Relevant bibliographies by topics / Fibre suspensions

Academic literature on the topic 'Fibre suspensions'

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Published: 4 June 2021
Last updated: 20 February 2023

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Journal articles on the topic "Fibre suspensions"

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Redlinger-Pohn, Jakob D., Melanie Mayr, Gregor Schaub, David Gruber, and Stefan Radl. "Fines mobility and distribution in streaming fibre networks: experimental evidence and numerical modeling." Cellulose 27, no. 16 (September 23, 2020): 9663–82. http://dx.doi.org/10.1007/s10570-020-03443-9.

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AbstractThe motion of flocculated fibres in a streaming suspension is governed by the balance of the network strength and hydrodynamic forces. With increasing flow rate through a channel, (1) the network initially occupying all space, (2) is then compressed to the centre, and (3) ultimately dispersed. This classical view neglects fibres-fines: we find that the distribution of these small particles differs in streaming suspensions. While it is known that fibre-fines can escape the fibre network, we find that the distribution of fibre-fines is non-homogenous in the network during compression: fibre-fines can be caged and retarded in the streaming fibre network. Hence, the amount of fibre-fines is reduced outside of a fibre network and enriched at the network’s interface. Aiming on selectively removing fibre-fines from a streaming network by suction, we identify a reduction of the fines removal rate. That documents a hindered mobility of fibre-fines when moving through the network of fibres. Additionally, we found evidence, that the mobility of fibre-fines is dependent on the fibre-fines quality, and is higher for fibrillar fines. Consequently, we suggest that the quality of fibre-fines removed from the suspension can be controlled with the flow regime in the channel. Finally, we present a phenomenological model to compute the length dependent fibre distribution in an arbitary geometry. For a fibre suspension channel flow we are able to predict a length-dependent fibre segregation near the channel’s centre. The erosion of a plug of long fibres was however underestimated by our model. Interestingly, our model with parameters fitted to streaming fibre suspension qualitatively agreed with the motion of micro-fibrillated cellulose. This gives hope that devices for handling flocculated fibre suspensions can be designed in the future with greater confidence.
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Manikantan, Harishankar, Lei Li, Saverio E. Spagnolie, and David Saintillan. "The instability of a sedimenting suspension of weakly flexible fibres." Journal of Fluid Mechanics 756 (September 9, 2014): 935–64. http://dx.doi.org/10.1017/jfm.2014.482.

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AbstractSuspensions of sedimenting slender fibres in a viscous fluid are known to be unstable to fluctuations of concentration. In this paper we develop a theory for the role of fibre flexibility in sedimenting suspensions in the asymptotic regime of weakly flexible bodies (large elasto-gravitation number). Unlike the behaviour of straight fibres, individual flexible filaments rotate as they sediment, leading to an anisotropic base state of fibre orientations in an otherwise homogeneous suspension. A mean-field theory is derived to describe the evolution of fibre concentration and orientation fields, and we explore the stability of the base state to perturbations of fibre concentration. We show that fibre flexibility affects suspension stability in two distinct and competing ways: the anisotropy of the base state renders the suspension more unstable to perturbations, while individual particle self-rotation acts to prevent clustering and stabilizes the suspension. In the presence of thermal noise, the dominant effect depends critically upon the relative scales of flexible fibre self-rotation compared to rotational Brownian motion.
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MACKAPLOW, MICHAEL B., and ERIC S. G. SHAQFEH. "A numerical study of the sedimentation of fibre suspensions." Journal of Fluid Mechanics 376 (December 10, 1998): 149–82. http://dx.doi.org/10.1017/s0022112098002663.

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The sedimentation of fibre suspensions at low Reynolds number is studied using two different, but complementary, numerical simulation methods: (1) Monte Carlo simulations, which consider interparticle hydrodynamic interactions at all orders within the slender-body theory approximation (Mackaplow & Shaqfeh 1996), and (ii) dynamic simulations, which consider point–particle interactions and are accurate for suspension concentrations of nl3=1, where n and l are the number density and characteristic half-length of the fibres, respectively. For homogeneous, isotropic suspensions, the Monte Carlo simulations show that the hindrance of the mean sedimentation speed is linear in particle concentration up to at least nl3=7. The speed is well predicted by a new dilute theory that includes the effect of two-body interactions. Our dynamic simulations of dilute suspensions, however, show that interfibre hydrodynamic interactions cause the spatial and orientational distributions to become inhomogeneous and anisotropic. Most of the fibres migrate into narrow streamers aligned in the direction of gravity. This drives a downward convective flow within the streamers which serves to increase the mean fibre sedimentation speed. A steady-state orientation distribution develops which strongly favours fibre alignment with gravity. Although the distribution reaches a steady state, individual fibres continue to rotate in a manner that can be qualitatively described as a flipping between the two orientations aligned with gravity. The simulation results are in good agreement with published experimental data.
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Sridang, P. Choksuchart, M. Heran, and A. Grasmick. "Influence of module configuration and hydrodynamics in water clarification by immersed membrane systems." Water Science and Technology 51, no. 6-7 (March 1, 2005): 135–42. http://dx.doi.org/10.2166/wst.2005.0631.

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Different immersed membrane systems were compared according to the module configuration. Filtering concentrated aqueous suspensions under constant permeate flux, the hydraulic performances of the systems were evaluated and compared through parameters such as critical permeate flux notion and trans-membrane pressure variation rates. Operational variables were membrane size and module fibre density, aeration inside or outside the fibre network, suspension concentration and physico-chemical conditioning. When using hollow fibres including a possible air injection inside the fibre network, results pointed out the positive role of the aeration on the fouling control. But too high a fibre density did not allow an optimal control when the aqueous suspension was very concentrated. On the other hand, when working with capillary membranes showing sufficient space between fibres, the major parameters were the transversal suspension flow circulation through the fibre network and the FeCl3 conditioning of the suspension. Experimental results show a possible working at a 0.07 m3.m2.h1 permeate flow rate under low TMP evolutions, 0.02 Pa/s, even if the filtration was operated under high concentrated suspension, 5 kgSS/m3.
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Nguyen, Hung Quoc, and Canh-Dung Tran. "Simulation of non-dilute fibre suspensions using RBF-based macro–micro multiscale method." Korea-Australia Rheology Journal 34, no. 1 (February 2022): 1–15. http://dx.doi.org/10.1007/s13367-022-00022-1.

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AbstractThe multiscale stochastic simulation method based on the marriage of the Brownian Configuration Field (BCF) and the Radial Basis Function mesh-free approximation for dilute fibre suspensions by our group, is further developed to simulate non-dilute fibre suspensions. For the present approach, the macro and micro processes proceeded at each time step are linked to each other by a fibre contributed stress formula associated with the used kinetic model. Due to the feature of non-dilute fibre suspensions, the interaction between fibres is introduced into the evolution equation to determine fibre configurations using the BCF method. The fibre stresses are then determined based on the fibre configuration fields using the Phan–Thien–Graham model. The efficiency of the simulation method is demonstrated by the analysis of the two challenging problems, the axisymmetric contraction and expansion flows, for a range of the fibre concentration from semi-dilute to concentrated regimes. Results evidenced by numerical experiments show that the present method would be potential in analysing and simulating various suspensions in food and medical industries.
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Feist, Markus, Hermann Nirschl, Jörg Wagner, Georg Hirsch, and Samuel Schabel. "Experimental Results for the Settling Behaviour of Particle-Fiber Mixtures." Physical Separation in Science and Engineering 2007 (February 11, 2007): 1–6. http://dx.doi.org/10.1155/2007/91740.

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Sedimentation of organic fibres and inorganic particles can be observed in several industrial applications. Fibres are involved not only in wastewater treatment but also in other separation applications. In the paper industry, the separation of inorganic filler and coating particles from short cellulose fibres is still a challenge in the recycling process. During that process, particles have to be removed to obtain a purified fibre suspension. These fibres can be used again to produce new paper. With the currently applied techniques, like screening and flotation, the efficiency of short fibre separation is very poor. Moreover, also separation by sedimentation fails due to similar settling velocities of heavy-small particles and the light and larger fibres. This paper concentrates on the sedimentation of organic fibres and inorganic particles in water. The investigated suspensions are made by resolving two different and specially produced papers a coated and an uncoated one, as well as the single components used for its production. We observe a different sedimentation behaviour according to the concentration of fibres and particles in the suspension and the pH-value of it. The main result is that, according to the fibre rate, the sedimentation behaviour is particle dominant or fibre dominant.
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Ahmed, Shams Forruque. "Theoretical Model Development for Energy Motion of Dusty Turbulent Flow of Fibre Suspensions in a Rotational Frame." Complexity 2022 (April 12, 2022): 1–11. http://dx.doi.org/10.1155/2022/8705997.

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Fibre suspension has garnered considerable attention in turbulent flows that are used in many industries. Solid particles, such as dust particles, notably affect the turbulent flow field in a rotational frame. In assessing their impacts, the dusty turbulent flow for fibre suspensions needs to be studied in a frame of rotation that can be substantially applied in many industries. This study, therefore, aims to build a theoretical model for the energy motion of dusty turbulent flow of fibre suspensions in a rotational frame. The turbulence momentum equation was considered to formulate the model in presence of dusty fluid rotating flow of fibre suspensions. The newly derived equation was derived in second-order correlation tensors Fi,j, Wi,j, Gi,j, Si,j, Xi,j, Yi,j, Qi,j, and Ri,j at any two points in the flow domain, where the tensors were expressed as space, time, and distance functions. The developed model is a considerable improvement because it takes into account all of the potential influential parameters that could affect the motion of turbulent energy, such as dust particles, suspending particles (fibres), and rotating frame. However, the impact of these parameters on turbulence energy motion must be evaluated in order to assess the performance of turbulence systems utilized in a variety of industries, such as paper manufacturing. The present theoretical development will contribute to open up experimental and numerical research opportunities for the advancement of the industry, science, and technology.
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Mackaplow, Michael B., and Eric S. G. Shaqfeh. "A numerical study of the rheological properties of suspensions of rigid, non-Brownian fibres." Journal of Fluid Mechanics 329 (December 25, 1996): 155–86. http://dx.doi.org/10.1017/s0022112096008889.

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Using techniques developed in our previous publication (Mackaplow et al. 1994), we complete a comprehensive set of numerical simulations of the volume-averaged stress tensor in a suspension of rigid, non-Brownian slender fibres at zero Reynolds number. In our problem formulation, we use slender-body theory to develop a set of integral equations to describe the interfibre hydrodynamic interactions at all orders. These integral equations are solved for a large number of interacting fibres in a periodically extended box. The simulations thus developed are an accurate representation of the suspensions at concentrations up to and including the semidilute regime. Thus, large changes in the suspensions properties can be obtained. The Theological properties of suspensions with concentrations ranging from the dilute regime, through the dilute/semi-dilute transition, and into the semi-dilute regime, are surprisingly well predicted by a dilute theory that takes into account two-body interactions. The accuracy of our simulations is verified by their ability to reproduce published suspension extensional and shear viscosity data for a variety of fibre aspect ratios and orientation distributions, as well as a wide range of suspension concentrations.
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Xiao-Ke, Ku, and Lin Jian-Zhong. "Orientational Distribution of Fibres in Sheared Fibre Suspensions." Chinese Physics Letters 24, no. 6 (June 2007): 1622–25. http://dx.doi.org/10.1088/0256-307x/24/6/053.

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WU, JINGSHU, and CYRUS K. AIDUN. "A numerical study of the effect of fibre stiffness on the rheology of sheared flexible fibre suspensions." Journal of Fluid Mechanics 662 (September 27, 2010): 123–33. http://dx.doi.org/10.1017/s0022112010003885.

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A recently developed particle-level numerical method is used to simulate flexible fibre suspensions in Newtonian simple shear flow. In this method, the flow is computed on a fixed regular ‘lattice’ using the lattice Boltzmann method, where each solid particle, or fibre in this case, is mapped onto a Lagrangian frame moving continuously through the domain. The motion and orientation of the fibre are obtained from Newtonian dynamics equations. The effect of fibre stiffness on the rheology of flexible fibre suspensions is investigated and a relation for the relative viscosity is obtained. We show that fibre stiffness (bending ratio, BR) has a strong impact on rheology in the range BR < 3. The relative viscosity increases significantly as BR decreases. These results show that the primary normal stress difference has a minimum value at BR ~ 1. The primary normal stress difference for slightly deformable fibres reaches a minimum and increases significantly as BR decreases below one. The results are explained based on Batchelor's relation for non-Brownian suspensions.
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Dissertations / Theses on the topic "Fibre suspensions"

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Joung, Clint Gwarngsoo. "Direct simulation studies of suspended particles and fibre-filled suspensions." Thesis, The University of Sydney, 2003. http://hdl.handle.net/2123/554.

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A new Direct Simulation fibre model was developed which allowed flexibility in the fibre during the simulation of fibre suspension flow.This new model was called the 'Chain-of-Spheres' model.It was hypothesised that particle shape and deformation could significantly affect particle dynamics,and also suspension bulk properties such as viscosity.Data collected from the simulation showed that flexible fibres in shear flow resulted in an order of 7 −10% bulk relative viscosity increase over the 'rigid' fibre result.Results also established the existence of a relationship between bulk viscosity and particle stiffness. In comparison with experimental results,other more conventional rigid fibre based methods appeared to underpredict relative viscosity.The flexible fibre method thus markedly improved the ability to estimate relative viscosity.The curved rigid fibre suspension also exhibited increased viscosity of the order twice that of the equivalent straight rigid fibre suspension.With such sensitivity to fibre shape,this result has some important implications for the quality of fibre inclusions used.For consistent viscosity,the shape quality of the fibres was shown to be important. The 'Chain of Spheres' simulation was substantially extended to create a new simulation method with the ability to model the dynamics of arbitrarily shaped particles in the Newtonian flow field.This new '3D Particle' simulation method accounted for the inertial force on the particles,and also allowed particles to be embedded in complex flow fields.This method was used to reproduce known dynamics for common particle shapes,and then to predict the unknown dynamics of various other particle shapes in shear flow. In later sections, the simulation demonstrated inertia-induced particle migration in the non-linear shear gradient Couette cylinder flow,and was used to predict the fibre orientation within a diverging channel flow.The performance of the method was verified against known experimental measurements,observations and theoretical and numerical results where available.The comparisons revealed that the current method reproduced single particle dynamics with great fidelity. The broad aim of this research was to better understand the microstructural dynamics within the fibre-filled suspension and from it,derive useful engineering information on the bulk flow of these fluids.This thesis represents a move forward to meet this broad aim.It is hoped that future researchers may benefit from the new approaches and algorithms developed here.
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Joung, Clint Gwarngsoo. "Direct simulation studies of suspended particles and fibre-filled suspensions." University of Sydney. Chemical Engineering, 2003. http://hdl.handle.net/2123/554.

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A new Direct Simulation fibre model was developed which allowed flexibility in the fibre during the simulation of fibre suspension flow.This new model was called the �Chain-of-Spheres �model.It was hypothesised that particle shape and deformation could signi ficantly a ffect partic e dynamics,and also suspension bulk properties such as viscosity.Data collected from the simulation showed that flexible fibres in shear flow resulted in an order of 7 −10% bulk relative viscosity increase over the �rigid �fibre result.Results also es- tablished the existence of a relationship between bulk viscosity and particle sti ffness.In comparison with experimental results,other more conventional rigid fibre based methods appeared to underpredict relative viscosity.The flexible fibre method thus markedly improved the ability to estimate relative viscosity.The curved rigid fibre suspension also exhibited increased viscosity of the order twice that of the equivalent straight rigid fibre suspension.With such sensitivity to fibre shape,this result has some important implications for the quality of fibre inclusions used.For consistent viscosity,the shape quality of the fibres was shown to be important. The �Chain of Spheres �simulation was substantially extended to create a new simulation method with the ability to model the dynamics of arbitrarily shaped particles in the Newtonian flow field.This new �3D Particle �simulation method accounted for the inertial force on the particles,and also allowed particles to be embedded in complex flow fields.This method was used to reproduce known dynamics for common particle shapes,and then to predict the unknown dynamics of various other particle shapes in shear flow. In later sections, the simulation demonstrated inertia-induced particle migration inthe non-linear shear gradient Couette cylinder flow,and was used to predict the fibre orientation within a diverging channel flow.The performance of the method was verified against known experimental measurements,observations and theoretical and numerical results where available.The comparisons revealed that the current method reproduced single particle dynamics with great fidelity. The broad aim of this research was to better understand the microstruc- tural dynamics within the fibre-filled suspension and from it,derive useful engineering information on the bulk flow of these fluids.This thesis represents a move forward to meet this broad aim.It is hoped that future researchers may bene fit from the new approaches and algorithms developed here.
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Carlsson, Allan. "Near wall fibre orientation in flowing suspensions." Doctoral thesis, KTH, Linné Flow Center, FLOW, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-9995.

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This thesis deals with fibre orientation in wall-bounded shear flows. The primary application in mind is papermaking. The study is mainly experimental,but is complemented with theoretical considerations.The main part of the thesis concerns the orientation of slowly settlingfibres in a wall-bounded viscous shear flow. This is a flow case not dealt withpreviously even at small Reynolds numbers. Experiments were conducted usingdilute suspensions with fibres having aspect ratios of rp ≈ 7 and 30. It is foundthat the wall effect on the orientation is small for distances from the wall wherethe fibre centre is located farther than half a fibre length from the wall. Farfrom the wall most fibres were oriented close to the flow direction. Closer tothe wall than half a fibre length the orientation distribution first shifted to bemore isotropic and in the very proximity of the wall the fibres were orientedclose to perpendicular to the flow direction, nearly aligned with the vorticityaxis. This was most evident for the shorter fibres with rp ≈ 7.Due to the density difference between the fibres and the fluid there is anincreased concentration near the wall. Still, a physical mechanism is requiredin order for a fibre initially oriented close to the flow direction at about half afibre length from the wall to change its orientation to aligned with the vorticityaxis once it has settled down to the wall. A slender body approach is usedin order to estimate the effect of wall reflection and repeated wall contacts onthe fibre rotation. It is found that the both a wall reflection, due to settlingtowards the wall, and contact between the fibre end and the wall are expectedto rotate the fibre closer to the vorticity axis. A qualitative agreement withthe experimental results is found in a numerical study based on the theoreticalestimation.In addition an experimental study on fibre orientation in the boundarylayers of a headbox is reported. The orientation distribution in planes parallelto the wall is studied. The distribution is found to be more anisotropic closerto the wall, i.e. the fibres tend to be oriented closer to the flow direction nearthe wall. This trend is observed sufficiently far upstream in the headbox.Farther downstream no significant change in the orientation distribution couldbe detected for different distances from the wall.
QC 20100706
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Paterson, Daniel Thomas. "Understanding rapid dewatering of cellulose fibre suspensions." Thesis, University of British Columbia, 2016. http://hdl.handle.net/2429/58195.

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Rapid dewatering of cellulose fibre suspensions is a fundamental process in many unit operations in the production of pulp and paper. Understanding dewatering behaviour can be applied to optimizing designs of industrial equipment. In this project, we assess the suitability of a well-established modeling approach, referred to as the base model, at capturing the one dimensional dewatering behaviour of cellulose fibre suspensions seen experimentally. This modeling approach requires two closure relationships determined experimentally, i.e. compressive yield stress and permeability. Experimental equipment has been designed, constructed, and operated to obtain the closure relationships and collect dewatering results for validation of the model. Two experimental techniques, with close agreement, have been developed for the collection of compressive yield stress. Permeability results are obtained through Darcian permeation experiments. Two approaches, neglecting and accounting for flow induced compaction, were developed. Results were found to fall within values seen in the literature. The base model provided good representation of ideal nylon fibre suspension trials. These solid fibres are representative of the base models constitutive equation for an infinite solid phase rearrangement rate constant. The base model poorly represents the cellulose fibre suspensions' dewatering behaviour. The suggested source of discrepancy is the further dynamic due to the dewatering of the individual porous cellulose fibres which results in a finite solid phase rearrangement rate constant. The base model is expanded upon in hopes of capturing this rate dependent behaviour. This extended model, with the determined closure relationships, captured load versus solid volume fraction profiles at varying dewatering rates better than the base model for cellulose fibre suspensions. Further improvements in representation were seen through close representation of the solid phase velocity profiles found experimentally during dewatering. Various cellulose fibre suspensions were investigated to begin a catalog of different dewatering behaviours seen through variations in pulp production variables. Investigations included varying fibre species, pulping processes, levels of low consistency refining, and impacts of dewatering chemical additives.
Applied Science, Faculty of
Mechanical Engineering, Department of
Graduate
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Fletcher, Paul E. "Electrically assisted fibre filtration of aqueous suspensions." Thesis, Cranfield University, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.359519.

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Sykes, Paul. "Lubrication flows of semi-dilute fibre suspensions." Thesis, University of Cambridge, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.627460.

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Holm, Richard. "Fluid mechanics of fibre suspensions related to papermaking." Doctoral thesis, Stockholm, 2005. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-100.

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Zhang, Feng. "Eulerian Numerical Study of the Sedimentation of Fibre Suspensions." Licentiate thesis, KTH, Mekanik, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-96767.

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Sedimenting suspensions exist in a varity of natural phenomena and industrial applications. It is already observed in experiments that the dilute fibre suspensions experience a hydrodynamics instability under gravity at low Reynolds numbers. Initially well-mixed suspensions become inhomogeneous and anisotropic due to this instability.The main goal of this work is to understand the instability in a dilute fibre suspension by means of an Eulerian approach which is based on the Navier-Stokes equations coupled to Fokker-Planck equation for the PDF of fibres.Using a linear stability analysis, we show that inertia and hydrodynamic translational diffusion damp perturbations at long wavelengths and short wavelengths, respectively, leading to a wavenumber selection. For small, but finite Reynolds number of the fluid bulk motion, the most unstable wavenumber is a finite value which increases with Reynolds number, and where the diffusion narrows the range of unstable wavenumbers. With periodic boundary conditions, numerical simulations of the full non-linear evolution in time of a normal mode perturbation show that the induced flow may either die or saturate on a finite amplitude. The character of this long time behaviour is dictated by the wavenumber and the presence or absence of the translational and rotational diffusivities.In a simulation domain confined by vertical walls, a series of alternating structures of risers and streamers emerge continuously from the walls until they meet in the middle of the domain. For moderate times, this agrees qualitatively with experimental and theoretical results. Moreover, our simulation in a vessel of infinite height obtained an increasing wavelength evolution due to the congregation of the streamers or risers. In the end, there is constantly only one streamer left, and it drifts randomly to one side of the container until the evolution reaches a steady state. It is also found that the perturbations added to the initial conditions can induce more high density regions whose sizes and velocities are strongly linked to the initial perturbations of the number density or the flow field. In addition, the maximum number of streamers increases with Reynolds number, volume fraction and channel width.
QC 20120625
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Derakhshandeh, Babak. "Rheology of low to medium consistency pulp fibre suspensions." Thesis, University of British Columbia, 2011. http://hdl.handle.net/2429/37371.

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Papermaking is a major industry to manufacture products vital to education, communication, and packaging. Most operations in this industry deal with the flow of different mass concentrations of pulp suspensions. Therefore, the flow properties (rheology) of pulp suspensions are of great importance for the optimal functionality of most unit operations in the industry. Yield stress is one of the most important rheological properties in designing process equipment, thus needs to be determined by a reliable technique. Two established and extensively used methods for determining yield stress were compared with a velocimetry technique. The yield stresses were determined for commercial pulp suspensions at fibre mass concentrations of 0.5 to 5 wt. %. The results were compared and models were proposed to predict the yield stress as a function of fibre mass concentration. The yield stress values obtained by the velocimetry technique were found to be the most reliable. Conventional rheometry and local velocimetry techniques were further used to study the flow behaviour of pulp suspensions beyond the yield stress. Pulp suspensions were found to be shear-thinning up to a certain high shear rate. The Herschel–Bulkley constitutive equation was used to fit the local steady-state velocity profiles and to predict the steady-state flow curves obtained by conventional rheometry. Conventional rheometry was found to fail at low shear rates due to the presence of wall slip. Consistency between the various sets of data was found for all suspensions studied. Finally, the same approach was used to study thixotropy and transient flow behaviour of concentrated pulp suspension of 6 wt.%. Pulp was found to exhibit a plateau in the flow curve where a slight increase in the shear stress generated a jump in the corresponding shear rate, implying the occurrence of shear banding. The velocity profiles were found to be discontinuous in the vicinity of the yielding radius where a Herschel-Bulkley model failed to predict the flow. Shear history and the time of rest prior to the measurement were found to play a significant role on the rheology and the local velocity profiles of pulp suspension.
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Fan, Xijun. "Numerical study on some rheological problems of fibre suspensions." Thesis, The University of Sydney, 2006. http://hdl.handle.net/2123/1096.

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This thesis deals with numerical investigations on some rheological problems of fibre suspensions: the fibre level simulation of non-dilute fibre suspensions in shear flow; the numerical simulation of complex fibre suspension flows and simulating the particle motion in viscoelastic flows. These are challenging problems in rheology. Two numerical approaches were developed for simulating non-dilute fibre suspensions from the fibre level. The first is based on a model that accounts for full hydrodynamic interactions between fibres, which are approximately calculated as a superposition of the long-range and short-range hydrodynamic interactions. The long-range one is approximated by using slender body theory and includes infinite particle interactions. The short-range one is approximated in terms of the normal lubrication forces between close neighbouring fibres. The second is based on a model that accounts only for short-range interactions, which comprise the lubrication forces and normal contact and friction forces. These two methods were applied to simulate the microstructure evolution and rheological properties of non-dilute fibre suspensions. The Brownian configuration method was combined with the highly stable finite element method to simulate the complex flow of fibre suspensions. The method is stable and robust, and can provide both micro and macro information. It does not require any closure approximations in calculating the fibre stress tensor and is more efficient and variance reduction, compared to CONNFFESSITT, for example. The flow of fibre suspensions past a sphere in a tube and the shear induced fibre migration were successfully simulated using this method The completed double layer boundary element method was extended to viscoelastic flow cases. A point-wise solver was developed to solve the constitutive equation point by point and the fixed least square method was employed to interpolate and differentiate data locally. The method avoids volume meshing and only requires the boundary mesh on particle surfaces and data points in the flow domain. A sphere settling in the Oldroyd-B fluid and a prolate spheroid rotating in shear flow of the Oldroyd-B fluid were simulated. Based on the simulated orbit of a prolate spheroid in shear flow, a constitutive model for the weakly viscoelastic fibre suspensions was proposed and its predictions were compared with some available experimental results. All simulated results are in general agreement with experimental and other numerical results reported in literature. This indicates that these numerical methods are useful tools in rheological research.
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Books on the topic "Fibre suspensions"

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Plikas, Atanasis. Numerical modeling of fibre suspensions in grid-generated turbulent flow. Ottawa: National Library of Canada, 2000.

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Luo, Chitao. The investigation of turbulent statistics of a fibre suspension undergoing mixing. Ottawa: National Library of Canada, 1999.

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Hartley, James Joseph. The effects of electrical strength training on the contractile function and fiber morphometry of skeletal muscle during hindlimb suspension. Ottawa: National Library of Canada = Bibliothèque nationale du Canada, 1993.

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Segal, Jane. Rheological properties of fibre suspensions. 2005.

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Raghem-Moayed, Amir. Characterization of fibre suspension flows at papermaking consistencies. 1999.

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Book chapters on the topic "Fibre suspensions"

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Boger, D. V., D. U. Hur, and C. J. S. Petrie. "The Rheology of Fibre Suspensions." In Third European Rheology Conference and Golden Jubilee Meeting of the British Society of Rheology, 4–5. Dordrecht: Springer Netherlands, 1990. http://dx.doi.org/10.1007/978-94-009-0781-2_4.

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Zhao, L. H., H. I. Andersson, J. J. J. Gillissen, and B. J. Boersma. "Simulating Fibre Suspensions: Lagrangian versus Statistical Approach." In Springer Proceedings in Physics, 347–50. Berlin, Heidelberg: Springer Berlin Heidelberg, 2009. http://dx.doi.org/10.1007/978-3-642-03085-7_84.

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Gyr, A., and H. W. Bewersdorff. "Drag Reduction in Fibre- and Non-Fibrous Suspensions." In Drag Reduction of Turbulent Flows by Additives, 175–90. Dordrecht: Springer Netherlands, 1995. http://dx.doi.org/10.1007/978-94-017-1295-8_7.

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Gyr, A., and H. W. Bewersdorff. "Rheology of Polymer and Surfactant Solutions, and of Fibre Suspensions." In Drag Reduction of Turbulent Flows by Additives, 33–68. Dordrecht: Springer Netherlands, 1995. http://dx.doi.org/10.1007/978-94-017-1295-8_3.

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Lohmann, Christoph. "Simulation of fiber suspensions." In Physics-Compatible Finite Element Methods for Scalar and Tensorial Advection Problems, 211–61. Wiesbaden: Springer Fachmedien Wiesbaden, 2019. http://dx.doi.org/10.1007/978-3-658-27737-6_6.

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Eberle, Aaron P. R., Kevin Ortman, and Donald G. Baird. "Structure and Rheology of Fiber Suspensions." In Applied Polymer Rheology, 113–51. Hoboken, NJ, USA: John Wiley & Sons, Inc., 2011. http://dx.doi.org/10.1002/9781118140611.ch4.

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Blanc, R. "Order and Disorder in Fiber Suspensions." In Mobile Particulate Systems, 105–28. Dordrecht: Springer Netherlands, 1995. http://dx.doi.org/10.1007/978-94-015-8518-7_9.

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Tucker III, Charles L. "Suspension Rheology and Flow-Orientation Coupling." In Fundamentals of Fiber Orientation, 173–204. München: Carl Hanser Verlag GmbH & Co. KG, 2022. http://dx.doi.org/10.3139/9781569908761.006.

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Laigaard-Jensen, J., Harikrishna Narasimhan, and Jakob Mouritsen. "Fire protection of suspension bridge cables." In Bridge Safety, Maintenance, Management, Life-Cycle, Resilience and Sustainability, 1939–46. London: CRC Press, 2022. http://dx.doi.org/10.1201/9781003322641-240.

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Shanker, R., J. W. Gillespie, and S. I. Güçeri. "Computer Simulation of Hydrodynamic Interactions in Fiber Suspensions." In Computer Aided Design in Composite Material Technology III, 21–35. Dordrecht: Springer Netherlands, 1992. http://dx.doi.org/10.1007/978-94-011-2874-2_2.

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Conference papers on the topic "Fibre suspensions"

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Sullivan, Pierre E., C. Luo, M. Loewen, D. C. S. Kuhn, and M. Buffle. "Turbulence Measurements within Fibre Suspensions." In First Symposium on Turbulence and Shear Flow Phenomena. Connecticut: Begellhouse, 1999. http://dx.doi.org/10.1615/tsfp1.920.

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AbuYousef, Imad A., James A. Olson, D. Mark Martinez, and Sheldon Green. "Pumping Performance Increase Through the Addition of Turbulent Drag-Reducing Polymers to Pulp Fibre Suspensions." In ASME 2010 International Mechanical Engineering Congress and Exposition. ASMEDC, 2010. http://dx.doi.org/10.1115/imece2010-37697.

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The addition of a small amount of long chain polymers to a turbulent fluid is known to reduce the wall shear stress and drag. Similarly, the addition of pulp fibres to a turbulent suspension is also turbulent-drag reducing despite pulp fibres having a length scale that is 1000 times larger than polymer molecules. The mechanism of drag reduction and its impact on centrifugal pump performance is poorly understood, especially when there is a combination of polymer and fibres in suspension. Centrifugal (slurry) pump performance was measured as a function of pulp fibre and PAM polymer concentration. Both the pump best efficiency and maximum head rise were greater when pumping modest concentrations of polymer solutions and low consistency pulp fibre than pure water. We measured an efficiency increase of 22 percent and a maximum head increase of 4.3 percent with the addition of 150 ppm PAM polymer relative to pure water. We measured an increase of 8 percent and 2.3 percent in pump efficiency and maximum head coefficient, respectively, with 2 percent pulp fibres over that of water alone. With both 1 percent consistency pulp fibres and 100 ppm of PAM polymers, we measured a 12 percent increase in efficiency over that of pulp suspension alone. With both 2 percent consistency pulp fibres and 100 ppm of PAM polymers, we measured an 8 percent increase in efficiency over that of pulp fibre suspension alone. The reasons for the increased pump efficiency with addition of additives is not known but are thought to be due to the turbulent-drag-reducing properties associated with flow of these suspensions.
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Bilro, L., S. Prats, J. L. Pinto, J. J. Keizer, and R. N. Nogueira. "Turbidity sensor for determination of concentration, ash presence and particle diameter of sediment suspensions." In 21st International Conference on Optical Fibre Sensors (OFS21). SPIE, 2011. http://dx.doi.org/10.1117/12.885112.

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Ghatrehsamani, Shirin, Yiannis Ampatzidis, and Sahar Ghatrehsamani. "Friction Loss and Heat Transfer of Fibre and Wood Pulp Suspensions: A Review." In 2018 Detroit, Michigan July 29 - August 1, 2018. St. Joseph, MI: American Society of Agricultural and Biological Engineers, 2018. http://dx.doi.org/10.13031/aim.201800042.

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Azouri, Assaf, Ming Ge, Kun Xun, Klaus Sattler, Joe Lichwa, and Chittaranjan Ray. "Colloidal Stability of Nanosoil/Nanofiber Aqueous Suspensions From Natural Environment in Hawaii." In ASME 2006 Multifunctional Nanocomposites International Conference. ASMEDC, 2006. http://dx.doi.org/10.1115/mn2006-17074.

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Nanoparticles from iron-oxide rich soil and nanofibers from bark of the plumeria tree in Hawaii have been studied using photon correlation spectroscopy (PCS). Particles with sizes of several hundred nanometers have been investigated in aqueous suspension. The zeta potentials have been determined as a function of pH for soil, fiber, and the soil/fiber mixture. It is found that all three suspensions have negative zeta potentials and no isoelectric point within the pH range from 4 to 11. This shows that the suspensions are stable over a wide range of conditions. Both soil and fiber samples have approximately constant zeta potentials within this range. However, the zeta potential changes significantly for the nanosoil/nanofiber mixture when the pH is varied. We conclude that the nanoparticles of soil and fiber interact in the suspension and that this depends on the pH value of the suspension.
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Yasuda, Kazunori, and Noriyasu Mori. "Fiber Orientation and Concentration Distribution in a Concentrated Suspension Flow Through a Complex Geometry." In ASME/JSME 2003 4th Joint Fluids Summer Engineering Conference. ASMEDC, 2003. http://dx.doi.org/10.1115/fedsm2003-45778.

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Distributions of fiber orientation and fiber concentration in slit flows of concentrated suspensions were measured. Slit channels were used in the experiments: a channel with an abrupt expansion and a crank geometry with six L-shaped corners. Such channels are usually used in a polymer processing. For visualization of fibers, an index-of-refraction matching method was employed, and tracer fibers having birefringence were suspended to observe between crossed polarizers. When fibers flow through an abrupt expansion, they rapidly orient in the direction perpendicular to the flow direction near the centerline. The fiber orientation, however, returns to the flow direction in the downstream region. In the L-shaped corner, fibers randomly orient because of the decelerating flow. In the downstream region of the L-shaped corner, fiber orientation is not symmetric with respect to the centerline. This seems to result from fiber-fiber interactions in the concentrated suspension. The fiber concentration is uniform over a width of a channel except adjacent to the side wall in the concentrated suspension, while it has a maximum apart from the side wall in the dilute suspension.
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Zhang, Dongdong, Douglas E. Smith, David A. Jack, and Stephen Montgomery-Smith. "Rheological Study on Multiple Fiber Suspensions for Fiber Reinforced Composite Materials Processing." In ASME 2011 International Mechanical Engineering Congress and Exposition. ASMEDC, 2011. http://dx.doi.org/10.1115/imece2011-64498.

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This paper studies the rheological properties of a semi-dilute fiber suspension for short fiber reinforced composite materials processing. For industrial applications, the volume fraction of short fibers could be large for semi-dilute and concentrated fiber suspensions. Therefore, fiber-fiber interactions consisting of hydrodynamic interactions and direct mechanical contacts could affect fiber orientations and thus the rate of fiber alignment in the manufacturing processing. In this paper, we study the semi-dilute fiber suspensions, i.e. the gap between fibers becomes closer, and hydrodynamic interactions becomes stronger, but the physical/mechanical contacts are still rare. We develop a three-dimensional finite element approach for simulating the motions of multiple fibers in low-Reynolds-number flows typical of polymer melt flow. We extend our earlier single fiber model to consider hydrodynamic interactions between fibers. This approach computes the hydrodynamic forces and torques on fibers by solving governing equations of motion in fluid. The hydrodynamic forces and torques result from two scenarios: gross fluid motion and hydrodynamic interactions from other fibers. Our approach seeks fibers’ velocities that zero the hydrodynamic torques and forces acting on the fibers by the surrounding fluid. Fiber motions are then computed using a Runge-Kutta approach to update fiber positions and orientations as a function of time. This method is quite general and allows for solving multiple fiber suspensions in complex fluids. Examples with fibers having various starting positions and orientations are considered and compared with Jeffery’s single fiber solution (1922). Meanwhile, we study the effect of the presence of a bounded wall on fiber motions, which is ignored in Jeffery’s original work. The possible reasons why fiber motions observed in experiments align slower than those predicted by Jeffery’s theory are discussed in this paper.
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Braghin, Francesco, Edoardo Sabbioni, and Francesco Annoni. "Design of a Leaf Spring Suspension for an FSAE Vehicle." In ASME 2007 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. ASMEDC, 2007. http://dx.doi.org/10.1115/detc2007-35474.

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FSAE is a competition in which engineering students are asked to conceive, design, fabricate and compete with small, formula style, autocross racing cars ([1]). To give teams the maximum design flexibility and the freedom to express their creativity and imaginations there are very few restrictions on the overall vehicle design. DynamiΣ team (from Politecnico di Milano) has designed and optimized a new leaf spring suspension that allows to significantly reduce the weight and lower the centre of gravity of traditional suspensions that are based on linear dampers and coil springs. In fact, besides being extremely adjustable, the proposed leaf spring suspension weights a half, being made of carbon fiber and aluminum sandwich, and lowers the centre of gravity of the suspension system, being placed below the vehicle frame.
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Carlsson, A., F. Lundell, and L. D. So¨derberg. "Fibre Orientation Control Related to Papermaking." In ASME 2006 2nd Joint U.S.-European Fluids Engineering Summer Meeting Collocated With the 14th International Conference on Nuclear Engineering. ASMEDC, 2006. http://dx.doi.org/10.1115/fedsm2006-98408.

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The wall effect on the orientation of fibres suspended in a shear flow has been studied experimentally. A fibre suspension, driven by gravity down an inclined glass plate, constitutes the shear flow field. A CCD-camera was mounted underneath the flow in order to visualize the flow. The orientation of fibres in the plane perpendicular to the plate was determined, by using the concept of steerable filters. In a region close to the smooth plate surface the fibres oriented themselves perpendicular to the flow direction. This did not occur when the surface structure was modified with ridges.
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KUZHIR, PAVEL, GEORGES BOSSIS, ALAIN MEUNIER, MODESTO T. LOPEZ-LOPEZ, and ANA GOMEZ-RAMIREZ. "RHEOLOGY OF MAGNETIC FIBER SUSPENSIONS." In Proceedings of the 12th International Conference. WORLD SCIENTIFIC, 2011. http://dx.doi.org/10.1142/9789814340236_0049.

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