الفهرس 
CHAPTER 1: INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
The study presents in details, experimental and numerical studies on emulsion (oil-in-water) flow in rectangular cross-sectional area S-shaped diffusers. The experimental setup was designed and constructed in the fluid
mechanics laboratory of the faculty of engineering, Menoufia University to
obtain the experimental data since the measurements have been performed
on twelve S-shaped diffusers.
Different parameters including area ratio, curvature ratio, turning angle
(45◦/45◦, 60◦/60◦, and 90◦/90◦), flow path (45◦/45◦, 60◦/30◦, and 30◦/60◦), inflow
Reynolds number, holdup (0.03, 0.06, 0.10, 0.15, and 0.25) and emulsion
stability have been considered. The static pressure distributions along the
outer and inner walls of the S-diffuser including upstream and downstream
tangents were measured. Based on these measurements, the energy-loss
coefficient of all models could be extracted. The diffusers performance has
been plotted versus inflow Reynolds number at different geometrical and
inflow parameters.
The studies were carried out using two types of oil-in-water (o/w)
emulsions; stable o/w emulsion by using an emulsifier named by Sodium
Dodecyl Sulfate (SDS) and unstable o/w emulsion without any additives at
different holdup values.
The experimental data for different S-diffuser configurations have been used
for assessing credibility of the numerical code using ANSYS R-15.0
software Fluid Flow Fluent (FFF) - 3D with different solution methods.
Computations with different turbulence closures have been carried out for
prediction of the performance of S-shaped diffusers at different inflow and
geometrical conditions in case of water as well as emulsion flows. With
emulsion flow, besides the standard k-ε model, the mixture model was used The study presents in details, experimental and numerical studies on
emulsion (oil-in-water) flow in rectangular cross-sectional area S-shaped
diffusers. The experimental setup was designed and constructed in the fluid
mechanics laboratory of the faculty of engineering, Menoufia University to
obtain the experimental data since the measurements have been performed
on twelve S-shaped diffusers.
Different parameters including area ratio, curvature ratio, turning angle
(45◦/45◦, 60◦/60◦, and 90◦/90◦), flow path (45◦/45◦, 60◦/30◦, and 30◦/60◦), inflow
Reynolds number, holdup (0.03, 0.06, 0.10, 0.15, and 0.25) and emulsion
stability have been considered. The static pressure distributions along the
outer and inner walls of the S-diffuser including upstream and downstream
tangents were measured. Based on these measurements, the energy-loss
coefficient of all models could be extracted. The diffusers performance has
been plotted versus inflow Reynolds number at different geometrical and
inflow parameters.
The studies were carried out using two types of oil-in-water (o/w)
emulsions; stable o/w emulsion by using an emulsifier named by Sodium
Dodecyl Sulfate (SDS) and unstable o/w emulsion without any additives at
different holdup values.
The experimental data for different S-diffuser configurations have been used
for assessing credibility of the numerical code using ANSYS R-15.0
software Fluid Flow Fluent (FFF) - 3D with different solution methods.
Computations with different turbulence closures have been carried out for
prediction of the performance of S-shaped diffusers at different inflow and
geometrical conditions in case of water as well as emulsion flows. With
emulsion flow, besides the standard k-ε model, the mixture model was used as a solution multi-phase model using fine grid to obtain a more accurate
flow prediction.
The continuous phase (water) has been simulated using standard k-ε model
by solving Reynolds-Averaged Navier-Stokes equations (RANS), while
the dispersed phase (oil) has been simulated using mixture multi-phase
model by solving oil liquid particle equations using 4th order Runge-Kutta
method. Comparisons between present CFD code predictions and available
experimental results from literature as well as the present experimental
data showed good matching and better agreement.
The results showed that the S-shaped diffuser energy-loss coefficient is
strongly affected by the geometrical and inflow parameters. Increasing area
ratio, curvature ratio, and inflow Reynolds number leads to improving
diffuser performance. Whereas, decreasing the emulsion holdup (Φ) leads
to decreasing diffuser performance. The turning angle plays an important
role in improving the S-shaped diffuser performance. S-shaped diffuser
energy-loss coefficient of water flow is lower than that of emulsion flow.
Also the S-shaped diffuser energy-loss coefficient of stable o/w emulsion
flow is higher than that of unstable, one.
A general new correlation of energy-loss coefficient including geometrical
and flow parameters for the validated studied cases of S-diffusers is
extracted from the measurements.