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The ever-changing legislation and every increasing awareness of the environment have led to a change in the production processes used up to new and especially in the production auxiliaries such as coolants. It has been widely accepted that a considerable proportion of the process costs are caused by the application of metalworking fluids. In this aspect the costs for coolant concentrates themselves...
The compressible elastohydrodynamic (EHD) lubrication of two surfaces under line contact has been investigated in steady state operating conditions. The modified Reynolds equation with non-Newtonian fluids has been formulated using Carreau viscosity model. The simultaneous systems of modified Reynolds and elasticity equations with boundary conditions were solved numerically using Newton Raphson technique...
The thermohydrodynamic behavior of the lubricant flow in a Rayleigh step is described by a mathematical model that uses the bidimensional Navier-Stokes and energy equations written in terms of the primary variables u, v, p and T. The non-Newtonian behavior of the lubricant is described by a power law model. The lubricant is assumed to be incompressible and the process is steady-state and laminar....
The rheological properties (flow curves and the viscoelastic behavior) of the dispersions prepared from plas-ma-processed Al2O3 powders and epoxy wax were investigated on wide ranges of shear rates (from 0.018 to 1350s-1) and frequencies (from 0.063 to 157s-1). Oleic acid and Hypermer LP1 was chosen as dispersants for preparation of the dispersions. It is stated that, at the concentration f ? 15 vol...
Six model polydimethylsiloxane (PDMS) networks were obtained by hydrosilation of a difunctional vinyl-terminated PDMS prepolymer with a SiH containing crosslinker. Viscoelastic experiments were performed in order to study the influence of molecular parameters on the dynamic properties around the sol-gel threshold. Critical parameters were determined close to and above the sol-gel threshold. Our results...
Taking into account the increasing need to artificial joints for in-vitro use, this paper presents a layout of a challenge leading to detail analyzing in aspects of rheology for the tissue cultivation and regeneration and gives a step-by-step plan for designing a novel intelligent bioreactor.
Flow of confined polymer melts in narrow channels is considered on base of the activation model for polymer melt friction. While melt infiltrates a dense fibrous bed under high pressure, the polymer segments in the adsorbed layer are gradually involved in flow and the effective activation energy increases as compared with that for the melt in bulk. The theoretical prediction was proved experimentally.
The flow of a couple -stress fluid in an annular curvilinear channel with a porous insert is considered. The porous insert is connected with a inner impermeable rotating surface which approaches the outer fixed surface of an annular curvilinear channel. The equations of motion governing of the flow reduce to the coupled Reynolds and Poisson equations which can be uncoupled by using the Morgan-Cameron...
The viscous, two-dimensional, incompressible and laminar time dependent heat transfer flow through a ferromagnetic fluid is considered in this paper. Flow takes place in channel between two parallel flat plates under the influence of the magnetic dipole located below the channel. It is assumed that there is no electric field effects and the variation in the magnetic field vector that could occur due...
The helical flow of a Casson fluid between infinitely long coaxial cylinders is analyzed, when the inner cylinder has a given constant angular velocity, and a constant axial flow rate is imposed. Perturbation methods are applied in two circumstances of physical interest - that of low axial flow rates; and that of small intercylindrical gap width - to yield approximate expressions describing the fluid...
In this note, the unsteady flow of a Maxwell fluid produced by non-coaxial rotation while a disk and the fluid at infinity are initially rotating with the same angular velocity about a common axis is considered. Even in the case of a non-Newtonian fluid, it is shown that there is an exact solution for this flow geometry. The velocity field is obtained with the help of the Laplace transform technique.
The two-dimensional steady incompressible flow past an impermeable sphere embedded in a porous medium is studied analytically using the Brinkmann model- specifying a uniform shear away from the sphere. A closed form solution is obtained for the governing equations. It is found that the increase in the permeability of a porous medium and viscosity ratio is to increase the thickness of the Brinkman...
The aim of the present problem is to investigate the efficiency of the method of Adomian for the solution of non-linear and complicated differential equation in a random medium. Here the problem is connected with the investigation of the mean and variance of the displacement distribution in a thin linear random non-homogeneous Biot type viscoelastic semi-infinite rod, due to general time-dependent...
The instability of streaming Walters B' elastico-viscous fluids in hydromagnetics through porous medium is considered. The case of two uniform streaming fluids separated by a common horizontal interface is considered. It is found that for the special case when perturbations in the direction of streaming are ignored, the system can be stable or unstable, depending upon kinematic viscoelasticity, medium...
This paper presents a numerical study of a fully developed laminar flow of a non-Newtonian fluid in a helical pipe. An orthogonal helical coordinate system is utilized and the Navier-Stokes equations for the non-Newtonian fluid in this coordinate system are derived. The SIMPLE algorithm with a staggered grid is adopted to solve the governing equations. The effects of the pressure gradient, the curvature,...
In this article it has been sought to study the effect of transverse roughness on the behaviour of slider bearings with squeeze film formed by a magnetic fluid. The roughness of the bearing surface is modelled by a stochastic random variable with non zero mean, variance and skewness. The associated Reynolds' equation is stochastically averaged with respect to the random roughness parameter. Results...
A boundary layer analysis is presented to study the effects of thermal dispersion of a non-Newtonian fluid on non-Darcy axisymmetric free convection over a horizontal surface embedded in a porous medium. The Ostwald-de-Waele power-law model is used to characterize the non-Newtonian fluid behavior. The thermal diffusivity coefficient has been assumed to be the sum of the molecular diffusivity and the...
The analytic expressions for the displacements, microrotation, stresses and volume fraction field on the free surface of a micropolar elastic half-space with voids as a result of moving an inclined load have been obtained. The inclined load is assumed to be a linear combination of a normal load and a tangential load. The problem has been solved by employing the Eigen-value approach after using the...
The steady state response at viscous fluid/micropolar elastic solid interface to a moving point load has been studied for subsonic, supersonic and transonic load velocities. The Fourier transform has been used to solve the problem. The displacement, microrotation and stress components for a micropolar elastic solid so obtained in the physical domain are computed numerically by using the numerical...
An analysis is presented to investigate the flow and heat transfer characteristic of a viscous incompressible and electrically conducting fluid through a porous medium bounded by two long vertical parallel plates in the presence of a uniform magnetic field applied transversely to the flow. The governing momentum and energy equations are solved by the Laplace transform technique and the solutions are...
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