scholarly journals CFD Modeling of Gas–Solid Cyclone Separators at Ambient and Elevated Temperatures

Processes ◽  
2020 ◽  
Vol 8 (2) ◽  
pp. 228 ◽  
Author(s):  
Mohammadhadi Nakhaei ◽  
Bona Lu ◽  
Yujie Tian ◽  
Wei Wang ◽  
Kim Dam-Johansen ◽  
...  
Keyword(s):  
Elevated Temperatures ◽  
Cfd Simulation ◽  
Separation Efficiency ◽  
Flow Behavior ◽  
Industrial Applications ◽  
High Mass ◽  
Cfd Modeling ◽  
Solid Flow ◽  
Solids Loading ◽  
Wide Range

Gas–solid cyclone separators are widely utilized in many industrial applications and usually involve complex multi-physics of gas–solid flow and heat transfer. In recent years, there has been a progressive interest in the application of computational fluid dynamics (CFD) to understand the gas–solid flow behavior of cyclones and predict their performance. In this paper, a review of the existing CFD studies of cyclone separators, operating in a wide range of solids loadings and at ambient and elevated temperatures, is presented. In the first part, a brief background on the important performance parameters of cyclones, namely pressure drop and separation efficiency, as well as how they are affected by the solids loading and operating temperature, is described. This is followed by a summary of the existing CFD simulation studies of cyclones at ambient temperature, with an emphasis on the high mass loading of particles, and at elevated temperatures. The capabilities as well as the challenges and limitations of the existing CFD approaches in predicting the performance of cyclones operating in such conditions are evaluated. Finally, an outlook on the prospects of CFD simulation of cyclone separators is provided.

CFD Simulation of Large Dust Collection Cyclones Positioned Vertically in Staggered Downward Cascade Arrangement

2013 ◽  
Author(s):  
Eugen-Dan Cristea ◽  
Pierangelo Conti
Keyword(s):  
Cfd Simulation ◽  
Solid Phase ◽  
Phase Particle ◽  
High Mass ◽  
Cfd Modeling ◽  
Cement Kiln ◽  
Dust Collection ◽  
Dry Process ◽  
Cascade Arrangement ◽  
Simulation Results

Three dimensional, time dependent Euler-Euler simulation approach for numerical calculation of multiphase strongly swirling turbulent gas-heavy laden particulate flow in large industrial collection cyclones, positioned vertically, in staggered downward cascade arrangement has been performed. The multiphase flow was featured high mass loading. This paper specifically addresses a CFD modeling of a “suspension preheater”, typical equipment for dry process cement kiln. Big sized cyclone separator is a key component of this device. The simulation case study was developed in the frame of the commercial general-purpose code ANSYS-Fluent R13. In cyclone separators the swirling gas motion induces a centrifugal force on the solid particulate phase which is the driving force behind the separation process. The turbulence disperses the solid particulates and enhances the probability that particles are discharged, as reject. Both phenomena are related to solid phase particle size distribution (PSD) and flow pattern into the collection cyclones. The multiphase turbulence was modeled using the RSM Mixture Turbulence Model. The simulation results were validated against industrial measurements carried out on an industrial suspension preheater, in the frame of heat and mass balance of cement kiln energy audit. The numerical simulation results were found in reasonable agreement with the collected industrial measurements. This CFD simulation represents a powerful engineering tool on behalf of the cement process engineer either for new cutting-edge design or for performance verification of an existing plant.

Gas Liquid Vane Separators in High Pressure Applications

2010 ◽  
Author(s):  
Dani Fadda ◽  
David Barker
Keyword(s):  
Separation Efficiency ◽  
Pressure Vessels ◽  
Cfd Modeling ◽  
Test Results ◽  
Capacity Curves ◽  
Liquid Handling ◽  
Wide Range ◽  
Computational Fluid Dynamics Cfd ◽  
Very High ◽  
High Separation

Vane separators are inertial devices used to remove entrained liquids from gas. They are utilized in pressure vessels operating at a wide range of temperatures and pressures. Computational Fluid Dynamics (CFD) modeling and sizing calculations are used to evaluate the loading to a vane separator and determine the maximum overall gas and liquid handling capacity of the pressure vessel. Test results, performed at operating pressures up to 133 bar (1931 psia) using live natural gas illustrate that, when sized correctly based on the vane’s capacity curves and CFD modeling, vane separators continue to have high separation efficiency at very high operating pressures.

scholarly journals Complex Electrical Conductivity of Biotite and Muscovite Micas at Elevated Temperatures: A Comparative Study

Materials ◽  
2020 ◽  
Vol 13 (16) ◽  
pp. 3513
Author(s):  
Vassilios Saltas ◽  
Despoina Pentari ◽  
Filippos Vallianatos
Keyword(s):  
Electrical Conductivity ◽  
Elevated Temperatures ◽  
Small Polaron ◽  
Complex Impedance ◽  
Bound Water ◽  
Data Representation ◽  
Industrial Applications ◽  
Mechanical And Thermal Properties ◽  
Wide Range ◽  
Complex Electrical Conductivity

The unique physicochemical, electrical, mechanical, and thermal properties of micas make them suitable for a wide range of industrial applications, and thus, the interest for these kind of hydrous aluminosilicate minerals is still persistent, not only from a practical but also from a scientific point of view. In the present work, complex impedance spectroscopy measurements were carried out in muscovite and biotite micas, perpendicular to their cleavage planes, over a broad range of frequencies (10−2 Hz to 106 Hz) and temperatures (473–1173 K) that have not been measured so far. Different formalisms of data representation were used, namely, Cole-Cole plots of complex impedance, complex electrical conductivity and electric modulus to analyze the electrical behavior of micas and the electrical signatures of the dehydration/dehydroxylation processes. Our results suggest that ac-conductivity is affected by the structural hydroxyls and the different concentrations of transition metals (Fe, Ti and Mg) in biotite and muscovite micas. The estimated activation energies, i.e., 0.33–0.83 eV for biotite and 0.69–1.92 eV for muscovite, were attributed to proton and small polaron conduction, due to the bound water and different oxidation states of Fe.

Multiphase CFD Model Development for a Rotating Centrifugal Separator

2012 ◽  
Author(s):  
Daniel DeMore ◽  
William Maier
Keyword(s):  
Separation Efficiency ◽  
Fluid Dynamic ◽  
Model Development ◽  
Modeling Method ◽  
Operating Conditions ◽  
Cfd Modeling ◽  
Separation Performance ◽  
Centrifugal Separator ◽  
Wide Range ◽  
The Impact

The present paper describes the development of a Computational Fluid Dynamic (CFD) modeling approach suitable for the analysis, design, and optimization of rotating centrifugal separator stage geometries. The Homogeneous Multiple Size Group (MUSIG) model implemented in the commercial code CFX V13.0 was utilized as a basis for the CFD modeling method. The model was developed through a series of studies to understand the impact of droplet size distribution, particle coalescence, rotor/stator interface treatment, and mesh resolution on the prediction of separation efficiency for a given rotating separator geometry. This model was then validated against the OEM’s extensive in-house experimental separation testing database. The resulting CFD modeling method is shown to adequately reproduce observed trends in separation performance over a wide range of operating conditions.

scholarly journals CFD Simulation Based Investigation of Cavitation Dynamics during High Intensity Ultrasonic Treatment of A356

Metals ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1529
Author(s):  
Eric Riedel ◽  
Niklas Bergedieck ◽  
Stefan Scharf
Keyword(s):  
Ultrasonic Treatment ◽  
High Intensity ◽  
Aluminium Alloys ◽  
Cfd Simulation ◽  
Numerical Models ◽  
Acoustic Streaming ◽  
Industrial Applications ◽  
Software Environment ◽  
Wide Range ◽  
Semi Solid

Ultrasonic treatment (UST) and its effects, primarily cavitation and acoustic streaming, are useful for a high range of industrial applications, e.g., welding, filtering, cleaning or emulsification. In the metallurgy and foundry industry, UST can be used to modify a material’s microstructure by treating metal in the liquid or semi-solid state. Cavitation (formation, pulsating growth and implosion of tiny bubbles) and its shock waves, released during the implosion of the cavitation bubbles, are able to break forming structures and thus refine them. In this context, especially aluminium alloys are in the focus of the investigations. Aluminium alloys, e.g., A356, have a significantly wide range of industrial applications in automotive, aerospace and machine engineering, and UST is an effective and comparatively clean technology for its treatment. In recent years, the efforts for simulating the complex mechanisms of UST are increasing, and approaches for computing the complex cavitation dynamics below the radiator during high intensity ultrasonic treatment have come up. In this study, the capabilities of the established CFD simulation tool FLOW-3D to simulate the formation and dynamics of acoustic cavitation in aluminium A356 are investigated. The achieved results demonstrate the basic capability of the software to calculate the above-mentioned effects. Thus, the investigated software provides a solid basis for further development and integration of numerical models into an established software environment and could promote the integration of the simulation of UST in industry.

scholarly journals CFD Modeling and Simulation of Hydrodynamics in a Fluidized Bed Dryer with Experimental Validation

2011 ◽  
Vol 2011 ◽  
pp. 1-9 ◽  
Author(s):  
Mahdi Hamzehei
Keyword(s):  
Fluidized Bed ◽  
Fluid Dynamic ◽  
Expansion Ratio ◽  
Industrial Applications ◽  
Solid Particles ◽  
Cfd Modeling ◽  
Momentum Exchange ◽  
Fluidized Bed Dryer ◽  
Wide Range ◽  
Simulation Results

Gas-solid fluidized bed dryers are used in a wide range of industrial applications. With applying computational fluid dynamic (CFD) techniques, hydrodynamics of a two-dimensional nonreactive gas-solid fluidized bed dryer was investigated. A multifluid Eulerian model incorporating the kinetic theory for solid particles was applied to simulate the unsteady state behavior of this dryer and momentum exchange coefficients were calculated by using the Syamlal-O'Brien drag functions. A suitable numerical method that employed finite volume method was used to discretize the equations. Simulation results also indicated that small bubbles were produced at the bottom of the bed. These bubbles collided with each other as they moved upwards forming larger bubbles. Also, solid particles diameter and superficial gas velocity effect on hydrodynamics were studied. Simulation results were compared with the experimental data in order to validate the CFD model. Pressure drops and bed expansion ratio as well as the qualitative gas-solid flow patterns predicted by the simulations were in good agreement with experimental measurements at superficial gas velocities higher than the minimum fluidization velocity. Furthermore, this comparison showed that the model can predict hydrodynamic behavior of gas solid fluidized bed reasonably well.

scholarly journals Comparative Analysis and Biochemical Characterization of Two Endo-β-1,3-Glucanases from the Thermophilic Bacterium Fervidobacterium sp.

Catalysts ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 830 ◽  
Author(s):  
Burkhardt ◽  
Schäfers ◽  
Claren ◽  
Schirrmacher ◽  
Antranikian
Keyword(s):  
Elevated Temperatures ◽  
Biochemical Characterization ◽  
Hot Spring ◽  
Biomass Conversion ◽  
Catalytic Efficiency ◽  
Industrial Applications ◽  
Thermophilic Bacterium ◽  
Metagenomic Sample ◽  
Wide Range ◽  
Active Site Cleft

Laminarinases exhibit potential in a wide range of industrial applications including the production of biofuels and pharmaceuticals. In this study, we present the genetic and biochemical characteristics of FLamA and FLamB, two laminarinases derived from a metagenomic sample from a hot spring in the Azores. Sequence comparison revealed that both genes had high similarities to genes from Fervidobacterium nodosum Rt17-B1. The two proteins showed sequence similarities of 62% to each other and belong to the glycoside hydrolase (GH) family 16. For biochemical characterization, both laminarinases were heterologously produced in Escherichia coli and purified to homogeneity. FLamA and FLamB exhibited similar properties and both showed highest activity towards laminarin at 90 °C and pH 6.5. The two enzymes were thermostable but differed in their half-life at 80 °C with 5 h and 1 h for FLamA and FLamB, respectively. In contrast to other laminarinases, both enzymes prefer β-1,3-glucans and mixed-linked glucans as substrates. However, FLamA and FLamB differ in their catalytic efficiency towards laminarin. Structure predictions were made and showed minor differences particularly in a kink adjacent to the active site cleft. The high specific activities and resistance to elevated temperatures and various additives make both enzymes suitable candidates for application in biomass conversion.

Effect of the Mould Rotational Speed on the Quality of Bimetallic Pipe Fabricated by Centrifugal Casting Process

2018 ◽  
Vol 6 (7) ◽  
pp. 215
Author(s):  
Shatrudhan Pandey ◽  
Shreyanshu Parhi ◽  
Sanjay Kumar Jha
Keyword(s):  
Elevated Temperatures ◽  
Centrifugal Casting ◽  
High Strength ◽  
Casting Process ◽  
Industrial Applications ◽  
Bond Quality ◽  
X Ray ◽  
Wide Range ◽  
Bimetallic Pipe

Bimetallic pipes have found a wide range of applications in the present market scenario. It is due to the fact that they possess really impressive mechanical properties like high corrosion resistance at elevated temperatures, high strength, high toughness, etc. The bimetal pipes can be made by using several combinations of metals depending on the requirements like Al-Cu, Al-Ni, etc. Bimetallic pipes are manufactured by the principle of cladding where one metal is made to clad over another one. They have found their applications in steam condenser, heat exchangers, water supply, industrial applications, etc. These pipes are manufactured using the centrifugal casting process. This paper deals with the effect of the various mould rotational speeds on the quality of the bond produced in the Al-Cu bimetallic pipe while fabricating through the centrifugal casting process. The vertical centrifugal casting setup is used for the process. The detailed analysis of the bond quality is done using Scanning Electron Microscope (SEM). Furthermore, the chemical composition of the bond is studied by using Energy Dispersive X-Ray Spectroscopy (EDS). The strength and quality of the Al-Cu bimetallic bond is studied at varying rotational speeds of the mould and finally the observations are taken. The conclusion is framed accordingly based on the observations.

2D CFD Simulation of Hydrodynamics of the Dense Zone of a 65t/h High-Low Bed CFB

2012 ◽  
Vol 614-615 ◽  
pp. 596-599
Author(s):  
Qing Wang ◽  
Jian Bo Xiao ◽  
Hong Peng Liu
Keyword(s):  
Size Distribution ◽  
Cfd Simulation ◽  
Volume Fraction ◽  
Flow Behavior ◽  
Solid Volume Fraction ◽  
Multiphase Model ◽  
Interphase Interaction ◽  
Solid Flow ◽  
Drag Model ◽  
Dense Zone

Gas-solid flow behavior of the bottom zone of a 65t/h High-low bed CFB was simulated using the commercial computational fluid dynamics (CFD) software package Fluent. The Eulerian-Eulerian model (EEM) based on the kinetic theory of granular flow (KTGF) was adopted. This approach treated each phase as continuous separately. The link between the gas and solid phases was through drag model and turbulence model. While the turbulence was simulated by the standard k-ε and mixture multiphase model, the Gidaspow drag model was used to model the interphase interaction. Four phases were set to achieve size distribution in the EEM. Gas and solid flow profiles are obtained for solid velocity, solid volume fraction, pressure, and size distribution. The results show that EEM can predict preferably the internal circulation process of the dense zone high-low bed CFB.

scholarly journals Controlling Angular Distortion in Manual Metal Arc Welding of Austenitic Stainless Steels Using Back-step Technique

2018 ◽  
Vol 26 (2) ◽  
pp. 311-319
Author(s):  
Abdul Sameea Jasim Abdul Zehra Jilabi
Keyword(s):  
Stainless Steels ◽  
Nuclear Power ◽  
Elevated Temperatures ◽  
Austenitic Stainless Steels ◽  
Industrial Applications ◽  
The Other ◽  
Angular Distortion ◽  
Mma Welding ◽  
Other Hand ◽  
Wide Range

Nowadays, austenitic stainless steels (A.S.S.) have many industrial applications in the fields of chemical and petrochemical processing, marine, medicine, water treatment, petroleum refining, food and drinks processing, nuclear power generation etc. The secret behind this wide range of applications is the fact that A.S.S. have great corrosion resistance, high strength and scale resistance at elevated temperatures, good ductility at low temperatures approached to absolute zero in addition to notable weldability. On the other hand, manual metal arc (MMA) is probably the most common process used for the welding of A.S.S. Unfortunately, MMA welding of A.S.S. could be associated with considerable distortion. Uncontrolled or excessive distortion usually increases the cost of the production process due to the high expense of rectification or replacing the weldment by a non-distorted one. MMA welding of A.S.S. was carried out using the back-step technique with various bead lengths, and without using this technique for comparison. Results have showed that the angular distortion was a function of the bead length in the back-step welding of A.S.S. The angular distortion decreased by (14.32%) when the back-step technique was used with a (60 mm) length for each bead, and by (41.08%) when the bead length was (40 mm). On the other hand, it increased by (25%) when the back-step technique was done with a (30 mm) length for each bead.

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