The convergence behavior of Bird’s Direct Simulation Monte Carlo (DSMC) method is explored for nearcontinuum, one-dimensional Fourier flow. An argon-like, hard-sphere gas is confined between two parallel, fully accommodating, motionless walls of unequal temperature. The simulations are performed using a one-dimensional code based on Bird’s DSMC prescription. The convergence metric is taken as t...

We numerically simulate the traveling time of a tracer in convective flow between two points (injection and extraction) separated by a distance r in a model of porous media, d=2 percolation. We calculate and analyze the traveling time probability density function for two values of the fraction of connecting bonds p: the homogeneous case p=1 and the inhomogeneous critical threshold case p=p(c). ...

In the present study, the production of dextran from date extract and sucrose as carbon sources by the bacterium Leuconostoc mesenteroides NRRL B512 (f) was investigated. In comparison to blue dextran (Mw≈2000 Da), dextran molecular weight was reduced (Mw2000 KDa). Flow behavior indices of dextran solutions from date extracts were investigated and rheological parameters were evaluated at concen...

Experimental realizations of Taylor-Couette flow often include rigid end plates at bottom and top of the system. As a consequence of such end plates the bifurcation behavior of the basic laminar flow as well as the spatio-temporal properties of the emerging pattern, such as e.g. spiral vortex flow, can change. The latter point is in the focus of our present experimental study. The spatio-tempor...

Objective(s):The aim of this study was to improve flowability and compressibility characteristics of starch to use as a suitable excipient in direct compression tabletting. Quasi-emulsion solvent diffusion was used as a crystal modification method. Materials and Methods: Corn starch was dissolved in hydrochloric acid at 80˚C and then ethanol as a non-solvent was added with lowering temperature ...

In present paper, dynamic behavior and control of a fluidized bed reactor for polyethylene production has been considered. A double active sites model for Ziegler-Natta catalysts is used for simulation of polymerization reaction. Hydrodynamic behavior of the bed is modeled using a two phase model including bubble and emulsion phases in which bubble phase has plug flow pattern with different...

Wax deposition phenomenon changes the rheological behavior of waxy crude oil completely. In the current work, the rheological time-dependent and time-independent behaviors of waxy crude oil samples are studied and flow curve and compliance function are measured for the oil samples with various wax contents at different temperatures. A decrease in temperature and an increase in wax content lead ...

A Laser Induced Fluorescence technique (LIF) has been used to study the mixing behavior of two emerging streams in a T-Type mixing chamber. A mixing index on the basis of digital image light intensities is calculated. It has been shown that averaging over more than 800 images leads to a stable mixing index calculation. Moreover, the effect of equal and un-equal flow rates on the mixing behavior...