Numerical investigation of bubble breakup in a four. Pseudoplastic fluid article about pseudoplastic fluid by. A finite difference technique is used to calculate the velocity profile, maximum shear stress, and friction factor. Bingham plastic and pseudoplastic fluid becomes less viscose when stress is increased.
A newtonian fluid is a fluid in which the viscous stresses arising from its flow, at every point, are linearly correlated to the local strain ratethe rate of change of its deformation over time. These fluids are characterized by the shape of the flow cure illustrated in figure 6. A fluid is a substance that continually deforms flows under an applied shear stress or in simpler terms, a fluid is a substance which cannot resist any shear force applied to it. The viscosity of a pseudoplastic fluid has a finite value at zero rate of shear, tall falling off asymptotically to a lower fixed value as the rate of shear increases to infinity.
Cfd analysis of nonnewtonian pseudo plastic liquid flow through. Rheology 49 demonstration a solution of starch is pseudoplastic. Download fulltext pdf pseudoplastic fluid flows for different prandtl numbers. What is the difference between a dilatant fluid, a rheopectic. The effective viscosity of a pseudoplastic fluid decreases with increasing shear rates. Though further effort is necessary to investigate the turbulent jet flow, the analysis presented here should make a definite contribution in this definition. Viscosity is the quantity that describes a fluids resistance to flow.
To solve such problems, powerful numerical techniques are usually used. Motion of a thin oblique layer of a pseudoplastic fluid. The power law equation uses two parameters, k and n. Pdf motion of a thin oblique layer of a pseudoplastic fluid. Numerical simulation of nonnewtonian pseudoplastic fluid in a. Ultrasonic doppler velocimetry udv, a noninvasive fluid flow measurement technique for opaque systems, was used to measure xanthan gum velocity. Article views are the countercompliant sum of full text article downloads since november 2008 both pdf and html across all institutions and individuals. The nonnewtonian fluid which having value of b ty and n 1, because it having starting value of b is greater than 0, so its viscosity gradient is increased from that point. If hit with a hammer, it will shatter like a brittle solid. Ppt newtonian fluid powerpoint presentation free to. Download fulltext pdf newtonian and nonnewtonian fluids. Thus, if stress readings taken at high shear rates are extrapolated back to the axis, there appears to be a yield point similar to that of a bingham plastic, hence the name pseudoplastic see figure 5. Effects of a controllable axial flow on the stability of rotational flow of pseudoplastic fluids in the gap between concentric cylinders are studied.
Demonstration of upper and lower newtonian fluid behaviour in. Determination method of the cavern boundary viscosity in a. Herein, a novel highperformance sim is developed, which is primarily composed. The xanthan gums, produced from the alternative medium ssae using three different strains of xanthomonas campestris,gave k and n values typical of pseudoplastic fluids. The results show that the behavior of tfb is consistent with that of a pseudoplastic fluid, and the herschelbulkley model is more applicable to tfb. The curves are nonlinear, but approach linearity at high shear rates. This equation is a boundary value problem bvp with the high nonlinearity and a boundary condition at infinity. This work presents and experimental study of the generalization method of the reynolds number and the viscosity of pseudoplastic fluid flow in ducts of nonuniform crosssection. Pdf simple flows of pseudoplastic fluids based on dehaven. Its pseudoplasticity can be easily demonstrated by letting it flow from a burette and comparing its flow with that of a suitable viscosity newtonian fluid flowing from an identical burette.
For drilling fluids, pseudoplastic behavior is usually defined by using the power law equation. Utilization of foaming technology in cemented paste backfill of highmud superfine unclassified tailings. Here, through using differential transform method dtm, the bvp is replaced by two initial value problems ivp and then. The results obtained by schlichting for the newtonian fluid flow is shown to be the special case of the more general analysis given here. Download fulltext pdf annular flow characteristics of pseudoplastic fluids article pdf available in journal of energy resources technology 74. The newtonian fluid and the shear thinning fluid pseudoplastic with n 0. Those fluids which obeys newtons law of viscosity are called newtonian fluids. Pseudoplastic definition is lacking the capacity for major modification or evolutionary differentiation. In nonnewtonian fluids, viscosity can change when under force to either more liquid or more solid. The laminar twodimensional free jet of an incompressible. Once the critical force is exceeded, it flows like a newtonian fluid with constant viscosity.
Compared with the traditional velocity method, the boundary viscosity method can maintain its high accuracy for exhibiting the cavern boundary, and the predicted cavern size and development. The most common type of nonnewtonian fluid is the pseudoplastic fluid. These metrics are regularly updated to reflect usage leading up to the last few days. He discovered that the viscosity of most fluids is only affected by temperature. On the laminar twodimensional free jet of an incompressible pseudoplastic fluid atkinson, c. Fountain flow is a wellknown fluid mechanics phenomenon present in all cases where a moving fluid displaces another immiscible fluid.
The native strain 1182 showed the best performance with respect to the k and n values, the percentage of substrate used, and the viscosity. A nonnewtonian fluid is a fluid that does not follow newtons law of viscosity, i. Fullydeveloped circularpipe flow of a nonnewtonian horizon. A free powerpoint ppt presentation displayed as a flash slide show on id. The lower line gives the n p r e i relationship for pseudoplastic fluid with r e i 10 rei102 103. Pdf pseudoplastic fluid flows for different prandtl. On the other hand, when viscosity decreases when stress increases, the fluid is called pseudoplastic fluid. Within the context of nonnewtonian fluid mechanics, this type of flow is of interest in polymer processing, and in particular in the. Newtonian and non newtonian fluids linkedin slideshare. A semiplastic fluid is a material that will sustain a certain shear. In contrast to a bingham fluid, a pseudoplastic fluid is a fluid that increases viscosity as force is applied. The boundary layer equation of the pseudoplastic fluid over a flat plate is considered.
Heat transfer to pseudoplastic fluids in laminar flow. What is meant by newtonian and nonnewtonian fluids in fluid. The larger the value of k, the more viscous is the fluid at low shear rates. For a fluid with 0 fluid is called shearthinning or pseudoplastic fluid. This application is highly favored within the body, as it allows the viscosity of blood to decrease with increased shear strain rate 20. A one layer model of laminar nonnewtonian fluids ostwaldde waele model past a semiinfinite flat plate is revisited. It does not flow until a critical force is applied. Hrt n is proposed to represent the rheological properties of pseudoplastic fluids. A previous study authored by us described that pseudoplastic fluid was more suitable for highperformance sims than newtonian fluid.
Development of sodium polyacrylatebased highperformance. Pseudoplastic definition of pseudoplastic by merriamwebster. A fluid with high viscosity resists motion, while a. Shear stress vs shear rate for dilatant and pseudoplastic nonnewtonian fluids compared to newtonian fluid.
Fountain flow of pseudoplastic and viscoplastic fluids. Though the exact cause of shear thinning is not fully understood, it is widely regarded to be the effect of small structural changes within the fluid, such that microscale geometries within the fluid rearrange to facilitate shearing. Apr 24, 2007 the study was carried out using a pseudoplastic fluid with yield stress in the laminar mixing region. Flow behavior of complex fluids is traditionally characterized through the distinction between newtonian and nonnewtonian based on each fluids viscosity dependence on the rate of deformation and the rate of shear rate. The stretching and the suctioninjection velocities are assumed to be proportional to x 1 1. A closedform solution is obtained to boundarylayer equations given by lemieux and unny 1 for the free outflow of a nonnewtonian pseudoplastic fluid from a twodimensional orifice into a. Rotational and axial flow of pseudoplastic fluids springerlink. Ppt nonnewtonian fluids powerpoint presentation free to. Suspensions of longchain polymers are typical pseudoplastics. Pdf fullydeveloped circularpipe flow of a nonnewtonian. Example of bingham plastic is sewage slug, drilling mud.
The friction factorreynolds number relation for the steady. Reynolds number for bingham plastic fluid is defined as \displaystyle \displaystyle re \fracd. It is a liquid, but when stirred it becomes thicker and more difficult to stir. This equation is combined with the differential equations describing steady state laminar flow and heat conduction to a moving fluid when natural convection and thermal energy generation are negligible.
Interesting properties of nonnewtonian fluids if you punch a bucket full of nonnewtonian fluid such as cornstarch, the stress introduced by the incoming force causes the atoms in the fluid to rearrange such that it behaves like a solid. Pseudoplastic fluid an overview sciencedirect topics. Using cfd and ultrasonic velocimetry to study the mixing of. Velocity profiles, viscosity data, and laminar flow friction factor equations for flow in a circular duct conference paper pdf available. The ratio of the cavern boundary viscosity and the fluid yield viscosity.
Newtonian fluid apparent viscosity the shear rate dependence of categorizes nonnewtonian fluids into several types. This note is concerned with a laminar pipe flow of a nonnewtonian fluid under the action of a small pulsating pressure. The development of highperformance submucosal injection materials sims has significantly contributed to the advancement of rapid and safe endoscopic submucosal dissection esd. However, we have tested the case of a newtonian fluid and compared the convergence performance and the mass imbalances between the different regions with those obtained for a nonnewtonian fluid. In addition to his many other discoveries, isaac newton did some groundbreaking work with fluids. Pdf simple flows of pseudoplastic fluids based on dehaven model.
When the shear stressshear rate plot of such fluids is made on logarithmic scale, a straight line is obtained. Newtons law of viscosity is given for 1d flow as where. Dilatant fluids show higher viscosity when the magnitude of the stress is high for example, when you run on wet sand it behaves as a hard surface pseudoplastic fluids show lower viscosity when the magnitude of the stress is high for example, k. The viscosity of pseudoplastic fluids nomenclature symo d g n n p r re rea r8 sg so g w pag b fa id pod. Solution of the boundary layer equation of the powerlaw. Steady and timedependent solutions article pdf available in international journal of thermal sciences 145 july. Within the context of nonnewtonian fluid mechanics, this type of flow is of interest in polymer processing, and in particular in the flow of polymer melts in injectionmold filling 2. Bingham plastic and pseudoplastic fluid becomes less viscose.
The pseudoplastic fluid is characterised by a constant viscosity at very low shear rates, a viscosity which decreases with. Pseudoplastic fluid definition of pseudoplastic fluid by. Fountain flow is a wellknown fluidmechanics phenomenon present in all cases where a moving fluid displaces another immiscible fluid. Pdf annular flow characteristics of pseudoplastic fluids. In the paper, the model of a dehaven fluid and some other models of nonnewtonian fluids, in which the shear strain rates are known functions of the powers of shear stresses, are considered. Newtonian fluids which can be characterized by a power. This method will permit to reduce 1 degree of freedom of hydrodynamical. The viscosity of pseudoplastic fluids sciencedirect. Pdf in this paper, the problem of axial annular flow of nonnewtonian fluids is examined. Citations are the number of other articles citing this article, calculated by crossref and updated daily. Pseudoplastic fluids drilling fluids netwas group oil.
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