Teymuraz Abbasov

A theoretical model for estimation of drag force in the flow of non-newtonian fluids around spherical solid particles

A theoretical approach for estimation of the drag correlation coefficients in the flow of Newtonian or weak non-Newtonian liquids around spherical solid particles is presented. Some new analytical relations are derived by using a stream function and the energy dissipation equation to approximate the drag coefficients to the experimental data. It is shown that these relationships can be applicable in a wide range of Reynolds number, Re, up to Re<1000 for the liquids with a flow behavior index, n, in the range of 0.5<n<1. The predicted coefficients from these relationships are in very good agreement with the experimental data given in the literature.

Theory of high-gradient magnetic filter performance

A unique general model for high-gradient magnetic filters is presented. The functional dependence of the filter performance on the systems physical and geometrical parameters is derived. The derived theoretical expression makes it possible to explain both of the two different, apparently opposite, experimental results reported in the literature. The new quality factor does not include the suspension viscosity, but instead depends on the suspension density, which leads to the application of the formula for a larger class of filtration media including liquids, gases, and vapors.

Particle capture in axial magnetic filters with power law flow model

A theory of capture of magnetic particle carried by laminar flow of viscous non-Newtonian (power law) fluid in axially ordered filters is presented. The velocity profile of the fluid flow is determined by the Kuwabara-Happel cell model. For the trajectory of the particle, the capture area and the filter performance simple analytical expressions are obtained. These expressions are valid for particle capture processes from both Newtonian and non-Newtonian fluids. For this reason the obtained theoretical results make it possible to widen the application of high-gradient magnetic filtration (HGMF) to other industrial areas. For Newtonian fluids the theoretical results are shown to be in good agreement with the experimental ones reported in the literature.

Some Aspects of Magnetic Filtration Theory for Removal of Fine Particles from Aqueous Suspensions

The magnetic filtration theory was evaluated to intensify the filtration of industrial fluids by magnetic filters. Effects of filtration velocity and external magnetic field intensity on filter performance were investigated and the dependence of the logarithmic efficiency coefficient on filtration velocity was questioned. It was concluded that change in the magnetic susceptibility of the dispersion particles, caused by external magnetic field, and change in the flow rate properties of the liquid alongside the filter pores are the most essential factors to be considered in the design, development, and modeling of magnetic filtration systems in various industrial areas.

Filtration model of high gradient magnetic filters with granular matrix

Abstract Considering the flow regime of the fluid through the pores of a magnetic filter having a granular matrix composed of ferromagnetic spheres and the accumulation process of the captured particles, the filtration mechanism is investigated. The effect of the different parameters of the filtration system on the efficiency of the magnetic filter is identified. New mathematical expressions are obtained to explain some events which take place in the filtration mechanism and which have not been described completely in the literature so far. The efficiency of the magnetic filter is expressed in terms of the ratios of the magnetic and static pressures which can be measured or identified easily. The theoretical results are compared with the experimental data and it is concluded that they are in good agreement.

Determination of the particle capture radius in magnetic filters with velocity distribution profile in pores

The determination of the liquid velocity profile in packed bed pores is a well-known problem in the practical applications and the theory of filtration and separation processes. Because the pore sizes are very small, the measurement of the liquid velocity in these areas is very difficult or impossible. By using the modified Kuwabara–Happel cell model, the liquid velocity profile in the pores of packed bed consisting of solid spheres and cylindrical wires was determined. The variation of the liquid velocity with the packed bed porosity and pore geometry has been investigated. By using these results, the expressions for drag force affecting the small particles in the pores and particle capture radius in magnetic filter have been obtained. The effect of the variation of some parameters of filtration system on the particle capture radius has been investigated. Comparisons of the theoretical and experimental results were found to be in good agreement.

Theoretical interpretation of the filtration process in magnetized packed beds

Abstract The purity of industrial liquids and gases is effected by particles having micron and submicron sizes. Many of the particles in those streams are ferro- or paramagnetic substances. Because of the low concentration of these particles, classical filters (mechanical, separator, etc.) do not perform significant filtration process, and magnetic filters (MFs) which have magnetized packed bed show greater capacity of capturing these particles. Also, MFs show different properties of non-stationary performance characteristics compared to the other type filters. The variation of the MF performance with time is initially constant for some period of the filtration process but falls after that filtration time. A magnetic filtration equation which takes these properties into account has been developed. This equation includes magnetic, hydrodynamic and geometric parameters of the filtration system. The equation obtained is a linear partial-differential equation, which must be solved analytically. The theoretical results obtained from the analytical solution have been compared with the experimental results obtained from various industrial areas using MFs. It can be concluded that a good agreement was found.

Performance of High Gradient Magnetic Filters with Granular Matrix

The performance characteristics of high gradient magnetic filters composed of spherical ferromagnetic granules are determined in terms of dimensionless parameters for a wide range of system parameters. The results obtained are used to overcome some contradictions seen in the literature related to magnetic filters. They are in a good agreement with the experimental data given in the literature for the filters used in laboratories and industry.

Enhanced endometrial response to a magnetic intrauterine device: A preliminary study

Objective To evaluate the effects of an intrauterine device producing a static magnetic field on the endometrial histology of rats. Methods The experiments involved 20 adult female Wistar albino rats that were divided into five groups. Group 1 was sham-operated; Groups 2, 3 and 4 had a copper intrauterine device (IUD), an uncovered intrauterine magnet (IUM) or an intrauterine silicone-coated IUM, respectively, inserted into one of the uterine horns; in Group 5 an uncovered IUM was implanted subcutaneously. Six days later the rats were sacrificed; endometrial and subcutaneous tissues were harvested and examined microscopically. Results Copper IUDs caused classical cellular infiltration through the endometrium. IUMs, producing a static magnetic field, also caused leucocyte and monocyte infiltration of the endometrium and, in addition, a significant leucocyte accumulation over the endometrial surface. Conclusion This preliminary study reveals that an intrauterine magnet induces the accumulation of leucocytes in the uterine cavity in addition to the classic stromal infiltration caused by commercially available nonmagnetic IUDs. This activity could contribute to a greater efficacy of intrauterine contraception and should be investigated further.

Model for Predicting Filtration Efficiency and Pressure Drop in Axial Magnetic Filters

The theory of filtration efficiency and filter impedance in axially ordered magnetic filters in conditions of laminar flow is described. The flow profile of the suspension that flows axially along the longitudinally ordered wires is determined by the Kuwabara–Happel cell model. Expressions for both filter impedance and filtration efficiency are obtained. In general, they are different from those predicted by previous filtration theories in ideal flow conditions. The derived theoretical formulas are simplified so they can be used easily in engineering applications. The results are compared with the experimental ones presented in the literature, and it is seen that they are consistent with each other.