Modeling of Particle-Laden Cold Flow in a Cyclone Gasifier

2018 ◽  
Vol 141 (2) ◽  
Author(s):  
Pantea Hadi Jafari ◽  
Dzmitry Misiulia ◽  
J. Gunnar I. Hellström ◽  
B. Rikard Gebart
Keyword(s):  
Gas Flow ◽  
Numerical Approach ◽  
Solid Particles ◽  
Bottom Plate ◽  
Single Particles ◽  
Cold Flow ◽  
Lagrangian Simulation ◽  
Swirl Intensity ◽  
The Impact ◽  
Simulation Time

Isothermal transient Eulerian–Lagrangian simulation of the turbulent gas–solid flow in a cyclone gasifier with two inlet tubes at 890 °C has been performed. The single-phase gas flow is modeled using SSG Reynolds stress turbulence model. Ten thousand representative solid particles of different sizes are injected from each inlet continuously at every second of simulation time. Particles are finally stopped as soon as they arrive at the outlet or reach the bottom plate of the gasifier. The effect of particle-to-gas coupling on the pressure and velocity of the flow and particles motion inside the gasifier is studied. The numerical approach can reasonably predict the impact of particle load on the gas flow as presented in the experimental results. Single particles are traveled throughout the transient gas flow field by using Lagrangian approach. High temperature of the gas flow inside the gasifier has significant effects on the swirl intensity reduction, damping the turbulence in the core region, pressure, and particle behaviors. However, the presence of solid particles does not have a notable influence on the swirl intensity and turbulence.

scholarly journals OpenFOAM Based Approach for the Prediction of the Dam Break with an Obstacle

2020 ◽  
Author(s):  
Mohamed Osman Elamin Busharads
Keyword(s):  
Numerical Solution ◽  
Vertical Wall ◽  
Leading Edge ◽  
Numerical Approach ◽  
Dam Break ◽  
Free Surface Elevation ◽  
Before And After ◽  
The Difference ◽  
The Impact ◽  
Simulation Time

The phenomenon of the flow impact on a vertical wall resulting from a dam problem is simulated by using OpenFOAM. In this simulation, a dam break was also simulated with the addition of obstacles with various dimensions. The aim of this study is to assess the accuracy of the solver for problems in the impact wave category from the experimental results of previous researchers and other numerical solution techniques compared with the results of this solver. Different aspects of flow such as free surface elevation before and after the initial impact have been observed in depth. The method used in this research is numerical computation simulation with the OpenFOAM approach which has the advantage of being more accurate and fast simulation time. The variations in the dimensions of the obstacle in this study were b / h = 0.25, b / h = 0.5 and b / h = 1.0. From the simulation data, it is found that the numerical approach has been validated through quantitative comparisons with experimental measurements. The computational positions of the leading edge of the collapsed water column match the experimental data. The difference between the experiment and this numerical solution is below 2%.

scholarly journals OpenFOAM Based Approach for the Prediction of the Dam Break with an Obstacle

2020 ◽  
Author(s):  
Richmond Sam Quarm
Keyword(s):  
Numerical Solution ◽  
Vertical Wall ◽  
Leading Edge ◽  
Numerical Approach ◽  
Dam Break ◽  
Free Surface Elevation ◽  
Before And After ◽  
The Difference ◽  
The Impact ◽  
Simulation Time

The phenomenon of the flow impact on a vertical wall resulting from a dam problem is simulated by using OpenFOAM. In this simulation, a dam break was also simulated with the addition of obstacles with various dimensions. The aim of this study is to assess the accuracy of the solver for problems in the impact wave category from the experimental results of previous researchers and other numerical solution techniques compared with the results of this solver. Different aspects of flow such as free surface elevation before and after the initial impact have been observed in depth. The method used in this research is numerical computation simulation with the OpenFOAM approach which has the advantage of being more accurate and fast simulation time. The variations in the dimensions of the obstacle in this study were b / h = 0.25, b / h = 0.5 and b / h = 1.0. From the simulation data, it is found that the numerical approach has been validated through quantitative comparisons with experimental measurements. The computational positions of the leading edge of the collapsed water column match the experimental data. The difference between the experiment and this numerical solution is below 2%.

scholarly journals Separation of Fine Particles from Gas in Paint-Spraying Booths

2021 ◽  
Vol 346 ◽  
pp. 03070
Author(s):  
Rustem Ya. Bikkulov ◽  
Andrey V. Dmitriev ◽  
Vadim E. Zinurov ◽  
Guzel R. Badretdinova
Keyword(s):  
Gas Flow ◽  
Fine Particles ◽  
Solid Particles ◽  
Dust Particles ◽  
Technological Parameters ◽  
Separation Device ◽  
Dispersed Particles ◽  
Quality Of Products ◽  
The Impact

Nowadays, at production facilities with paint-spraying booths that use paint and varnish materials to cover the surfaces of product, the problem of gas flow contamination with finely dispersed solid particles of dust and rubbish, which negatively affect the quality of products, is increasingly being raised. In order to minimize the content of solid particles in the gas flow, coarse and fine filters are installed in the paint-spraying booths, which prevent dust particles from entering the surface of products. However, the existing purification devices have a number of disadvantages that affect the efficiency of collecting finely dispersed particles from the gas flow with a size of 0.5-5 microns. The authors of article developed a square separator to increase the efficiency of collecting finely dispersed particles from gas flows in the paint-spraying booths. The installation of proposed separation device in the paint-spraying booths affects not only the quality of collecting solid particles, but also increases the service life of fine and coarse filters In the course of numerical studies, the results of impact of structural and technological parameters, namely, the impact of inlet rate and scale of separation device on the efficiency of collecting solid particles from the gas flow, were obtained.

Numerical Experiments With Solid Handling Pumps

2008 ◽  
Author(s):  
Hitesh Jogiya ◽  
J. T. Kshirsagar
Keyword(s):  
Experimental Test ◽  
Numerical Experiments ◽  
Numerical Approach ◽  
Solid Particles ◽  
Test Facility ◽  
Test Case ◽  
Test Results ◽  
Clear Water ◽  
Overall Performance ◽  
The Impact

Solid handling pumps are used in Sewage applications, Slurry transportation, transportation of floating solids etc. Many manufacturers supply such solid handling pumps for different applications. Few of the manufactures have test facility to study the impact of solid particles on overall performance of pump. It is then possible to experimentally bring out effect of solid size, its concentration etc. on overall performance. The literature is available for several such tests conducted by pump manufacturers. In absence of experimental test facility for solid handling pumps, a numerical approach was proposed to investigate the effect of solid particles on the pump performance. Commercially available CFD tool was used to carry out numerical experiments. A standard pump in production was chosen as a test case. It was ensured that experimental test results of similar size pump are available in literature. The work presented here is the extension of the work done by Gupta Amit for a solid handling impeller [8]. The similar impeller assembled with casing for solid handling pump was analyzed first to compute the performance of whole pump with clear water. This was compared with test results available from factory tests conducted experimentally with clear water. The same geometry was then analyzed using particle tracking drag models available in the software given the new boundary conditions of solid additions. Results from the numerical experiments, including effect of particle size, their concentrations etc were brought out. The particle trajectory from impeller entry to exit of casing gave idea as how particles travel in solid handing pumps. The computational results were compared with the ones presented in the Pump Handbook by Karassik. The software results were useful in getting additional information on loss in impeller and casing separately. This gives a clue to as which component needs improvement. The paper describes the approach used in numerical experiments and the results thereof.

Prediction of Erosion Damage in a Choke Valve Working in Severe Slurry Conditions

2018 ◽  
Author(s):  
Stefano Malavasi ◽  
Gianandrea Vittorio Messa ◽  
Marco Negri
Keyword(s):  
Gas Flow ◽  
Oil And Gas ◽  
Production Systems ◽  
Quantitative Estimation ◽  
Petroleum Industry ◽  
Solid Particles ◽  
Operation Condition ◽  
Present Contribution ◽  
The Impact ◽  
Impact Erosion

Wellhead choke valves, frequently used to control oil and gas flow rates from producing wells in the petroleum industry, may experience loss of material due to the impingements of solid particles within the extraction fluids. This phenomenon, called impact erosion, is a serious concern to engineers, as it can result in loss of performance or even failure of the devices. Being capable to identify the valve components which are most vulnerable to impact erosion and provide quantitative estimation of the useful life of the chokes under actual production conditions may open the way to improved design and maintenance. The present contribution focuses on the use of Computational Fluid Dynamics techniques for predicting the impact erosion of a choke valve working in severe slurry conditions. The in-house erosion prediction library E-CODE, developed within the authors’ research group and illustrated in previous works, was employed to model the complex phenomena occurring in the valve. The good agreement between the numerical estimates and the outcomes of a test performed in the Hydraulic Laboratory of Politecnico di Milano indicated that, given the composition of the slurry environment and the operation condition of the valve, it is possible to estimate with reasonable accuracy the erosion characteristics of the device. This will allow gathering useful information for improving the scheduled maintenance of the production systems and the design of heavy-duty equipment.

scholarly journals The High-Rate Sealed MRPC to Promote Pollutant Exchange in Gas Gaps: Status on the Development and Observations

2021 ◽  
Vol 11 (11) ◽  
pp. 4722
Author(s):  
Botan Wang ◽  
Xiaolong Chen ◽  
Yi Wang ◽  
Dong Han ◽  
Baohong Guo ◽  
...  
Keyword(s):  
Gas Flow ◽  
High Rate ◽  
Stable Operation ◽  
Beam Test ◽  
High Luminosity ◽  
Rate Test ◽  
3D Printed ◽  
Resistive Plate Chambers ◽  
The Impact ◽  
Current Behavior

This work reports the latest observations on the behavior of two Multigap Resistive Plate Chambers (MRPC) under wide high-luminosity exposures, which motivate the development and in-beam test of the sealed MRPC prototype assembled with low-resistive glass. The operation currently being monitored, together with previous simulation results, shows the impact of gas pollution caused by avalanches in gas gaps, and the necessity to shrink the gas-streaming volume. With the lateral edge of the detector sealed by a 3D-printed frame, a reduced gas-streaming volume of ~170 mL has been achieved for a direct gas flow to the active area. A high-rate test of the sealed MRPC prototype shows that, ensuring a 97% efficiency and 70 ps time resolution, the sealed design results in a stable operation current behavior at a counting rate of 3–5 kHz/cm2. The sealed MRPC will become a potential solution for future high luminosity applications.

scholarly journals Influence of Age on the Technical Wear of Tenement Houses

2020 ◽  
Vol 11 (1) ◽  
pp. 297
Author(s):  
Jarosław Konior ◽  
Marek Sawicki ◽  
Mariusz Szóstak
Keyword(s):  
Residential Buildings ◽  
Residential Building ◽  
Numerical Approach ◽  
Technical Condition ◽  
Visual Methods ◽  
Secondary Importance ◽  
Building Maintenance ◽  
Technical Maintenance ◽  
Traditional Construction ◽  
The Impact

The research presented in the article, which includes methods, models, and conclusions, contains synthetic and analytical model solutions concerning the problems of the technical maintenance and wear of residential buildings with a traditional construction. The cause and effect relationships between the occurrence of damage in the elements of tenement houses (treated as proof of their maintenance conditions), and the size of the technical wear of these elements were determined using a representative and purposefully selected sample of 102 residential buildings erected during the second half of the nineteenth and early twentieth centuries in Wroclaw’s “Downtown” district. Quantitative damage analysis, which was carried out using empirical (visual) methods of assessing the technical condition of a building, indicates the type and size of damage to the building’s elements that are characteristic for the relevant maintenance conditions. Research concerning the cause–effect relationships (“damage–technical wear”) in observed states allows for a numerical approach to the impact of building maintenance conditions on the degree of the technical wear of its components. The maintenance and exploitation conditions determine the degree of the technical wear of the elements of an old residential building. The exploitation condition of these buildings is manifested by damage to elements caused by water and moisture penetration, which is especially important for poorly maintained buildings. The article shows that the age of the elements of an old residential building with a traditional construction is of secondary importance in the process of the intensity of losing its serviceability value. It was calculated that no more than 30% of the damage of building components is explained by the passage of time, and it is therefore not age that determines the course of the technical wear of the elements of the analyzed tenement houses.

scholarly journals A new method of inferring the size, number density, and charge of mesospheric dust from its in situ collection by the DUSTY probe

2019 ◽  
Vol 12 (3) ◽  
pp. 1673-1683 ◽  
Author(s):  
Ove Havnes ◽  
Tarjei Antonsen ◽  
Gerd Baumgarten ◽  
Thomas W. Hartquist ◽  
Alexander Biebricher ◽  
...  
Keyword(s):  
New Method ◽  
Production Model ◽  
Dust Particles ◽  
Bottom Plate ◽  
Charged Dust ◽  
Fundamental Parameters ◽  
Dust Charge ◽  
Analysis Technique ◽  
June July ◽  
The Impact

Abstract. We present a new method of analyzing measurements of mesospheric dust made with DUSTY rocket-borne Faraday cup probes. It can yield the variation in fundamental dust parameters through a mesospheric cloud with an altitude resolution down to 10 cm or less if plasma probes give the plasma density variations with similar height resolution. A DUSTY probe was the first probe that unambiguously detected charged dust and aerosol particles in the Earth's mesosphere. DUSTY excluded the ambient plasma by various biased grids, which however allowed dust particles with radii above a few nanometers to enter, and it measured the flux of charged dust particles. The flux measurements directly yielded the total ambient dust charge density. We extend the analysis of DUSTY data by using the impact currents on its main grid and the bottom plate as before, together with a dust charging model and a secondary charge production model, to allow the determination of fundamental parameters, such as dust radius, charge number, and total dust density. We demonstrate the utility of the new analysis technique by considering observations made with the DUSTY probes during the MAXIDUSTY rocket campaign in June–July 2016 and comparing the results with those of other instruments (lidar and photometer) also used in the campaign. In the present version we have used monodisperse dust size distributions.

Hydrogen Concentration Analysis in Pecvd and Rtcvd Silicon Nitride Thin Films and It's Impact on Device Performance

2001 ◽  
Vol 664 ◽  
Author(s):  
C. Y. Wang ◽  
E. H. Lim ◽  
H. Liu ◽  
J. L. Sudijono ◽  
T. C. Ang ◽  
...  
Keyword(s):  
Chemical Vapor Deposition ◽  
Threshold Voltage ◽  
Vapor Deposition ◽  
Gas Flow ◽  
Chemical Vapor ◽  
Gate Oxide ◽  
Nitride Film ◽  
Device Performance ◽  
Gas Flow Ratio ◽  
The Impact

ABSTRACTIn this paper the impact of the ESL (Etch Stop layer) nitride on the device performance especially the threshold voltage (Vt) has been studied. From SIMS analysis, it is found that different nitride gives different H concentration, [H] in the Gate oxide area, the higher [H] in the nitride film, the higher H in the Gate Oxide area and the lower the threshold voltage. It is also found that using TiSi instead of CoSi can help to stop the H from diffusing into Gate Oxide/channel area, resulting in a smaller threshold voltage drift for the device employed TiSi. Study to control the [H] in the nitride film is also carried out. In this paper, RBS, HFS and FTIR are used to analyze the composition changes of the SiN films prepared using Plasma enhanced Chemical Vapor deposition (PECVD), Rapid Thermal Chemical Vapor Deposition (RTCVD) with different process parameters. Gas flow ratio, RF power and temperature are found to be the key factors that affect the composition and the H concentration in the film. It is found that the nearer the SiN composition to stoichiometric Si3N4, the lower the [H] in SiN film because there is no excess silicon or nitrogen to be bonded with H. However the lowest [H] in the SiN film is limited by temperature. The higher the process temperature the lower the [H] can be obtained in the SiN film and the nearer the composition to stoichiometric Si3N4.

Two-Phase Flows in Mini-/Micro-Gas Flow Channels of PEM Fuel Cells

2013 ◽  
Author(s):  
Sung Chan Cho ◽  
Yun Wang
Keyword(s):  
Pressure Drop ◽  
Gas Flow ◽  
Fluid Model ◽  
Pem Fuel Cells ◽  
Two Phase ◽  
Micro Gas Flow ◽  
Two Fluid Model ◽  
The Impact ◽  
Two Fluid ◽  
Phase Pressure

In this paper, two-phase flow dynamics in a micro channel with various wall conditions are both experimentally and theoretically investigated. Annulus, wavy and slug flow patterns are observed and location of liquid phase on different wall condition is visualized. The impact of flow structure on two-phase pressure drop is explained. Two-phase pressure drop is compared to a two-fluid model with relative permeability correlation. Optimization of correlation is conducted for each experimental case and theoretical solution for the flows in a circular channel is developed for annulus flow pattern showing a good match with experimental data in homogeneous channel case.

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