High Shear Mixing for Lubricant Homogenization

Mixing liquids with unequal viscosity involves complex flows and a nontrivial diffusive feedback. As an insightful reference case, we study the deformation of a spherical blob with viscosity , sheared in a miscible bath with viscosity . Experiments resolve the transition from unbounded stretching, at low , to rollinglike motion, at large . In between the blob is transiently substretched before destabilizing into swirling structures. Exact solutions of the flow recover all three regimes and predict a transition ratio _{c}3.975. We discuss the dramatic impact of the flow transition on mixing and propose scaling laws for the blob mixing time in the limit of large Pclet numbers, suggesting mixing could be independent of shear rate at large .

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Pulping equipment and system that improves dispersion and mixing of pulp by utilizing a specially designed drive shaft and shell body configuration to generate enhanced shear forces.

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Determining an accurate state of lubrication is of utmost importance for the precise functionality of machine elements and to achieve elongated life and durability. In this work, a homogenized mixed-lubrication model is developed to study the effect of surface topographies on the coefficient of friction. Various measured real surface topographies are integrated in the model using the roughness homogenization method. The shear-thinning behavior of the lubricant is incorporated by employing the Eyring constitutive relation. Several Stribeck curves are generated to analyze the effect of roughness lays and root mean square (RMS) roughness on the coefficient of friction. The homogenized mixed lubrication model is validated against experimental rolling/sliding ball-on-disc results, and a good agreement between simulated and experimental coefficient of friction is found.

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ABSTRACT This study aims to evaluate homogenization techniques and conditions for producing stable, small dropletsize waterinoil (W/O) emulsions intended for incorporation into casein hydrolysateloaded double emulsions. Three commonly used homogenization methods; rotorstator, ultrasonic, and highpressure homogenization were individually optimized utilizing response surface methodology. Instances of overprocessing were observed, particularly with the rotorstator and ultrasonic homogenizers under specific conditions. Nevertheless, optimal conditions were identified for each technique: 530 s at 17,800 rpm agitation speed for the rotorstator homogenizer, 139 s at 39% amplitude for the ultrasonic homogenizer, and 520 s at 1475 bar for the highpressure homogenizer. Subsequently, the W/O emulsions produced under optimal conditions and their respective W 1 /O/W 2 double emulsions were compared. The rotorstator and highpressure homogenized W/O emulsions exhibited comparable narrow dropletsize distributions, as indicated by similar Span values. However, highpressure homogenizatio... Read More

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This chapter provides an overview of the concepts discussed in part 2 of this book. The part provides an introduction to the topics such as mixing and stirrer types, mixing time, power consumption, liquid/liquid dispersions and gas distribution. In the recent past, micromixing has received special attention; this refers to the production of very small eddies with the purpose of mixing the reacting components as fast as possible. Three different types of mixers can be distinguished: mechanical mixers, static mixers, and jet mixers. Stirred vessels are important process items in chemical plants. For heating or cooling, a vessel is often provided with a jacket or a half-pipe jacket. The mixing time 0 is the most important parameter at homogenization. The importance of the mixing time can be investigated on small scale by carrying out experiments at which the mixing time is varied by, for example, variation of the rotational speed of the impeller.

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In this study, a dynamic mixer was designed to mix polymer melts online during extrusion, and the flow of a polymer melt in a mixer was simulated using Polyflow software. The Orthogonal experiment was conducted to analyze the effects of three geometrical parameters (i.e. the length of entrance zone (Li), the gap between the rotor and wall (g), and the diameter of cone-shaped rotor (d2)) on mixing properties of a dynamic mixer. The Li, g, and d2 were optimized for the minimum product of segregation scale (S) and power consumption (P). Finally, the mixing properties of the dynamic mixer were compared with those of SK and SX static mixers. The results indicated that among the above-mentioned three parameters, the g was the most important parameter influencing S, and SP. The minimum SP of 1059 mW was obtained when the Li was 16 mm, the g was 1 mm, and the d2 was 24 mm. The S decreased with the increase of the rotation speed from 120 to 360 r/min, and increased with the increase of the flow rate from 15 to 45 mL/min. However, the P increased with the increase of both the rotation spee... Read More

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Lubricant is vital to improve energy efficiency and workpiece durability for the moving counterpart. High-temperature lubricants are important for the hot rolling process to reduce the rolling force and protect the roller and the strips. The current paper concerns eco-friendly sodium metasilicate as a high-temperature lubricant. A hot rolling mill is employed to evaluate the lubrication effect of sodium metasilicate. The influence of crucial factors of concentration of lubricant and descaling is discussed; the rolled surface was analyzed by scanning electron microscopy, energy dispersive spectroscopy, and 3D profilometer. The results depict that the sodium metasilicate can reduce the rolling force by about 7.8% when the concentration of sodium metasilicate is 18% and above, and descaling of the hot stripe makes the lubrication effect more effective, which can reach a 12.7% reduction in the rolling force. This lubrication is attributed to the formed melts of the sodium silicate layer that offers an easy shearing interface. For the un-descaled samples, the lubricant will be compacted a... Read More

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High-intensity acoustic vibration is a new technology for solving the problem of uniform dispersion of highly viscous materials. In this study, we investigate the mixing characteristics of high-viscosity solidliquid phases under high-intensity acoustic vibration and explore the effect of vibration parameters on the mixing efficiency. A numerical simulation model of solidliquidgas multiphase flow, employing the volume of fluid (VOF) and discrete phase model (DPM), was developed and subsequently validated through experimental verification. The results show that the movement and deformation of the gasliquid surface over the entire field are critical for achieving rapid and uniform mixing of the solidliquid phases under acoustic vibration. Increasing the amplitude or frequency of vibration can intensify the movement and deformation of the free surface of gas and liquid, improve the mixing efficiency, and shorten the mixing time. Under the condition of constant acceleration, the mixing efficiency of materials is higher at low frequency and high amplitude. Further, we define a relatio... Read More

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A method for mixing medium to highly viscous fluids and suspensions using an agitator device driven by a drive shaft. The agitator device features close-clearance stirring blades and counter-stirring blades that work together to efficiently mix thick materials. The device is particularly suited for mixing pastes and other highly viscous substances.

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A solid-liquid mixing and dispersion device that achieves high slurry filling rates and efficient dispersion through a unique design. The device features a cylindrical dispersing wheel and a tangential discharge port, allowing for continuous circulation of liquid and powder while maintaining optimal feed and discharge speeds. The design enables efficient mixing and dispersion of solid-liquid slurries, particularly in applications where high viscosity and uniformity are critical, such as battery manufacturing, food processing, and pharmaceutical production.

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Through laboratory experiments of oil-in-water emulsification, we show that we can construct a high-shear-rate mixer (precession mixer) by using the precession of a cylindrical container without any mixing blades. For high-shear-rate mixing, a container with a larger diameter and its faster spin are preferable so that the wall velocity becomes large enough. Then, emulsification is most efficient when we set the Poincar number Po=p/s, which is the ratio of the spin and precession rotation speeds, about 0.20.3. When Po is smaller than these values, shear rates in the mixer get much lower, though mixing in the bulk of the container is enhanced. On the other hand, when Po is larger, shear rates near the cylindrical wall get higher but mixing in the bulk drastically declines. Through our systematic parameter survey for efficient emulsification by the precession mixer, we have also discovered an experimental law describing the maximum shear rate in the mixer. Since we can use it to appropriately choose the driving conditions of the mixer according to the properties of the materials to ... Read More

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Abstract Pertaining to the mixing of the nonNewtonian Carreau fluid under electrokinetic actuation inside a plane microchannel, we propose a new design of micromixer that involves inserting a twopart cylinder bearing zeta potential of the same sign but different magnitude in the upstream and downstream directions. We numerically solve the transport equations to predict the underlying mixing characteristics. We demonstrate that a substantial momentum difference between the microchannel's plane wall and cylinder leads to the development of a vortex in the flow pathway, which in turn, enhances mixing substantially. As shown, for a fluid having a highly shearthinning nature, the vortexassisted convection mixing strength increases with diffusivity of the candidate fluids. Moreover, it is shown that for the higher shearthinning nature of the candidate fluid, an increase in cylinder radius enhances mixing efficiency and flow rate simultaneously, resulting in a quick and efficient mixing condition. Additionally, the fluid rheology significantly alters the kinetics of shearinduced bin... Read More

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Bubble evolution and shear thinning effect are main factors affecting lubrication behavior of bubbly oil. In this study, a thermohydrodynamic lubrication model for the bubbly oil considering the bubble evolution and the shear thinning effect was established based on the multiphase mixtures theory. The influence of bubble evolution and shear thinning effect on the static behavior of bubbly oil lubricated bearing was analyzed, and an experimental study was conducted to verify the model. The result shows that the bubble radius is mainly dependent on the liquid pressure; the bearing static behavior is affected by the bubble evolution through the interface effect; the shear thinning effect of the pure oil can be enhanced with regarding the bubble evolution effect.

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The structure and flow behavior of lubricating greases depend on the base oil and the type and concentration of the dissolved thickener. In this study, the linear viscoelastic properties of greases were characterized by combining oscillatory shear and squeeze flow covering a broad frequency range (0.1105 rad s1). Multiple-particle tracking (MPT) microrheology and scanning electron microscopy (SEM) provided further insight into local viscoelastic properties and sample structure on a submicron-length scale. The type and viscosity of the base oil did not affect the absolute value of the complex viscosity and the filament shape formed by a given thickener. High-frequency shear modulus data, however, indicated that the thickener lithium 12-hydroxystearate formed stiffer networks/filaments in poly--olefins than in mineral oils. As expected, the viscosity increased with increased thickener concentrations, but microscopy and high-frequency rheometry revealed that the thickness, length, and stiffness of the individual filaments did not change. In mineral oil, the 12-hydroxystearate thicken... Read More

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Abstract We implicitly assess the distributive mixing of generalized Newtonian fluids with shear-thinning behavior in a journal bearing flow geometry. For this purpose, we firstly develop a finite element code to calculate the flow field parameters. Our numerical algorithm splits the viscous stress tensor into arbitrary Newtonian stress and a source term, which grows gradually during the iterative solution. Therefore, we get a better converging solution than the Picard method, especially for highly shear-thinning fluids. Secondly, considering two inert fluids in the mixing domain, we employ a Lagrangian-Eulerian approach to predict the shape of the interface between two fluids. The results of our numerical analysis provide us the required information to evaluate three implicit mixing criteria: the concentration variance, the striation thickness, and the mean strain function. Then we conduct a parametric study to investigate the effects of different parameters (geometry and rheology) on the distributive mixing state. In addition, we discuss which mixing criteria provide a better evalu... Read More

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Abstract Type of lubricant used for fluid film bearings is one of the most important factors to consider. Bearing characteristics have to maintain steady throughout a wide range of conditions. However, viscosity, which is one of the primary lubricant properties, highly deviates depending on environmental and operational conditions. Macro-molecular micro-structure of lubricants is strongly correlated to temperature and shear rate, leading to a shear thinning behaviour. This work aims in studying a pad bearing lubricated by a shear thinning oil in hydrodynamic region. Hydrodynamic wedge was modelled for a small fixed pad bearing of 8.5 mm inner radius, 14.5 mm outer radius, 40 angle and 50 m inlet outlet film thickness difference. Variety of cases were studied for several runner rotational velocities and minimum film thickness. Lubricant was modelled as a carreau fluid. Load carrying capacity, power losses, friction coefficient, mass flow rate, temperature and viscosity were evaluated. From the aspect of load carrying capacity, this specific pad bearing is optimally operating for r... Read More

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Under limited lubricant supply condition, the lubrication of a slider bearing can be enhanced by discontinuous oil droplets on the lubrication track induced by poor surface wettability. This experimental finding is contrary to the general perception that strong surface wettability favors lubricating film build up. Theoretical lubrication models with the lubricant supply in the forms of oil droplets (Model ) and uniform oil layer (Model ) are established to clarify the odd experimental observation. Results show that oil supply in the form of droplets can achieve better lubrication performance than the uniform oil layer, which are correlated to the experimental finding. The mechanism is probably due to the early film pressure initiation when oil droplets enter the bearing contact.

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The mixing process is often used not only to homogenize the materials, but also to bring out better functions by mixing different materials. In the mixing process involving chemical reactions, it is also important to quickly remove the by-products of the reaction. In this study, a flow field around a single rotor rotating in a partially filled chamber was numerically simulated using a 3D model to examine the interface renewal characteristics of highly viscous fluids. The fluids examined were glycerin, which is Newtonian fluid, and aqueous solution of carboxymethylcellulose (CMC), which is Non-Newtonian fluid. A three-wing rotor was chosen as the mixing rotor. The evaluation of interface renewal was performed using history particles. Also, the flow states were classified into rotational, shear, and extensional flows using the Flow number to analyze the flow field. The velocity distribution obtained by the simulation was in good agreement with the experimental results under the same geometry and conditions. For distributive mixing and interface renewal, CMC results were superior to gly... Read More

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In order to mix highly viscous fluids with minimal energetic input, a new active in-line mixer has been developed in our previous study (El Omari et al., Phys. Rev. Fluids, 2021 [18]). Based on the principle of mixing by chaotic advection, we present in this paper an experimental characterisation of chaotic mixing of Newtonian fluid flows, at low Reynolds number. First, the flow is characterized using velocity field measurements. Distinct flow topologies are detected in the flow. The trajectories of the fluid particles are computed and show the generation of complex structures in the flow. Residence time distributions reveal that the fluid particles spend more time in the mixer under favorable controlling conditions. Finite size Lyapunov exponents are calculated and indicate that the flow is more chaotic for these conditions. Next, the mixing patterns are visualized and showed that the mixing is more homogeneous under the same favorable conditions for which the fluid particles are sufficiently subjected to the stretching and folding mechanism.

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The mixing process is used not only to homogenize the materials, but also to bring out better functionality by mixing different materials. In the mixing process, temperature control during mixing is important to prevent thermal deterioration of the material and control chemical reactions. In this study, a 3D model was used to numerically simulate the flow field around a single rotating rotor in a partially filled chamber to investigate the thermal flow characteristics of a highly viscous fluid. The liquids examined contained glycerin, a Newtonian fluid, and carboxymethyl cellulose (CMC) aqueous solution, a non-Newtonian fluid. A three-wing rotor was chosen as the mixing rotor and the shear heating of viscous fluid was modeled by heating the tip of the rotor wing with a heater. Obtained simulation results of the temperature distribution around the rotor was agreed well with the independently performed experimental results. Evaluation of thermal flow properties was performed using history particles. Also, in order to analyze the temperature field, the flow rate through the rotor tip wa... Read More

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Glidants and lubricants are often used to modify interparticle friction and adhesion in order to improve powder characteristics, such as flowability and compactability. Magnesium stearate (MgSt) powder is widely used as a lubricant. Shear straining causes MgSt particles to break, delaminate, and adhere to the surfaces of the host particles. In this work, a comparison is made of the effect of three mixer types on the lubricating role of MgSt particles. The flow behaviour of -lactose monohydrate, coated with MgSt at different mass percentages of 0.2, 0.5, 1, and 5 is characterised. The mixing and coating process is carried out by dry blending using Turbula, ProCepT, and Mechanofusion. Measures have been taken to operate under equivalent mixing conditions, as reported in the literature. The flow resistance of the coated samples is measured using the FT4 rheometer. The results indicate that the flow characteristics of the processed powders are remarkably similar in the cases of samples treated by Turbula and Mechanofusion, despite extreme conditions of shear strain rate. The least flow ... Read More

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Abstract Blending is the process of mixing of Base Oil and Additive to produce lubricating oil with the required specifications/characteristics. One of the determining factors to obtain the desired lubrication oil is the homogenization process. In this study, an analysis of the effect of the inlet position, circulation time, and flow velocity on the homogeneity of the resulting mixture was analyzed. The research method used is the computational fluid dynamic (CFD) simulation method with 2-dimensional (2D) fluent software. The flow that occurs in this condition is turbulent with the turbulent model used k- (epsilon). The results show that the upper inlet position within 10 minutes has gotten a homogeneous mixture compared to the lower inlet positions (30 minutes) and the center (20 minutes). Fluid flow velocity also affects the homogeneity of lubricating oil where the speed of 3 m/s within 10 minutes has obtained homogeneous results for all inlet positions compared to the velocity of 1.7 m/s and 2.5 m/s. In addition, the circulation time also affects the homogeneity level where for t... Read More

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A solid-liquid mixing device that integrates powder infiltration and high-efficiency dispersion into a single unit. The device employs a unique impeller assembly featuring a truncated cone-shaped body with unequal diameter blades, which generates a significant increase in suspension linear velocity. The assembly also includes at least one baffle without holes, strategically positioned to enhance mixing and dispersion effects. The baffle's tortuous flow path and rotating frictional shear action significantly improve dispersion consistency, enabling the production of high-viscosity and high-concentration suspensions.

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Abstract The mixing performance of baffles placed with a clearance between them and the mixing vessel wall was investigated in a shearthinning fluid, and decolorization experiments were conducted to observe the mixing pattern under nobaffle, standard baffle, and innerbaffle conditions. Velocity fields were obtained by particle image velocimetry to clarify the mixing mechanism in the fluid. No isolated mixing region was seen under the innerbaffle condition, and this condition promoted homogeneous mixing. The velocity profile clarified that the inner baffle prevented secondary circulation flow from forming an isolated mixing region and, thus, promoted homogeneous mixing in the fluid. An inner baffle with a small impeller can obtain homogeneous mixing in shearthinning fluids.

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Abstract A method to intensify the mixing process of scalar components within shearthinning fluids is proposed. A conical TaylorCouette flow enabled fluid elements to circulate in the entire fluid column owing to the global circulation flow (i.e., meridional flow) for keeping good local mixing within Taylor cells. The global convection and mixing characteristics were numerically investigated. The meridional flow was found to be enhanced with increasing shearthinning. In addition, the mixing performance was evaluated using a passive tracer. Global mixing with shearthinning fluids was promoted by the enhanced meridional flow compared with that of Newtonian fluids. Therefore, the conical TaylorCouette apparatus could be used for intensifying mixing processes in shearthinning fluid systems.

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Homogenizers function as mixers that reduce particle size or force immiscible liquids to mix. Pressure imparted on a product by the homogenizer is largely determined by pump pressure or flow diversion through valves and nozzles. In the case of low-pressure homogenizers, fluid velocity is incremented which reduces overall pressure. In addition to the valve homogenizers commonly used in the dairy industry, a number of emulsifying and homogenizing systems that employ different operating principles are available. High-shear blenders and mixers find wide application in the dairy and related industries for the preparation of coarse pre-emulsions. Colloid mills, which operate on the rotorstator principle, are used for homogenizing medium- and high-viscosity systems, for instance in the preparation of caseins and caseinates. Ultrasonic waves can be used for either preparing emulsions or reducing the size of existing emulsions. For preparing emulsions with extremely small fat globules and very narrow size distributions, microfluidization can be used, where fluid streams are forced to collide... Read More

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Lubricant behaves non-Newtonian at high shear stress and high shear rate. The non-Newtonian shear behavior of oil such as shear-thinning, viscoelasticity, and limiting shear stress could have influences on almost all characteristics of an elastohydrodynamic lubrication (EHL) contact, that is, the central film thickness, the coefficient of friction, and the temperature rise in the lubricating film. For example, for lubricants of large molecular weight or of polymer blended ones, there can be inlet shear-thinning, which would reduce the EHL film thickness. For the EHL traction in a rolling/sliding EHL contact, it cannot be reasonably predicted without the consideration of non-Newtonian rheology. In EHL numerical studies, the non-Newtonian properties and the constitutive equations are expressed by the concept of generalized viscosity [Formula: see text], which can be either a function of shear rate [Formula: see text] or a function of shear stress [Formula: see text]. In this way, a non-Newtonian lubrication problem could be solved as a generalized Newtonian problem based on solvers for... Read More

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The dynamic responses of hydrodynamically lubricated surfaces have attracted many researchers for the sake of improving both the lubrication performances and online lubrication monitoring. To gain insightful understandings of dynamic interactions in a fluid lubricated joint that are the fundamentals of many key mechanical components such as bearings and seals in the engine, a series of engine lubricants were tested in a cone-plate rheometer and the corresponding acoustic emission (AE) signals are acquired to monitor the dynamic interactions of tribofilm shearing with surface asperities. The observations show that the AE measurements are sensitive to the change of lubrication conditions, specifically shearing rates. A greater shear rate can excite a wider frequency bandwidth and stronger AE signals. This AE response with respect to the engine lubricants samples can be explained by the dynamic fluid-asperity shearing model. These findings provide important guidelines for analysing the online measured AE signals from complex machines.

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The movement of viscous fluid in a small gap between stationary and rotating disks is investigated and a mathematical description is given for flat and stepped disks. Using the mathematical apparatus of random Markov processes discrete in space and time, a model of the process of mixing grease with graphene plates in a rotary homogenizer disperser has been created. Decomposition of the process and consideration of separate mixing processes in the radial and circumferential directions made it possible to assess the intensity of these processes and develop recommendations for the transition from laboratory installations to industrial devices.

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The development of high-performance static mixers is a critical research topic in process intensification in the process industry. This research combines computational fluid dynamics simulation and experimental testing to design a new type of static micromixer: First, a variable-diameter swirl shear mixer was designed and its structure was optimized. Measured by Malvern laser particle size analyzer, the median particle size decreased from 41 m to 29 m in the designed micromixer compared to that of traditional static mixers. Subsequently, the dispersed phase injection method was upgraded to a jet injection method, and the static micromixer was designed with a combination of an ejector and a variable-diameter swirl shear mixer. The median particle size of the dispersed droplets further decreased to 23 m, achieving a dispersion effect at 21002400 rpm of the dynamic high-shear mixer. The micromixer greatly improved the static mixing effect and may replace dynamic high-shear mixers in the future.

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Advancements in mechanical expertise and rigorous need for gyratory components of machines expedite scientists towards essentiality of the eternal evolution of modified lubricants to corroborate the reliability, innocuous procedure and stability of sundry bearings. To enhance the performances at heftily ponderous load and high velocity, the high molecular polymers are utilized in mechanical bearings as lubricant. These lubricants are non-Newtonian in characteristics and comply with different constitutive relationships. One of them is the power law lubricant which complies with Ostwald model and is broadly utilized for the engineering lubrication. The derivation of the slip-flow conditions at the interface of bulk Jeffrey fluid and the thin layer non-Newtonian lubricant is performed over a disk spiraling with simultaneous radial stretching and rotation. To obtain a homogeneous solution, the power-law index is suggested 1/3 and no-slip boundary condition is converted into an incipient slip boundary condition. A single dimensionless slip parameter is introduced to regulate the velocity ... Read More

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Passive flow control tools have been widely used to enhance shear layer mixing in ramjet engines. Lobed mixer is an excellent method in mixing enhancement performance, while there is no comprehensive consensus on its mixing enhancement mechanism in a subsonic-supersonic shear layer. In this work, a sinusoidal lobed mixer is used to increase mixing between the subsonic and supersonic flows, and large eddy simulation (LES) is used to research the potential flow control mechanisms. Parameter experiments were carried out and the mixing performance was obtained. The numerical conclusions show good similarity with experimental conclusions. The impact of the geometric scales of the modified lobed mixer in the evolution of shear layer is investigated. It is found that sinusoidal lobed splitter plate with wavelength 10 mm and amplitude 2 mm shows the best mixing thickness experimentally and numerically, where compared with other cases, it is 3.3 times thicker than that of the flat plate. It is demonstrated that the sinusoidal lobed mixer performance is affected by its amplitude and wavelength... Read More

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High-pressure homogenizers (HPH) equipped with a Simultaneous Homogenization and Mixing (SHM) orifice allow for inducing a mixing stream directly into the disruption unit. Previous studies show that by doing so, synergies between the unit operations emulsification and mixing can be used to save energy, e.g., in homogenization of dairy products, or to extend the application range of HPH. Up to now, process design has mainly been based on the trial and error principle due to incomplete understanding of flow conditions and droplet break-up in the SHM unit. This study aims at a higher level of understanding of cavitation and mixing effects on emulsion droplet size. Experimental data were obtained using a model emulsion of low disperse phase concentration in order to avoid coalescence effects. The different flow conditions are created by varying the process and geometric parameters of an SHM unit. The results show that the oil droplet size only depends on mixing conditions when the emulsion droplets are added in the mixing stream. Furthermore, a smaller oil droplet size can be achieve... Read More

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The article describes the requirements for the lubricant used in injection molding of non-ferrous alloys. A methodology for conducting research to determine the sedimentation stability of a prepared lubricant is presented, as well as the results of a study of the sedimentation stability of a lubricant used in non-ferrous alloy die casting. It was established that in order to significantly increase the sedimentation stability of the compositions of lubricants for casting silumin based on the selected components, it is necessary to pre-heat the initial components to a temperature of at least 80 C and mix them at a rotational speed of the dispersant blades of at least 6000 min 1 . The optimal mode of lubrication with high sedimentation stability (more than 200 days) is observed at the following temperature and time indicators: the temperature of the heating of the starting components is at least 90 C, the mixing time is 5 minutes, and the mixing frequency is 18000 min 1 .

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Abstract The mixing characteristics of two initially stratified highviscosity fluids with a free surface under forced vertical vibration were studied experimentally and numerically. The flow characteristics and dynamics of the free surface and interface between liquids were analyzed and the effects of the vibration parameters on the mixing process were evaluated. The degree of mixing was determined by the frequency and amplitude of vibration. Effective mixing could not be achieved by merely using the deformation of the free surface because of the low fluidity of highviscosity fluids. However, an increase in vibration intensity disintegrated the free surface and interface, thereby significantly promoting the mixing of fluids and improving the mixing efficiency.

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Mixing is the degree of homogeneity of two or more phases and it plays a vital role in the quality of the final product. It is conventionally carried out by mechanical agitators or by static mixers. Static mixers are a series of geometric mixing elements fixed within a pipe, which use the energy of the flow stream to create mixing between two or more fluids or to inject metered liquid into a continuous process. The objective of this work is to predict hydrodynamic aspects of the static mixer designed. The mixing performance of a Komax static mixer has been determined for the blending of non-Newtonian fluid streams with identical or different rheology by using experimental study. The energy needed for mixing comes from the force created by the liquid due to turbulence and the geometry of the static mixer. Pressure drop in the static mixer depends strongly on the geometric arrangement of the inserts, properties of fluids to be mixed and flow conditions. Hence, pressure drop studies are carried out for different flow rates of fluids with different concentrations of two non-Newtonian flu... Read More

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Viscoelastic fluids have been recently proposed to promote mixing effect in microfluidic systems, where limited success has been obtained. However, the flow and mixing mechanism of a viscoelastic fluid is still poorly understood, particularly regarding the roles of injection on mixing at low Reynolds numbers. In this work, an efficient mixer by orthogonal injection into a primary flow is proposed. The mixing behaviors of shear-thinning fluids in a serpentine channel with an orthogonal injection are investigated experimentally. Dye visualization and concomitant statistical analysis are conducted to quantitatively characterize the mixing performance and to reveal the flow kinematics. Enhanced mixing is achieved just over a short effective mixing length. The probability distribution functions (PDFs) analysis shows that the mixing efficiency, defined by the normalized concentration of dye intensity (Gan et al., 2007), can be significantly improved from 22% for the Newtonian fluids to 69% and 76% by using a shear-thinning fluid with polymer concentrations of 25 and 50 ppm, respectively. T... Read More

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Tribological performance of mating surfaces can be improved by developing surfaces with predefined textures and it is crucial to understand their role in modifying the performance and action of boundary lubrication additives. An isotropic texture T1, intermediate texture T2 and anisotropic texture, T3, were imported into our mixed simulation framework. It was found that T3 outperforms by providing the most feasible conditions for the activation of the lubricant additive, molybdenum dithiocarbamate (MoDTC) i.e. generating higher pressure peaks (shear), making more lubricant (reactant) available and providing greater load bearing area (greater reaction probability). Hence, facilitating the formation of functional boundary films. T2 seems to generate highest pressure peaks but its performance is worst due to its inability to sustain lubricant within the contact.

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AbstractThe purpose of this paper is to study the lubricant shear-thinning effects on the film bearing performance.A thermal-hydrodynamic lubrication analysis model is presented, considering the shear-thinning effect, turbulent effect, and mass conserving cavitation boundary conditions.Then, the bearing performance is solved by finite element method.The correctness of the analytical model is verified by the comparison between the theoretical and existing experimental data.Under wide operating conditions, such as speeds, loads and oil supply temperatures, the effects of shear thinning on the lubrication performance, such as film thickness, film pressure, temperature rise, power consumption, flow rate, is systematically investigated.The applicability of the thermal model is discussed.It is showed that the shear thinning effect has important influence on the film bearing performance.The significance of the shear thinning effect is depending on the load and speed conditions.Shear thinning effects are improved the bearing performance in light load condition and deteriorate in heavy load ... Read More

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The better mixing of ingredients is the key to improving the quality of the process in the manufacturing of several products. Gyro Shaker is a dual rotation mixer commonly used for mixing highly viscous fluids. In this work, CFD simulation for the multiphase mixing of Gyro Shaker is carried out for obtaining numerical solutions. Simulations of three different mixing models namely Eulerian granular model, mixture model and volume of fluid (VOF) model are compared with each other. Reynolds number and power number based on characteristic velocity were derived for the Gyro Shaker. Experiments were conducted to validate the mixing power by the simulation using torque method and viscous dissipation method. The viscous dissipation method for mixing power demonstrates a low deviation from the experiment data than torque method. Among the three simulation models, the multiphase mixture model shows the minimum variation of the experimental data. A comparison of the flow field of the different mixing models is also carried out.

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