Epalrestat and Pregabalin in bulk and Pharmaceutical dosage form

A new rapid, accurate, precise and economical reverse phase high performance liquid chromatographic method has been developed and validated for simultaneous estimation of Methylcobalamin, Epalrestat and Pregabalin in bulk and pharmaceutical dosage form. The separation was accomplished utilizing Agilent C18, 150 x 4.6mm, 5 column at a detection wavelength of 210nm utilizing the mobile phase water and acetonitrile 60: 40 v/v at the flow rate of 0.8ml/min and injection volume of 10µl. The total run time was 6.0 min. Validation discovered the method was specific, rapid, accurate, precise, reliable and reproducible. The calibration curve was linear over the concentration range of 0.37 – 2.25μg/ml of Methylcobalamin, 37.5-225μg/ml of Epalrestat and 37.5-225μg/ml of Pregabalin respectively with correlation coefficient of 0.999. The accuracy was determined by recovery studies and was found to be 99.5-100%. The precision of the results stated that the %RSD was <2%. The limits of detection for Methylcobalamin, Epalrestat and Pregabalin were 0.2, 0.9 and 1.2μg/ml, while the limits of quantification were 0.5, 1.5 and 0.9μg/ml respectively. Forced degradation study was carried out under acidic, alkaline, oxidative, photolytic and thermal conditions to prove the stability-indicating ability of the developed HPLC method. The high recovery confirms the suitability of developed method and can be further used in routine analysis.

Towards complete assignment of the infrared spectrum of the protonated water cluster H+(H2O)21

The spectroscopic features of protonated water species in dilute acid solutions have been long sought after for understanding the microscopic behavior of the proton in water with gas-phase water clusters H+(H2O)n extensively studied as bottom-up model systems. We present a new protocol for the calculation of the infrared (IR) spectra of complex systems, which combines the fragment-based Coupled Cluster method and anharmonic vibrational quasi-degenerate perturbation theory, and demonstrate its accuracy towards the complete and accurate assignment of the IR spectrum of the H+(H2O)21 cluster. The site-specific IR spectral signatures reveal two distinct structures for the internal and surface four-coordinated water molecules, which are ice-like and liquid-like, respectively. The effect of inter-molecular interaction between water molecules is addressed, and the vibrational resonance is found between the O-H stretching fundamental and the bending overtone of the nearest neighboring water molecule. The revelation of the spectral signature of the excess proton offers deeper insight into the nature of charge accommodation in the extended hydrogen-bonding network underpinning this aqueous cluster.