Discrete Particle Study of Turbulence Coupling in a Confined Jet Gas-Liquid Separator

2007 ◽  
Vol 130 (1) ◽  
Author(s):  
Wayne Strasser
Keyword(s):  
Liquid Phase ◽  
Gas Phase ◽  
Volume Fraction ◽  
Liquid Droplet ◽  
Reynolds Stress Model ◽  
Continuous Phase ◽  
Liquid Entrainment ◽  
Induced Flow ◽  
Flow Effects ◽  
Liquid Separator

A 3D computational fluid dynamics investigation of particle-induced flow effects and liquid entrainment from an industrial-scale separator has been carried out using the Eulerian–Lagrangian two-way coupled multiphase approach. A differential Reynolds stress model was used to predict the gas phase turbulence field. The dispersed (liquid) phase was present at an intermediate mass loading (0.25) but low volume fraction (0.05). A discrete random walk method was used to track the paths of the liquid droplet releases. It was found that gas phase deformation and turbulence fields were significantly impacted by the presence of the liquid phase; these effects have been parametrically quantified. Substantial enhancement of both the turbulence and the anisotropy of the continuous phase by the liquid phase was demonstrated. It was also found that a large number (⩾1000) of independent liquid droplet release events were needed to make conclusions about liquid entrainment. Known plant run conditions and entrainment rates validated the numerical method.

Comparative Assessment of Turbulence Models for Prediction of Flow-Induced Corrosion Damages

2011 ◽  
Author(s):  
Kaushik Das ◽  
Debashis Basu ◽  
Todd Mintz
Keyword(s):  
Corrosion Rate ◽  
Cross Sections ◽  
Volume Fraction ◽  
Solid Phase ◽  
Turbulence Models ◽  
Reynolds Stress Model ◽  
Continuous Phase ◽  
Comparative Assessment ◽  
Solid Particles ◽  
Protective Film

The present study makes a comparative assessment of different turbulence models in simulating the flow-assisted corrosion (FAC) process for pipes with noncircular cross sections and bends, features regularly encountered in heat exchangers and other pipeline networks. The case study investigates material damage due to corrosion caused by dissolved oxygen (O2) in a stainless steel pipe carrying an aqueous solution. A discrete solid phase is also present in the solution, but the transport of the solid particles is not explicitly modeled. It is assumed that the volume fraction of the solid phase is low, so it does not affect the continuous phase. Traditional two-equation models are compared, such as isotropic eddy viscosity, standard k-ε and k-ω models, shear stress transport (SST) k-ω models, and the anisotropic Reynolds Stress Model (RSM). Computed axial and radial velocities, and turbulent kinetic energy profiles predicted by the turbulence models are compared with available experimental data. Results show that all the turbulence models provide comparable results, though the RSM model provided better predictions in certain locations. The convective and diffusive motion of dissolved O2 is calculated by solving the species transport equations. The study assumes that solid particle impingement on the pipe wall will completely remove the protective film formed by corrosion products. It is also assumed that the rate of corrosion is controlled by diffusion of O2 through the mass transfer boundary layer. Based on these assumptions, corrosion rate is calculated at the internal pipe walls. Results indicate that the predicted O2 corrosion rate along the walls varies for different turbulence models but show the same general trend and pattern.

Formation of Light-weight Low-density Materials via Gas Phase Aerosol Gelation

2011 ◽  
Vol 1306 ◽  
Author(s):  
Christopher M. Sorensen ◽  
Rajan Dhaubhadel ◽  
Corey S. Gerving ◽  
Amitabha Chakrabarti
Keyword(s):  
Liquid Phase ◽  
Gas Phase ◽  
Large Volume ◽  
Volume Fraction ◽  
Sol Gel ◽  
Low Density ◽  
Light Weight ◽  
Large Volume Fraction ◽  
Explosive Combustion

ABSTRACTWe have demonstrated that gas phase explosive combustion can lead to nanoparticle aerosols with sufficiently large volume fraction to cause a volume spanning gel to form on the order of ten’s of seconds. The term “aerosol gel” was coined to name these materials. So far we have made aerosol gels of carbon and silica. These aerosol gels are similar to well-known, liquid-phase, sol-gel synthesized aerogels.

Volume fraction gradient-induced flow patterns in a two-liquid phase mixing layer

2003 ◽  
Vol 58 (17) ◽  
pp. 3985-3993 ◽  
Author(s):  
F. Augier ◽  
J. Morchain ◽  
P. Guiraud ◽  
O. Masbernat
Keyword(s):  
Liquid Phase ◽  
Volume Fraction ◽  
Mixing Layer ◽  
Flow Patterns ◽  
Phase Mixing ◽  
Induced Flow

scholarly journals The Experimental Study on Effects of Height and Hold up on performance of Vertical Gas-Liquid Separator using Amin Contactor Tower

2015 ◽  
Vol 37 ◽  
pp. 93 ◽  
Author(s):  
Iman Naderipour ◽  
Jamshid Khorshidi
Keyword(s):  
Liquid Droplet ◽  
Three Dimensional ◽  
Continuous Phase ◽  
Three Dimension ◽  
Liquid Droplets ◽  
Discrete Phase Model ◽  
Effective Parameters ◽  
Discrete Phase ◽  
Droplet Tracking ◽  
Liquid Separator

In present research, first the treatment of flow in designed vertical gas-liquid separator and Amin contactor tower at refinery in order to reduce of liquid percent was simulated. In order to simulation was used three dimension model with finite volume method numerically. Then separator and contactor tower has been modeled three dimensional and for droplet tracking in continuous phase has been used discrete phase model (DPM) with turbulence RNG k-Ɛ model. Also the gambit software is used for three dimension designs and fluent is used for solution governing equations of flow field. After simulation, the governing model of separator and contactor tower, fluid flow, the effect of growing of liquid droplet, droplet settling length (disengagement time) was studied. After analysis and compare behavior of flow in separator and tower, the results of simulation compared with experimental results at sweetening unit in Sarkhoun and Qeshm gas treating company that has 95% compatibility. The simulation results has shown that TOTAL method has more compatibility with relation to other methods so that one of effective parameters in improvement of separation process is growing of liquid droplets and separation factor depend on that, also more disengagement time causes increase hold up time and finally growing of liquid droplets. Additionally according to younger's comment gas-liquid separators can applied in horizontal or vertical status so that he founded if L/D be 1.7 to 3.6, the separators should be used vertically also Branan has proved that if L/D > 5, a horizontal separator should be used. The results of research are shown that in special conditions with L/D>6.5 can apply vertical separator. Finally experimental data has shown that the settling length can be 36 ft (11m) that separation works well and according to Schiman this length should be 0.75D or a minimum 12in (0.305 m) whereas Gerunda recommends a length equal to the diameter or a minimum of 3 ft (0.914 m) that present result is new recommendation.

Application of Disk Aerators to Recarbonation of Alkaline Wastewater from Wet Gasification of Carbide

1991 ◽  
Vol 24 (7) ◽  
pp. 277-284 ◽  
Author(s):  
E. Gomólka ◽  
B. Gomólka
Keyword(s):  
Carbon Dioxide ◽  
Liquid Phase ◽  
Gas Phase ◽  
Flue Gas ◽  
Carbonic Acid ◽  
Low Cost ◽  
Flue Gases ◽  
Carbon Dioxide Content ◽  
Patent Claim ◽  
Phase Dispersion

Whenever possible, neutralization of alkaline wastewater should involve low-cost acid. It is conventional to make use of carbonic acid produced via the reaction of carbon dioxide (contained in flue gases) with water according to the following equation: Carbon dioxide content in the flue gas stream varies from 10% to 15%. The flue gas stream may either be passed to the wastewater contained in the recarbonizers, or. enter the scrubbers (which are continually sprayed with wastewater) from the bottom in oountercurrent. The reactors, in which recarbonation occurs, have the ability to expand the contact surface between gaseous and liquid phase. This can be achieved by gas phase dispersion in the liquid phase (bubbling), by liquid phase dispersion in the gas phase (spraying), or by bubbling and spraying, and mixing. These concurrent operations are carried out during motion of the disk aerator (which is a patent claim). The authors describe the functioning of the disk aerator, the composition of the wastewater produced during wet gasification of carbide, the chemistry of recarbonation and decarbonation, and the concept of applying the disk aerator so as to make the wastewater fit for reuse (after suitable neutralization) as feeding water in acetylene generators.

Modeling of aerated upflow fixed bed reactors for nitrification

1999 ◽  
Vol 39 (4) ◽  
pp. 85-92 ◽  
Author(s):  
J. Behrendt
Keyword(s):  
Mathematical Model ◽  
Mass Transfer ◽  
Liquid Phase ◽  
Gas Phase ◽  
Fixed Bed ◽  
Fixed Bed Reactor ◽  
Bulk Liquid ◽  
Initial Value ◽  
Fixed Bed Reactors ◽  
Number Of Cells

A mathematical model for nitrification in an aerated fixed bed reactor has been developed. This model is based on material balances in the bulk liquid, gas phase and in the biofilm area. The fixed bed is divided into a number of cells according to the reduced remixing behaviour. A fixed bed cell consists of 4 compartments: the support, the gas phase, the bulk liquid phase and the stagnant volume containing the biofilm. In the stagnant volume the biological transmutation of the ammonia is located. The transport phenomena are modelled with mass transfer formulations so that the balances could be formulated as an initial value problem. The results of the simulation and experiments are compared.

Theoretical analysis of counter-current absorption of a poorly soluble gas based on the PDE-AD model

1986 ◽  
Vol 51 (6) ◽  
pp. 1222-1239 ◽  
Author(s):  
Pavel Moravec ◽  
Vladimír Staněk
Keyword(s):  
Experimental Data ◽  
Liquid Phase ◽  
Gas Phase ◽  
Transfer Functions ◽  
Packed Bed ◽  
Packed Bed Column ◽  
Interfacial Transport ◽  
Gaseous Component ◽  
Poorly Soluble ◽  
Counter Current

Expression have been derived in the paper for all four possible transfer functions between the inlet and the outlet gas and liquid steams under the counter-current absorption of a poorly soluble gas in a packed bed column. The transfer functions have been derived for the axially dispersed model with stagnant zone in the liquid phase and the axially dispersed model for the gas phase with interfacial transport of a gaseous component (PDE - AD). calculations with practical values of parameters suggest that only two of these transfer functions are applicable for experimental data evaluation.

Reesterification of ethyl acetate by propanol catalysed by glycidyl methacrylate copolymers containing sulphonic acid groups

1981 ◽  
Vol 46 (8) ◽  
pp. 1941-1946 ◽  
Author(s):  
Karel Setínek
Keyword(s):  
Liquid Phase ◽  
Ethyl Acetate ◽  
Kinetic Study ◽  
Gas Phase ◽  
Nonlinear Regression ◽  
Kinetic Data ◽  
Glycidyl Methacrylate ◽  
Kinetic Equations ◽  
Methacrylate Copolymers ◽  
Styrene Divinylbenzene

A series of differently crosslinked macroporous 2,3-epoxypropyl methacrylate-ethylenedimethacrylate copolymers with chemically bonded propylsulphonic acid groups were used as catalysts for the kinetic study of reesterification of ethyl acetate by n-propanol in the liquid phase at 52 °C and in the gas phase at 90 °C. Analysis of kinetic data by the method of nonlinear regression for a series of equations of the Langmuir-Hinshelwood type showed that kinetic equations which describe best the course of the reaction are the same as for the earlier studied sulphonated macroporous styrene-divinylbenzene copolymers. Compared types of catalysts differ, however, in the dependence of their activity on the degree of crosslinking of the copolymer used.

scholarly journals Quantification of shear viscosity and wall slip velocity of highly concentrated suspensions with non-Newtonian matrices in pressure driven flows

2021 ◽  
Author(s):  
Patrick Wilms ◽  
Jan Wieringa ◽  
Theo Blijdenstein ◽  
Kees van Malssen ◽  
Reinhard Kohlus
Keyword(s):  
Shear Stress ◽  
Liquid Phase ◽  
Shear Rate ◽  
Shear Viscosity ◽  
Slip Velocity ◽  
Volume Fraction ◽  
Solid Volume Fraction ◽  
Wall Slip ◽  
Flow Index ◽  
Concentrated Suspensions

AbstractThe rheological characterization of concentrated suspensions is complicated by the heterogeneous nature of their flow. In this contribution, the shear viscosity and wall slip velocity are quantified for highly concentrated suspensions (solid volume fractions of 0.55–0.60, D4,3 ~ 5 µm). The shear viscosity was determined using a high-pressure capillary rheometer equipped with a 3D-printed die that has a grooved surface of the internal flow channel. The wall slip velocity was then calculated from the difference between the apparent shear rates through a rough and smooth die, at identical wall shear stress. The influence of liquid phase rheology on the wall slip velocity was investigated by using different thickeners, resulting in different degrees of shear rate dependency, i.e. the flow indices varied between 0.20 and 1.00. The wall slip velocity scaled with the flow index of the liquid phase at a solid volume fraction of 0.60 and showed increasingly large deviations with decreasing solid volume fraction. It is hypothesized that these deviations are related to shear-induced migration of solids and macromolecules due to the large shear stress and shear rate gradients.

Solid–liquid–liquid phase envelopes from temperature-scanned refractive index data

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Alcides J. Sitoe ◽  
Franco Pretorius ◽  
Walter W. Focke ◽  
René Androsch ◽  
Elizabeth L. du Toit
Keyword(s):  
Refractive Index ◽  
Liquid Phase ◽  
Volume Fraction ◽  
Solution Temperature ◽  
Linear Behavior ◽  
Upper Critical Solution Temperature ◽  
Novel Method ◽  
Using Data ◽  
Solid Liquid ◽  
Liquid Liquid Phase Separation

Abstract A novel method for estimating the upper critical solution temperature (UCST) of N,N-diethyl-m-toluamide (DEET)-polyethylene systems was developed. It was validated using data for the dimethylacetamide (DMA)-alkane systems which showed that refractive index mixing rules, linear in volume fraction, can accurately predict mixture composition for amide-alkane systems. Furthermore, rescaling the composition descriptor with a single adjustable parameter proved adequate to address any asymmetry when modeling the DMA-alkane phase envelopes. This allowed the translation of measured refractive index cooling trajectories of DEET-alkane systems into phase diagrams and facilitated the estimation of the UCST values by fitting the data with an adjusted composition descriptor model. For both the DEET- and DMA-alkane systems, linear behavior of UCST values in either the Flory–Huggins critical interaction parameter, or the alkane critical temperature, with increasing alkane molar mass is evident. The UCST values for polymer diluent systems were estimated by extrapolation using these two complimentary approaches. For the DEET-polyethylene system, values of 183.4 and 180.1 °C respectively were obtained. Both estimates are significantly higher than the melting temperature range of polyethylene. Initial liquid–liquid phase separation is therefore likely to be responsible for the previously reported microporous microstructure of materials formed from this binary system.

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