scholarly journals Empirical correlation for prediction of the elutriation rate constant

2003 ◽  
Vol 7 (2) ◽  
pp. 43-58 ◽  
Author(s):  
Valentino Stojkovski ◽  
Zvonimir Kostic
Keyword(s):  
Steady State ◽  
Size Distribution ◽  
Fluidized Bed ◽  
Rate Constant ◽  
Flow Rate ◽  
Gas Flow ◽  
Particle Density ◽  
Coarse Particles ◽  
Gas Flow Rate ◽  
Mean Size

In vessels containing fluidized solids, the gas leaving carries some suspended particles. This flux of solids is called entrainment, E or carryover and the bulk density of solids on this leaving gas stream is called the holdup. For design we need to know the rate of this entrainment and the size distribution of these entrained particles Rim in relation to the size distribution in the bed, Rib, as well as the variation of both these quantities with gas and solids properties, gas flow rate, bed geometry and location of the leaving gas stream. Steady-state elutriation experiments have been done in a fluidized bed 0,2 m diameter by 2,94 m high freeboard with superficial gas velocities up to 1 m/s using solids ranging in mean size from 0,15 to 0,58 mm and with particle density 2660 kg/m3. When the fine and coarse particles were mixed, the total entrainment flux above the freeboard was increased. None of the published correlations for estimating the elutriation rate constant were useful. A new simple equation, which is developed on the base of experimental results and theory of dimensional analyses, is presented.

Experimental, Numerical, and Statistical Investigation of Two Phase Flow in a Cylindrical Perforation Tunnel

2021 ◽  
Author(s):  
Ekhwaiter Abobaker ◽  
Abadelhalim Elsanoose ◽  
Mohammad Azizur Rahman ◽  
Faisal Khan ◽  
Amer Aborig ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Steady State ◽  
Statistical Analysis ◽  
Flow Rate ◽  
Gas Flow ◽  
Two Phase Flow ◽  
Phase Flow ◽  
Gas Flow Rate ◽  
Two Phase ◽  
Flow Through

Abstract Perforation is the final stage in well completion that helps to connect reservoir formations to wellbores during hydrocarbon production. The drilling perforation technique maximizes the reservoir productivity index by minimizing damage. This can be best accomplished by attaining a better understanding of fluid flows that occur in the near-wellbore region during oil and gas operations. The present work aims to enhance oil recovery by modelling a two-phase flow through the near-wellbore region, thereby expanding industry knowledge about well performance. An experimental procedure was conducted to investigate the behavior of two-phase flow through a cylindrical perforation tunnel. Statistical analysis was coupled with numerical simulation to expand the investigation of fluid flow in the near-wellbore region that cannot be obtained experimentally. The statistical analysis investigated the effect of several parameters, including the liquid and gas flow rate, liquid viscosity, permeability, and porosity, on the injection build-up pressure and the time needed to reach a steady-state flow condition. Design-Expert® Design of Experiments (DoE) software was used to determine the numerical simulation runs using the ANOVA analysis with a Box-Behnken Design (BBD) model and ANSYS-FLUENT was used to analyses the numerical simulation of the porous media tunnel by applying the volume of fluid method (VOF). The experimental data were validated to the numerical results, and the comparison of results was in good agreement. The numerical and statistical analysis demonstrated each investigated parameter’s effect. The permeability, flow rate, and viscosity of the liquid significantly affect the injection pressure build-up profile, and porosity and gas flow rate substantially affect the time required to attain steady-state conditions. In addition, two correlations obtained from the statistical analysis can be used to predict the injection build-up pressure and the required time to reach steady state for different scenarios. This work will contribute to the clarification and understanding of the behavior of multiphase flow in the near-wellbore region.

Predicting bed dynamics in three-phase, fluidized-bed biofilm reactors

1994 ◽  
Vol 29 (10-11) ◽  
pp. 231-241 ◽  
Author(s):  
H. T. Chang ◽  
B. E. Rittmann
Keyword(s):  
Fluidized Bed ◽  
Flow Rate ◽  
Liquid Flow ◽  
Gas Flow ◽  
Liquid Flow Rate ◽  
Gas Flow Rate ◽  
Biofilm Growth ◽  
Biofilm Thickness ◽  
Three Phase ◽  
Proper Design

This paper presents a unified model that inter-relates gas flow rate, liquid flow rate, and hold-ups of each of the liquid, gas, and solid phases in three-phase, fluidized-bed biofilm (TPFBB) process. It describes how carrier properties, biofilm properties, and gas and liquid flow velocities control the system dynamics, which ultimately will affect the density, thickness, and distribution of the biofilm. The paper describes the development of the mathematical model to correlate the effects of gas flow rate, liquid flow rate, solid concentration, and biofilm thickness and density. This knowledge is critically needed in light of the use of TPFBB processes in treating industrial wastewater, which often has high substrate concentration. For example, the proper design of the TPFBB process requires mathematical description of the cause-effect relationship between biofilm growth and fluidization.

Recent Knowledge From an Experimental Investigation on Self-Leveling Behavior of Debris Bed

2013 ◽  
Author(s):  
Songbai Cheng ◽  
Hidemasa Yamano ◽  
Tohru Suzuki ◽  
Yoshiharu Tobita ◽  
Yuya Nakamura ◽  
...  
Keyword(s):  
Flow Rate ◽  
Large Scale ◽  
Gas Flow ◽  
Particle Density ◽  
The Self ◽  
Gas Flow Rate ◽  
Energy Agency ◽  
Experimental Parameters ◽  
The Status ◽  
Series Of Experiments

Studies on the self-leveling behavior of debris bed are crucial in the assessment of core-disruptive accident (CDA) that could occur in sodium-cooled fast reactors (SFR). To clarify the mechanisms of this behavior, several series of experiments were elaborately designed and performed in recent years under the collaboration between Japan Atomic Energy Agency (JAEA) and Kyushu University (Japan). This paper presents the recent knowledge obtained from the newly developed large-scale experiments using gas-injection to simulate coolant boiling. Compared to previous investigations, it can cover a much wider range of gas velocities (presently up to a flow rate of around 300L/min). Based on the experimental data obtained, influence of various experimental parameters, including gas flow rate (∼ 300 L/min), water depth (180 mm and 400mm), bed volume (5L, 7L), particle size (2 ∼ 6 mm), particle density (beads of alumina, zirconia and stainless steel) along with particle shape (spherical and irregularly-shaped) on the leveling was checked and compared. In addition, the status of developing empirical model to predict the self-leveling over current setup was also presented. This work, which gives a large palette of favorable data for a better understanding and an improved estimation of CDAs in SFRs, is expected to benefit future analyses and verifications of computer models developed in advanced fast reactor safety analysis codes.

Experimental Characterization of Aerosol Production, Transport, Vaporization, and Atomization Systems. Part II: Factors Controlling Aerosol Size Distributions Produced

1985 ◽  
Vol 39 (6) ◽  
pp. 920-925 ◽  
Author(s):  
R. K. Skogerboe ◽  
S. J. Freeland
Keyword(s):  
Flow Rate ◽  
Gas Flow ◽  
Cross Flow ◽  
Size Distributions ◽  
Experimental Characterization ◽  
Gas Flow Rate ◽  
Mean Size ◽  
The Mean ◽  
Model Equations

The effects of nebulization conditions on the size characteristics of the aqueous aerosol produced have been investigated for a cross-flow nebulizer. It is shown that the nebulizer gas flow rate does not affect the upper limit mean sizes of the aqueous droplets transported from the nebulization chamber but that the mean size of the analyte-containing aerosol itself is affected. Model equations are presented descriptive of the effects of gas flow rate and analyte concentrations on analyte aerosol size characteristics.

scholarly journals Effect Of Sparging In Microalgae (Dunaliella Tertiolecta) Cuture Using Bubble Column

REAKTOR ◽  
2017 ◽  
Vol 6 (2) ◽  
pp. 56
Author(s):  
Hadiyanto Hadiyanto ◽  
M. Barbosa ◽  
R. Wijffels
Keyword(s):  
Cell Death ◽  
Rate Constant ◽  
Flow Rate ◽  
Death Rate ◽  
Gas Flow ◽  
Bubble Column ◽  
Animal Cell ◽  
Gas Flow Rate ◽  
Cell Death Rate ◽  
Entrance Velocity

Microalgae as a photosynthetic microorganism that contain chlorophyll has high potential to produce novel high value compounds that can be used in food, pharmaceutical and cosmetic industries. With lack of rigid cell wall, microalgae susceptible to have  hydrodynamic stress by increasing aeration rate. Increasing gas flow rate will increase the productivity to optimum condition, but after this condition the productivity will  decrease due to cell disruption. In this research has been  focused on effect of sparging on  microalgae cell damage. Sparging experiment was carried out by varying gas flow rate between 0.59 to 5.13 L.min-1 with a sparger made from needle inserted to a piece of silicon. The needle was used with diameter 0.4 to 1.2 mm and 1-9 needles. With this variables resulted gas entrance velocity between 2.56-104 m.s-1. The cell death rate constant (kd) was calculated by loss of cell viability in time using Coulter counter and Flowcytometer. From the experiments resulted gas entrance velocity was main cause for cell damagae. The small bubble was more detrimental than bigger size of bubble. Bubble rising as like in animal cell culture was no effect to detrimental cell.Keywords : D. tertiolecta, cell death rate constant, gas entrance velocity

Statistical study of fluctuation of gas flow rate in caps in fluidized-bed processing units

1982 ◽  
Vol 43 (3) ◽  
pp. 949-951
Author(s):  
A. P. Baskakov ◽  
V. G. Tuponogov ◽  
N. F. Filippovskii
Keyword(s):  
Fluidized Bed ◽  
Flow Rate ◽  
Gas Flow ◽  
Statistical Study ◽  
Gas Flow Rate
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