Abstract: The present study is carried out to investigate the magneto-viscous effects on incompressible ferrofluid flow over a porous rotating disc with suction or injection on the surface of the disc subjected to a magnetic field. The flow under consideration is axi-symmetric steady ferrofluid flow of electrically non-conducting fluid. Karman’s transformation is used to convert the governing boundary layer equations involved in the problem to a system of non linear coupled differential equations. The solution of this system is obtained by using power series approximation. The flow characteristics i.e. radial, tangential, axial velocities and boundary layer displacement thickness are calculated for various values of MFD (magnetic field dependent) viscosity and for different values of suction injection parameter. Besides this, skin friction coefficients are also calculated on the surface of the disk. The results thus obtained are presented numerically and graphically in the paper.
Abstract: An attempt has been made to study the effect of rotation on incompressible, electrically non-conducting ferrofluid in porous medium on Axi-symmetric steady flow over a rotating disk excluding thermal effects. Here, we solved the boundary layer equations with boundary conditions using Neuringer-Rosensweig model considering the z-axis as the axis of rotation. The non linear boundary layer equations involved in the problem are transformed to the non linear coupled ordinary differential equations by Karman's transformation and solved by power series approximations. Besides numerically calculating the velocity components and pressure for different values of porosity parameter with the variation of Karman's parameter we have also calculated the displacement thickness of boundary layer, the total volume flowing outward the z-axis and angle between wall and ferrofluid. The results for all above variables are obtained numerically and discussed graphically.
Abstract: The article deals with experimental and numerical
investigation of axi-symmetric subsonic air to air ejector with
diffuser adapted for boundary layer suction. The diffuser, which is
placed behind the mixing chamber of the ejector, has high divergence
angle and therefore low efficiency. To increase the efficiency, the
diffuser is equipped with slot enabling boundary layer suction. The
effect of boundary layer suction on flow in ejector, static pressure
distribution on the mixing chamber wall and characteristic were
measured and studied numerically. Both diffuser and ejector
efficiency were evaluated. The diffuser efficiency was increased,
however, the efficiency of ejector itself remained low.
Abstract: The article deals with pneumatic and hot wire
anemometry measurement on subsonic axi-symmetric air ejector.
Performances of the ejector with and without pulsations of primary
flow are compared, measuring of characteristic pressures and mass
flow rates are performed and ejector efficiency is evaluated. The
pulsations of primary flow are produced by a synthetic jet generator,
which is placed in the supply line of the primary flow just in front of
the primary nozzle. The aim of the pulsation is to intensify the
mixing process. In the article we present: Pressure measuring of
pulsation on the mixing chamber wall, behind the mixing chamber
and behind the diffuser measured by fast pressure transducers and
results of hot wire anemometry measurement. It was found out that
using of primary flow pulsations yields higher back pressure behind
the ejector and higher efficiency. The processes in this ejector and
influences of primary flow pulsations on the mixing processes are
described.
Abstract: This study presents an exact general solution for
steady-state conductive heat transfer in cylindrical composite
laminates. Appropriate Fourier transformation has been obtained
using Sturm-Liouville theorem. Series coefficients are achieved by
solving a set of equations that related to thermal boundary conditions
at inner and outer of the cylinder, also related to temperature
continuity and heat flux continuity between each layer. The solution
of this set of equations are obtained using Thomas algorithm. In this
paper, the effect of fibers- angle on temperature distribution of
composite laminate is investigated under general boundary
conditions. Here, we show that the temperature distribution for any
composite laminates is between temperature distribution for
laminates with θ = 0° and θ = 90° .