Design of Venturi-tube gas distributors for bubble-type reactors

1984 ◽  
Vol 49 (9) ◽  
pp. 1939-1948 ◽  
Author(s):  
Milan Rylek ◽  
Jindřich Zahradník
Keyword(s):  
Experimental Data ◽  
Gas Holdup ◽  
Venturi Tube ◽  
Design Parameters ◽  
Dispersion Characteristics ◽  
Liquid Circulation ◽  
Bed Porosity ◽  
Gas Distributor ◽  
Liquid Dispersion

The effect of individual parts of a Venturi-tube gas distributor on quality of the gas-liquid dispersion formed was studied in a bubble-type reactor with forced liquid circulation. Gas holdup (bubble-bed porosity) was used as the dispersion characteristics, type and geometry of nozzles, suction chamber arrangement, and dimensions of the mixing tube and diffuser were chosen as variable design parameters. Experimental data of gas holdup presented in dependence on the rate of energy dissipation in the place of dispersion formation characterized then the dispersion efficiency of the Venturi tube at given conditions. Recommendations for design of Venturi-tube gas distributors are presented based upon the results of the study.

Hydrodynamic characteristics of gas-liquid beds in contactors with ejector-type gas distributors

1982 ◽  
Vol 47 (7) ◽  
pp. 1939-1949 ◽  
Author(s):  
Jindřich Zahradník ◽  
František Kaštánek ◽  
Jan Kratochvíl ◽  
Milan Rylek
Keyword(s):  
Energy Dissipation ◽  
Energy Dissipation Rate ◽  
Gas Holdup ◽  
Nozzle Geometry ◽  
Hydrodynamic Characteristics ◽  
Gas Distributor ◽  
Liquid Dispersion ◽  
Interfacial Mass Transfer ◽  
Ejector Nozzle ◽  
Nozzle Type

The effect of ejector-nozzle geometry on gas holdup and on the rate of interfacial mass transfer characterized by values of kLa was studied in a tower reactor with ejector-type gas distributor. It has been established that both gas holdup and kLa values are, in contactors of this type, unambiguously determined by the rate of energy dissipation in the place of gas-liquid dispersion formation i.e. in the ejector. No effect of nozzle type and geometry was observed on the character of dependences of gas holdup and kLa on the energy dissipation rate and consequently on the values of coefficients of empirical exponential-type relations used for experimental data correlation.

scholarly journals PREPARATION OF WOOD FIBER SEMI-FINISHED PRODUCTS IN KNIFE MACHINES OF VARIOUS MODIFICA-TION

2020 ◽  
pp. 459-466
Author(s):  
Natal'ya Geral'dovna Chistova ◽  
Venera Nurullovna Matygulina ◽  
Yuri Davydovich Alashkevich
Keyword(s):  
Experimental Data ◽  
Regression Models ◽  
Wood Fiber ◽  
Wood Pulp ◽  
Design Parameters ◽  
Grinding Process ◽  
Technological Parameters ◽  
Grinding Machines ◽  
Qualitative Characteristics

In this paper, we consider the results of a study of the influence of the design and technological parameters of grinding machines of various modifications on the quality of wood pulp. According to the results of processing multifactor experiments implemented according to the second-order B-plan, a mathematical description was obtained of the dependence of the degree of grinding of pulp on the gap between the grinding disks, wear of the segments, the rotational speed of the lower screw and the concentration of pulp. The obtained regression models are adequate to the process and can be applied in practice for predicting the qualitative characteristics of wood pulp depending on the parameters of the grinding process. Analyzing the obtained experimental data, it can be noted that such factors as the state of the surfaces of grinding disks, the gap between them and the concentration of wood fiber have the greatest influence on the degree of grinding of the mass. Evaluation of graphical dependencies allows you to determine the extent to which you can vary the operating and design parameters of the grinding process to obtain wood fiber with the required grinding quality.

Орошение томата F1 Донской в открытом грунте Московской области

2019 ◽  
Author(s):  
D.I. Engalychev ◽  
N.A. Engalycheva ◽  
A.M. Menshikh
Keyword(s):  
Experimental Data ◽  
Agricultural Technology ◽  
Tomato Fruits ◽  
River Floodplain ◽  
Yield And Quality ◽  
Open Ground ◽  
Alluvial Meadow ◽  
Standard Production ◽  
Moscow River

Представлены экспериментальные данные о влиянии капельного орошения на урожайность и качество плодов томата при выращивании культуры в открытом грунте Московской области. На плодородных аллювиальных луговых почвах Москворецкой поймы при соблюдении агротехники без орошения в среднем за три года исследований в полевых условиях получена урожайность томата F1 Донской 31,9 т/га, с орошением 48,5 т/га, в т.ч. стандартной продукции 42,6 т/га.The article presents experimental data on the effect of drip irrigation on the yield and quality of tomato fruits when growing crops in open ground of the Moscow Region. On fertile alluvial meadow soils of the Moscow river floodplain, with the observance of agricultural technology without irrigation, the field yield of tomato hybrid F1 Donskoi on average for three years of research was 31.9 t/ha, with irrigation 48.5 t/ha, incl. standard production 42.6 t/ha.

DIAGNOSING QUALITY OF FRICTION SYSTEMS OF MECHANISMS OF DEVICES

2019 ◽  
Vol 1 (7) ◽  
pp. 10-13
Author(s):  
D. Yu. Ershov ◽  
I. N. Lukyanenko ◽  
E. E. Aman
Keyword(s):  
Surface Defects ◽  
Diagnostic Methods ◽  
Design Parameters ◽  
Diagnostic Model ◽  
Mechanical Assemblies ◽  
Local Defects ◽  
Relationship Of ◽  
The Relationship ◽  
Production And Operation

The article shows the need to develop diagnostic methods for monitoring the quality of lubrication systems, which makes it possible to study the dynamic processes of contacting elements of the friction systems of instrument mechanisms, taking into account roughness parameters, the presence of local surface defects of elements and the bearing capacity of a lubricant. In the present article, a modern diagnostic model has been developed to control the quality of the processes of production and operation of friction systems of instrument assemblies. With the help of the developed model, it becomes possible to establish the relationship of diagnostic and design parameters of the mechanical system, as well as the appearance of possible local defects and lubricant state, which characterize the quality of friction systems used in many mechanical assemblies of the mechanisms of devices. The research results are shown in the form of nomograms to assess the defects of the elements of friction mechanisms of the mechanisms of the devices.

Effect of gas distributor on gas–liquid dispersion and mass transfer characteristics in stirred tank

2019 ◽  
Vol 145 ◽  
pp. 314-322 ◽  
Author(s):  
Baoqing Liu ◽  
Qing Xiao ◽  
Ning Sun ◽  
Pengfei Gao ◽  
Fangyi Fan ◽  
...  
Keyword(s):  
Mass Transfer ◽  
Stirred Tank ◽  
Transfer Characteristics ◽  
Gas Distributor ◽  
Liquid Dispersion

Research on the Optimal Design Method of the Main Components for the Wheelchair Pickup

2013 ◽  
Vol 791-793 ◽  
pp. 799-802
Author(s):  
Ya Ping Wang ◽  
H.R. Shi ◽  
L. Gao ◽  
Z. Wang ◽  
X.Y. Jia ◽  
...  
Keyword(s):  
Parametric Design ◽  
Design Method ◽  
Basic Function ◽  
Design Parameters ◽  
Algorithm Optimization ◽  
Optimization Analysis ◽  
Research Designs ◽  
Optimal Design Method ◽  
Main Components

With the increasing of the aging of population all over the world, and With the inconvenience coming from diseases and damage, there will be more and more people using the wheelchair as a tool for transport. When it cant be short of the wheelchair in the daily life, the addition of the function will bring the elevation of the quality of life for the unfortunate. Staring with this purpose, the research designs a pickup with planetary bevel gear for the wheelchair. After determining the basic function of the wheelchair aids, the study determines the design parameters by using the knowledge of parametric design and completes the model for the system with Pro/E, on the other hand, it completes key components optimization analysis which is based on genetic algorithm optimization.

Research on the Reliability of Box for Gear Test Bed

2011 ◽  
Vol 121-126 ◽  
pp. 1744-1748
Author(s):  
Xiang Yang Jin ◽  
Tie Feng Zhang ◽  
Li Li Zhao ◽  
He Teng Wang ◽  
Xiang Yi Guan
Keyword(s):  
Power Flow ◽  
Dynamic Performance ◽  
Three Dimensional ◽  
Design Parameters ◽  
The Finite Element Method ◽  
Test Bed ◽  
Kinematics Simulation ◽  
Beveloid Gears ◽  
Overall Performance

To determine the efficiency, load-bearing capacity and fatigue life of beveloid gears with intersecting axes, we design a mechanical gear test bed with closed power flow. To test the quality of its structure and predict its overall performance, we establish a three-dimensional solid model for various components based on the design parameters and adopt the technology of virtual prototyping simulation to conduct kinematics simulation on it. Then observe and verify the interactive kinematic situation of each component. Moreover, the finite element method is also utilized to carry out structural mechanics and dynamics analysis on some key components. The results indicate that the test bed can achieve the desired functionality, and the static and dynamic performance of some key components can also satisfy us.

scholarly journals Effect of Surfactants on Gas Holdup in Shear-Thinning Fluids

2017 ◽  
Vol 2017 ◽  
pp. 1-7 ◽  
Author(s):  
Shaobai Li ◽  
Siyuan Huang ◽  
Jungeng Fan
Keyword(s):  
Experimental Data ◽  
Liquid Phase ◽  
Sodium Dodecyl ◽  
Shear Thinning ◽  
Gas Holdup ◽  
Bubble Columns ◽  
Gas Velocity ◽  
Shear Thinning Fluids ◽  
Liquid Surface Tension ◽  
Superficial Gas Velocity

In this study, the gas holdup of bubble swarms in shear-thinning fluids was experimentally studied at superficial gas velocities ranging from 0.001 to 0.02 m·s−1. Carboxylmethyl cellulose (CMC) solutions of 0.2 wt%, 0.6 wt%, and 1.0 wt% with sodium dodecyl sulfate (SDS) as the surfactant were used as the power-law (liquid phase), and nitrogen was used as the gas phase. Effects of SDS concentration, rheological behavior, and physical properties of the liquid phase and superficial gas velocity on gas holdup were investigated. Results indicated that gas holdup increases with increasing superficial gas velocity and decreasing CMC concentration. Moreover, the addition of SDS in CMC solutions increased gas holdup, and the degree increased with the surfactant concentration. An empirical correlation was proposed for evaluating gas holdup as a function of liquid surface tension, density, effective viscosity, rheological property, superficial gas velocity, and geometric characteristics of bubble columns using the experimental data obtained for the different superficial gas velocities and CMC solution concentrations with different surfactant solutions. These proposed correlations reasonably fitted the experimental data obtained for gas holdup in this system.

A Cyclic Plasticity Modeling for Uniaxial and Multiaxial Ratcheting Simulation of Austenitic Steel

2012 ◽  
Author(s):  
Salim Meziani ◽  
Lynda Djimli
Keyword(s):  
Experimental Data ◽  
Stainless Steel ◽  
Constitutive Model ◽  
Data Base ◽  
Good Choice ◽  
Cyclic Plasticity ◽  
Strain History ◽  
Material Parameters ◽  
Plastic Shakedown

The first objective of this paper investigates the influence of the previous strain history on ratcheting of the 304 L stainless steel on ambient temperature. The identification is done using the Chaboche constitutive model. New tests were performed where different strain-controlled histories have been applied prior to ratcheting tests. It is demonstrated that under the same conditions, one can observe ratcheting, plastic shakedown or elasticity according to the prior strain-controlled history. The second objective points out the correlation between the experimental data base devoted to the identification of the material parameters and the quality of the predictions in cyclic plasticity. The results suggest that the choice of the tests should be closely linked to the capabilities of the model. In particular, the presence of non proportional strain-controlled tests in the data base may be not a good choice if the model itself is not able to represent explicitly such a character.

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