An exact solution of the convective-dlffuslon equation for fully developed parallel plate lammar flow was obtamed It allows the denvatlon of theoretical relatlonshps for calculating the Peclet number m the axmlly dispersed plug flow model and the concentration dlstrlbutlon perpendicular to the direction of the flow, provided that the correspondmg solution of this model IS known. The convective-...

We apply the finite volume method to a spherically symmetric conservation law of advection-diffusion-reaction type. For the numerical flux we use the so-called complete flux scheme. In this scheme the flux is computed from a local boundary value problem for the complete equation, including the source term. As a result, the numerical flux is the superposition of a homogeneous flux and an inhomog...

Understanding the dissolution behavior of dense non-aqueous phase liquids (DNAPLs) in rock fractures under different entrapment conditions is important for remediation activities and any related predictive modeling. This study investigates DNAPL dissolution in variable aperture fractures under two important entrapment configurations, namely, entrapped residual blobs from gravity fingering and p...

Homogenization method is used to analyse the equivalent behavior of transient flow of a passive solute through highly heterogeneous porous media. The flow is governed by a coupled system which includes an elliptic equation and a linear convection-diffusion concentration equation with a diffusion term small with respect to the convection, i.e. a high Peclet number is considered. Asymptotic expan...

Nanofluids are generally utilized in providing cooling, lubrication phenomenon, and controlling the thermophysical properties of working fluid. In this paper, nanoparticles Al2O3 added to base fluid, which flows through counterflow arrangement a turbulent flow condition. The fluids employed ethylbenzene water, have differing velocities on both tube shell side cylinders. A tube-type heat exchang...

We simulate flow and transport directly on pore-space images obtained by micro-CT scanning of rock cores. An efficient Stokes solver is used to simulate low-Reynolds number flows. The flow simulator uses a finite-difference method along with a standard predictor-corrector procedure to decouple pressure and velocity. An algebraic multigrid technique solves the linear systems of equations. We the...

Homogeneous–heterogeneous chemical reactions for second-grade nanofluid and gyrotactic microorganisms in a rotating system with the effects of magnetic fields thermal radiation are examined. The boundary layer equations problem non-dimensional form evaluated by strong technique, namely, homotopy analysis method (HAM). rates flow, heat, mass, microorganism motion obtained augmentations pertinent...

An experimental study is reported on the physical characterization of the structure of ethanol/argon/oxygen coflow laminar spray diffusion flames in the pressure range 0.1–0.9 MPa. Diagnostic techniques include phase Doppler anemometry to measure the droplet size distribution and the axial and radial velocity components of the droplets. The gas-phase velocity is determined using measurements fr...

A pulsed plasma enhanced chemical vapor deposition (PECVD) reactor is used for the preparation of thin polyacetylene films. A theoretical model based on the mass transport characteristics of the reactor is developed in order to correlate with experimentally obtained spatial deposition profiles for the acetylene plasma polymer film deposited within the cylindrical reactor. Utilizing a free radic...

The miscible liquid-liquid two phases based on Taylor flow in microchannels was investigated by high-speed imaging techniques and Villermaux/Dushman reaction. The mixing based on Taylor flow was much better compared with that without introducing gas in microchannels, even the ideal micromixing performance could be obtained under optimized superficial gas and liquid velocities. In the mixing pro...