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The Suspension Aspect of Suspension Plasma Spray Process (SPS)
Published in Navid Hosseinabadi, Hossein Ali Dehghanian, Suspension Plasma Spray Coating of Advanced Ceramics, 2022
Navid Hosseinabadi, Hossein Ali Dehghanian
As a result, the concentrated, colloidally stable suspensions display shear thinning because of a perturbation of the suspension structure by shear. At low shear rates, the suspension structure is close to equilibrium because thermal motion dominates over the viscous forces. At higher shear rates, viscous forces affect the suspension structure, and shear thinning occurs. At very high shear rates, viscosity increases as the shear rate increases.
Bio-based emulsifiers for pavement material: Emulsion formulation and cold asphalt mix properties
Published in Inge Hoff, Helge Mork, Rabbira Garba Saba, Eleventh International Conference on the Bearing Capacity of Roads, Railways and Airfields, Volume 3, 2022
F. Lévenard, V. Gaudefroy, C. Petiteau, E. Chailleux, I. Capron, B. Bujoli
The flow curves, presented in Figure 5, were performed on Em-A and Em-B2. Both emulsions showed a shear thinning behavior as the viscosity decreases with increasing shear rate. Em-B2 had a significantly higher viscosity than Em-A. For a shear rate of 500 s-1, where viscosities reached a plateau, Em-A had a viscosity of 0.01 Pa.s, corresponding to conventional bitumen emulsions viscosities, while Em-B2 had a viscosity of 0.13 Pa.s. Em-B2 also showed a thixotropic behavior: a lower viscosity was measured when decreasing the shear rate than when increasing it and this phenomenon was reversible after a restructuring time. This means that the shear induces a deformation of the material which is reflected in a delayed way in time. Once at rest, the emulsion regains its original structure and mechanical properties. This behavior implies that shearing the emulsion at a constant rate for a certain time will lead to a decrease in viscosity, reaching one more suitable for pumping.
Fluid Flow
Published in C. Anandharamakrishnan, S. Padma Ishwarya, Essentials and Applications of Food Engineering, 2019
C. Anandharamakrishnan, S. Padma Ishwarya
Shear rate: It is the velocity gradient established in a fluid as a result of an applied shear stress. It can also be defined as the relative change in velocity divided by the distance between the fluid layers. Shear rate is denoted by γ and can be calculated from the following equation: γ=dudy
Selection of emulsification system for high temperature and high salt reservoir and evaluation of reservoir adaptability
Published in Journal of Dispersion Science and Technology, 2023
Wanfen Pu, Meiming He, Xuerui Yang, Jianyong Xie, Yanjie Chu, Rui Liu
It can be seen from Figure 4-1 that oil and water with different shear rates can be emulsified completely. And the viscosity of the emulsion increases with the increase of the shear rate, and the viscosity is greater than that of the crude oil, so the viscosity of the emulsion is all W/O emulsion. It can be seen from Figure 4-2 that as the shear rate increases, the size of the emulsion droplets becomes smaller and the distribution becomes more uniform. This can also correspond well to the changing law of viscosity. It can be seen from Figure 4-4 that as the shear rate increases, the water separation rate of the emulsion decreases, and the corresponding emulsion stability increases. As we all know, the smaller the particle size of the emulsion, the more difficult it is to coalesce between droplets, and the corresponding emulsion is more stable. Figure 5a shows that the higher the shear rate, the shorter the time for forming the emulsion. The reason may be that the greater the shear rate, the greater the agitation energy obtained by the oil–water mixture, so the time to form the emulsion is correspondingly reduced.
The experimental comparison between the effect of copper oxide and graphene nanoparticles on rheological behavior and thermal properties of engine oil
Published in Petroleum Science and Technology, 2022
Alireza Fazlali, Vahab Ghalehkhondabi, Fatemeh Alahyarpur
The lower viscosity causes easier oil pumping and draining back to the crankcase, while higher viscosity causes a greater load at the bearing on the crankshaft and this leads to an increase in engine durability. Therefore, using suitable engine oil can lead to higher efficiency and low fuel consumption (Aberoumand and Jafarimoghaddam 2017). Figure 2 presents the variation in dynamic viscosity and shear stress of nano-lubricants with different nanoparticle mass fractions (0.1–1 wt.%) as a function of the shear rate (0.1–1000 s−1) at 25 °C. It has been observed that the viscosity of nano-lubricants decreases with an increase in shear rate. The variation in viscosity with shear rate increases with an increase in nanoparticle mass fraction. As can be seen in Figure 2a and b, increasing the mass fraction of nanofluids is the behind of changing the rheological behavior from Newtonian to non-Newtonian. This depicts the shear-thinning behavior of nano-lubricants at a lower shear rate. Figure 2c and d show that shear stress increases linearly with the shear rate, satisfying the Bingham plastic model. As the mass fractions of nanoparticles in the suspension increase, the distance between the particles decreases, which increases viscosity. Also, as the shear rate increases, the fluid resistance to flow decreases, which reduces the viscosity to a certain value.
Biopesticide formulations of karanj and castor oil using soapnut
Published in Journal of Dispersion Science and Technology, 2022
Kartiki B. Jadhav, Mrunal Ghag Sawant, Trupti Satvekar, Jayashree M. Nagarkar
Figure 2 depicts the variation of viscosity with shear rate. It is clear that viscosity decreases with increase in shear rate. Eventually shear thinning is observed in case of stable emulsions K-1, K-2 and C-1, C-2. These results are in compliance with the results presented in earlier work.[28] All emulsions show a rapid decrease in viscosity at the initial shear rate. The viscosity further decreased slowly at higher shear rate which is an indication of increased spray efficiency. Figure 3 depicts the graphs plotted between log of viscosity and log of shear rate for all the stable emulsions. The power law equation {μ=K(δu/δy)n−1} was applied to these emulsion systems. The apparent viscosity “μ” decreases with increase in shear rate (δu/δy) and the value of slope comes out negative. The calculated values of flow behavior index “n” for all the stable emulsions are less than “1” which explain the non-Newtonian flow behavior. The results are given in Table 3. The variation of shear rate with shear stress of all stable emulsions is depicted in Figure 4. The rheogram clearly shows the pseudoplastic flow behavior of the emulsions.