Application of isokinetic sampling technique for local solid densities in upward liquid-solid flows through an annulus

Camçı, Gülden
In this study, radial solid density distributions in upward flowing water-feldspar mixtures through a concentric annulus were investigated. Local solid density measurements were performed at a test cross-section in the fully developed flow region of a concentric annulus, which is a part of a closed-loop system consisting of a head tank, a variable speed slurry pump, an orificemeter, a heat exchanger, an annulus, a temperature probe, and a drain line. The solid particles with mean diameters of 72 and 138 ?m at two different feed solid concentrations of 1 and 2 % v/v were used in the prepared slurries. The dependent variables being local solid density, local mixture velocity, and axial frictional pressure drop along the test-section, an experimental work was performed to obtain the radial solid density profiles and axial pressure gradients at different operating conditions. To determine the local solid densities, a sampling probe was used. At the beginning, this probe was used as a pitot tube to measure the local velocities in the test cross-section. Making use of these data, local solid densities were measured with the same probe under isokinetic and nonisokinetic conditions to compare both. For this purpose, an isokinetic sampling unit was designed and constructed to withdraw the samples under isokinetic flow conditions, at which the sampling velocity in the probe equated to the true flow velocity in the annulus very closely. The required constant back-pressure was supplied by pressurized N2 gas to equate these velocities to each other. The amounts of solids in the slurry samples collected at seven different radial locations in the test area under isokinetic and non-isokinetic conditions were determined by the gravimetric method. Local solid densities showed more uniform trends at the feed solid concentration of 1% v/v than those at 2% v/v. Increasing the feed solid


Application of non-convex rate dependent gradient plasticity to the modeling and simulation of inelastic microstructure development and inhomogeneous material behavior
Klusemann, Benjamin; Yalçınkaya, Tuncay; Geers, M. G. D.; Svendsen, Bob (Elsevier BV, 2013-12-01)
In this study, a two-dimensional rate-dependent gradient crystal plasticity model for non-convex energetic hardening is formulated and applied to the simulation of inelastic microstructure formation. In particular, non-convex hardening is modeled via a Landau-Devonshire potential for self-hardening and two interaction-matrix-based forms for latent hardening. The algorithmic formulation and the numerical implementation treats the displacement and the glide-system slips as the primary field variables. The num...
Akkus, Yigit; ÇETİN, BARBAROS; Dursunkaya, Zafer (2017-08-30)
In this study, a computational model for the evaporation from a sessile liquid droplet fed from the center to keep the diameter of the droplet constant is presented. The continuity, momentum and energy equations are solved with temperature dependent thenno-physical properties using COMSOL Multi-physics. At the surface of the droplet, convective heat and evaporative mass fluxes are assigned. Since the flow field is affected by evaporative flux, an iterative scheme is built and the computation is automated us...
Application of the spectroscopic modifications of Pippard relations to NaNO2 in the ferroelectric phase
Yurtseven, Hasan Hamit (2001-01-01)
This study examines a linear variation of the specific heat C-P with the frequency shifts 1/nu(partial derivative nu/partial derivativeT) for the Brillouin frequencies of the L-mode [010], [001] and [100] in the ferroelectric phase of NaNO2 according to our spectroscopically modified Pippard relation. We obtain this linear relationship for those modes studied and calculate dT(C)/dP in the ferroelectric phase of NaNO2. Our calculated values of dT(C)/dP for the [001] and [100] modes are in good agreement with...
Design rules for suspending concentrated mixtures of solids in stirred tanks
Ayrancı Tansık, İnci (2011-10-01)
This study examines complete off-bottom suspension conditions for slurries containing mixtures of solids at a wide range of concentrations. Binary combinations of five different particles; bronze, two sizes of glass beads, ion exchange resin, and nickel were tested with two impellers: the Lightnin A310 and the down pumping 45 degrees PBT. The effect of particle size ratio and density ratio of the two solid phases on N(js) was investigated. Solids loadings were varied from 3 to 56 wt% (weight percent) with w...
Calculation of a phase diagram for the ice II-V-VItransitions
Tari, O; Yurtseven, Hasan Hamit; Salihoglu, S (2000-12-01)
In this study we calculate the P - T phase diagram of ice II - V - VI using a mean field model. Our calculated phase line equations are fitted to the experimental data from the literature. There is a very good agreement between our calculated and experimentally observed P - T phase diagram of ice II - V - VI.
Citation Formats
G. Camçı, “Application of isokinetic sampling technique for local solid densities in upward liquid-solid flows through an annulus,” M.S. - Master of Science, Middle East Technical University, 2003.