TJ452 : Numerical simulation of the electroosmotic flow of the Carreau-Yasuda model in the rectangular microchannel
Thesis > Central Library of Shahrood University > Mechanical Engineering > MSc > 2017
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Abstarct: A dilute solution in contact with a pregnant surface that leads to the redistribution of ions leads to the formation of a double electric laxyer (EDL). Electrostatic current is created by applying an effective electric field in the direction of flow. In a number of special applications, electrostatic pressure and current gradients may interfere. The constant viscosity assumption does not apply to a wide class of non-Newtonian fluids. The change in the non-Newtonian fluid-forming equations, which includes cut-rate viscosity, can describe a large number of industrial fluids. The Carreau Yasoda model has sufficient flexibility for a large variety of laboratory viscosity curves.
The non-Newtonian fluid flow, baxsed on the Carreau-Yasoda model, needs to be examined in a rectangular microchannel combined with the electrostatic pressure and flow gradient. In this study, first we compute the computational field in the form of a rectangular cube into a square cubic form and use a finite difference method to disjoint the Poisson-Boltzmann complete equation. Then, using the Newton Raphson method, we obtain the potential values at all points in the domain. After calculating the potential of the dual electric laxyer (EDL), we investigate the equation governing the electrostatic current and the pressure for the non-Newtonian Carreau-Yasoda fluid in the microchannel in the current and developed flow conditions. First, we control the governing equation for the Carreau-Yasuda fluid by considering the direct current DC voltage (DC). Then, using the finite difference method, these equations are discrete and using the Newton-Raphson method, we obtain the velocity values in all points. After calculating the velocity of the equation, we solve the energy for this non-Newtonian fluid. The energy equation is discrete and solved using a finite difference method.
The small values of the flow behavior index (n), the degree of concentration, as well as the smaller velocities, are indicated. The flow field is strongly affected by the frequency. A plug like speed profile is obtained at almost low frequencies, while the flow field may be immobile and constant at frequencies high enough. Deviation from the channel center is observed when the pressure gradient applied over the channel. The nonlinear behavior of the current was increased by the Weisenberg number through a fixed time model. Large or small amounts of shear stress over a period can lead to rapid changes in viscosity.
Keywords:
#Electrostatic Flux #Non-Newtonian Fluids #Newtons Ruffson's Method #Flow Behavior Index #Wiesenberg Number
Keeping place: Central Library of Shahrood University
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Keeping place: Central Library of Shahrood University
Visitor: