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article

Application of a high density ratio lattice-Boltzmann model for the droplet impingement on flat and spherical surfaces

Duo Zhang, K. Papadikis, Sai Gu, D. Zhang, more

International Journal of Thermal Sciences > 2014 > 84 > Complete > 75-85

In the current study, a 3-dimensional lattice Boltzmann model which can tolerate high density ratios is employed to simulate the impingement of a liquid droplet onto a flat and a spherical target. The four phases of droplet impact on a flat surface, namely, the kinematic, spreading, relaxation and equilibrium phase, have been obtained for a range of Weber and Reynolds numbers. The predicted maximum...

article

Influence of tube configuration on the gas–solid hydrodynamics of an internally circulating fluidized bed: A discrete element study

Shiliang Yang, Kun Luo, Mingming Fang, Jianren Fan, more

Chemical Engineering Journal > 2014 > 239 > Complete > 158-170

Three-dimensional modeling of the gas–solid flow in an internally circulating fluidized bed is conducted by means of the computational fluid dynamics combined with the discrete element method to explore the effect of the tube bundle on the gas–solid hydrodynamics of the system. Gas motion is resolved at the computational grid level, while solid motion is obtained in the Lagrangian view. The influences...

article

Coarse grid simulation of heterogeneous gas–solid flow in a CFB riser with EMMS drag model: Effect of inputting drag correlations

Quan Zhou, Junwu Wang, Q. Zhou, J. Wang

Powder Technology > 2014 > 253 > Complete > 486-495

Two-fluid model combined with Energy-Minimization Multi-Scale (EMMS) drag model has been accepted as an effective method to simulate the hydrodynamics of heterogeneous gas–solid flow in circulating fluidized beds. In the EMMS drag model, a drag correlation obtained from homogeneous fluidization and/or packed bed, denoted as traditional drag correlation, is necessary to describe the homogeneous gas–solid...

article

Experimental study on flow patterns for water boiling in horizontal heated tubes

Shaowu Yin, Junxia Zhang, Lige Tong, Yuan Yao, more

Chemical Engineering Science > 2013 > 102 > Complete > 577-584

An experimental study on flow patterns for water boiling in horizontal heated tubes was conducted to observe the evolution and transition of flow patterns while controlling various parameters, such as heat flux, mass velocity, and tube diameter. Six boiling flow patterns are observed in the test tubes, namely, bubble, plug, slug, wave, stratified, and annular flows, which can be further classified...

article

Stencil adaptive diffuse interface method for simulation of two-dimensional incompressible multiphase flows

L. Ding, C. Shu, H. Ding, N. Zhao

Computers and Fluids > 2010 > 39 > 6 > 936-944

Diffuse interface method is becoming a more and more popular approach for simulation of multiphase flows. As compared to other solvers, it is easy to implement and can keep conservation of mass and momentum. In the diffuse interface method, the interface is not considered as a sharp discontinuity. Instead, it treats the interface as a diffuse layer with a small thickness. This treatment is similar...

article

A comparison of pendulum experiments and discrete‐element simulations of oblique collisions of wet spheres

Oscar Punch, Megan Danczyk, Mathew Hawken, Daniel J. Holland

AIChE Journal > 69 > 3 > n/a - n/a

Oblique collisions of two spherical particles coated with a thin layer of viscous liquid are considered. Experimental measurements are performed using particle tracking velocimetry and the results are compared to viscous force and capillary force models via numerical simulation using the discrete‐element method. Comprehensive experimental data for collisions with an impact angle between 0° and 60°...

article

Analysis of short‐ and long‐term system response during gas production from a gas hydrate deposit at the UBGH2‐6 site of the Ulleung Basin in the Korean East Sea

George J. Moridis, Jihoon Kim, Matthew T. Reagan, Se‐Joon Kim

The Canadian Journal of Chemical Engineering > 101 > 2 > 735 - 763

This study is a continuation of an investigation into the feasibility of long‐term production from a marine hydrate accumulation that has the properties and conditions of the UBGH2‐6 (UBGH2, Ulleung Basin Gas Hydrates 2; 2 is the number of the scientific expedition) site at the Ulleung Basin in the Korean East Sea. The 12.7 m‐thick system is in deep water (2157 m), but at 140 m below the seafloor...

article

Gas phase hydrodynamics in a surface‐aerated tank with a long‐short blades agitator

Yongjun Wu, Jian Wang, Pan You, Peicheng Luo

AIChE Journal > 69 > 1 > n/a - n/a

This work aims to study the gas phase hydrodynamics in a stirred tank with a surface‐aerated long‐short blades agitator by the Eulerian–Eulerian approach coupled with population balance model. Predicted local gas holdup and bubble size distribution agree well with those measured by a conductivity probe technique. The predictions demonstrate that the pressure depression in the center is the main driving...

article

Predicting Interfacial Tension via the Entrainment Master Curve of a Bubble Rising through the Immiscible Liquids Interface

Abdolaziz Edrisi, Mitra Dadvar, Bahram Dabir

Chemical Engineering & Technology > 45 > 12 > 2150 - 2158

Liquid‐liquid interfacial tension is an important parameter in gas‐liquid‐liquid multiphase flows. Here, bubble passage through an immiscible liquids interface was used for determining the interfacial tension. The method is based on measuring the volume of the heavy liquid entrained into the light one. Two different semi‐empirical models were developed for determining the entrainment ratio. The results...

article

Numerical investigation of flow, heat transfer, and kinetic reaction in a large‐difference bidisperse, circulating fluidized‐bed reactor

Chen Song, Juan Xiao, Weixiang Lin, Simin Wang, more

The Canadian Journal of Chemical Engineering > 100 > 12 > 3777 - 3792

To study particle bidispersity effect on the comprehensive performance of a gas–solid fluidized system, multi‐field coupling numerical research of large‐difference bidisperse circulating fluidized bed was performed. First, numerical simulation was conducted on the dynamic characteristic of a bidisperse gas–solid system that contained both Geldart A and B particles; heat transfer and reaction performances...

article

Characteristics of flow fields in the gas–liquid mini‐bubble columns with particle image velocimetry measurements

Chen Li, Yongli Ma, Mingyan Liu, Kaiyue Wang

AIChE Journal > 68 > 9 > n/a - n/a

As a new type of gas–liquid microreactors, the gas–liquid mini‐bubble column has potential applications. However, few studies on the flow fields in the mini‐bubble column can be found at present. In this work, particle image velocimetry (PIV) was used to visually study the velocity fields, vorticity fields and bubble dynamics in the gas–liquid mini‐bubble columns with column inner diameters of 1–3...

article

Effect of ultrasonic waveforms on gas–liquid mass transfer in microreactors

Qiang Zhang, Zhengya Dong, Zhikai Liu, Guangwen Chen

AIChE Journal > 68 > 8 > n/a - n/a

This study aims to investigate the effect of ultrasonic waveforms on the gas–liquid mass transfer process. For a given load power (P), continuous rectangular wave yielded stronger bubble oscillation and higher mass transfer coefficient (k_La) than continuous triangular and sinusoidal wave. For pulsed ultrasound, the k_La decreased monotonically with decreasing duty ratio (D), resulting in weak enhancement...

article

Gas–liquid flows through porous media in microgravity: Packed Bed Reactor Experiment‐2

Mahsa Taghavi, Brian J. Motil, Henry Nahra, Vemuri Balakotaiah

AIChE Journal > 68 > 8 > n/a - n/a

Modifications were made to the Packed Bed Reactor Experiment (PBRE) and flown on the International Space Station as PBRE‐2 to eliminate external pressure oscillations at higher liquid flow rates and the packing diameter was reduced to increase the pressure gradient for lower flows. It is found that gas hold‐up is a function of bed history at low liquid and gas flow rates whereas higher gas hold‐up...

article

Characterization of the hydrodynamics within a toroid wear tester

Oluwaseun E. Adedeji, Lisheng Zhang, Nitish R. Sarker, David E. S. Breakey, more

The Canadian Journal of Chemical Engineering > 100 > 8 > 1941 - 1953

The toroid wear tester (TWT) is a lab‐scale device used for the assessment of slurry erosion in pipelines. Historically, its application has been limited to the relative ranking of material performance under different slurry flow conditions; however, recent studies have indicated that TWT tests could be predictive and directly applied to slurry pipeline design—provided that the flow inside a TWT is...

article

Phase‐resolving direct numerical simulations of particle transport in liquids—From microfluidics to sediment

Jochen Fröhlich, Thomas E. Hafemann, Ramandeep Jain

GAMM‐Mitteilungen > 45 > 2 > n/a - n/a

The article describes direct numerical simulations using an Euler–Lagrange approach with an immersed‐boundary method to resolve the geometry and trajectory of particles moving in a flow. The presentation focuses on own work of the authors and discusses elements of physical and numerical modeling in some detail, together with three areas of application: microfluidic transport of spherical and nonspherical...

article

Revisit to the THINC/QQ scheme: Recent progress to improve accuracy and robustness

Dezhu Chen, Bin Xie, Feng Xiao

International Journal for Numerical Methods in Fluids > 94 > 7 > 719 - 755

In this article, we revisit to the THINC/QQ (tangent of hyperbola interface capturing method with quadratic surface representation and Gaussian quadrature) scheme to make thorough investigations on its numerical property. Furthermore, it presents some recent progress made extensively on THINC/QQ algorithm to improve numerical accuracy and robustness which include (1) construct the interface equation...

article

Very small‐scale, segregating‐fluidized‐bed experiments: A dataset for CFD‐DEM validation and uncertainty quantification

W. Casey Q. LaMarche, Steven R. Dahl, William D. Fullmer, Christine M. Hrenya

AIChE Journal > 68 > 6 > n/a - n/a

Fluidization experiments were conducted on a small scale and with a rapid response (short duration) to enable corresponding simulations at low‐computational cost. Rise times are reported for four or fewer polyethylene particles (intruders) in an air‐fluidized bed of ~5000 group D glass beads. Experimental inputs were completely characterized—particle properties, system dimensions and operating conditions—which...

article

Computational fluid dynamics modeling of biomass catalytic fast pyrolysis in bubbling fluidized reactor: Effects of catalyst parameters on process performance

Yajun Qiu, Qixiang Xu, Shusheng Pang, Xiaoyuechuan Ma

AIChE Journal > 68 > 6 > n/a - n/a

In this study, a computational fluid dynamics mathematical model has been developed for catalytic fast pyrolysis (CFP) of biomass based on multiphase flow, transfer process, and biomass pyrolysis reactions in a bubbling fluidized bed reactor. The multiphase fluid flow, and the inter‐phase momentum and energy transfer processes are modeled with Eulerian multiphase formulas, representing the flows of...

article

Esterification of Acetic Acid with Methanol and Simultaneous Product Isolation by Liquid‐Liquid Extraction in a Taylor‐Couette Disc Contactor

Georg Rudelstorfer, Maximilian Neubauer, Matthäus Siebenhofer, Susanne Lux, more

Chemie Ingenieur Technik > 94 > 5 > 671 - 680

Isolation of carboxylic acids from dilute aqueous effluents can be achieved by the combination of liquid‐phase catalyzed reaction with liquid‐liquid extraction. Exemplarily the heterogeneously catalyzed esterification of acetic acid with methanol, accelerated with a cation‐exchange resin and simultaneous transfer of the product methyl acetate into the solvent ShellSol T, was successfully performed...

article

Bubble‐scale observations of polyurethane foam expansion

Christine Roberts, Lisa Mondy, Grant Soehnel, Casper Brady, more

AIChE Journal > 68 > 5 > n/a - n/a

We describe experiments designed to inform computational models of the dynamic filling process of chemically blown, polyurethane foams, especially subgrid models to predict bubble size affecting foam properties. Three experimental methods are used to observe the evolution of bubble sizes during blowing. Magnified views of bubbles at a transparent wall of a channel are recorded during the foaming....

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Search results

Application of a high density ratio lattice-Boltzmann model for the droplet impingement on flat and spherical surfaces

Influence of tube configuration on the gas–solid hydrodynamics of an internally circulating fluidized bed: A discrete element study

Coarse grid simulation of heterogeneous gas–solid flow in a CFB riser with EMMS drag model: Effect of inputting drag correlations

Experimental study on flow patterns for water boiling in horizontal heated tubes

Stencil adaptive diffuse interface method for simulation of two-dimensional incompressible multiphase flows

A comparison of pendulum experiments and discrete‐element simulations of oblique collisions of wet spheres

Analysis of short‐ and long‐term system response during gas production from a gas hydrate deposit at the UBGH2‐6 site of the Ulleung Basin in the Korean East Sea

Gas phase hydrodynamics in a surface‐aerated tank with a long‐short blades agitator

Predicting Interfacial Tension via the Entrainment Master Curve of a Bubble Rising through the Immiscible Liquids Interface

Numerical investigation of flow, heat transfer, and kinetic reaction in a large‐difference bidisperse, circulating fluidized‐bed reactor

Characteristics of flow fields in the gas–liquid mini‐bubble columns with particle image velocimetry measurements

Effect of ultrasonic waveforms on gas–liquid mass transfer in microreactors

Gas–liquid flows through porous media in microgravity: Packed Bed Reactor Experiment‐2

Characterization of the hydrodynamics within a toroid wear tester

Phase‐resolving direct numerical simulations of particle transport in liquids—From microfluidics to sediment

Revisit to the THINC/QQ scheme: Recent progress to improve accuracy and robustness

Very small‐scale, segregating‐fluidized‐bed experiments: A dataset for CFD‐DEM validation and uncertainty quantification

Computational fluid dynamics modeling of biomass catalytic fast pyrolysis in bubbling fluidized reactor: Effects of catalyst parameters on process performance

Esterification of Acetic Acid with Methanol and Simultaneous Product Isolation by Liquid‐Liquid Extraction in a Taylor‐Couette Disc Contactor

Bubble‐scale observations of polyurethane foam expansion

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