Showing papers in "Chemical Engineering Science in 1968"

TL;DR: An exact solution of the linearised Stokes flow equations was derived for a viscous flow about a fixed sphere in contact with a fixed plane wall when the fluid motion in the absence of the sphere is assumed to be a uniform linear shear flow as mentioned in this paper.

TL;DR: In this article, the authors measured dispersion coefficients from response curves measured using an ionisation detector situated in the gas stream and showed that at low Reynolds numbers ( = udpe/ν), the dispersion is effected by molecular diffusion, but at high Reynolds numbers eddy diffusion predominates.

TL;DR: In this article, the effects of a basic flow, of solid boundaries and of inertia are jointly included in a theory which is used to examine the behaviour of spheres in laminar tube flows.

TL;DR: In this paper, it was shown that the suspension speed is a function of impeller clearance, as well as fluid flow pattern and the distribution of particles throughout the vessel, contrary to the findings of Zwietering for this particular impeller.

TL;DR: In this article, a rheological model for polymeric fluids is proposed, which can describe non-Newtonian viscosity, shear-rate-dependent normal stresses, frequently-dependent complex viscosities, stress relaxation after large deformation shear flow, recoil, and hysteresis loops.

TL;DR: In this article, the authors used a modified thermo-balance to measure the diffusion coefficient and thermal conductivity of the porous lime layer, and the mass and heat transfer coefficients to the surface of the compact.

TL;DR: In this paper, the temperature dependence of the binary diffusion coefficients is expressed in terms of an Arrhenius-type exponential relationship, and sensitivity of aqueous diffusivities to solute molecular weight, solute molecule size and solute-solvent interactions is discussed.

TL;DR: In this paper, a theoretical treatment for the problem of a solid or viscous fluid sphere settling in the presence of a plane surface formed by the contact of two immiscible viscous fluids is presented.

TL;DR: In this paper, the axial dispersion coefficient was measured in water filled bubble columns of 5·08, 14·0 and 29·0 cm dia. as a function of the superficial gas velocity.

TL;DR: In this paper, an expression for the periodic variation of local voidage near the containing walls is derived by first considering the periodic variations through a regular close-packed hexagonal array of spheres, and then introducing two randomising parameters.

TL;DR: In this paper, an equation relating the profile of a thin film formed between a drop and an interface, or between two drops, to the pressure drop due to flow is derived, and the influence of interfacial tension gradients on tangential movement of the interface itself is examined in detail.

TL;DR: In this article, a theory of the tensile strength of powders, incorporating the effect of powder density, particle size distribution and interparticle force, has been developed, which enables the experimental results for different size fractions of each of five materials of different chemical and physical nature to be correlated with the particle size distributions.

TL;DR: In this article, the problem of finding the optimal temperature policy in a batch reactor was formulated as a Bolza problem of the calculus of variations, and an analytical solution was obtained for the optimal policy.

TL;DR: In this paper, the authors measured individual particle velocities by photographing the movement of tracer particles in a completely transparent bed of glass particles fluidised with dimethyl phthalate.

TL;DR: In this article, theoretical and experimental studies on the solid-liquid mass transfer from a rotating disk to non-Newtonian solutions are reported, and an expression for the mass transfer has been derived in terms of the system parameters and the power-law constants of the liquid.

TL;DR: In this paper, a free surface cell model which takes into account hindering effects among neighbor particles has been used to solve the equations of viscous fluid motion and continuity simultaneously with a conservation equation for diffusing surfactants.

TL;DR: In this paper, the frequency and velocity of disturbance waves in two phase annular flow have been measured and correlated as functions of the flow rates, and the velocities of individual waves were found to be normally distributed about the mean with a standard deviation that was independent of the mean velocity.

TL;DR: In this paper, a generalized treatment is formulated for a catalyst pellet consisting of a porous solid within which a homogeneous liquid-phase catalyst is dispersed, and the theoretical relations governing diffusion and reaction kinetics in such a catalyst are derived.

TL;DR: In this paper, the rate of fall of oscillating drops is found to be proportional to the inverse square root of the drop diameter, and the measurements follow quite well the empirical equation developed from the seven high interfacial tension systems of the present work.

TL;DR: In this article, a phosphorescence method is described to visualize flow patterns in the laminar flow of a viscous liquid, and velocity distributions for Newtonian fluids were determined in rectangular ducts of various height-breadth ratios.

TL;DR: In this article, the experimental velocities of four sizes of precision sapphire spheres (0·794 −0·4764 cm dia) and six sizes of glass spheres ( 0·0208−0·505 cm dIA) have been measured in a vertically oscillating water column at conditions of constant velocity, amplitude, acceleration and frequency of vibration.

TL;DR: In this article, two conditions for the existence of multiple solutions were stated: (1) the value of parameter γβ has to be greater than a certain critical value, (γβ)*, and (2) Thiele's modulus has to simultaneously be simultaneously in the definite range φ1 ⩽ φ ⩾ φ2 on the basis of the model, where the state of the particle is described by means of mean values of concentration and temperature.

TL;DR: In this article, a mathematical scheme for obtaining the exact thermal-entry-region temperature solutions for laminar flow (Poiseuille's parabolic velocity profiles) heat transfer subject to significant axial conduction and the boundary condition of the third kind was devised.

TL;DR: In this article, the authors have made measurements in uniformly superheated water at pressures from 0·5 to 1·2 atm which supplement the data of Dergarabedian and of Hooper and Abdelmessih, both of whom worked at 1 atm.

TL;DR: In this paper, an equation for the liquid distribution in a packed column is established by using a diffusional model for the spreading of the liquid in the packing and by assuming that the variation of the flow-rate in the wall region is determined by the difference between two flow-rates, one towards the wall and another one returning from the wall.

TL;DR: In this paper, the authors studied the kinetics of absorption of oxygen in aqueous solutions of sodium dithionite in a jet apparatus and found that the reaction was zero order with respect to oxygen.

TL;DR: In this paper, mass transfer from gas to liquid is markedly enhanced by gravity-controlled roll waves and not from the more regular sinusoidal waves, despite the presence of waves in the real case.

TL;DR: In this paper, a perturbation method was used to get an approximate solution of the second order differential equation of the longitudinal dispersion model for both large and small Peclet numbers assuming a general kinetics of the chemical reaction.