Flow Properties Of Solids Research Articles

Drug Technology in Hunting Practice

Abstract Antiparasitic therapy in living ratites is based on the right dose and efficacy is only when the drug is pharmaceutically stable and safe. Ivermectin is considered to be the most widely used drug in the treatment of parasitosis in ruminants worlwide. For these reasons, in our study, we focused on the pharmaceutical investigation of ivermectin by SEM analysis of its powder particle shape and size, flow properties of solids (angle of repose, compressibility index, Hausner ratio) and zeta potential.

Predicting the silo discharge behavior of wood chips - A choice of method

Storage, transfer and feeding of biomass particulate solids often cause problems at biobased production sites. Irregular flow and blockage in storage units create supply uncertainties and production stops with economically detrimental consequences. Despite the industrial awareness of these problems, reliable analysis methods for prediction of larger particle size biomass bulk solid flow properties are lacking.In this study, the silo discharge and arching behavior of different size fractions of wood chips from beech and pine forest residues were analyzed, utilizing a parallelepiped bin and a wedge-shaped hopper. The wood chip assortments were analyzed by Schulze shear testing, angle of repose, Hausner ratio, and bulk density. Obtained material data was utilized to build regression models versus the experimentally obtained critical hopper outlet size for material flow.The best fitted regression model for explaining the critical hopper outlet size was obtained with an equation with linear proportionality to the hopper half opening angle and to the square of the angle of repose. This regression model was well fitted to both assortments and over the whole particle size range, indicating robustness and that the proposed model can be useful to diagnose the silo discharge behavior for broad ranges of wood chip materials. The extension of the results of this paper to larger scale silos requires further investigation.

Properties of an inclined standpipe for feeding solids into a bubbling fluidized-bed

Flow properties of solids in an inclined standpipe were investigated while the solid particle was fed to the bottom of a bubbling fluidized bed (diameter 0.1m, 1.34m tall) via the standpipe and discharged out of the bed through the overflow exit. A group of K-based CO2 adsorbent particles was used as solids. The pressure drop of the fluidized bed, the height of solids bed in the standpipe, and flow rate of gas bypassing the fluidized bed through the standpipe were measured at room temperature and pressure as varying the fluidizing gas velocity, solids flow rate, and height of the overflow exit of fluidized solids. The pressure drop of the fluidized bed, the height of the solids bed in the standpipe, and the ratio of gas bypassing through the standpipe to the total gas in flow rate decreased with increasing the fluidizing gas velocity. Both the pressure drop of the fluidized bed and the height of the solids bed in the standpipe increased a little with the solids feed rate. The effect of the solids feed rate on the flow rate of gas bypassing through the standpipe could be ignored. The pressure drop of the fluidized bed and the height of the solids bed in the standpipe increased as the height of the overflow exit for solids increased in the fluidized bed. However, the effect of the height of the overflow exit on the flow rate of gas bypassing through the standpipe was negligible. Correlations on the pressure drop of the fluidized bed, the height of the solids bed in the standpipe, and the flow rate of gas bypassing through the standpipe were proposed successfully.

Prediction of particle distribution and particle impact erosion in inclined cavities

The cavity is one of the basic structures in pipe systems, but it is vulnerable in erosive environments. Cavities can occur in various places throughout industrial processes, each making a difference in the distribution of erosion. The aim of this study is to investigate gas (air)-solid flow properties and erosion characteristics in inclined cavities. A two-way URANS (SST)-DPM method was adopted. The simulations were carried out for three Stokes numbers (St), eight height differences (h) from 0 to 0.8H, and ten inclination angles from 0° to 90°. Results indicated that gas flow properties change little with inclination angle (φ). However, a variation in φ resulted in a change in the distribution of the particles and erosion on the aft wall, especially when St were 1.2 and 9.1. The particle number (N) in the zone 10mm from the aft wall decreases linearly with φ for both previously mentioned St, and the slopes of N-φ curves increase exponentially with h. The maximum erosion rate (Em) on the aft wall also decreases linearly with φ for the St of 1.2, and the negative slope of Em-φ curve follows an exponentially increasing with h. But Em decreases quadratically with φ when St is 9.1, and the function coefficient appears a Gaussian relationship with h.

Pseudophysical Compartment Modeling of an Industrial Rotary Dryer with Flighted and Unflighted Sections: Solids Transport

A novel pseudophysical compartment model describing the solids transport within a case-study cocurrent industrial rotary dryer is presented. The model is novel and distinctive because it combines both multiscale partial differential equation and ordinary differential equation modeling techniques to represent the five separate sections occurring within the dryer, including both flighted and unflighted sections. The solid phase in the unflighted sections was modeled as an axial dispersed plug flow system. The solid transport in the flighted sections was partitioned into the usual series–parallel formulation of well-mixed tanks representing airborne and flight-borne solids. Parameter values and compartment numbers were estimated using mechanistic geometric modeling, dryer design loading constraints, and solids flow properties. Geometric modeling enabled the effects of internal scaling arising from solid materials sticking to the internal walls of the dryer to be accounted for in a realistic manner. Industria...

PHYSICAL AND AERODYNAMIC PROPERTIES OF FLAXSEEDS FOR PROPER SEPARATION BY USING AIRSTREAM

ABSTRACT This study aimed to develop simple empirical equations to predict flaxseeds properties. The first part of the present study deals with the physical, aerodynamic and solid flow properties of flaxseeds which were evaluated as a function of change in moisture content from 8.60 to 23.90% dry basis (d.b.); the dimensions of the length, width and thickness varied from 4.14 to 4.32 mm, 2.03 to 2.13 mm and 0.88 to 0.93 mm, respectively. As the moisture content increased from 8.60 to 23.90% d.b., the bulk density, true density and porosity were found to decrease from 46.65 to 44.89 kg/m3, 1,244 to 1,176 kg/m3 and 46.65 to 44.89%, whereas angle of repose and terminal velocity were found to increase from 27.6 to 35.80 and 2.46 to 3.56 m/s, respectively. The static coefficient of friction on various surfaces, namely plywood, stainless steel, galvanized iron, iron and internal also increased linearly with the increase in moisture content. The results of the experimental investigation may help to optimize some engineering parameters of separation equipment. The present work was carried out to separate flaxseed from light impurities (chaff, other debris from threshed flaxseed since the introduction of harvesting machine). It is difficult to separate seeds from straw and other foreign materials by using primary separation equipment. The difficulty comes from the narrow size and shape, angle for both of natural slope and friction between foreign materials and seeds. The second part was carried out on a series of experiments to specify the optimum conditions of separating operations which insure the highest grade of separation efficiency with minimum losses. Pneumatic separation equipment was manufactured and tested under different combinations of the following factors: airstream velocity, feed rateand sample moisture content. The performance of the equipment was evaluated by using the indices separation efficiency and percentage of seed losses. The results of the equipment performances showed that the combinations of airstream velocity, feed rate and sample moisture content affected significantly the separation efficiency and grain losses. Airstream velocity of 2–6 m/s combined with 8.5 kg/h feed rate and 8.6% moisture content can be considered the most favorable combination values of these variables. They gave the highest grades of separation efficiency and the minimum grain losses. PRACTICAL APPLICATIONSThere are several applications of the physical properties data. Physical attributes and aerodynamic properties are required in the design of combines as well as cleaning and grading equipment. Information about solid flow properties is needed to design handling equipment. Physical properties data are needed for the development of sensors to control machines and processes, as well as detect quality. Physical properties of crops are requisite for better design of storage and ventilation system. The physical properties that we are investigating include: (1) physical attributes such as dimensions and densities; (2) aerodynamic properties such as terminal velocity and drag coefficient; and (3) solid flow properties like angles of repose and internal friction.

Aerodynamic and solid flow properties for flaxseeds for pneumatic separation by using air stream

This study aimed to develop simple empirical equations to predict flaxseeds properties. The first part of the present study deals with the physical, aerodynamic and solid flow properties of flaxseeds which are evaluated as a function of change in moisture content from 8.60% to 23.90% dry basis (d.b.), the dimensions of the length, width and thickness varied from 4.14 to 4.32 mm, 2.03 to 2.13 mm and 0.88 to 0.93 mm, respectively. As the moisture content increased from 8.60% to 23.90% d.b., the bulk density, true density and porosity were found to decrease from 46.65 to 44.89 kg / m 3 ; 1244 to 1176 kg / m 3 and 46.65 % to 44.89%, whereas angle of repose and terminal velocity were found to increase from 27.60 to 35.80 and 2.46 to 3.56 m / s, respectively. The static coefficient of friction on various surfaces, namely, plywood, stainless steel, galvanized iron, iron and internal also increased linearly with the increase in moisture content. The results of the experimental investigation may help to optimize some engineering parameters of separation equipment. The second part was carried out on a series of experiments to specify the optimum conditions of separating operation which insure the highest grade of separation efficiency with minimum losses. Pneumatic separation equipment was manufactured and tested under different combinations of the following factors: air stream velocity, feed rate and sample moisture content. The performance of the equipment was evaluated by using the indices separation efficiency and percentage of seed losses. The results of the equipment performances showed that the combinations of air stream velocity, feed rate and sample moisture content affected significantly the separation efficiency and grain losses. Air stream velocity of 2–6 m/s combined with 8.5 kg/h. feed rate and 8.6% moisture content can be considered the most favorable combination values of these variables. They gave the highest grades of separation efficiency and the minimum grain losses. Keywords: f laxseed , p hysical property, a erodynamic s, s olid flow properties, p neumatic separation DOI: 10.3965/j.issn.1934-6344.2009.0 4 .0 31 -0 45 Citation: Ayman Hafiz Amer Eissa. a erodynamic and solid flow properties for flaxseeds for pneumatic separation by using air stream . Int J Agric & Biol Eng, 2009; 2( 4 ): 31 <span style=line-height: 140%; font-family:

Preliminary Assessment of a Simple Method for Evaluating the Flow Properties of Solid Recovered Fuels

The increasing interest in combustion of solid recovered fuels (SRF), whose physical properties may significantly differ from those of conventional solid fuels, draws attention to the handling of these materials. In this article a simple method for evaluating particulate solids flow properties based on a solid extrusion procedure is assessed. The effects of the main geometrical parameters of the tester and of the testing operating condition are investigated. Results are critically discussed by comparing them with the flow properties evaluated in a Schulze ring shear tester.

Numerical simulation of fluid–particle hydrodynamics in a rectangular spouted vessel

A three-dimensional, Eulerian simulation was developed to describe isothermal, two-phase flow of the continuous (water) and dispersed (solid particles) phases in a rectangular spouted vessel. The mass and momentum conservation equations for each phase were solved using the finite volume technique, which treats each phase separately, while coupling them through drag, turbulence, and energy dissipation due to particle fluctuations. Particle–particle interactions via friction were also included. Model results in terms of fluid and solid flow properties, such as volume fraction, pressure and velocity fields were validated with experimental results obtained in a rectangular spouted vessel apparatus. The effects of inlet jet velocity, particle loading, particle diameter, and density on solids volume fraction distributions, pressure field, and particle recirculation rate were investigated with the resultant model. The model is shown to be able to successfully predict the experimentally observed phenomenon of particle “choking” where the particle recirculation rate remains constant with increasing particle loading once a “critical loading” is achieved. Simulations also confirmed the manner in which particle size, density, loading, and inlet jet velocity affect solids circulation. This investigation was motivated by the need for hydrodynamic information related to the development of spouted bed electrolytic reactors (SBER) as moving bed cathodes for metals recovery.

Model-Based Optimization of Particle Size Distribution in Batch-Cooling Crystallization of Paracetamol

The control objectives of batch crystallization processes are often defined in terms of particle size distribution (PSD), or properties related to the PSD, viz. average particle size, product filterability, dry solids flow properties, etc. To achieve these control objectives, a constrained nonlinear model-based optimization strategy has been adopted. This involves the detailed modeling of batch crystallization including model validation and parameter estimation, on-line monitoring of supersaturation and PSD, and the application of optimization strategies. A deterministic population balance model accounting for solution thermodynamics, crystal growth, and nucleation has been developed. State estimation is achieved by the on-line monitoring of temperature, concentrations in the liquid phase, particle density, and PSD. For this purpose, the focused beam reflectance measurement (FBRM) provides an on-line, in-situ information of crystal size and particle concentration in the form of a chord length distribution...

Analysis and modelling of solid flow in a closed loop circulating fluidized bed with secondary air injection

The goal of the work presented here is to analyse the influence of secondary air on the solid circulating phenomenon in a closed loop circulating fluidized bed (CFB; by “closed loop”, we mean a free solid circulating system as shown in one of the figures). Variables of such a system are “gas velocity”, gas distribution ratio between “primary” and “secondary” levels and solid inventory. Solid circulating flow rate, solid mean concentration in the column and local gas–solid flow properties are measured for a large set of operating conditions. The analysis of results obtained lets us develop a simple model for estimating the solid circulating flow rate in industrial CFB. In this model, the suspension flow pattern is divided into three components: “dilute”, “cluster” and “wall flow” phases. The velocity and the concentration of each phase, as well as the solid flow rate, are estimated by means of a simple force balance including some basic hypothesis. The results obtained show that the model fits experimental values quite well. However, it is imprecise for low values of air velocity (here <1.5 m/s).

A new laboratory method to characterize the sticking properties of free-flowing solids

The flow properties of solids, both powders and granulated materials, depend on moisture and temperature. If a free-flowing solid with a given moisture content is heated beyond a certain temperature, its flow properties change abruptly, as the particles begin to stick to each other once this temperature is reached. This temperature is called the sticking point. It declines with increasing moisture content in a given solid. The sticking behavior of a solid in the presence of the solvent must be known, as must its thermal decomposition temperature and the solid–vapor sorption isotherm, in order to design a drying unit for the solid that operates in a safe and reliable way. The operational diagram of a dryer calculated from these system properties is explained in detail. The sticking behavior of solids is measured with a newly developed laboratory apparatus and may thus be determined significantly faster and more reliably than with previous methods. A rotating sample of the free-flowing solid with a known moisture content—either water or solvent—is subjected to a temperature program. The motion of the product is observed with an optical sensor and recorded. The sticking point is the temperature at which the product assumes a different flow behavior, thus causing significant change to the sensor signal.

An alternative presentation of the design parameters for mass flow hoppers

The procedure for determining the critical hopper outlet dimension and wall slope for mass flow hoppers by the Jenike method is well established and documented. However, existing presentations relating the bulk solid flow properties of effective angle of internal friction and the kinematic angle of wall friction with the hopper wall slope and flow factor for mass flow are often inconvenient for manual use and present difficulties when included in design programs suitable for microcomputers. This paper details an alternative presentation of the original Jenike flow factor charts. These alternative charts have been abbreviated to display only the critical design values in the border region between mass flow and funnel flow. The charts eliminate the need for imprecise parameter interpolations by displaying the required design parameters in the form of contours of constant wall slope and critical flow factor as a function of the effective angle of internal friction and the kinematic angle of wall friction. An illustrative example is provided to demonstrate the inherent advantages of this presentation for the evaluation of mass flow hopper geometries.

Moving‐bed solids flow in an inclined pipe leading into a fluidized bed: Part II. The solids flow properties

AbstractThe purpose of part II of this paper is to theoretically analyze and experimentally examine moving‐bed solids flow in an inclined pipe connecting a fluidized bed and a solids storage vessel. The macroscopic momentum balance equation is simplified and applied to the present system. A friction factor correlation is developed. Based on the flow curves constructed, we found that the power law model is suitable for describing moving‐bed solids flow.

Modeling flow of bulk solids

One approach to problems of gravity flow of bulk solids such as catalysts, powders, limestone and powdered lime has been to study the flow of such materials in scale models. Such observations can be helpful only when the scale-up parameters are understood. The theory of flow of bulk solids provides these scale-up parameters. The purpose of this paper is to discuss each of these parameters, to list the information about the solids flow properties necessary for meaningful small-scale tests, and to show examples of effective scale-up.