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1
Content available Viscoelastic effects under water-polymer flooding conditions of the fractured-porous reservoir
Pogrebnyak Volodymyr G., Shimanskii Volodymyr Y., Pogrebnyak Andriy V., Perkun Iryna V.
Nafta-Gaz
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2023
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R. 79, nr 7
455--463
EN
The work is devoted to the numerical simulation of the flow of simple and viscoelastic (polymer solution) fluids through a fracture by using polymer solutions for enhanced oil recovery from a reservoir. Polymer solutions have viscoelastic properties. Therefore, when polymer solution flows through the slot, we use the well-known Maxwell’s fluid model with the Jaumann derivative to evaluate deformation characteristics of the flow (stream functions, distributions of the longitudinal velocity gradient and normal stress) resulting in the manifestation of abnormal (compared with the behaviour of the ordinary fluid) effects. The case of slow flow is considered. In this case, the inertial terms can be neglected, the velocities, stresses, and stream functions can be written as the decomposition by Weisenberg number, and we can assume that the Weissenberg number is less than one. The determined regularities of viscoelastic (polymer solution) liquid behaviour with longitudinal velocity gradient and the elastic deformations effects manifested in this case have a decisive meaning in understanding the mechanism of anomalously high oil recovery capacity of a reservoir by using water-polymer flooding of the fractured-porous reservoir. Understanding the nature of the effects of elastic deformations under the conditions of water-polymer flooding of the fractured-porous reservoir enables hydrodynamic calculations of the optimal flow of the polymer solution. One of the main issues that need to be solved when developing the technology for increasing oil recovery from formations using polymer solutions is to determine the optimal flow regime in the fractured-porous reservoir. The calculation results verify the ideas obtained from the experimental solution of this problem concerning the strain-stress state of polymer macromolecules (liquid elements) during polymer flow in the inlet area of the fracture in the oil reservoir and confirm the possibility of using numerical analysis of convergent polymer flow for calculating longitudinal velocity gradients in the inlet area of the fracture and can also serve as additional substantiation of the proposed earlier mechanism for increasing oil recovery from reservoirs by using polymer solutions.
PL
Praca poświęcona jest symulacji numerycznej przepływu płynów prostych i lepkosprężystych (roztworów polimerowych) przez szczelinę z wykorzystaniem roztworów polimerowych w celu zwiększenia wydobycia ropy naftowej ze złoża. Dlatego, gdy roztwór polimeru przepływa przez szczelinę, używamy dobrze znanego modelu cieczy Maxwella z pochodną Jaumanna do oceny charakterystyk deformacji przepływu (funkcje strumienia, rozkład gradientu wzdłużnego prędkości i normalnego naprężenia), co skutkuje pojawieniem się nietypowych (w porównaniu z zachowaniem zwykłego płynu) efektów. Rozważany jest przypadek spowolnionego przepływu. W tym przypadku składowe inercyjne można pominąć, prędkości, naprężenia i funkcje strumienia można zapisać jako rozkład wg liczby Weisenberga i możemy założyć, że liczba Weissenberga jest mniejsza niż jeden. Określone prawidłowości lepkosprężystych właściwości cieczy (roztworu polimeru) z gradientem prędkości wzdłużnej, jak i przejawiające się w tym przypadku efekty odkształceń sprężystych, mają decydujące znaczenie dla zrozumienia mechanizmu anomalnie wysokiej wydajności wydobycia ropy naftowej ze złoża poprzez nawadnianie złoża szczelinowo-porowego cieczą wodno-polimerową. Zrozumienie natury efektów odkształceń sprężystych w warunkach nawadniania szczelinowo-porowatego złoża cieczą wodno-polimerową umożliwia przeprowadzenie obliczeń hydrodynamicznych optymalnego przepływu roztworu polimeru. Jednym z głównych zagadnień, które należy rozwiązać podczas opracowywania technologii zwiększania wydobycia ropy naftowej z formacji za pomocą roztworów polimerowych, jest określenie optymalnego reżimu przepływu w zbiorniku szczelinowo-porowym. Wyniki obliczeń weryfikują koncepcje uzyskane z eksperymentalnego rozwiązania tego problemu dotyczącego stanu naprężenia makrocząsteczek polimeru (elementów ciekłych) podczas przepływu polimeru w obszarze wlotowym szczeliny w zbiorniku ropy naftowej i potwierdzają możliwość zastosowania analizy numerycznej zbieżnego przepływu polimeru do obliczania gradientów prędkości wzdłużnej w obszarze wlotowym szczeliny, a także mogą służyć jako dodatkowe uzasadnienie proponowanego wcześniej mechanizmu zwiększania wydobycia ropy naftowej ze złóż za pomocą roztworów polimerowych.
2
Content available remote Radiative MHD Walter’s liquid-B flow past a semi-infinite vertical plate in the presence of viscous dissipation with a heat source
Damala Chenna Kesavaiah, Bhumarapu Venkateswarlu, Makinde Oluwole Daniel
Engineering Transactions
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2021
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Vol. 69, iss. 4
373--401
EN
The free convective magnetohydrodynamics (MHD) flow of a non-Newtonian fluid due to a semi-infinite vertical plate under the influence of radiation and viscous dissipation is investigated. The system of partial differential equations is derived and solved for the solutions of velocity and temperature profiles along with the Nusselt number and skin friction by using the perturbation technique. The related important dimensionless parameters of Eckert, Grashof, and Prandtl numbers, magnetic field, radiation and heat source are discussed and shown in graphs. Also, the Nusselt number and skin friction at the plate are obtained and presented in the tabular forms. Finally, the corresponding result of Newtonian fluid is obtained by setting viscoelastic parameter k1 = 0. It is worth mentioning that the obtained results coincide with the previously published results.
3
Content available remote Cross-diffusion effects on MHD mixed convection over a stretching surface in a porous medium with chemical reaction and convective condition
Bhuvaneswari Marimuthu, Eswaramoorthi Sheniyappan, Sivasankaran Sivanandam, Hussein Ahmed Kadhim
Engineering Transactions
|
2019
|
Vol. 67, iss. 1
3--19
EN
In this paper, we investigate the Dufour and Soret effects on MHD mixed convection of a chemically reacting fluid over a stretching surface in a porous medium with convective boundary condition. The similarity transformation is used to reduce the governing non-linear partial differential equations into ordinary differential equations. Then, they are solved analytically by using the homotopy analysis method (HAM) and are solved numerically by the Runge-Kutta fourth-order method. The analytical and numerical results for the velocity, temperature, concentration, skin friction, Nusselt number and Sherwood number are discussed.
4
Content available Metody pomiaru własności sprężystolepkich
Kiljański T.
Inżynieria i Aparatura Chemiczna
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2014
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Nr 5
344--346
PL
Objawy sprężystolepkości płynu z reguły są szkodliwe w procesach technologicznych ze względu na generowanie dodatkowych naprężeń i związanych z nimi odkształceń, często obniżających jakość produktu. Te efekty mogą być zmniejszone przez odpowiedni dobór parametrów procesu technologicznego. Omówiono metody badania własności sprężystolepkich wykorzystujące przepływy ustalone (wiskozymetryczne), przepływy jednokierunkowe nieustalone i przepływy oscylacyjne. Przedstawiono test naprężeń normalnych, test pełzania, test relaksacyjny i badania oscylacyjne oraz wskazano, który z nich wybrać w celu uzyskania charakterystyki reologicznej płynu odpowiedniej dla danego procesu technologicznego.
EN
Manifestation of fluid viscoelasticity is usually a disadvantage in technological processes due to the generation of additional stresses and relevant deformations often decreasing product quality. These effects can be restricted via appropriate selection of technological process parameters. Testing methods of viscoelastic properties using steady-state (viscometry), one-directional unsteady-state and oscillatory flows are discussed. The creep, relaxation and normal stresses tests are presented. It was indicated which of these tests should be chosen to obtain the fluid rheological characteristics appropriate for a given technological process.
5
Content available Heat transfer of viscoelastic fluid flow due to nonlinear stretching sheet with internal heat source
Nandeppanavar M. M., Siddalingappa M. N., Jyoti H.
International Journal of Applied Mechanics and Engineering
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2013
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Vol. 18, no. 3
739--760
EN
In the present paper, a viscoelastic boundary layer flow and heat transfer over an exponentially stretching continuous sheet in the presence of a heat source/sink has been examined. Loss of energy due to viscous dissipation of the non-Newtonian fluid has been taken into account in this study. Approximate analytical local similar solutions of the highly non-linear momentum equation are obtained for velocity distribution by transforming the equation into Riccati-type and then solving this sequentially. Accuracy of the zero-order analytical solutions for the stream function and velocity are verified by numerical solutions obtained by employing the Runge-Kutta fourth order method involving shooting. Similarity solutions of the temperature equation for non-isothermal boundary conditions are obtained in the form of confluent hypergeometric functions. The effect of various physical parameters on the local skin-friction coefficient and heat transfer characteristics are discussed in detail. It is seen that the rate of heat transfer from the stretching sheet to the fluid can be controlled by suitably choosing the values of the Prandtl number Pr and local Eckert number E, local viscioelastic parameter k1 and local heat source/ sink parameter β.
6
Content available remote Simulation of the electrospinning process
Karra S., Srinivasa A. R.
International Journal of Applied Mechanics and Engineering
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2009
|
Vol. 14, no 1
175-188
EN
The electrospinning process is modeled and the bending instability of a slender viscoelastic jet is simulated. This is accomplished by modifying the discrete bead model by Reneker et al. (2000). Specifically, the force due to surface tension is incorporated using the expression suggested by Kowalewski et al. (2005) (see Eq.(7)). The results obtained by the use of this modification seem to be in accord with the experimental observations reported in Reneker et al. (2000) (Fig.2). An attempt is also made to simulate the effect of a secondary electric field which could be used to control the electrospinning process and whipping instability. It is observed that the external secondary field considered here, unwinds the jet spirals, reduces the whipping instability and increases the tension in the fiber.
7
Content available remote A bi-phasic model for artificial replacement
Bali R., Shukla A. K., Sharma S. K.
International Journal of Applied Mechanics and Engineering
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2009
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Vol. 14, no 3
633-643
EN
Joint replacement is widely used for treatment when joints fail to support loads or normal functions due to some accidental force or diseases. The analytical models for artificial human knee joints introducing the concept of porous implants with bone in growth into the pores, may provide better implantation than using cement or rigid, plastic/metallic materials. The purpose of the present study is to determine theoretically the articular contact mechanics of an artificial knee joint containing biphasic cartilage layers under restricted motion during normal walking. The present work incorporates the effect of a viscoelastic fluid as a lubricant on the parameter related to the lubrication mechanism. It has been observed that the load carrying capacity increases with increasing values of viscoelastic parameters. The effect of an increase in the viscoelastic parameter of the lubricant in similar to that of an increase in concentration of hyaluronic acid molecules in the synovial fluid. This helps in sustaining the greater loads. Further, we also observe that as the slip velocity at the porous boundary increases, load carrying capacity decreases owing to the increased filtration of base fluid into the porous cartilage. Thus, the slip velocities existing at the porous boundary play on important role in the self-adjusting nature of the artificial joint.
8
Content available remote Boundary layer viscoelastic fluid flow over an exponentially stretching sheet
Khan S. K.
International Journal of Applied Mechanics and Engineering
|
2006
|
Vol. 11, no 2
321-335
EN
In the present paper, a viscoelastic boundary layer fluid flow over an exponentially stretching continuous sheet has been examined. The flow is assumed to be generated solely by the application of two equal and opposite forces along the x-axis such that stretching of the boundary surface is of exponential order in x. Approximate analytical similarity solutions (zero and first order) of the highly non-linear boundary layer equation are obtained for the dimensionless stream function and velocity distribution function after transforming the boundary layer equation into Riccati type and solving that sequentially. The first-order solution is derived in the form of confluent hypergeometric Whittaker functions. The solutions are verified at the boundary sheet. These solutions (zero and first order) involve an exponential dependence of the similarity variable, the stretching velocity and the stream function on the axial coordinate. The accuracy of the analytical solutions is also verified by the numerical solutions obtained by employing the Runge-Kutta fourth order method with shooting. The effects of various physical parameters on the velocity profile and skin-friction coefficient are also discussed in this paper.
9
Content available remote Boundary layer MHD flow of a viscoelastic fluid over a porous quadratic stretching sheet
Khan S. K.
International Journal of Applied Mechanics and Engineering
|
2005
|
Vol. 10, no 2
267-279
EN
A mathematical analysis on the boundary layer MHD flow of a viscoelastic fluid over a porous stretching sheet has been presented in this paper. A typical choice of quadratic stretching of the boundary, which generates a quadratic part in velocity parallel to the boundary sheet and a linear mass flux part in the velocity normal to the stretching sheet, has been assumed. Streamline patterns and skin friction coefficients are discussed for various values of nondimensional physical parameters. The result of the analysis reveals that the combined effect of the non-dimensional viscoelastic parameter and Hartmann number is to increase significantly the values of skin friction coefficient, whereas, the combined effect of the nondimensional constant mass flux parameter and modified linear mass flux parameter is to reduce largely the values of skin friction coefficient. For positive values of the linear mass flux parameter the stream functions attain a positive slope away from the origin while they attain a negative slope everywhere for zero value. The limiting cases of our results yield the results of Andersson (1992) and Kumaran and Ramanaiah (1996).
10
Content available remote Tribology of stochastic phenomena on the hard tissue
Wierzcholski K. C.
International Journal of Applied Mechanics and Engineering
|
2004
|
Vol. 9, no spec.
283-289
EN
The aim of this paper is to show analytical solutions of friction forces and the velocity component of viscoelastic nutrient fluid in the thin layer resting on the surface sample of tissue. Friction forces and stresses are caused by the perfusion in bioreactor. Stochastic Christensen model of rough surfaces of tissue sample is taking into account.
11
Content available remote Viscoelastic boundary layer MHD flow through a porous medium over a porous quadratic stretching sheet
Kumar Khan S., Sanjayanand E.
Archives of Mechanics
|
2004
|
Vol. 56, nr 3
191-204
EN
Boundary layer MHD flow of a viscoelastic fluid in a porous medium over a porous stretching sheet has been presented in this article. A typical choice of quadratic stretching of the boundary, having a quadratic part in velocity parallel to the boundary sheet and a linear mass flux in the velocity normal to the stretching sheet, constitutes the boundary conditions of the problem. The effect of various values of nondimensional physical parameters on streamline patterns and skin friction coefficient are discussed. Some of the important findings of the article are: (a) the flow is enhanced by the positive values of linear mass flux parameter and suppressed by the negative values of linear mass flux parameter; (b) the effect of permeability parameter is not significant when linear mass flux parameter takes zero or negative values; (c) the combined effect of reduction of the values of permeability parameter, Hartmann number and linear mass flux parameter is expected to reduce largely the values of skin friction coefficient.
12
Content available remote On the viscoelastic core of a line vortex embedded in a stagnation point flow
Erdogan M. E.
International Journal of Applied Mechanics and Engineering
|
2003
|
Vol. 8, no 4
577-588
EN
The viscoelastic core of a line vortex embedded in a radially inward axisymmetric stagnation point flow for a Maxwell fluid and an Oldroyd B fluid is considered. Velocity, vorticity and stress distributions are calculated and compared with those of the Newtonian fluid. It is found that there are pronounced effects of viscoelastic properties on these distributions with respect to those of the Newtonian fluid.
13
Content available remote Pulsatile flow of electrically conducting non-Newtonian fluid and heat transfer through porous medium in a circular pipe
Eldabe N. T. M., Ghaly A. Y., El-hassan M., Oaf M. E.
Mechanics and Mechanical Engineering
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2001
|
Vol. 5, nr 1
5-20
EN
The influence of elasticity and magnetic field on pulastile viscoelastic flow and heat transfer in a circular pipe is examined. By means of the perturbation method of the velocity and temperature fields, the analytical solution of the velocity and temperature are obtained in terms of Bessel and hypergeometric functions .The discharge and the rate of heat transfer are determined through the course of discussions.
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