scholarly journals Classification of bulk material from the gas flow in a device with coaxially arranged pipes

2020 ◽  
Vol 193 ◽  
pp. 01056
Author(s):  
V. E. Zinurov ◽  
A. V. Dmitriev ◽  
M. A. Ruzanova ◽  
O. S. Dmitrieva
Keyword(s):  
Silica Gel ◽  
Gas Flow ◽  
Bulk Material ◽  
Gas Flows ◽  
Dusty Gas

The paper deals with the problem of classification of bulk material, based on silica gel, larger than 30 µm, from dusty gas flow. In order to solve this problem, the design of a classifier with coaxially arranged pipes is proposed. According to the conducted studies, it is more efficient to use a classifier with an inner conical pipe to solve the problems of separating the particles from the gas flows of various sizes, since a greater value is achieved for the centrifugal, inertial, gravitational and other forces acting on the dusty flow, that contribute to knocking the particles out of its structure, than in a classifier with a cylindrical inner pipe. On average, the efficiency of a classifier with a conical inner pipe is by 35.3% higher than that of a classifier with a cylindrical inner pipe. Classification of particles of bulk material, based on silica gel, larger than 30 µm from the dusty gas flows is solved most effectively by using a classifier with a conical inner pipe and hd parameter of 50 mm and a classifier with a cylindrical inner pipe and hd parameter of –10 mm.

Detoxification of Heterophase Wastes Using Controlled Gas-Contact Technologies

2019 ◽  
Vol 23 (2) ◽  
pp. 4-9
Author(s):  
K.L. Chertes ◽  
D.V. Zelentsov ◽  
O.V. Tupitsyna ◽  
V.N. Pystin ◽  
O.I. Kondratyev
Keyword(s):  
Contaminated Soils ◽  
Gas Flow ◽  
Main Element ◽  
Gas Flows ◽  
Natural Conditions ◽  
Aeration System ◽  
Scope Of Application ◽  
Water Saturated ◽  
Artificial Pressure

The methods of natural and forced supply and removal of gases in arrays of heterophase wastes of various nature used in controlled gas-contact detoxification technologies are considered. The classification of the main parameters of the waste is divided into groups – mechanical, filtration, temperature, chemical and biological. Based on the analysis of the parameters, generalized criteria for determining the scope of application of gas-contact technologies are proposed. The implementation of gas flow control technology is described, an example of which are complexes biothermal treatment of oil-contaminated soils. The main element of this complex is the combined aeration system, which is necessary to increase the rate of biochemical decomposition of hardly decomposable hydrocarbons in oil waste. The results of the experiment conducted in the framework of the calculation and design of the aeration system due to the insufficiency of the initial data are presented. Shown the need to create a general theoretical model of controlled gas flows in porous, water-saturated, hard plastic media, both in natural conditions and under the action of an artificial pressure drop.

Breathing Systems

2011 ◽  
Author(s):  
Patrick Magee ◽  
Mark Tooley
Keyword(s):  
Gas Flow ◽  
Anaesthetic Machine ◽  
Breathing System ◽  
Gas Flows ◽  
Co2 Absorption ◽  
Volatile Agent ◽  
Expiratory Valve ◽  
And Function ◽  
Expiratory Limb

An anaesthetic breathing system is a means of transferring the breathing gas mixture from the anaesthetic machine common gas outlet to the patient. It is also the means of transferring the exhaled gas from the patient to the outside world, usually via a scavenging system. Alternatively, after the carbon dioxide is absorbed from the exhaled gas, the unused fresh gas components of the exhaled gas are recirculated back to the patient. In general, a breathing system consists of a fresh gas limb, an inspiratory and expiratory limb, an expiratory valve, a reservoir bag and it may also consist of one or more unidirectional valves and a CO2 absorber. The simpler devices have fewer components and usually involve some rebreathing of expiratory gas, depending on the level of fresh gas flow. The ability to minimise rebreathing at as economical a fresh gas flow as possible is a measure of the breathing system’s efficiency. Depending on the precise design of the breathing system, such efficiency will vary depending on whether the patient is breathing spontaneously or is undergoing controlled artificial ventilation (see Chapter 26). The more complex systems ensure minimum rebreathing by the use of unidirectional valves and CO2 absorption systems; in this way, the additional complexity allows more economical use of fresh gas and volatile agent. The systems that use higher fresh gas flows (FGF) and involve some rebreathing were classified in 1954 by Professor Mapleson, according to their behaviour in terms of the FGF requirement to prevent CO2 rebreathing [Mapleson 1954]. At the time and for three decades beyond, they were the most popular breathing systems in UK anaesthetic practice. The Mapleson Classification of rebreathing systems is shown in Figure 25.1. Their design lends their structure and function to mathematical analysis [Dorrington 1989]. The Magill breathing system was invented by Sir Ivan Whiteside Magill in the early twentieth century. As shown in Figure 25.1A and Figure 25.2, the system is characterised by having the expiratory valve close to the patient and the fresh gas inflow at a distance from the patient, but close to the reservoir bag. Because of this particular configuration, the system is very economical in spontaneous breathing.

scholarly journals Simulation of the kinematics and gas dynamics of the centrifugal dispersion stand

2021 ◽  
Vol 2094 (4) ◽  
pp. 042046
Author(s):  
A E Zverovshchikov ◽  
G S Bolshakov
Keyword(s):  
Powder Material ◽  
Gas Dynamics ◽  
Gas Flow ◽  
Heterogeneous Medium ◽  
Deposition Process ◽  
Gas Flows ◽  
Working Chamber ◽  
Operational Analysis ◽  
Centrifugal Dispersion

Abstract The article studies the kinematics and gas dynamics of the centrifugal dispersion stand for spheroidizing hard alloy materials. When studying the process of centrifugal spraying on an experimental setup, it was found that the behavior of particles in the volume of the dispersion chamber is determined by the aerodynamics of gas flows formed in the working chamber. It is assumed that under the influence of gas flows, a spontaneous classification of the particles of the medium occurs, determined by the size of the latter. To study the trajectory of movement of particles of powder material in the working chamber and the deposition process, a gas-dynamic model of a centrifugal dispersion unit in the SolidWorks FlowSimulation application is proposed. The developed model of the centrifugal dispersion unit showed the possibility of operational analysis of the behavior of the gas flow, the trajectory of the particles of the powder material and the temperature of the obtained powder material, depending on the design and technological factors. The simulation results allow one to determine the principles of separation of a heterogeneous medium of particles into fractions, directly at the installation for the implementation of the method.

Focusing of inertial particles after the shock-wave intersection point

2007 ◽  
Vol 5 ◽  
pp. 145-150
Author(s):  
I.V. Golubkina
Keyword(s):  
Shock Wave ◽  
Mass Concentration ◽  
Gas Flow ◽  
Intersection Point ◽  
Plane Shock ◽  
Inertial Particles ◽  
Dusty Gas ◽  
Focusing Effect ◽  
Aerodynamic Focusing ◽  
Particle Mass Concentration

The effect of the aerodynamic focusing of inertial particles is investigated in both symmetric and non-symmetric cases of interaction of two plane shock waves in the stationary dusty-gas flow. The particle mass concentration is assumed to be small. Particle trajectories and concentration are calculated numerically with the full Lagrangian approach. A parametric study of the flow is performed in order to find the values of the governing parameters corresponding to the maximum focusing effect.

Modeling of dusty gas flows due to plume impingement on a lunar surface

2021 ◽  
Vol 33 (5) ◽  
pp. 053307
Author(s):  
Arun K. Chinnappan ◽  
Rakesh Kumar ◽  
Vaibhav K. Arghode
Keyword(s):  
Lunar Surface ◽  
Gas Flows ◽  
Dusty Gas

scholarly journals Thermochemical Heat Storage in a Lab-Scale Indirectly Operated CaO/Ca(OH)2 Reactor—Numerical Modeling and Model Validation through Inverse Parameter Estimation

2021 ◽  
Vol 11 (2) ◽  
pp. 682
Author(s):  
Gabriele Seitz ◽  
Farid Mohammadi ◽  
Holger Class
Keyword(s):  
Numerical Model ◽  
Gas Flow ◽  
Reaction Rate ◽  
Heat Storage ◽  
Bulk Material ◽  
Fixed Bed ◽  
Experimental Results ◽  
Fixed Bed Reactor ◽  
Thermochemical Heat Storage ◽  
Speed Up

Calcium oxide/Calcium hydroxide can be utilized as a reaction system for thermochemical heat storage. It features a high storage capacity, is cheap, and does not involve major environmental concerns. Operationally, different fixed-bed reactor concepts can be distinguished; direct reactor are characterized by gas flow through the reactive bulk material, while in indirect reactors, the heat-carrying gas flow is separated from the bulk material. This study puts a focus on the indirectly operated fixed-bed reactor setup. The fluxes of the reaction fluid and the heat-carrying flow are decoupled in order to overcome limitations due to heat conduction in the reactive bulk material. The fixed bed represents a porous medium where Darcy-type flow conditions can be assumed. Here, a numerical model for such a reactor concept is presented, which has been implemented in the software DuMux. An attempt to calibrate and validate it with experimental results from the literature is discussed in detail. This allows for the identification of a deficient insulation of the experimental setup. Accordingly, heat-loss mechanisms are included in the model. However, it can be shown that heat losses alone are not sufficient to explain the experimental results. It is evident that another effect plays a role here. Using Bayesian inference, this effect is identified as the reaction rate decreasing with progressing conversion of reactive material. The calibrated model reveals that more heat is lost over the reactor surface than transported in the heat transfer channel, which causes a considerable speed-up of the discharge reaction. An observed deceleration of the reaction rate at progressed conversion is attributed to the presence of agglomerates of the bulk material in the fixed bed. This retardation is represented phenomenologically by mofifying the reaction kinetics. After the calibration, the model is validated with a second set of experimental results. To speed up the calculations for the calibration, the numerical model is replaced by a surrogate model based on Polynomial Chaos Expansion and Principal Component Analysis.

Co-Current and Countercurrent Migration of Gas Kicks in “Horizontal” Wells

1999 ◽  
Vol 121 (2) ◽  
pp. 96-101 ◽  
Author(s):  
H. Baca ◽  
J. Smith ◽  
A. T. Bourgoyne ◽  
D. E. Nikitopoulos
Keyword(s):  
Test Section ◽  
Gas Flow ◽  
Gas Injection ◽  
Horizontal Wells ◽  
Gas Flows ◽  
Countercurrent Flow ◽  
Drilling Operations ◽  
Operating Window ◽  
Annular Pipes ◽  
Injection Rates

Results from experiments conducted in downward liquid-gas flows in inclined, eccentric annular pipes, with water and air as the working fluids, are presented. The gas was injected in the middle of the test section length. The operating window, in terms of liquid and gas superficial velocities, within which countercurrent gas flow occurs at two low-dip angles, has been determined experimentally. The countercurrent flow observed was in the slug regime, while the co-current one was stratified. Countercurrent flow fraction and void fraction measurements were carried out at various liquid superficial velocities and gas injection rates and correlated to visual observations through a full-scale transparent test section. Our results indicate that countercurrent flow can be easily generated at small downward dip angles, within the practical range of liquid superficial velocity for drilling operations. Such flow is also favored by low gas injection rates.

Calculation of dusty-gas flow in an inertial scrubber

1996 ◽  
Vol 31 (6) ◽  
pp. 848-853
Author(s):  
Sh. F. Araslanov ◽  
Sh. Kh. Zaripov
Keyword(s):  
Gas Flow ◽  
Dusty Gas

Newtonian flow theory for slender bodies in a dusty gas

1981 ◽  
Vol 108 ◽  
pp. 147-157 ◽  
Author(s):  
R. M. Barron ◽  
J. T. Wiley
Keyword(s):  
Shock Wave ◽  
Gas Flow ◽  
The Body ◽  
Dusty Gas ◽  
Newtonian Theory ◽  
Wedge Surface ◽  
Slender Bodies ◽  
Two Phases ◽  
Flow Variables ◽  
Thin Wedge

Hypersonic small-disturbance theory is extended to consider the problem of dusty-gas flow past thin two-dimensional bodies. The mass fraction of suspended particles is assumed to be sufficiently large that the two-way interaction between particle phase and gas phase must be considered. The system of eight governing equations is further reduced by considering the Newtonian approximation γ → 1 andM∞→ ∞. The Newtonian theory up to second order is studied and the equations are solved for the case of a thin wedge at zero angle of attack. Expressions for the streamlines, dust-particle paths, shock-wave location and all flow variables are obtained. It is seen that the presence of the dust increases the pressure along the wedge surface and tends to bend the shock wave towards the body surface. Other effects of the interaction of the two phases are also discussed.

Sign in / Sign up

Export Citation Format

Share Document