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Heavy oil, with high viscosity and complex compositions, often faces a series of challenges in the process of its exploitation and utilization. There are huge amounts of compositions with different...

We report novel supramolecular polymers, which possess a reversed viscosity/temperature profile. To this end, we developed a series of ditopic monomers featuring two self-complementary binding sites, either the guanidiniocarbonyl pyrrole carboxylic acid (GCP) or the aminopyridine carbonyl pyrrole carboxylic acid (ACP). At low temperatures, small cyclic structures are formed. However, at elevated temperatures, a ring–chain transformation leads to the formation of a supramolecular polymer. We demonstrate that this effect is dependent on the concentration of the solution and on the polarity of the solvent. This effect can counteract the loss of viscosity of the solvent at elevated temperatures, thus opening an application of our systems as viscosity index improvers (VIIs) in working fluids. This was tested for different motor oils and led to the identification of one compound as a promising VII.

In order to explore the construction performance of zeolite asphalt mixture, the microproperties of zeolite and the macroproperties of zeolite asphalt mixture were studied. The structure composition, surface properties, and pore characteristics of zeolite were analyzed by infrared spectroscopy and pressure pump method. The structure, composition, and thermal stability of zeolite were analyzed by differential scanning calorimetry and thermogravimetry, the mechanism of moisture absorption and loss of water was explored, and the properties of moisture absorption and loss of water were studied. The effect of the type and amount of zeolite on the viscosity of asphalt was studied by the viscosity test. According to the mixing current and the compaction void ratio, the influence of zeolite on the construction performance of zeolite asphalt mixture was studied. The results show that zeolite contains special zeolite water and the pore content of zeolite is much higher than that of mineral powder. Zeolite loses water at 90°C∼120°C, which is the necessary condition for zeolite to be used in warm mix asphalt mixture. The water absorption and loss capacity of zeolite mainly depend on pore volume. The larger the pore volume is, the stronger the water holding capacity of zeolite is. Meanwhile, the water holding capacity and loss capacity of zeolite are related to pore size distribution. According to the viscosity temperature equation, the mixing and compaction temperature of the asphalt mixture are determined. The mixing and initial pressure temperature of the zeolite asphalt mixture are lower than those of the hot asphalt mixture. Based on the principle of mixing current equivalence, the mixing temperature of zeolite asphalt mixture can be reduced by 20°C compared with that of hot asphalt mixture. The better the water loss performance of zeolite is, the easier the mixture is to be compacted. For the base asphalt mixture, the compaction temperature of the mixture is 120–130°C, and, for the modified asphalt mixture, the compaction temperature is 130–140°C.

Rheological behaviors of several commercial mold slags, which were designed for continuous casting of high-carbon steel, peritectic steel, and high-Al steel were studied using rotational viscometer with various rotating speeds. The crystallization rates, which were correlated with rheological behaviors, were detected by in-situ observation. The effect of steel-slag interface reaction between high-Al steel and CaO–Al2O3-based slag on the non-Newtonian fluid behaviors was also discussed. The main results demonstrated that these mold slags all belonged to pseudoplastic fluid and exhibited shear thinning characteristics. The index of flow characteristics in high temperature zone was less than 1 and fluctuated around 0.9, while in low temperature zone, n rapidly decreased from 0.9 to 0.3. The results show that the low temperature zone is more obvious than the high temperature zone for the shear thinning characteristics of the mold fluxes below the break temperature. The shear thinning was closely related to the crystallization rate and grain size of crystals precipitated within melts. Steel-slag interface reaction decreased the content of glass formers, such as SiO2 and B2O3. The crystallization capacity was enhanced, followed by a reduction of lubrication ability. It is found non-Newtonian behaviors of commercial mold slag are closely associated with their crystallization capacity, and the discussion range of viscosity temperature is more in line with the actual temperature drop range of molten flux during continuous casting, which is of great significance to understand the mechanism of shear thinning and optimize the comprehensive performances of commercial mold slags.

Gasification or combustion of coal and biomass is the most important form of power generation today. However, the use of coal/biomass at high temperatures has an inherent problem related to the ash generated. The formation of ash leads to a problematic phenomenon called slagging. Slagging is the accumulation of molten ash on the walls of the furnace, gasifier, or boiler and is detrimental as it reduces the heat transfer rate, and the combustion/gasification rate of unburnt carbon, causes mechanical failure, high-temperature corrosion and on occasions, superheater explosions. To improve the gasifier/combustor facility, it is very important to understand the key ash properties, slag characteristics, viscosity and critical viscosity temperature. This paper reviews the content, compositions, and melting characteristics of ashes in differently ranked coal and biomass, and discusses the formation mechanism, characteristics, and structure of slag. In particular, this paper focuses on low-rank coal and biomass that have been receiving increased attention recently. Besides, it reviews the available methodologies and formulae for slag viscosity measurement/prediction and summarizes the current limitations and potential applications. Moreover, it discusses the slagging behavior of different ranks of coal and biomass by examining the applicability of the current viscosity measurement methods to these fuels, and the viscosity prediction models and factors that affect the slag viscosity. This review shows that the existing viscosity models and slagging indices can only satisfactorily predict the viscosity and slagging propensity of high-rank coals but cannot predict the slagging propensity and slag viscosity of low-rank coal, and especially biomass ashes, even if they are limited to a particular composition only. Thus, there is a critical need for the development of an index, or a model or even a measurement method, which can predict/measure the slagging propensity and slag viscosity correctly for all low-rank coal and biomass ashes.

Viscosity-temperature characteristics of high borosilicate glass were investigated in detail by means of rotor viscometer and dilatometer. The neck-down deformation process of glass tube was simulated by Polyflow software, and the simulation was verified by the secondary drawing of glass perform. The results showed that the high temperature viscosity of borosilicate glass is higher compared to that of ordinary optical glass. In the high temperature stage, the fitting curves of VFT, AV, AG and MYEGA models are all in good agreement with the tested curve. However, in the low temperature stage, only viscosity fitted by VFT model is close to the tested value. Based on Navier-Stokes equation, a mathematical model of neck-down deformation of glass tube during secondary drawing is established. It is found that viscosity is the key material intrinsic factor affecting neck-down process of glass tube. The distribution of inner and outer diameters of glass tube along the drawing direction is simulated and analyzed under different feeding and drawing rates. The deviation between the steady-state dimension simulated and that actually drawn is only ±0.06 mm.

Received: 02.07.2021. Revised: 16.08.2021. Accepted: 13.09.2021. Available online: 21.09.2021. The viscosity of cryolite melts of conventional composition NaF–AlF3–CaF2–Al2O3 was studied by rotational viscometry using the FRS 1600 high-temperature rheometer. The cryolite ratio of the NaF–AlF3 melt was 2.1, 2.3, and 2.5; the Al2O3 content varied from 2 to 6.6, and CaF2 – from 0 to 8 wt%. The measurements were carried out in the temperature range from liquidus to 1200 °C. The conditions for the laminar flow of the investigated melts were determined, based on the measurements of the cryolite melts viscosity as a function of the shear rate at a constant temperature. A shear rate of 12 ± 1 s–1 was chosen for studying the viscosity temperature dependence for all samples. The viscosity temperature dependence of cryolite melts is described by a linear equation. The temperature coefficient b in this equation has negative values and varies in the range of (–0.01)–(–0.06) mPa·s/deg. It was found that the viscosity of cryolite melts of conventional composition in the range of operating temperatures of aluminum electrolysis (950–970 °C) varies from 2.5 to 3.7 mPa·s (depending on the composition and temperature). The viscosity of cryolite-alumina melts increases with the rise of alumina content: 1 wt% Al2O3 increases the viscosity, on average, by 1%. However, the influence of CaF2 is more significant: the addition of 1 wt% CaF2 leads to an increase in viscosity by 3%. A decrease in the CR of the melt by 0.1 (in the range of 2.1–2.5) leads to a decrease in the viscosity of cryolite melts by 2.3%. A viscosity regression equation for the cryolite melts of conventional composition as a function of several independent parameters (temperature, CR, CaF2 and Al2O3 content) is obtained by the multivariable approximation of experimental data. The equation satisfactorily (within 1.5%) describes the viscosity of conventional industrial electrolytes and can be used for estimation of their viscosity.

Coal ash slag viscosity is critical for slag tapping in entrained-flow coal gasifiers, so the accurate prediction of slag viscosity and the critical temperature of viscosity (Tcv) will help the coal selection, flux addition and gasifier operation. Many empirical correlation models based on ash fusion temperature have been proposed to calculate Tcv. In order to correlate the viscosity with the fusion behavior and then improve the prediction of Tcv, we measured the viscosity of several synthetic coal ash slags with a high-temperature rotary viscometer and studied their ash fusion behavior through thermomechanical analysis. X-ray diffraction was used to compare the mineral transformation before and after Tcv combined with the FactSage calculation. The viscosity measurement shows that the viscosity above Tcv of glassy slags is higher than that of the crystalline type. The mineral transformation from FactSage also demonstrates that the precipitation rate of solid phase is lower for glassy slags. The fusion behavior for the glassy and the crystalline slag is also distinctly different. The fusion range from deformation temperature (DT) to flow temperature (FT) of the ash for the glassy slag was larger than that of the crystalline one, and the shrinkage above FT in TMA trace slopes gently. The correlation between the fusion behavior and viscosity-temperature behavior for the glassy slag is reasonable, because the large temperature range from DT to FT and the low shrinking rate of the stage III indicate the high viscosity of the liquid phase formed and the slow melting of the remained solid phase respectively, which are also the correlative condition prefer for the formation of glass as mentioned above. For the crystalline slag, the small fusion range from DT to FT means the rapid melting of the solid phase and the high flowability of the liquid phase which are indicative for the rapid precipitation during cooling. The slow rate of the stage III indicates the slow melting of the remained solid which can be the crystal nucleus. When the viscosity of the liquid phase is low, it also benefit for the formation of crystalline slags. The characteristic in fusion behavior for different type of slag also suggested that the predicting Tcv by applying one method to all the crystalline slags and non-crystalline slags is not appropriate.

The analysis of viscosity of fluid systems is in great demand by the optimisation of industrial products and processes. For this instance, numerous empirical expressions have been suggested...

The flow of a viscous model fluid in a flat channel with a non-uniform temperature field is considered. The problem of the stability of a thermoviscous fluid is solved on the basis of the derived generalized Orr-Sommerfeld equation by the spectral decomposition method in Chebyshev polynomials. The effect of taking into account the linear and exponential dependences of the fluid viscosity on temperature on the spectral characteristics of the hydrodynamic stability equation for an incompressible fluid in a flat channel with given different wall temperatures is investigated. Analytically obtained profiles of the flow rate of a thermovisible fluid. The spectral pictures of the eigenvalues of the generalized Orr-Sommerfeld equation are constructed. It is shown that the structure of the spectra largely depends on the properties of the liquid, which are determined by the viscosity functional dependence index. It has been established that for small values of the thermoviscosity parameter the spectrum compares the spectrum for isothermal fluid flow, however, as it increases, the number of eigenvalues and their density increase, that is, there are more points at which the problem has a nontrivial solution. The stability of the flow of a thermoviscous fluid depends on the presence of an eigenvalue with a positive imaginary part among the entire set of eigenvalues found with fixed Reynolds number and wavenumber parameters. It is shown that with a fixed Reynolds number and a wave number with an increase in the thermoviscosity parameter, the flow becomes unstable. The spectral characteristics determine the structure of the eigenfunctions and the critical parameters of the flow of a thermally viscous fluid. The eigenfunctions constructed in the subsequent works show the behavior of transverse-velocity perturbations, their possible growth or decay over time.

The entrained flow gasification process employs a high temperature, high pressure slagging gasifier, in which the viscosity of the slag plays a key role in determining operating conditions. Many studies have focused on the viscosity of slag under the reducing atmosphere, especially CO + CO2 and CO + H2. As an important component in the gasification syngas, the effect of water vapor on the slag viscosity temperature properties is not yet clear. In order to keep the stable operation of the gasifier, the effect of water vapor on the viscosity temperature properties of the slag were studied in this work. Ash fusion temperatures (AFTs) decrease with the increasing water vapor proportion. Although mineral species do not change obviously, the content of SiO2 in the ash decreases, and more amorphous substances forms when water vapor is added. The slag viscosity and temperature of critical viscosity (TCV) also decrease with the introduction of water vapor, while the effect is not obvious due to the low solubility at ambient pressure. It is confirmed that water vapor weakens the melts network structure by breaking [Si–O–Si] bonds. Meanwhile, the network modifier, [AlO6]9−, increases with the increasing water vapor proportion. Besides, water vapor inhibits the growth of the crystal. As its proportion increases, the average particle size of crystals decreases, leading to the decrease of the slag viscosity and TCV. The results provide a theoretical basis for the effect of water vapor on the slag viscosity and will be benefit for the operation of entrained flow gasification, especially for the coal water slurry gasification.

For the long-term stable operation of the entrained flow gasifier in the coal chemical industry, the flux agents are generally adopted to adjust the fusibility of coal ash. Therefore, it is necessary to understand the underlying mechanism for the impact of typical oxide flux agents on viscosity temperature properties of coal ash from structures and thermodynamics. In this work, the role of calcium oxide, sodium oxide and ferrous oxide on viscosity temperature properties is investigated by a combination of molecular dynamics simulations and thermodynamic calculations. The variations of viscosity and temperature of critical viscosity are obtained for different ternary coal ash systems by thermodynamic calculation. Ternary phase diagrams are applied to evaluate the effect of different flux agents, which are also found to cause mineral transformation from high-temperature minerals to low-temperature minerals. Oxygen bond species are employed as the indicator of the structural evolution originating from addition of different flux agents. The sodium atoms may more readily weaken the tricluster oxygen bonds than calcium or ferrous atoms according to the results. Higher content of bridging oxygen bonds in the sodium oxide ternary coal ash system can enhance the stability of the structures and induce higher viscosity. Stability coefficients are defined here and a function to describe the relationship between the viscosity and flux agent content is established. The results from the current work are expected to provide new clues to find strategies controlling the fusion behaviour of coal ash systems.

Evaluating ash slagging can alleviate the operational problems and improve the efficiency of coal-fired boilers. This paper presents methods to quantify the extent of slagging in a 500 MWe tangential firing boiler by determining the thermal resistance and relating it to ash properties. To determine the thermal resistance by slagging, the operational data of the boiler were extracted for six coal-blend cases and analyzed using a one-dimensional process model. Although the conventional slagging indices based on ash composition have generated conflicting results, new indices based on thermo-mechanical analysis (TMA) of the coal-blend samples provided reasonable agreement with the operational data. In particular, the second peak of the TMA associated with the growth rate was correlated with the thermal resistance of the superheaters, and the third peak representing the slag melting was inversely correlated with that of the furnace wall. It was also found from the numerical modeling of the slag flow on the furnace wall that the critical viscosity temperature at 25 Pa·s can be positively related with the thermal resistance, and consequently, with the slagging propensity of specific coal ashes.

Removing heavy components through solvent separation is a potential routine for the viscosity reduction of Canadian oil sand bitumen. The mixing rule for the viscosity of extracted fraction is the basis of process simulation and optimization. In this study, supercritical fluid extraction fractionation was applied to separate Canadian oil sand bitumen vacuum residue (VR) into various fractions. The viscosity blending behavior of extracted fractions was experimentally evaluated. Several available viscosity mixing rules were tested. To predict the viscosity–temperature profile of derived fractions at different blending ratio, we proposed a new mixing rule based on empirical equation parameters. We also correlated the viscosity–temperature parameters to conventional bulk property, providing a method for the rapid viscosity estimation for VR, extracted fractions, and their mixtures.

The hydrostatic bearing oil film plays a key role in supporting and lubricating. As the speed increases, the temperature of the lubricating oil increases and the viscosity decreases. As a result, the bearing capacity of the oil film is reduced, which affects the motion accuracy of the hydrostatic bearing. In this paper, the simulation and analysis of the temperature rise of the hydrostatic bearing oil film under the constant viscosity and the viscosity-temperature effect are performed respectively. Then, based on the fluid-heat-solid coupling analysis theory, the temperature field of the hydrostatic bearing and the thermal deformation of the spindle shaft with and without the viscosity-temperature effect are analyzed separately. The temperature field of the shaft and the thermal deformation of the spindle shaft are analyzed separately. Finally, the bearing temperature and shaft deformation are compared with the experimental values for error analysis. It is found that the error rate is smaller when the viscosity-temperature effect is considered. Considering the viscosity-temperature effect, the maximum error rates of the temperature of the radial and thrust bearing bushes are 11.05% and 7.82%, and the maximum error rates of the thermal deformation of the spindle shaft in the axial and radial directions are 12.03% and 18.57%.

The behavior of lubricants at operational conditions, such as at high pressures, is a topic of great industrial interest. In particular, viscosity and the viscosity-pressure relation are especially important for applications and their determination by computational simulations is very desirable. In this study, we evaluate methods to compute these quantities based on fully atomistic molecular dynamics simulations, which are computationally demanding but also have the potential to be most accurate. We used the 9,10-dimethyloctadecane molecule, main component of PAO-2 base oil as the lubricant for our tests. The methods used for the viscosity simulations are the Green-Kubo equilibrium molecular dynamics (EMD-GK) and nonequilibrium molecular dynamics (NEMD), at pressures of up to 1.0 GPa and various temperatures (40-150 degrees Celsius). We present the theory behind these methods and investigate how the simulation parameters affect the results obtained, to ensure viscosity convergence with respect to the simulation intervals and all other parameters. We show that, by using each method in its regime of applicability, we can achieve good agreement between simulated and measured values. NEMD simulations at high pressures captured zero shear viscosity successfully; while at 40 degrees Celsius, EMD-GK is only applicable to pressures up to 0.3 GPa, where the viscosity is lower. In NEMD, longer and multiply repeated simulations improve the confidence interval of viscosity, which is essential at lower pressures. Another aspect of these methods is the choice of the utilized force field for the atomic interactions. This was investigated by selecting two different commonly used force fields.

This paper reports for the first time the possible formation of a novel room temperature therapeutic deep eutectic solvent (THEDES) of risperidone (RIS) with some fatty acids, namely capric acid (C10; CA), lauric acid (C12; LA), and myristic acid (C14; MA). All mixtures of RIS and MA yielded a solid or pasty-like solid and were readily discarded. Some of the prepared THEDESs from RIS and CA or LA have spontaneously transformed into a transparent liquid, without any precipitate at room temperature by simple physical mixing of the components. From the DSC thermograms, phase diagrams of the eutectic systems were constructed and the lowest obtained melting point for a RIS:CA mixture was 17°C at 40:60% w/w ratio. While 22°C was recorded as the lowest melting point for RIS:LA at a ratio of 30:70% w/w, solubility improvement of RIS was up to 70,000-fold compared with water. Freeze-drying microscopy provided valuable information regarding the phase change and transitions the drug undergoes as a function of temperature and it clarifies the interpretation of the DSC results and provides valuable evidence of drug crystals co-melting within the fatty acid base. The presence of natural fatty acid as one component of THEDES and the depression in the melting point significantly (P

Asphalt binders have been modified with Crumb rubber (CR) as an effort to fulfil the demand for the development of eco-friendly and sustainable pavements. The objective of this study was to investigate the high temperature rheological behaviors and fatigue performance of crumb rubber modified asphalt (CRMA) binder activated using trans-polyoctenamer (TOR). Long-term and short-term aging tests were performed on samples by thin film oven test (TFOT) and pressure aging vessel (PAV). Rotational viscosity (RV), softening point, and dynamic shear rheometer (DSR) tests were conducted to characterize the rheological and physical performance. A linear amplitude sweep (LAS) test was employed to evaluate the fatigue performance. The results show that TOR-activated CRMA is more capable of hardening the matrix bitumen and improving its high-temperature viscoelastic properties after TFOT. The high temperature viscoelasticity is significantly better than styrene-butadiene-styrene block (SBS) modified asphalt (SBSMA) and CRMA. TOR-activated CRMA exhibits strong rutting resistance, but it is more likely to generate fatigue cracks under the violent advancement of complex modulus. Therefore, TOR active agent has a negative impact on the fatigue performance of CRMA. SBSMA exhibited superior fatigue resistance. The viscosity temperature index (VTS) of TOR-activated CRMA and CRMA was basically identical, the TOR did not significantly improve the temperature sensitivity of CRMA.

The long term and safe operation of entrained gasifiers strongly depends on smooth and steady removal of the ash slag. Management of slag behavior for safe slag-tapping requires the well understanding of slag viscosity temperature behavior and reliable prediction model for the slag viscosity in presence of water vapor. Based on the ratio of acidic to basic oxides (A/B) in coal ash, the viscosity temperature characteristics were studied under Ar with water vapor, and the optimization model for predicting the slag viscosity as a function of T and slag composition, including the constituent H2O was established. When water vapor is present in Ar, the slag viscosities decreased due to the breaking of Si-O-Si bridge bonds for the slags with A/B

Extensive attention is being paid to the exploitation of unconventional oils, mainly heavy and ultra-heavy oils. Thereinto, the high viscosity nature of heavy and ultra-heavy oils is a major obstru...

The equilibrium nature of viscosity and fluidity is discovered on the basis of the Boltzmann distribution within the framework of the concept of randomized particles as a result of the virtual presence of crystal-mobile, liquid-mobile and vapor-mobile particles. It allows one to consider the viscosity and fluidity of solutions, in particular, melts of metal alloys, from the point of view of the equilibrium partial contributions of each component in the total viscosity and fluidity, despite the kinetic interpretation of natural expressions for these properties of the liquid. A linearly additive partial expression of viscosity is possible only for perfect solutions, in this case, for alloys with unrestricted mutual solubility of the components. Alloys with eutectics, chemical compounds and other features of the state diagram are characterized by viscosity dependencies that repeat the shape of liquidus curve over entire range of the alloy composition at different temperatures, with an increase in smoothness and convergence of these curves at increasing temperature. It was established that these features of viscosity temperature dependence are completely revealed within the framework of the concept of randomized particles and the virtual cluster model of viscosity in calculating the fraction of clusters determining the viscosity of the alloy. That viscosity of the alloy is found by the formula in which thermal energy RTcr at liquidus temperature is the thermal barrier of chaotization, characterizing the crystallization temperature of the melt Tcr, as well as the melting point of pure substances. On this basis, a method is proposed for calculating the alloys viscosity by phase diagrams using the temperature dependences of pure components viscosity to change the alloy’s viscosity in proportion to ratio of the clusters fractions at any temperature above liquidus line and for the pure component, taking into account the mole fraction of each component. As a result, a three-factor model of the liquid alloy viscosity has been obtained in which the thermal barrier of chaotization RTcr is used as variable for the first time. It determines the fraction of clusters for both pure substances (at RTcr = RTm ) and for alloys. This thermal barrier reflects the essence of the virtual cluster theory of liquid and adequacy of the concept of randomized particles.

In entrained flow partial oxidation processes of carbonaceous, ash containing feedstock, the slag behaviour is important to ensure a safe and reliable operation. Inside the reactor, the inorganic content of the fuel is converted into slag which is deposited at the walls of the cooling screen where a stationary and a mobile slag layer are formed. For design and operation, a detailed understanding of the slag layers as well as the slag physical properties is important. In order to reduce the amount of CO2 emissions during the process and to generate renewable syngas, biomass can be applied as feedstock. However, the slag properties and the amount of ash are different for biomass compared to what is known for coal. The bioliq® demonstration plant has been erected to demonstrate sustainable, high quality fuel production from biomass. The gasification unit is a 5 MWth entrained flow reactor equipped with a cooling screen. Experiments at 40 bar(a) with a plant load of approximately 5 MWth and an ash content of the feedstock lower than 5 wt% were performed. Results of the local heat flux to the cooling screen, slag thickness at the reactor wall and thermophysical properties of the slag were applied in the ‘slag model’ to evaluate the slag flow under different operating conditions. Compared to results from coal gasification reported in literature, a very low slag thickness has been determined for biomass that is in the range of 3 mm at the bottom of the cylindrical part of the cooling screen. The slag flow for different positions of the cooling screen is calculated with the ‘slag model’. The sensitivity analysis shows that three variables have the strongest effect on the slag mass flow: the heat flux to the cooling screen, the total slag thickness and the interface viscosity temperature (Tint), defined as being the temperature at the interface between the stationary and mobile slag layers. According to our study, a Tint corresponding to a slag viscosity in the range of ∼1000 Pa·s is identified to best represent the slag mass flow. Even for very low ash contents of the feedstock, a complete and homogeneous coverage of the cooling screen can be obtained even at the top section which exhibits very low depositions rates according to the model.

The aim of this work was to study the influence of a high efficient halogen-free phenylphosphonic amide flame retardant (FP1) to epoxy resin (brand name RTM6) on the rheological, mechanical and water absorption properties of the carbon fiber/RTM6 epoxy composite (CFR). With a 8 wt% loading FP1 in RMT6, the processing of CFR/FP1 was able to use the equal condition with that of CFR since the viscosity of RTM6 was maintained at a similar level in the minimum viscosity temperature region. The addition of FP1 showed negligible impacts on the interlayer share strength (ILSS) and in-plane share strength (IPSS) of CFR. The interfacial strength between RTM6 matrix and carbon fiber was decreased due to the impact of FP1 on cross-linking density and polarity of RTM6. The flame retardant efficiency of FP1 showed difference in presence of carbon fiber or not in RTM6. RTM6/FP1 (8 wt%) had a LOI value of 38%, achieved a V-0 rating at thickness of 3.2 mm in UL 94 test and showed 60% reduction in peak of heat release rate. RTM6/carbon fiber/FP1 (8 wt%) had a LOI of 43%, while it showed reduced performance in UL 94 and cone calorimeter tests.

Purpose The hydro-viscous drive (HVD) has been widely used in fan transmission in vehicles, fans, and scraper conveyors for step-less speed regulating and soft starting. It is an efficient method to save energy and reduce consumption. This study aims to analyze the influencing factors of oil film shear torque accurately. Design/methodology/approach The shear torque calculation model of double arc oil groove friction pairs was established. The influence of groove structure parameters on shear torque was analyzed. The interaction between viscosity temperature and shear torque was considered. Meanwhile, the equivalent radius was calculated when the rupture of oil film appeared. Finally, the test rig of torque characteristics was set up. The variance of shear torque with the input rotation speed under different oil film thickness, different oil temperature, and different flow rate was seen. Findings The results show that the shear torque increases with the growth of rotation speed. However, the increase of torque is quite gradual because of the effect of the change of viscosity, which is caused by the rise of temperature. The shear torque increases with the decrease of thickness, the increase of inlet flow rate, and the decrease of inlet oil temperature. Meanwhile, when the feeding flow rate is less than the theoretical, the oil film gets ruptured and the shear torque decreases sharply. Originality/value The influence on shear torque during full film shear stage in HVD can be achieved much more accurately through both experimental research and theoretical modeling in which groove parameters, influence of temperature, and oil film rupture are considered. Therefore, the shear torque of HVD can be predicted by theoretical model and experimental research in full film shear stage.

Many industrial processes utilize a liquid phase with large amounts of dissolved gases at elevated pressures; e.g. CO2 capture; enhanced oil recovery; CO2-expanded Liquids; etc. In order to understand the transport properties, the experimental dynamic viscosity and calculated kinematic viscosity are reported for binary systems of CO2-saturated n-alkanes, n-hexane, n-decane, or n-tetradecane, at 25°, 40°, and 55 °C and pressures up to 107 bar. The global phase behavior was investigated and transitions from vapor-liquid equilibrium were confirmed. Equation of state modeling of literature vapor-liquid equilibrium data was used to determine the compositions at the conditions of interest. Increasing composition of CO2 (pressure) results in significant decrease in the viscosity of the binary mixtures. Measured viscosities decrease in a relatively manner at low to moderate compositions of CO2 in liquid phase. “Excess viscosities” were calculated to help understand the phenomena. These properties have implications for fluid transport, heat transfer, and mass transfer.

It is well-known that certain dynamical properties such as the dielectric relaxation times and the viscosity of liquids can be graphically superpositioned onto a single master curve as a function of the thermodynamic potential (ργ/T), where T is the temperature, ρ is the density, and γ is a state-independent scaling exponent. We presently applied the aforementioned thermodynamic scaling to the viscosity of typical hydrogen-bonding formers and polar fluids such as water, hydrogen sulfide, ammonia, methanol and an ionic liquid: [bmim][PF6]. Unlike previous studies on density scaling of transport properties, a more suitable reduction and normalization of the viscosity was introduced here in order to obtain improved correlations of viscosity over much wider temperature and pressure ranges encompassing the zero-density limit, the high-density region, the gas-liquid saturation line and the vicinity of the critical point. A calculation procedure is also described here to optimize the value of the scaling exponent γ that ensures the best super-positioning of all experimental isotherms considered for each substance.

In current research, MWCNT-SiO2/oil hybrid nano-lubricant viscosity is experimentally examined. By dispersing 0.05%, 0.1%, 0.2%, 0.4%, 0.8% and 1% volume of MWCNTs and SiO2 nanoparticle into the engine oil SAE 20W50, the temperature and solid volume fraction consequences were studied. At 40 to 100 °C temperature, the viscosities were assessed. The results indicated Newtonian behavior for the hybrid nano-lubricant. Moreover, solid volume fraction augmentation and temperature enhanced the viscosity enhancement of hybrid nano-lubricant. At highest solid volume fraction and temperature, nano-lubricant viscosity was 171% greater compared to pure 20W50. Existed models lack the ability to predict the hybrid nano-lubricant viscosity. Thus, a new correlation regarding solid volume fraction and temperature was suggested with R-squared of 0.9943.

Measurements of viscosity, density and surface tension of waste lubricant oil (WLO) were conducted at different temperatures. The dataset was constituted by nine WLO samples from different producers. The main objective of the work is the investigation of the temperature dependence of viscosity, including the glass transition, T g , and dynamic crossover, T x , temperatures. In addition, different correlations were evaluated to predict viscosity and surface tension starting from a property easily obtained such as density. WLO show rapid decrease of viscosity with shear rate, followed by an extensive and well defined Newtonian plateau. The temperature dependence of viscosity at the Newtonian plateau of WLO deviated from the Arrhenius behavior, and was accurately described by four different models: Williams–Landel–Ferry (WLF), MYEGA, power law and Ghatee. The minimum and maximum absolute average relative deviation (AARD) were 0.08% and 0.9%, respectively. T g predicted by WLF equation varied between T = 170.5 K and T = 198.7 K, while MYEGA tends to predict lower T g (about T = 20 K). The power law and Ghatee models estimate T x nearly with the same accuracy. A ratio T x / T g of about 1.28 ± 0.03 was obtained for WLO, which agrees with the literature. Waste oil is a moderately fragile glass forming fluid with a fragility parameter, m , ranging from 47.8 and 64.5. New correlations were developed for the prediction of viscosity and surface tension from density at different temperatures. AARD of 7% was observed for viscosity and 2% for surface tension.

We present three-dimensional lattice Boltzmann simulations of dilute suspensions containing porous particles. The fluid flow around and inside a porous particle is described by the volume-averaged macroscopic equations in terms of intrinsic phase average. The energy dissipation of the suspended particle in a Couette flow is calculated to obtain the relative viscosity of the suspension. Results show that the relative viscosity of the suspension increases linearly with the particle volume fraction. A correlation equation is obtained for the intrinsic viscosity as a function of Darcy number. It is found that when the suspension is at the inertial flow regime, its intrinsic viscosity increases linearly with Reynolds number, and the increasing rate depends on Darcy number.

Among some of the generalized Newtonian viscosity functions used in hydrodynamic lubrication, the Cross and Ellis equations have a transition from the first Newtonian plateau to the power-law regime that is much broader than is typical of polymer-thickened oils. The Dobson method employs the Cross equation to extract the second Newtonian viscosity for a polymer-thickened oil from ambient pressure viscometry. This method will always produce a second Newtonian viscosity for a polymer thickened oil, even if none is present in the data. Shear-thinning measured at elevated pressure removes this issue. An improved viscosity function is offered which describes the shear-dependence of the polymer and of the base oil without the artifacts associated with a sum of individual viscosity equations.

The article presents a comprehensive physicochemical and biological study of water-soluble fullerene adduct with glycine. The investigation included density, speed of sound, and viscosity temperature and concentration data with subsequent calculation of thermodynamic characteristics; correlation of the obtained results using fourth-order polynomial; determination of associate sizes; measurements of isobaric heat capacity; binding to human serum albumin; antiradical activity in the reaction with 2,2-diphenyl-1-picrylhydrazyl radical.

Ionic liquids analogues known as Deep Eutectic Solvents (DESs) are gaining a surge of interest by the scientific community, and many applications involving DESs have been realized. Moisture content is one of the important factors that affects the physical and chemical characteristics of these fluids. In this work, the effect of mixing water with three common type III DESs on their viscosity was investigated within the water mol fraction range of (0–1) and at the temperature range (298.15–353.15 K). Similar trends of viscosity variation with respect to molar composition and temperature were observed for the three studied systems. Due to the asymmetric geometry of the constituting molecules in these fluids, their viscosity could not be modeled effectively by the conventional Grunberg and Nissan model, and the Fang–He model was used to address this issue with excellent performance. All studied aqueous DES mixtures showed negative deviation in viscosity as compared to ideal mixtures. The degree of intermolecular interactions with water reaches a maximum at a composition of 30% aqueous DES solution. Reline, the most studied DES in the literature, showed the highest deviation. The information presented in this work on the viscosity of aqueous DES solutions may serve in tuning this important property for diverse industrial applications involving these novel fluids in fluid flow, chemical reactions, liquid–liquid separation and many more.

Grouting is the main method of water damage treatment in underground engineering. Viscosity is a key parameter affecting grouting. However, the viscosity is significantly affected by temperature. The grouting scheme at normal temperatures is not suitable for grouting at high temperatures. Therefore, it is important to study the viscosity-temperature characteristics of grout in high-temperature grouting engineering. This study investigated the effect of temperature on the gelation time of cement-sodium silicate (C-S) slurries. The standard test method and inverted cup method were used to test the gelation time of the C-S slurries. Through the viscosity test, the viscosity-temperature characteristics of C-S grouts were analysed, considering the time-varying behaviour of viscosity. The results show that there are optimal proportions of w/c ratio, retarder, and sodium silicate for gelation time development. The gelation time of the C-S slurries was negatively correlated with temperature. The variation in the stable viscosity value of C-S slurries with temperature can be divided into three stages: the viscosity declining stage, viscosity steady stage, and viscosity rising stage. The fitted viscosity-temperature equation can accurately reflect the viscosity-temperature characteristics. This study can provide effective guidance for the establishment of dynamic water grouting theories, numerical calculations, and grouting parameter design in high-temperature environments.

Thermo-physical properties for binary and multi-components alloys are important for controlling and designing metallurgical processes. However, it is difficult to get data from systems of a high order in terms of experience. On the theoretical level, different formalisms have been adopted for determining the structural, transport, and electronic properties, therefore, most thermo-physical data from calculations theoretical. Indeed, to choose the best substitute alloy, many criteria must be taken into account, in particular the surface tension, density, viscosity, and friccohesity. The Sn-Ag binary alloy is one of the most common lead-free solders. It is characterized by more interesting thermo-physical properties. In the present work, we have suggested novel empirical expressions of these physicochemical properties against the temperature where the corresponding obtained optimal coefficients are expressed with mole composition of tin which permit us to combine the two dependences and propose unified equations correlating thermophysical properties of the alloy as the function of both the independent variables the temperature and composition.

Sustainability 13(14), 7570 (2021). doi:10.3390/su13147570 special issue: "Special Issue "Evaluation and Application of Sustainable Engineering Materials" / Special Issue Editors: Assoc. Prof. Dr. Marcin K. Widomski, Guest Editor ; Prof. Dr. Danuta Barnat-Hunek, Guest Editor ; Dr. Anna Musz-Pomorska, Guest Editor", Published by MDPI, Basel

Excess quantities calculated from literature values of experimental density and viscosity in 1,2-dimethoxyethane + water binary systems (from 303.15 to 323.15 K) can lead us to test different corre...

Tremendous sodium-rich coal in China has unique ash compositions, and the entrained flow gasification is one of the best choices to use sodium-rich coal for coal chemical industry. The entrained flow gasifiers require smooth slag tapping for long term and safe running, but the viscosity-temperature behavior of high-sodium slags is unknown, which limits the utilization of sodium-rich coal. In this study, viscosity-temperature behavior of high-sodium coal ash slags was revealed for the first time, and the parameter of slag network structure and index of slag crystallization tendency is raised for slag viscosity evaluation. The results show that Na 2 O provides O 2− ions which break Si O Si bonds and slag network structure. However, Al 3+ ions are absorbed into silicate network, acting as a network former with the ionic charge-compensation effect of Na + . The classic structural parameter (fraction of non-bridging oxygen, NBO) is modified to evaluate the high-sodium slag viscosity accurately by taking Al 3+ into account. NBO fraction decreases as Na 2 O content increases, leading to the decrease of slag viscosity. Below T liq , slags are prone to be crystalline slag with increasing Na 2 O content or glassy slag with increase in SiO 2 /Al 2 O 3 ratio (S/A). A novel index, namely glassy slag formation ability (G), is established to quantitatively evaluate the crystallization tendency of coal ash slags. G is the ratio of activation energy for viscous flow ( E η ) to T liq . The slag will exhibit the glassy behavior when G is higher than 0.16 kJ/(mol·K). The results enhance the knowledge of viscosity-temperature behavior of high-sodium coal ash slags and will be helpful for coal selection and blending to avoid slag blockage in entrained flow gasification.

Take palm oil and soybean oil biodiesels as example, crystallization behavior and rheological property of methyl and ethyl biodiesels were investigated. Differential scanning calorimeter (DSC) technique was used to analyze the crystallization behaviors of methyl and ethyl biodiesels, including the crystallization onset temperature and the variation of amount of crystal precipitation with temperature. Meanwhile, a thermodynamic model of regular solution was proposed and compared with the crystallization experiments. Comparisons suggested that the model can give a reasonable description of crystal precipitation of biodiesel. The rheological properties of methyl and ethyl biodiesels including the viscosity temperature curves as well as the variation of viscoelastic parameters with temperature during the cooling gelation process were measured by rheometer. Experimental results suggested that the crystallization onset temperature and the gelation temperature of ethyl biodiesels are decreased as compared with methyl biodiesels. When temperature is just below the crystallization onset temperature of methyl biodiesel, the crystal precipitation of ethyl biodiesel is much lower than methyl biodiesel, meanwhile, the same characteristic can be observed for the viscosity and storage modulus of methyl and ethyl biodiesels. As the temperature decreased, the crystal precipitation of ethyl biodiesel is gradually close to until equal to the methyl biodiesel. So as the temperature decreased, the differences between the viscosity, storage modulus of methyl and ethyl biodiesels are getting smaller, and then the viscosity and storage modulus of ethyl biodiesel are greater than those of methyl biodiesel.

Well understanding the role fluxing agents in the CaO-Al 2 O 3 -based slag system is essential to devise new mold fluxes for heat-resistant steel as well as for further improvement of data for viscosities and structure properties of the molten fluxes. The role of Li 2 O in CaO-Al 2 O 3 -Li 2 O-Ce 2 O 3 slag system was investigated through measuring viscosity combined with the FTIR spectra analysis. It was noted that Li 2 O show obvious effect of decreasing viscosity in the CaO-Al 2 O 3 -based slag system. The viscosity of the CaO-Al 2 O 3 -Li 2 O-Ce 2 O 3 slag melts decreased with increasing Li 2 O content. The relationship between the viscosity and the slag structure was discussed. Under the condition of increasing Li 2 O addition from 10 to 14 mass%, the relative ratio of [AlO 4 ]-tetrahedrons and [AlO 6 ]-octahedrons remain constant. The O 2– dissociated from Li 2 O just cut the network formed by [AlO 4 ]-tetrahedrons. The depolymerization of [AlO 4 ]-tetrahedrons from Q 4 units to Q 3 and Q 2 units was the main reason of the decrease of the viscosity. When the content of Li 2 O increased from 14 to 18 mass%, more and more O 2– dissociated from Li 2 O reacted with [AlO 4 ]-tetrahedrons to form [AlO 6 ]-octahedrons. The decrease of viscosity was mainly induced by the increase of free oxygen and the formation of [AlO 6 ]-octahedrons, which acts as a network modifier.

Abrasive flow machining has become an efficient and economical ultra precision process for machining micro-bore parts. In this paper, aiming at viscosity temperature characteristics of abrasive flow finishing on micro-bore nozzle, under the guidance of the three governing equations of fluid mechanics theory, mixed phase model and discrete phase model were conducted, FLUENT software was resorted to simulate the discrete and fluid phase numerical characteristics of the solid-liquid two-phase flow field in the nozzle orifice with various field temperature and viscosity of slurry, the mechanism of erosion and wear of particles and effect of different processing parameters on particle erosion rate were uncovered, which provides a theoretical basis for the nozzle structure of abrasive flow machining.

The efficient control of microbubbles is achieved by using the alcohol shear flows in ceramic membrane channels. The dependence of hydrodynamic and mass transfer properties of microbubbles on liquid viscosity is investigated in a bubble column with 32 mm i.d. and 800 mm height. The multi-channel ceramic membrane with an average pore size of 200 nm works as the gas sparger, and the shear flow on the membrane surface controls the microbubble generation. Oxygen gas and glycerin solutions with different viscosities (μl = 1 - 42 mPa·s) are used as gas phase and liquid phase, respectively. The microbubbles are massively generated at different liquid viscosities. With increasing viscosity, the bubble size first decreases (μl < 2.0 mPa·s) and then increases. The dual effect of viscosity on bubble size is related to bubble coalescence. In low viscosity range, increasing viscosity hinders liquid film drainage and thus inhibits coalescence. At high viscosity, liquid turbulence intensity is weakened and bubble coalescence is enhanced. However, the dual effect of viscosity on gas holdup is not observed for microbubble. Increasing viscosity makes the monotonic increase in Sauter diameter and specific interfacial area, while the mass transfer coefficient decreases as viscosity increases at small cross flow velocities.

The mathematical aspects of Dufour and Soret phenomena on the peristalsis of magnetohydrodynamic (MHD) Jeffrey liquid in a symmetric channel are presented. Fluid viscosity is taken variably. Lubrication approach has been followed. Results for the velocity, temperature, and concentration are constructed and explored for the emerging parameters entering into the present problem. The plotted quantities lead to comparative study between the constant and variable viscosities fluids. Graphical results indicate that for non-Newtonian materials, pressure gradient is maximum, whereas pressure gradient is slowed down for variable viscosity. Also both velocity and temperature in the case of variable viscosity are at maximum when compared with results for constant viscosity.

The article presents viscosity measurements on mixtures of poly(ethyleneglycol) 200 (PEG 200) saturated with supercritical CO 2 , along three isotherms, at approximately 313 K, 333 K and 348 K, and pressures up to 25 MPa. The measurements have been performed with a previously described vibrating wire instrument. The results show a steep initial viscosity decrease with increasing pressure of CO 2 , followed by a flatter zone, extending up to 25 MPa. This behavior, which is quantitatively temperature dependent, seems to be closely related to the solubility of CO 2 as a function of pressure. The experimental method for the determination of the viscosity requires the density of the samples. For this purpose, the density data for the mixtures were calculated from phase equilibrium studies by Gourgouillon and Nunes da Ponte, using the Sanchez-Lacombe equation of state. The measured viscosity data for CO 2 saturated PEG 200 solutions were then correlated using the Kelly-Bueche theory.

One of the efforts in minimizing energy consumption chiller type air conditioning system is the use of phase changing material in secondary refrigerant. Secondary refrigerant functions to obtain heat from the air to cool a room and to release heat in chiller evaporator. Based on working temperature of secondary refrigerant, the fluid can flow in liquid form, and can also be in fluid solid form or slurry at the temperature of its phase change. This research studies the effect of temperature toward flow characteristics, with the parameter analyzed being the pressure decrease and friction coefficient. Besides that, in order to support data analysis, it was initiated by viscosity testing, density and concentration of solid mass. Data taken were viscosity, density, solid mass concentrate, and pressure difference found in copper pipe. Data were taken for several fluid temperatures, and at pressure decrease was added by variation of flow speed. Hydrate salt tested were CaCl2 and Na2HPO4. Viscosity and density increased with the decrease in temperature. The formation of solid particles within phase change temperature range also gave an impact on the increase in the value of viscosity and density. Pressure drop increased when using hydrate salt fluid. The use of CaCl2 solution resulted in the highest pressure decrease. This salt hydrate has far higher viscosity and density compared to water. This has an effect toward an increase in pressure drop. This increase started to be significant in the phase change temperature area in which solid particle started to form. The same thing happened in the friction coefficient value. Keywords: Phase change temperature, salt hydrate, pressure drop, viscosity, slurry.