Showing papers in "Particulate Science and Technology in 2003"
TL;DR: In this paper, a series of calculations were performed on experimental data in order to estimate solids friction factor for four types of material conveyed in the fluidized dense-phase flow regime.
Abstract: There have been numerous correlations proposed for determining a solids friction factor ( u s ) for fully suspended (dilute phase) pneumatic conveying. Currently, there are no equivalent correlations that predict u s in nonsuspension dense-phase flows. In dense-phase conveying there are two basic modes of flow: plug/slug flow, which is predominantly based on granular products, and fluidized dense-phase flow, which is more suited to fine powders exhibiting good air retention capabilities. In plug/slug type flow, the stresses between the moving plug of material and the pipe wall dominate the solid-phase frictional losses. In fluidized dense-phase flow the frictional losses are characterized as a mixture of particle-wall and particle-particle losses but are heavily influenced by the gas-solid interactions. In this paper, a series of calculations were performed on experimental data in order to estimate u s for four types of material conveyed in the fluidized dense-phase flow regime. The solids frictional fact...
63 citations
TL;DR: In this article, the axial and radial powder movements during the compaction process were investigated using flat and curved-face punches for the case of single-ended axial strain applications, and the density distributions in microcrystalline cellulose tablets were determined experimentally using a colored layer technique and digital image analysis.
Abstract: The axial and radial powder movements during the compaction process were investigated using flat- and curved-face punches for the case of single-ended axial strain applications. The density distributions in microcrystalline cellulose tablets were determined experimentally using a colored layer technique and digital image analysis. Nondestructive topography measurements were taken to assess the variation in surface roughness of the tablets and relate this to the forming pressure and density distribution. Results showed that the tablets produced were highly nonhomogeneous with high density regions in the "top corners" (adjacent to the moving punch surface) and "middle bottom half" for the flat-face tablets. For instance, at 92.7 MPa, density values were recorded at greater than 1.2 g/cc in the high density regions and greater than 0.6 g/cc in low density regions with regards to experimental results. High density regions were noted in the corners where the powder was in contact with the die wall for the curv...
47 citations
TL;DR: In this article, coal maceral and mineral particles are passed through a separator consisting of two plate electrodes, across which a high voltage is applied, and the positively charged coal particles are separated from the negatively charged mineral particles.
Abstract: In one method of electrostatic beneficiation, pulverized coal is tribocharged by contact with electrically grounded copper. Coal maceral and mineral particles charge with positive and negative polarities, respectively. The charged particles are passed through a separator consisting of two plate electrodes, across which a high voltage is applied, and the positively charged coal particles are separated from the negatively charged mineral particles. The efficiency of separation is dependent upon coal bulk and surface composition, and fineness of grind. Analyses of total sulfur and ash content of the charge-separated particles were used to evaluate beneficiation success of the Illinois No. 6 and Pittsburgh No. 8 coals studied. Two-stage beneficiation demonstrated improved separation. Exposing coal powders to chemical vapors of SO 2 , NH 3 , or acetone prior to beneficiation did not enhance beneficiation.
47 citations
TL;DR: In this article, a simplified discrete element computational model was developed for modeling fabric dynamics in a rotating horizontal drum, where individual pieces of bundled fabric are represented by spherical particles and the simulation results indicate that fill percentage, drum rotation speed, and friction coefficient play significant roles in the fabric bundle dynamics.
Abstract: In order to provide a tool for designing more efficient methods of mixing fabric, a simplified discrete element computational model was developed for modeling fabric dynamics in a rotating horizontal drum. Because modeling the interactions between actual pieces of fabric is quite complex, a simplified model was developed where individual pieces of bundled fabric are represented by spherical particles. This model is essentially a ball mill. The simulations are used to investigate fabric bundle kinematics, the power required to drive the rotating drum, and the power dissipated through normal and tangential contacts. Parametric studies were performed to investigate the effects of fill percentage, baffles, rotation speed, friction coefficient, and coefficient of restitution. The simulation results indicate that fill percentage, drum rotation speed, and friction coefficient play significant roles in the fabric bundle dynamics. For example, the specific drum power increases by a factor of 600% to 800% as the fi...
24 citations
TL;DR: In this article, a simple model for pressure drop calculation has been proposed based on the classical Darcy's equation with some modifications, which is suitable for scaling up to pipe sizes different from those used in laboratory-scale tests.
Abstract: A brief survey has shown that although scaling-up techniques in pneumatic conveying systems have generally been based on laboratory-scale test data, there still exists a divergence of opinions about the right choice of certain basic parameters such as solids friction factor and air friction factor. In this article, a simple model for pressure drop calculation has been proposed based on the classical Darcy's equation with some modifications. A parameter K, called pressure drop coefficient, has been shown to be independent of pipe diameter and hence suitable for scaling up to pipe sizes different from those used in laboratory-scale tests. For each of the bulk material and pipe size combinations used in this study, we calculated the standard deviation of predicted pressure values from the experimental values along the central 45° line passing through the origin; it varied from±165 mbar to a maximum±285 mbar. It has been shown that the model can be used for both horizontal and vertical pneumatic conveying.
23 citations
TL;DR: In this article, a finite element discretization of an assembly of particles is used to analyze the effect of tensile stresses on low ductility particles in die compaction, and it is shown that high friction results in a higher number of particles under tensile principal stresses.
Abstract: Although the average macroscopic stresses are compressive during die compaction, tensile stresses develop locally, and lead to fragmentation in low ductility particles In this article, this phenomenon is analyzed using finite element discretization of an assembly of particles The simulations show that there are two stages in die compaction, an early stage in which increased levels of tensile stresses develop in a number of particles located along discrete load transmission paths, and a second stage where the increasing homogeneity of the stress field leads to a decrease of the number of particles developing tensile principal stresses A comparison between two scenarios with interparticle friction of w =0 and w =05 is presented It is shown that: (1) high friction results in a higher number of particles under tensile stresses especially at low relative density, and (2) the peak fraction of material under high tensile stresses is double for w =05 compared to the frictionless case, and occurs at ~85% ver
22 citations
TL;DR: A brief overview of acoustic emission-based particle monitoring in general and focusing on flange-mounted sensors in the monitoring of particle flow can be found in this article, where the particle velocity can also be evaluated.
Abstract: Acoustic emission (AE) has been used in many applications in the field of particle science and technology. AE sensors have been used in particle concentration measurements both in gas-continuous and oil-continuous flows in the oil and gas industry. To avoid formation sand flowing into pipelines, leading to erosion of valves and in many cases even to complete blockage of the flow of oil and gas, AE sensors are almost exclusively used in sand monitoring and control. These are very often among standard sensors stipulated by the operators of oil and gas production facilities in offshore, on shore, and subsea applications. Special types of sensor design have led to easy mounting of these AE sensors, which are very often clamp-on devices. This article presents a brief overview of AE-based particle monitoring in general and focuses on flange-mounted sensors in the monitoring of particle flow. By using two or more AE sensors located suitably in the process line, the particle velocity can also be evaluated, as is ...
22 citations
TL;DR: New insight is presented into the mechanisms governing the air-core dynamics and particle separation within the hydrocyclone that have been achieved by means of CFD, and the potential for application of tomographic techniques to the challenging verification of high-solids CFD has been demonstrated.
Abstract: Hydrocyclones form an important stage within conveying systems for dewatering or size classification. Over the past few decades they have been subject to significant modeling and experimental investigations. Yet, it is only with modern developments in computational fluid dynamics (CFD) and nonintrusive measurements such as tomography and laser techniques that a proper understanding of the internal flow dynamics is being developed. This paper presents new insight into the mechanisms governing the air-core dynamics and particle separation within the hydrocyclone that have been achieved by means of CFD. In particular, the flow field is identified to be distinctly asymmetric, such that the commonly assumed deterministic and symmetric assumptions of particle separation are inaccurate. In fact, radial particle transport is identified to rely upon the positive correlation of the mean and fluctuating components of radial velocity. The mechanism for air-core development during start-up is also inferred and for the...
21 citations
Abstract: This article presents finite element (FE) calculations of stresses in a silo structure caused by the loads exerted by the discharging material. Two different conical hoppers were studied, concentric and eccentric withdrawal. The eccentricity was introduced by the change of the outlet position towards one side of the hopper, and the influence of this modification is presented. The simulation of silo flow with the common Drucker-Prager model for bulk solids was performed in order to obtain the wall pressure distribution. All FE calculations are carried out with aid of the commercial software ABAQUS. Significant differences are found in the hopper-wall stresses between the concentric and eccentric cases. Strong bending actions appear in the eccentric hopper, and they are influenced by stiffness of the hopper/cylinder junction.
21 citations
Abstract: Experimental investigations indicate that placing a passive insert in a silo is a method for influencing the discharging flow pattern. These inserts have consisted of an inverted cone, a cone-in-cone, and a double cone. However, providing unequivocal guidelines on where those inserts should be placed for an optimum effect has not been possible experimentally. A numerical approach was therefore developed to predict material flow in the presence of such inserts in silos. Simulation results showed that all these inserts could make a funnel-flow silo perform in mass flow under certain circumstances if positioned correctly. The inserts should be installed at higher levels close to the transition rather than at lower positions close to the outlet, especially with the cone-in-cone insert and the inverted inserts; the maximum diameter of the inverted cone and the double cone should, however, be below the transition of the silo. Among the three inserts investigated, the double cone appeared to be the best, althoug...
17 citations
TL;DR: In this paper, the concept of axial heterogeneity in relation to axial mixing in continuous mixers is investigated and a linear time-invariant (LTI) model is proposed for continuous mixer.
Abstract: The concept of heterogeneity in relation to axial mixing in continuous mixers is investigated. The state of the mixture along the axial direction can be described by an axial heterogeneity function. It is shown that this function can be decomposed into two independent components. The first component describes the fluctuations caused by the feeding system. The second component is the fluctuations due to the particulate nature of the material. In addition, the second component, or the random component, can be modeled as a band-limited Gaussian white noise. Moreover, the variogram function is shown to be a useful tool in determining the variance of the random component. A linear time-invariant (LTI) model is proposed for continuous mixers. This model also implies that the Danckwerts-Weinekotter formula is applicable for the variance reduction ratio (VRR). However, it is shown that the Danckwerts formula for VRR is more appropriate for determination of mixer efficiency.
TL;DR: In this paper, the authors investigated the impurity separation characteristics of graphite along with its expansion and found that simple mechanical impact with Ro-Tap and scrubbing was able to easily raise the carbon content to over 99.9%.
Abstract: Impurity separation characteristics of graphite were investigated along with its expansion. Inclusion states of typical clay minerals as impurity in the expanded graphite particles were observed and classified into four distinct types (Type I-IV). Removal of the minerals by the application of simple mechanical impact with Ro-Tap and scrubbing was performed with two expanded graphite specimens prepared from graphite concentrates of 93% fixed carbons from two different mines. It was found that the mechanical treatments were able to easily raise the carbon content to over 99.9%, depending on the impurity inclusion type.
TL;DR: In this paper, the authors describe the recent developments in the computer modeling of packing of complex-shaped particles and prediction of physical properties of the structures represented by the packing, including liquid permeability, mechanical strength/stability, compaction and sintering, and dissolution and leaching.
Abstract: This article describes the recent developments in the computer modeling of packing of complex-shaped particles and prediction of physical properties of the structures represented by the packing. The computer model DigiPac is capable of packing particles of any shapes and sizes in a container of arbitrary geometry. The ability to predict the packing structure of real particle shapes and to compute directly some structure-dependent physical properties such as liquid permeability, mechanical strength/stability, compaction and sintering, and dissolution and leaching is obviously highly desirable and has significant potential in industrial applications. Examples are presented relating to the packing of bulk and granular materials.
TL;DR: In this paper, a generic mass flow measurement device was developed as a variation on the theme of counting, which uses the measured cluster lengths to reconstruct the total number of particles in each passing cluster.
Abstract: A generic mass flow measurement device was developed as a variation on the theme of counting. In a hypothetical infinitely sparse mass flow, the number of passing particles could be counted in a time frame and multiplied by the mean mass per particle to obtain a mass flow per time unit. In a mass flow of realistic density, however, particles travel in cluster formation and direct counting of individual particles is impossible. If a method could be available that reconstructs the original number of particles in a cluster, the mass flow can be computed for realistic clustered mass flows. This reconstruction algorithm was developed in this research; it uses the measured cluster lengths to reconstruct the total number of particles in each passing cluster. The lengths of the clusters were measured with an optoelectronic device. The reconstruction algorithm was developed using simulation, augmented by clustering theory. For identical diameter particle flow, simulation results showed that the number of particles in a cluster could be reconstructed using a very simple reconstruction formula. This formula uses only the total number of clusters per time frame and the total number of individual particles measured in the same time frame. However, identical diameter flow is not realistic, since even identical particles are measured with a certain error. Reconstruction of the realistic distributed diameter particle flow was approximated using the identical particle method. The optical mass flow sensor has major advantages over traditional methods. It is virtually insensitive to vibrations, contamination, temperature drift, and misalignment and the underlying measurement concept is well understood. But most importantly, the sensor does not require calibration. The mass flow of identical particles (4.5 mm air gun pellets) was measured with an error smaller than 3% even for high density flow rates.
TL;DR: In this article, an analysis technique was developed on the basis of a modified version of Sudduth's model for calculating maximum packing fraction (MPF), which was compared with experimental values obtained with rheological methods.
Abstract: An analysis technique was developed on the basis of a modified version of Sudduth's model for calculating maximum packing fraction (MPF). Calculated MPF values were compared with experimental values obtained with rheological methods. By analysis of MPF data for three commercial titania powders dispersed in low molecular weight polyethylene, a large difference was observed between the experimental and calculated MPF values. For instance, a TiO 2 P25/VF sample had an experimental MPF of 0.15 while the calculated value was ~0.8. To address this issue, f was incorporated as a variable that would influence the packing fraction. By studying the behavior of three different types of submicron titania, an empirical equation was devised, that correlated f with particle size, particle size distribution, and packing structure. This overall treatment appeared to be relevant for predicting the f for binary millimeter steel powder mixtures. Thus, the form of this empirical function may guide us towards developing a deri...
TL;DR: In this article, a new elasto-viscoplastic constitutive model (PSU-EVP) was developed for predicting a dry powder's mechanical behavior during compaction.
Abstract: A new elasto-viscoplastic constitutive model (PSU-EVP) was developed for predicting a dry powder's mechanical behavior during compaction. The PSU-EVP model was developed in two stages. In the first stage, an elastoplastic model was formulated by using the fundamentals of critical state theory and key elements of the modified Cam-clay model. In the second stage, the elasto-viscoplastic model was formulated using the elastoplastic model developed in the first stage and the approach used by and given in the Adachi and Oka model. Based on these considerations, the PSU-EVP model explicitly incorporates the work done in volumetric compression of pore air during powder compaction. This aspect of the PSU-EVP model is different from the modified Cam-clay model that assumes the interparticle pore space in a powder mass to be filled with fluid. This key feature of the PSU-EVP model helps in isolating the effect of entrapped pore air on the mechanical properties of powders undergoing compression. The key parameter th...
TL;DR: In this article, the interfacing effects between a nozzle gas supplier, a rotary valve solids feeder with dropout box, and the pipeline of a pneumatic conveying test rig for low-velocity dense-phase flow are analyzed.
Abstract: Gas and solids feeding is a key operation in pneumatic conveying of particulate materials. This article presents an analysis of the interfacing effects between a nozzle gas supplier, a rotary valve solids feeder with dropout box, and the pipeline of a pneumatic conveying test rig for low-velocity dense-phase flow. Experiments were carried out to examine the flow pattern of slugs in different combinations of gas flow conditions and solids loading ratios. The effect of gas and solids feeding on the formation of slugs is analyzed by using both experimental data and computer-modeled results. Solids accumulation and sliding motion at the bottom of the dropout box and near the entrance of the downstream pipe, which happen prior to the bulk motion in the form of a slug, are found important in determining the size of a slug. Gas retention and pressure buildup characteristics in the feed section are also found crucial in influencing the flow patterns of slugs.
TL;DR: In this paper, the authors present experimental findings on the nature of the variation of pneumatic transport capacity for alumina for various sub-45 μm particle concentrations, and they show that the change in fine particles in bulk solids has been known to affect the pnumatic transport characteristics.
Abstract: The presence of fine particles in bulk solids has been known to affect the pneumatic transport characteristics. However, there is still no tool available to predict the exact nature of the variation of transport capacity with change in fines concentration in a bulk material. This article presents experimental findings on the nature of the variation of pneumatic transport capacity for alumina for various sub-45 μm particle concentrations. It has been shown that the nature of the variation of the transport capacity depends upon the solids loading ratio and, consequently, the amount of air used for pneumatic transportation. Above a solids loading ratio of 35, alumina transport capacity first decreased with increase in fines concentration and then increased beyond a certain value of fines concentration. For a solids loading ratio less than 35, such a trend was not seen, but a trend of reaching a peak value of transport capacity at increasing fines concentration was seen.
TL;DR: In this article, the effect of geometrical parameters, flow parameters, and materials characteristics on gas-particles flow behavior were studied, and it was observed that an increase in particle diameter, loading ratio, Re number (for constant loading ratio and variable mass flow rate), and particle density increased the acceleration length and the slip velocity.
Abstract: Turbulent flow patterns of dilute gas-particles flows in a vertical pipe are numerically investigated according to the Eulerian-Lagrangian approach by using the k = l model. Calibration of the numerical tools (commercial CFD software (FIDAP 8.6) and additional computer programs) is obtained by confirming the numerical predictions with available experimental results. Additionally, a comparison between the present work and experimental data showed an average deviation of about 3% and a maximum deviation of about 6% (for 0.1 mm particle diameter). The effect of geometrical parameters, flow parameters, and materials characteristics on gas-particles flow behavior were studied. It was observed that an increase in particle diameter, loading ratio, Re number (for constant loading ratio and variable mass flow rate), and particle density increased the acceleration length and the slip velocity. For a constant mass flow rate and variable loading ratio, a higher Re number increased slip velocity but decreased accelera...
TL;DR: In this paper, a finite element analysis using ABAQUS was carried out to investigate the loads on a hopper during filling, and meshes were designed to represent the granular material and the hopper.
Abstract: A finite element analysis using ABAQUS was carried out to investigate the loads on a hopper during filling. Simple geometries were chosen, and meshes were designed to represent the granular material and the hopper. An interaction between the contacting surfaces of the granular material and the hopper wall was modeled through a constitutive model of Coulomb friction. In order to simulate a filling process, the meshes representing the granular material and the interaction between the granular material and the wall of the hopper were suspended at the beginning of the analysis. They were then incrementally reactivated in a designed sequence. Such an operation of reactivation of meshes and interactions after initial suspension was assumed to represent the filling process. With this assumption, the development of loads exerted from the granular material on the hopper wall was investigated. Several material constitutive laws widely used for granular materials were adopted and implemented in parallel analyses. An...
TL;DR: In this article, a theory is presented to describe forced flow with varying degrees of air permeation up to and just beyond the fluidization point, taking into account the boundary and internal frictional properties, the degree of consolidation of the bulk granular material, and the stress fields that occur during forced flow.
Abstract: The problems associated with grain elevation and conveying under forced flow in vertical pipes are discussed. Based on experimental results, a theory is presented to describe forced flow with varying degrees of air permeation up to and just beyond the fluidization point. The theory takes into account the boundary and internal frictional properties, the degree of consolidation of the bulk granular material, and the stress fields that occur during forced flow. The force to elevate grain in a vertical tube is shown to be composed of two components, one to overcome Coulomb friction and initiate motion, and the other a time-dependent component that depends on the stiffness and damping characteristics of the granular material. The Coulomb friction component increases approximately exponentially with column height due to the positive feedback effect of the shear stresses at the pipe wall opposing the motion. Air permeation is shown to significantly reduce this component of the conveying force by reducing both th...
TL;DR: In this paper, the dust content and electrostatic charge of aluminium oxide (alumina) has been measured with the Faraday cup and in an electrostatic deflection apparatus.
Abstract: The dust content and electrostatic charge of aluminium oxide (alumina) has been measured with the Faraday cup and in an electrostatic deflection apparatus. The dust was made and released from a fluidized bed. After generation, the dust entered the measurement zone where it was separated according to charge. Large differences in the electrostatic charge and the dusting behavior were observed. The charge of the alumina dust is generally relatively neutral, but aluminas with highly charged particles were observed. The dusting profile varies considerably. Some powders released dust only in the beginning of the test, while others constantly released dust.
TL;DR: In this article, the capacity limitation boundary for low-velocity slug-flow pneumatic conveying of poly granules through horizontal pipes is investigated and a semi-empirical equation has been established to predict the maximum solids mass flow rate for a given air mass flow rates and conveying pipeline.
Abstract: The minimum transport or capacity limitation boundary for low-velocity slug-flow pneumatic conveying affects the design and operation of conveying systems. Unfortunately, the relevant mechanisms involved with this boundary still lack full understanding and assessment. Investigations have been carried out to model the capacity limitation for the low-velocity slug-flow pneumatic conveying of poly granules through horizontal pipes. Pipeline diameter, air mass flow rate, and operating pressure have been found to affect the maximum slugging capacity of this material. A semiempirical equation has been established to predict the maximum solids mass flow rate for a given air mass flow rate and conveying pipeline. Good agreement has been achieved between the model predictions and the experimental results over a wide range of airflows and pressures.
TL;DR: In this article, the simulation of the stress field within a slug aims at developing an accurate prediction model for the pressure drop along a pneumatic conveying line, which strongly depends on an accurate assessment of the particle properties, the pipeline dimensions, and the operating conditions.
Abstract: In dense-phase pneumatic conveying, particles are transported along a pipeline at relatively low conveying speeds. Due to the relatively gentle handling characteristics of this mode of flow, it is suitable for conveying fragile and brittle bulk materials used in the food and chemical industries. The simulation of the stress field within a slug aims at developing an accurate prediction model for the pressure drop along a pneumatic conveying line. A reliable prediction of the pressure drop strongly depends on an accurate assessment of the particle properties, the pipeline dimensions, and the operating conditions. In past decades, a few models have been developed to serve this purpose, most of them including the mean particle diameter as a crucial parameter. This generally limits the selection of materials to those of nearly spherical particle shape, as it is extremely difficult to obtain a representative diameter for irregularly shaped particles or bulk commodities comprising differently sized and/or shaped...
TL;DR: In this article, an experimental cold model (152 mm ID 2 610 mm height) of an FBC freeboard model was designed and fabricated with the assistance of an advanced laser-based particle image velocimetry (PIV) instrumentation.
Abstract: The transient solid particle velocity analysis in a fluidized bed combustor (FBC) freeboard is critical for its efficient and reliable operation. An experimental cold model (152 mm ID 2 610 mm height) of an FBC was designed and fabricated. Transient solid particle velocities in the FBC freeboard model were measured and analyzed with the assistance of an advanced laser-based particle image velocimetry (PIV) instrumentation. The PIV was applied to the FBC cold model to visualize the transient solid particle movement in the area of interest (AOI). Sixteen particle velocity profiles were generated in a 1.6 s time period. In each profile, a 3 (columns) 2 1 (row) grid was set. The regression analysis with the independent variables of X (x coordinate) and t (time) were applied to develop a specific empirical model for a transient solid particle vertical velocity component (V y ) within the AOI. The model shows that the V y within the AOI could be expressed as V y =f{sin C 1 X, cos C 2 t, e m C3t }, where C 1 , C...
TL;DR: In this article, the issue of anisotropy in plastic flow of compacted metal powders is addressed using a combination of analytical and experimental methods, and a yield function based on the first two stress invariants and associative plastic flow is modified for anisotropic by introducing coefficients on the stress terms.
Abstract: The issue of anisotropy in plastic flow of compacted metal powders is addressed using a combination of analytical and experimental methods. A yield function, based on the first two stress invariants and associative plastic flow, is modified for anisotropy by introducing coefficients on the stress terms. The test method uses die-compacted cylinders that are pressed into metal sleeves positioned inside a rigid die. When the sleeves and specimens are removed from the die, subsequent axial pressing causes pressure to be transmitted through the powder onto the inner surface of the sleeve. Yield of the sleeve sets the value of radial stress, and punch load sets the value of axial stress, at yield of the powder compact.
TL;DR: In this article, a computer simulation study of gas flow and particle transport and deposition in a pilot-scale furnace with cooling system is described, which includes nonlinear drag, gravity, Brownian, lift, and thermophoretic forces.
Abstract: The present work describes a computer simulation study of gas flow and particle transport and deposition in a pilot-scale furnace with cooling system The Gambit code is used to generate the geometry and the computational grid An unstructured mesh is generated for the pilot-scale boiler The FLUENT code is used for evaluating the gas mean velocity, turbulence fluctuation energy, and mean pressure, as well as temperature fields and chemical species concentrations The particle equation of motion includes the nonlinear drag, gravity, Brownian, lift, and thermophoretic forces The gas velocity and thermal conditions in the furnace are studied Ensembles of particle trajectories are generated and statistically analyzed Particle deposition rates on different walls are evaluated, and the effect of particle size is studied