Effect of salt and aging on aqueous surfactant formulations for tertiary oil recovery: A correlation of physical properties with microstructure using spin-labels

Physical properties and molecular packing in surfactant aggregates of the surfactant formulation 5% (w/w) TRS 10–410 (a petroleum sulfonate), 3% (w/w) isobutanol and desired quantities of sodium chloride in distilled water were studied using electron spin resonance (ESR) technique and pH, density, viscosity, screen factor, specific conductance, surface tension and free sodium ion measurements of fresh and aged solutions. The results suggested that both salt concentration and aging lead to changes in molecular packing of surfactant aggregates. At optimal salinity, the order parameter was a maximum. With increasing salt concentration, the correlation time increases initially and decreases at higher salt concentration. Various physical property data substantiate the observed microstructural changes. A detailed discussion is presented of the interrelations of these parameters operative in this complex surfactant formulation. Presently with the Whiteshell Nuclear Research Establishment, Atomic Energy of Canada Ltd., Pinawa, Manitoba, Canada ROE 1LO.     

Influence of alkali on pyrolysis of coals

Pyrolysis of several Indian coals of different rank in the presence of NaOH showed that the best yield of hydrogen was obtained from medium rank (C, 83.5%) Poniati-Girimint coal. With this coal, other alkalis (Ca(OH)₂, CaCO₃, Na₂CO₃) gave much less hydrogen, but significantly more methane in the product gas.     

Laminar radial flow electrochemical reactors. I. Flow fields

The velocity fields of three laminar radial flow electrochemical reactors are modeled using numerical and semi-analytical techniques. The capillary gap cell configuration is modeled using Galerkin finite element (GFEM) analysis and the asymptotic form of its velocities presented. An approximate asymptotic expression for entry length is also derived and compared to predicted entry lengths from the GFEM. Qualitative agreement is achieved. Two areas of flow separation are observed, their location being a function of gap width, flow Reynolds number (Re) and inlet pipe diameter. The rotating electrolyzer (REL) flow field is also simulated with the GFEM model. The insensitivity of the REL radial velocity profiles as a function of flow rate is shown. The shape of the radial velocity profiles and the degree of separation of the radial velocity jets are shown to be determined by the Taylor number (being the ratio of half-gap width over the theoretical boundary layer thickness). The asymptotic entry length solution is shown to provide a better estimate for this cell than for the capillary gap cell. Unlike the previous cells the pump cell shows less asymptotic behavior and is therefore more difficult to simulate. The GFEM approach is usually too costly for this cell and therefore perturbation techniques are applied. The resulting semi-analytical solution adequately represents laminar pump cell velocity profiles over a broad range of parameter values and is very short and easy to implement. One high Taylor number simulation is performed using the GFEM and the previously reported decoupling of electrodic mass transfer is interpreted via velocity profiles.Nomenclature a gap width - Q volumetric flow rate (m³ s^–1) - r dimensionless radius - R radius (m) - Re Reynolds number (v _c a/v) - Re _gap gap Reynolds number (a ²/v) - Re rotational Reynolds number (R ₀ ² /v) - Sc Schmidt number (v/D) - spin dimensionless group (Equation 8) - t time (s) - v _c characteristic velocity (m s^–1) two defined: for FEM analysis it wasQ/b ² for Perturbation analysis 6Q/(2R _in a) - v _r dimensionless radial velocity - v _z dimensionless axial velocity - v dimensionless azimuthal velocity - V velocity (m s^–1) - z dimensionless axial distance Greek symbols Taylor number (Equation 7) - ratio of characteristic lengths (a/R _o ) - viscosity (kg m^–1 s) - constant - density (kg m^–3) - azimuthal direction - kinematic viscosity (m² s^–1) - angular velocity (rad s^–1)     

Effect of magnetic field on two-layered natural/thermocapillary convection

Heat transfer in a two-layered fluid system is of great importance in a variety of applications. Control and optimization of convective heat transfer of the immiscible fluids needs complete understanding of all phenomena, especially those induced by surface tension at the fluid interface. The present work is focused on rather complex convective flow and heat transfer phenomena in a cavity, which can be subject to both buoyancy and thermocapillary effects in addition to the influence of magnetic field applied for flow control. With the encapsulant liquid posing magnetic properties, a magnetic force can arise to either enhance or counterbalance the gravity effect when the cavity is placed in a non-uniform magnetic field. In our study, the velocity and temperature distribution of the system can be significantly altered to change the heat transfer by varying intensity and gradient of the applied magnetic field. Preliminary results of numerical computation presented here are for a two-layered liquid cavity MnCl₂·4H₂O and Fluorinert FC40 under various magnetic fields intensities.     

The Effect of Acoustic Field on the Thermal Conductivity of composite propellants

A study is conducted to determine the effect of acoustic field on the thermal conductivity of composite propellants based on poly- butadiene and polyurethane binders. The thermal conductivity of the propellant is determined by a specially designed equipment. The thermal conductivity measurements are made in steady state conditions and in an acoustic field of constant amplitude at various frequencies ranging from 1 kHz to 6 kHz and at different temperatures ranging from 30°C to 50°C. The results indicate that the thermal conductivities of the composite propellants increase when they are subjected to an acoustic field. The data obtained are presented in the paper. Since the burning behaviour of solid propellants is influenced also by its thermal conductivity, the present work may be of direct relevance in improving upon some of the existing burning rate and combustion models.