Computational fluid dynamics (CFD) simulations were performed for four 10 cm2 serpentine flow-fields with single channel, double channel, cyclic-single channel, and symmetric-single channel patterns to investigate the effect of flow-field design. High and low inlet humidity operating conditions were studied by calculating the distributions of overpotentials, current density distribution, and me...

the narrow operating window between pore pressure and fracture pressure makes drilling difficult in some operations. a feasibility study of managed pressure drilling (mpd) is carried out on iran darquain oil field. the previous wells drilled in this field showed that mud returns were lost during drilling gadvan formation. the present work addresses this problem by means of surface back pressure...

fluids for various industrial applications because of their excellent thermal performance. this study analytically and experimentally examines the effects of nanoparticle dispersion on the entropy generation of eg–al2o3 nanofluid flows through a helical pipe as a heat exchanger under constant wall heat flux thermal boundary condition in laminar regime. it is found that adding nanoparticles impr...

Abstract: As for the measurement of polycyclic aromatic hydrocarbons (PAHs), ultra-performance liquid chromatography (UPLC) is used for PAH identification and densitometry. However, when a solvent containing a substance to be identified passes through a column of UPLC, a dedicated high-pressure-proof device is required. Recently, a liquid chromatography instrument using a monolithic column tech...

lemon is one of the most important citrus fruit and is consumed as fresh and dry. in this study the effect of fruit moisture content on the size, sphericity, geometric mean diameters and kernel density were studied. the bulk density and porosity were also evaluated in three different arrangements. airflow resistance is a fundamental parameter for designing an efficient drying and aeration syste...

the performance of a γ-al 2 o 3 /n-decane nanofluid shell-and-tube heat exchanger in a biomass heating plant is analyzed to specify the optimum condition based on the maximum heat transfer rate and performance index for wide range of nanoparticle volume fraction (0–7%). compared with pure          n-decane, the obtained results in this research show that by using γ-al 2 o 3 /n-decane nanofluid ...

In this paper, convection heat transfer of Al2O3-water nanofluid turbulent flow through internally ribbed tubes with different rib shapes (rectangular, trapezoidal and semi-circular) is numerically investigated. For each rib shape, the optimum geometric ratio and volume fraction were calculated using entropy generation minimization technique. The governing equations in...

in this paper, direct numerical simulation of two-phase incompressible gas-liquid flow for simulation of bubble motion in a microtube is presented. microtube radius is 10 µm. the interface is tracked using volume of fluid (vof) method with continuous surface force (csf) model. the flow is solved using a finite volume scheme, based on piso algorithm. numerical simulation is performed on a axisym...