Orientation and Order of Xanthene Dyes in the One-Dimensional Channels of Zeolite L: Bridging the Gap between Experimental Data and Molecular Behavior

This paper describes in detail the assessment of the CFD code CFX to predict adiabatic liquid-gas two-phase bubbly flow. This study has been divided into two parts. In the first exercise, the effect of Lift Force, Wall Force and the Turbulent Diffusion Force have been assessed using experimental data from the literature for air-water upward bubbly flows through a pipe. The data used here had a characteristic near wall void peaking which was largely influenced by the joint action of the three forces mentioned above. The simulations were performed with constant bubble diameter assuming no bubble interactions. This exercise resulted in selection of the most appropriate closure form and closure coefficients for the above mentioned forces for the range of flow conditions chosen. In the second exercise, the One-Group Interfacial Area Transport equation was introduced in the two-fluid model of CFX. The interfacial area density plays important role in the correct prediction of interfacial mass, momentum and energy transfer and is affected by bubble breakup and coalescence processes in adiabatic flows. The One-Group Interfacial Area Transport Equation (IATE) has been developed and implemented for one-dimensional models and validated using cross-sectional area averaged experimental data over the last decade by various researchers. The original one-dimensional model has been extended to multidimensional flow predictions in this study and the results are presented in this paper. The paper also discusses constraints posed by the commercial CFD code CFX and the solutions worked out to obtain the most accurate implementation of the model.

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Assessment of CFD turbulence models for free surface flow simulation and 1-D modelling for water level calculations over a broad-crested weir floodway

Water SA ◽

10.17159/wsa/2019.v45.i3.6739 ◽

2019 ◽

Vol 45 (3 July) ◽

Author(s):

Ahmed M Helmi

Keyword(s):

Experimental Data ◽

Free Surface ◽

Water Level ◽

Dimensional Analysis ◽

Turbulence Model ◽

Turbulence Models ◽

Cfd Simulations ◽

One Dimensional ◽

The Mean ◽

The One

Floodways, where a road embankment is permitted to be overtopped by flood water, are usually designed as broad-crested weirs. Determination of the water level above the floodway is crucial and related to road safety. Hydraulic performance of floodways can be assessed numerically using 1-D modelling or 3-D simulation using computational fluid dynamics (CFD) packages. Turbulence modelling is one of the key elements in CFD simulations. A wide variety of turbulence models are utilized in CFD packages; in order to identify the most relevant turbulence model for the case in question, 96 3-D CFD simulations were conducted using Flow-3D package, for 24 broad-crested weir configurations selected based on experimental data from a previous study. Four turbulence models (one-equation, k-ε, RNG k-ε, and k-ω) ere examined for each configuration. The volume of fluid (VOF) algorithm was adopted for free water surface determination. In addition, 24 1-D simulations using HEC-RAS-1-D were conducted for comparison with CFD results and experimental data. Validation of the simulated water free surface profiles versus the experimental measurements was carried out by the evaluation of the mean absolute error, the mean relative error percentage, and the root mean square error. It was concluded that the minimum error in simulating the full upstream to downstream free surface profile is achieved by using one-equation turbulence model with mixing length equal to 7% of the smallest domain dimension. Nevertheless, for the broad-crested weir upstream section, no significant difference in accuracy was found between all turbulence models and the one-dimensional analysis results, due to the low turbulence intensity at this part. For engineering design purposes, in which the water level is the main concern at the location of the flood way, the one-dimensional analysis has sufficient accuracy to determine the water level.

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Numerical Simulation and Experimental Validation of an Oil Free Scroll Compressor

Energies ◽

10.3390/en13225863 ◽

2020 ◽

Vol 13 (22) ◽

pp. 5863

Author(s):

Massimo Cardone ◽

Bonaventura Gargiulo

Keyword(s):

Experimental Data ◽

Experimental Validation ◽

Test Bench ◽

Outlet Temperature ◽

Analysis Software ◽

Scroll Compressor ◽

One Dimensional ◽

Geometrical Features ◽

The One ◽

Semi Empirical

This paper presents a virtual model of a scroll compressor developed on the one-dimensional analysis software Simcenter Amesim®. The model is semi-empirical: it needs some physical details of the modelled machine (e.g., the cubic capacity), but, on the other hand, it does not require the geometrical features of the spirals, so it needs experimental data to calibrate it. The model also requires rotational speed and the outlet temperature as boundary conditions. The model predicts the power consumption and the mass flow rate and considers leakages and mechanical losses. After the model presentation, this paper describes the test bench and the obtained data used to calibrate and validate the model. At last, the calibration process is described, and the results are discussed. The calculated values fit the experimental data also in extrapolation, despite the model is simple and performs calculations within 7 s. Due to these characteristics, the model is suitable for being used in a larger model as a sub-component.

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The Different Organization of Water in Zeolite L and Its MOF Mimic

10.26434/chemrxiv.7761791 ◽

2019 ◽

Author(s):

gloria tabacchi ◽

Ettore Fois

Keyword(s):

Hydrogen Bonds ◽

Metal Organic Framework ◽

Water Molecules ◽

One Dimensional ◽

Zeolite L ◽

High Proton ◽

Metal Organic ◽

The One ◽

The Individual ◽

Water Hydrogen

Abstract:<div>Confinement of molecules inside one dimensional arrays of channel-shaped cavities has led to an impressive number of technologically interesting materials. However, the interactions governing the properties of the supramolecular aggregates still remain obscure, even in the case of the most common guest molecule: water. Herein, we use computational chemistry methods (#compchem) to study the water organization inside two different channel-type environments: zeolite L – a widely used matrix for inclusion of dye molecules, and ZLMOF – the closest metal-organic-framework mimic of zeolite L. In ZLMOF, the methyl groups of the ligands protrude inside the channels, creating nearly isolated nanocavities. These cavities host well-separated ring-shaped clusters of water molecules, dominated mainly by water-water hydrogen bonds. ZLMOF channels thus provide arrays of „isolated supramolecule“ environments, which might be exploited for the individual confinement of small species with interesting optical or catalytic properties. In contrast, the one dimensional nanochannels of zeolite L contain a continuous supramolecular structure, governed by the water interactions with potassium cations and by water-water hydrogen bonds. Water molecules impart a significant energetic stabilization to both materials, which increases by increasing the water content in ZLMOF, while the opposite trend is observed in zeolite L. The water network in zeolite L contains an intriguing hyper-coordinated structure, where a water molecule is surrounded by 5 strong hydrogen bonds. Such a structure, here described for the first time in zeolites, can be considered as a water pre-dissociation complex and might explain the experimentally detected high proton activity in zeolite L nanochannels. </div>

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Radial Imbibition in Paper under Temperature Differences

Fluids ◽

10.3390/fluids4020086 ◽

2019 ◽

Vol 4 (2) ◽

pp. 86

Author(s):

Abel López-Villa ◽

Abraham Medina ◽

F. J. Higuera ◽

Jonatan R. Mac Intyre ◽

Carlos Alberto Perazzo ◽

...

Keyword(s):

Experimental Data ◽

Surface Tension ◽

Porous Material ◽

Radial Temperature ◽

Temperature Variations ◽

One Dimensional ◽

Blotting Paper ◽

Dimensional Equation ◽

The One ◽

Account Temperature

Spontaneous radial imbibition into thin circular samples of porous material when they have been subjected to radial temperature differences was analyzed theoretically and experimentally. The use of the Darcy equation allowed us to take into account temperature variations in the dynamic viscosity and surface tension in order to find the one-dimensional equation for the imbibition fronts. Experiments using blotting paper showed a good fit between the experimental data and theoretical profiles through the estimation of a single parameter.

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Numerical Solution for Two-Dimensional Elastic Wave Propagation in Finite Bars

Journal of Applied Mechanics ◽

10.1115/1.3607768 ◽

1967 ◽

Vol 34 (3) ◽

pp. 725-734 ◽

Cited By ~ 29

Author(s):

L. D. Bertholf

Keyword(s):

Experimental Data ◽

Wave Propagation ◽

Elastic Wave ◽

Numerical Solutions ◽

Step Change ◽

Two Dimensional ◽

One Dimensional ◽

Elastic Bar ◽

The One ◽

The Impact

Numerical solutions of the exact equations for axisymmetric wave propagation are obtained with continuous and discontinuous loadings at the impact end of an elastic bar. The solution for a step change in stress agrees with experimental data near the end of the bar and exhibits a region that agrees with the one-dimensional strain approximation. The solution for an applied harmonic displacement closely approaches the Pochhammer-Chree solution at distances removed from the point of application. Reflections from free and rigid-lubricated ends are studied. The solutions after reflection are compared with the elementary one-dimensional stress approximation.

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The Simulation of Photocatalysis Degradation of Formaldehyde Using Nano-TiO2 Based on the Diffusion Model

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.327.8 ◽

2013 ◽

Vol 327 ◽

pp. 8-12

Author(s):

Bin Li ◽

Kai Xiao Zhang ◽

Chao Yu Feng ◽

Xing Bin Zheng ◽

Kun Xie ◽

...

Keyword(s):

Experimental Data ◽

Photocatalytic Degradation ◽

Diffusion Model ◽

Degradation Rate ◽

Nano Tio2 ◽

Fick's Law ◽

One Dimensional ◽

Photocatalytic Mechanism ◽

Dimensional Diffusion ◽

The One

In this paper, the one-dimensional diffusion model about nano-TiO2 photocatalytic degradation of formaldehyde process was established ,through analyzing nano-TiO2 photocatalytic mechanism, and verifying the accuracy of the model by the experimental data combined with Fick's law. According to this model, it concluded that the degradation rate of the formaldehyde is related to the height of purification apparatus, and when the height is smaller, the degradation rate is greater. Within the same cleaning time (t = 200min), when the height is 0.15m, the rate of degradation of formaldehyde is 99%; when the height is 0.3m, the rate of degradation of formaldehyde is 88%; while the height is 0.7m , the rate is only 32%.

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Water in zeolite L and its MOF mimic

Zeitschrift für Kristallographie - Crystalline Materials ◽

10.1515/zkri-2018-2153 ◽

2019 ◽

Vol 234 (7-8) ◽

pp. 495-511 ◽

Cited By ~ 6

Author(s):

Ettore Fois ◽

Gloria Tabacchi

Keyword(s):

Hydrogen Bonds ◽

Metal Organic Framework ◽

One Dimensional ◽

Zeolite L ◽

High Proton ◽

Metal Organic ◽

The One ◽

The Individual ◽

First Time ◽

Water Hydrogen

Abstract Confinement of molecules in one dimensional arrays of channel-shaped cavities has led to technologically interesting materials. However, the interactions governing the supramolecular aggregates still remain obscure, even for the most common guest molecule: water. Herein, we use computational chemistry methods (#compchem) to study the water organization inside two different channel-type environments: zeolite L – a widely used matrix for inclusion of dye molecules, and ZLMOF – the closest metal-organic-framework mimic of zeolite L. In ZLMOF, the methyl groups of the ligands protrude inside the channels, creating nearly isolated nanocavities. These cavities host well-separated ring-shaped clusters of water molecules, dominated mainly by water-water hydrogen bonds. ZLMOF provides arrays of “isolated supramolecule” environments, which might be exploited for the individual confinement of small species with interesting optical or catalytic properties. In contrast, the one dimensional channels of zeolite L contain a continuous supramolecular structure, governed by the water interactions with potassium cations and by water-water hydrogen bonds. Water imparts a significant energetic stabilization to both materials, which increases with the water content in ZLMOF and follows the opposite trend in zeolite L. The water network in zeolite L contains an intriguing hypercoordinated structure, where a water molecule is surrounded by five strong hydrogen bonds. Such a structure, here described for the first time in zeolites, can be considered as a water pre-dissociation complex and might explain the experimentally detected high proton activity in zeolite L nanochannels.

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Prediction of the One-Dimensional Equilibrium Cutting Gap in Electrochemical Machining

Journal of Engineering for Industry ◽

10.1115/1.3591683 ◽

1969 ◽

Vol 91 (3) ◽

pp. 755-763 ◽

Cited By ~ 26

Author(s):

J. Hopenfeld ◽

R. R. Cole

Keyword(s):

Experimental Data ◽

Nonlinear Differential Equations ◽

Electrochemical Machining ◽

Local Variation ◽

Two Phase ◽

One Dimensional ◽

Proper Design ◽

Electrolyte Mixture ◽

The One ◽

State Case

In electrochemical machining the evolution of gas and heat in the electrolyte results in local variation of the gap between the electrodes. The ability to predict these variations for any given operating condition is a prerequisite of proper design of the cathode tool. This paper provides analytical predictions of the change in gap geometry for the one-dimensional steady-state case. Employing the basic conservation laws, a system of coupled nonlinear differential equations is derived for the gas-electrolyte mixture which flows between the electrodes. The assumption of homogeneity of the two-phase mixture is employed throughout the analysis. Numerical results from the solution of the equations are presented graphically and compared with experimental data. The local variation in gap and the relation between current, gap, and applied voltage compare favorably with the experimental data within the ranges of parameters investigated: current density 45–400 amps per sq in., electrolyte flow rate 0.22–0.98 gpm, entrance gap size 0.015–0.020 in., potassium chloride electrolyte normality 0.67–1.14.

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