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Pressure drop versus gas velocity for various bed heights using spherical particles, estimated minimum fluidization is marked by a line.
Source publication
Gas–solid beds are ubiquitous in industrial and energy production applications. Examples include fluidized beds, which are used in many systems such as in integrated gasification combined cycle power plants or in chemical looping systems. These examples and others involve complicated interactions between each phase of reactants in the system. The m...
Contexts in source publication
Context 1
... gas-solid packed bed experiments were first ver- ified using spherical particles. The pressure drop across the bed was measured for various gas velocities (V g ) (Figure 3). Estimation of the void fraction of (" g ) of 0.37 was done using predetermined weight of par- ticles along with a high-speed camera to measure height of the packed solids column right before min- imum fluidization. ...
Context 2
... This same value for velocity at minimum fluidization was observed in experiments within AE 5% for the different bed heights. Figure 3 also shows that minimum fluidization did not signifi- cantly vary for different bed heights. This is also in agreement with Ergun's assumption that minimum fluidization velocity is independent of bed height. ...
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... Gas-solid flow is widely used in various industrial applications, such as pharmacy, chemical industry, food processing and energy and environment [1]. Therefore, gas-solid flow has drawn the attention of great number of researchers on its interaction between gas and particle, rate of reaction and the dynamic characters of flow field, which can provide the basic theory for prediction and control of gas-solid flow process [2]. However, the mechanism of gas-solid flow has been explored far from completely. ...
This thesis aims at the TFM-DEM hybrid model, taking advantage of open source software MFIX, and takes gas-solid flow process in coal beneficiation fluidized bed (CBFB) as object of research. In gas-solid flow of the coal beneficiation fluidized bed, different diameters of coal/gangue particles are investigated and the existence of effective particle diameter in this apparatus is validated. The coal back mixing phenomenon due to the drag effect of rising bubble in the bed is captured from the particle level in hybrid model, and the time to reach balance in different diameters of coal/gangue particle is compared, which provides the reference for future applications of hybrid model.
Modern data center facilities administrators are finding it
increasingly difficult to lower the costs incurred in mechanical
cooling of their IT equipment. This is especially true for high
computing applications like Artificial Intelligence, Bitcoin
Mining, Deep Learning, etc. Airside Economization/free air
cooling reduces the mechanical cooling costs by using outside
air to cool IT equipment under favorable ambient conditions.
In this process, administrators risk their equipment to the
exposure of fine particulate/gaseous contaminants that might
enter the data center facility with the cooling airflow. Literature
suggests that the nature of failures caused by particulate
contamination is very intermittent which makes the failures
tough to predict. While the recommended filters can remove
PM10-2.5, it’s the fine and ultra-fine particulates like DPM
(Diesel Particulate Matter), corrosive salts of high ionic content
like sulfates and nitrates with low DRH (Deliquescent Relative
Humidity) values that are the cause of concern.
The present investigation utilizes a 3-D CFD modeling of
particle-laden flow in a rectangular flow domain, imitating the
flow through floor tiles as in a raised floor data center.
Literature was reviewed to study various numerical models that
have been used for simulating particle dispersion and particle
deposition in ventilated rooms, air ducts and particle behavior
across physical obstructions of various geometries. A Discrete
Phase Modeling approach was chosen using ANSYS FLUENT
to calculate trajectories of the dispersed contaminants.
6SigmaRoom was used to predict accurate boundary and flow
conditions of the fluid flow leaving the floor tiles.
As a novel model for gas solid flow simulation, the investigation of TFM-DEM hybrid model is far from completely, including mutual interaction of TFM and DEM phase, selection of DEM portion and coherence of the predicted results from both phases. Therefore, in present study, the consistency of velocity distribution between TFM and DEM phase is investigated. The correlation of instantaneous and time-averaged velocity distribution of TFM and DEM phase in specific area in CBFB for mining is studied. And the differences of the axial and radial velocity between the particles of different sizes are discussed. The influence of particle diameter and the ratio of DEM and TFM phase on the correlation of velocity, both instantaneous and time-averaged, are taken into consideration.
