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ARPN Journal of Engineering and Applied
Sciences
July 2011 | Vol. 6 No. 7 |
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Title: |
Numerical
analysis of fin-tube plate heat exchanger by using CFD technique |
Author (s): |
Ahmed F.
Khudheyer and Mahmoud Sh. Mahmoud |
Abstract: |
Three-dimensional CFD simulations are carried out to
investigate heat transfer and fluid flow characteristics of
a two-row plain fin-and-tube heat exchanger using Open FOAM,
an open-source CFD code. Heat transfer and pressure drop
characteristics of the heat exchanger are investigated for
Reynolds numbers ranging from 330 to 7000. Model geometry is
created, meshed, calculated, and post-processed using open
source software. Fluid flow and heat transfer are simulated
and results compared using both laminar and turbulent flow
models (k-epsilon, and Menter SST k-omega), with
steady-state solvers to calculate pressure drop, flow, and
temperature fields. Model validation is carried out by
comparing the simulated case friction factor f and Colburn
factor j to experimental results from the literature. For
friction factor determination, little difference is found
between the flow models simulating laminar flow, while in
transitional flow, the laminar flow model produced the most
accurate results and the k-omega SST turbulence model was
more accurate in turbulent flow regimes. The most accurate
simulations for heat transfer in laminar flow are found
using the laminar flow model, while heat transfer in
transitional flow is best represented with the SST k-omega
turbulence model, and heat transfer in turbulent flow is
more accurately simulated with the k-epsilon turbulence
model. Reasonable agreement is found between the simulations
and experimental data, and the open-source software has been
sufficient for simulating the flow fields in tube-fin heat
exchangers. |
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Title: |
Informative
binarization based on unsharp masking |
Author (s): |
Yumnam Kirani
Singh |
Abstract: |
In the existing methods of binarization, most
of the edge information is lost and the resulted binary
image gets blurred. Edges carry most of the information in
an image. If we can preserve or retain most of the edge
information in a binary image, the image will be informative
and look natural. To preserve edge information in a binary
image, the edges in the grey image must be enhanced using
some effective unsharp masks. We propose a new method of
generating unsharp masks, which can be used to enhance the
edges in an image effectively. Once an effective unsharp
mask is obtained, we apply it on an input grey image to get
enhance the edges in the image. The edge enhanced grey image
is binarized to give informative binary image. The
informative binary images look better and more informative
as compared with binary images obtained using by popular
Otshu’s method. |
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Title: |
Garnet group
minerals from the amphibolite facies metamorphic rocks of
Krivaja-Konjuh ultramafic massif in Bosnia and Herzegovina |
Author (s): |
M. Operta, S.
Hyseni, D. Balen, S. Salihović and B. Durmishaj |
Abstract: |
In
Bosnia
and
Herzegovina’s ophiolite
zone
there are six different
ophiolite
complexes
including
Krivaja-Konjuh
ultramafic
massif.
In
the
south-eastern
parts
of
the
massif,
the
basement
is
built
of
different
varieties of
amphibolites
with
subordinate
occurrence of
metamorphic
rocks
that
don’t
contain
amphiboles.
Locality
NE
of
Vareš
near
the
village
of
Vijaka
is
generally the
best
outcrop of
amphibolite
rocks.
The
results of
petrologic
studies
indicate
that
the
analyzed
rocks
can be
divided
into
several groups like
garnet-diopside amphibolite,
garnet-diopside-hypersthene amphibolite, plagioclase-garnet
rocks, garnet-pyroxene-plagioclase schist;
plagioclase-garnet-hornblende - diopside schist and
porphyryblastic hornblende and garnet bearing schist. The
garnets show wide variation in chemical composition with
prevalance of almandine and pyrope component in all of
analyzed samples. The differences in the composition profile
through the garnets are attributed to changes in the
metamorphic conditions during the growth of minerals. Abrupt
changes in distribution of elements were observed in a thin
zone on the very edge of the garnet grains which is
interpreted as a result of the retrograde phase of
metamorphism and rapid cooling. |
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Title: |
Formulation
of cost function for constructing a new transportation route |
Author (s): |
Asma Th.
Ibraheem and Abeer Jabbar Abd- Al Razaq |
Abstract: |
A principal objective of transportation route
design is to minimize the total cost including all
significant components. The cost functions for a highway,
which is developed in this thesis, have been incorporated
into programmed software named Transportation Route Cost
Analysis (TRCA) written using VBASIC Language. These
functions reflect the costs due to different cost function
characteristics such as Administrative Cost, Construction
Cost, Maintenance Cost, User Costs, which include: (Tire
Cost, Oil Cost, Fuel Cost, Travel Time Cost and Accident
Cost) and finally Social and Environmental Costs, while most
existing models in Iraq only considered Construction Cost,
or even just one component such as earthwork cost. A case
study is also presented to evaluate the modeled software of
a highway having a length (12.644) km including a bridge
crossing Tigris River of length (420) m with three
intersections. According to the State Corporation for Roads
and Bridges (SCRB), the gross domestic product is about
(60,000,000,000) ID. This value is greater than the value
obtained by the software (TRCA) because of the elimination
of Accident Cost since no information regarding this type of
cost is available in (TRCA), also, the duration of each cost
considered in this program is only one year. |
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Title: |
Investigation
of airfoil profile design using reverse engineering Bezier curve |
Author (s): |
J. Fazil and
V. Jayakumar |
Abstract: |
Though it is easier to model
and create an airfoil profile in CAD environment using
camber cloud of points, after the creation of vane profile
it is very difficult to change the shape of profile for
analysis or optimization purpose by using cloud of points.
In this paper, we investigate and describe the creation of
airfoil profile in CAD (CATIA) environment using the control
point of the camber profile. By means of changing the values
of control points the shape of the profile can be easily
changed and also the design of the cambered airfoil is
established without affecting the basic airfoil geometry. In
this paper, the Quintic Reverse Engineering of Bezier curve
formula is used to find the camber control points from the
existing camber cloud of points. |
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Title: |
A new method
to incorporate TCSC in optimal power flow using genetic
algorithm |
Author (s): |
Satyendra
Singh and K. S. Verma |
Abstract: |
In this work, Genetic Algorithm (GA) for the
solution of the optimal power flow (OPF) with use of
Thyristor Controlled Series Compensator (TCSC) is studied.
The specified power flow constraints due to use of TCSC are
included in the OPF in addition to the normal conventional
constraints. The sensitivity analysis is carried out for the
location of TCSC. This method provides an enhanced economic
solution. Traditionally, classical optimization methods were
used to effectively solve OPF. But more recently due to
incorporation of Flexible A.C. Transmission System (FACTS)
devices and deregulation of a power sector, the traditional
concepts and practices of power systems are superimposed by
an economic market management. So OPF have become complex.
In recent years, Artificial Intelligence methods (GA etc)
have emerged which can solve highly complex OPF problems.
5-bus system has been studied to show the effectiveness of
the algorithm. |
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Title: |
Nonlinear
damped oscillations- A case study of dysfunctions in smooth
pursuit eye tracking-II |
Author (s): |
C. V.
Pavankumar and N. Ch. Pattabhi Ramacharyulu |
Abstract: |
This paper presents a
simple deterministic model of dysfunctions of eye- tracking.
The model is formulated as a second order nonlinear ordinary
differential equation, incorporating non Hookesien cubic
restoring force. The equation is solved by employing a
perturbation technique with the nonlinear restoring force
coefficient as the perturbation parameter. Numerical
estimation of the angular velocity is computed for a wide
spectrum of the eye dysfunction. The significance of the
effects of time, the frequency and amplitude of the exiting
force on displacement has been discussed by adopting ANOVA
technique. The critical levels of time and frequency have also
been noted to be 2.761sec and 0.181149375, respectively
corresponding to the 0.05 level of significance. |
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Title: |
Strength and
water penetrability of fly ash geopolymer concrete |
Author (s): |
Monita Olivia
and Hamid R Nikraz |
Abstract: |
This paper presents a study on the strength
development, water absorption and water permeability of low
calcium fly ash geopolymer concrete. Geopolymer mixtures
with variations of water/binder ratio, aggregate/binder
ratio, aggregate grading, and alkaline/fly ash ratio were
investigated. OPC (Ordinary Portland Cement) concrete with
the same strength level was used as a control mix. Strength
was measured by compressive strength, while water
penetrability was evaluated by water absorption and water
permeability. In addition, the AVPV (Apparent Volume of
Permeable Voids) was measured. The results show that the
strength of fly ash geopolymer concrete was increased by
reducing the water/binder and aggregate/binder ratios; and
the water absorption of low calcium fly ash geopolymer was
improved by decreasing the water/binder ratio, increasing
the fly ash content, and using a well-graded aggregate.
There was no significant change in water permeability
coefficient for the geopolymer with different parameters.
The test data indicates that a good quality of low calcium
fly ash geopolymer concrete can be produced with appropriate
parameterisation and mix design. |
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Title: |
Possibilities
of GA in optimization of manufacturing cell formation |
Author (s): |
V. Modrák, S. Pandian and P. Knuth |
Abstract: |
Optimization of manufacturing cell formation
includes a whole virtual cell formation procedure and has
NP-hard complexity. In the last decades, evolutionary
algorithms have been widely applied to real-world
optimization including to manufacturing cell formation
problems. Genetic algorithms (GAs) are possibly the most
widespread variant of evolutionary algorithms and are now
frequently used for a number of optimization problems in
operation management. In this study it is discussed about
theoretical and practical aspects of GA to bridge the gap
between hypothetical analysis and real time implementation
of GA in a given domain. |
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Title: |
A study on
the engineering behaviour of Nairobi subsoil |
Author (s): |
Caroline
Onyancha, Eliud Mathu, Sixtas Mwea and Wilson Ngecu |
Abstract: |
Nairobi
city is underlain by volcanic materials that resulted from
the formation of the rift valley. Some of the challenges
that face design of structures in the city include the
following: need to develop structures even in areas with
poor site conditions; distress in structures that could be
related to foundation conditions; encounter of unexpected
subsoil conditions even after carrying out some geotechnical
investigations, and; development of defects related to
adjacent deep excavation. The objectives of this study were:
investigate the qualitative and quantitative properties of
subsurface materials, to establish the engineering property
variations and to provide properties that represent the best
estimates. Information available for this study included Atterberg limits, grading, consolidation, swell and
collapse, triaxial shear and direct shear, point load and
unconfined compressive strength. Failure investigation and
resistivity survey were carried out to fill in the gaps in
the available information. The results indicate that the
engineering properties of the materials are very variable.
Material property variations and the expected performance of
the various subsoil materials are provided. The study
concluded that before construction, it is necessary to carry
out geotechnical investigations to delineate sensitive
soils, determine weak and strong spots and evaluate the
relationship between total and differential settlements. |
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Title: |
High quality
rectifiers with reduced THD for enhanced mains power quality -
Vienna with synchronous logic |
Author (s): |
Anantha
Baddam Reddy and G. Tulasi Ram Das |
Abstract: |
A synchronous logic control based three-phase
boost unity power factor rectifier unit that works as an
interface to ensure high energy efficiency by reducing
reactive power consumption, as well as to maintain a
constant DC-bus voltage. This paper discusses the
determination of performance characteristics of Vienna
rectifier topology with the synchronous logic based control.
Furthermore this enabled the design and development of a
three-phase active converter system that was built and
tested with the inputs and output. This paper also describes
the Vienna Rectifier’s power stage and synchronous logic
control technique, with particular emphasis on finding
differences between real prototype results and the
simulation results. The design and experimental performance
of a three-phase PWM rectifier with a power output of 3 kW
is presented. The real prototype results confirm with the
simulation results. |
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Title: |
Experimental
study for heat and mass transfer from moist air flowing over
moving water film |
Author (s): |
Ahmed F.
Khudheyer |
Abstract: |
Heat and mass transfer from or
to a horizontal moving water film to airflow flowing over
the film inside a rectangular duct wind tunnel is
investigated, experimentally. To perform the experimental
study for this phenomenon air flows inside a rectangular
duct over a moving water film flow inside the duct, which is
fixed in the floor of the tunnel. Therefore, some of the
water film is evaporated from the water surface to the air
flowing over it. The following measurements for velocity of
moist air and water, temperature, humidity, are taken at
five positions along test section and upstream of the water
panel with a range of Reynolds number of (1000-30000). Also,
the amount of water evaporated through each experiment is
measured. The results show
that, Nusselt and Sherwood numbers increase with increasing
Reynolds number. Comparison between the obtained results and
the previous works show good agreement. |
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Title: |
Effect of
slip on heat transfer to peristaltic transport in the presence
of magnetic field with wall effects |
Author (s): |
A. V. Ramana
Kumari and G. Radhakrishnamacharya |
Abstract: |
The effects of slip and elasticity of
flexible walls on peristaltic transport of an incompressible
viscous fluid in a two dimensional uniform channel, with
heat transfer in the presence of magnetic field is
investigated. Using long wavelength approximation, a
perturbation solution has been obtained in terms of wall
slope parameter and closed form expressions are derived for
average velocity, temperature and heat transfer. The effects
of various pertinent parameters on average velocity and heat
transfer coefficient have been studied. The time average
velocity increase with slip but decrease with permeability.
Trapping phenomenon is more significant for lower values of
slip parameter, higher permeability and almost disappears
for higher values of magnetic parameter. Further, the heat
transfer coefficient increases with slip but decreases with
permeability. |
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Title: |
Seismic
analysis of t shape rigid Bridge with high piers |
Author (s): |
Qingxiang
Zheng and Wenhua Liu |
Abstract: |
Combined with seismic resistance of T shape
rigid bridge with high piers in Dina 2 gas-field of China,
comparative analysis on double thin-wall piers and hollow
thin wall pillar is carried out. Focusing on seismic
performance of their dynamic properties and structure under
the condition of one-way incentive and three-dimensional
space incentive, we conclude that the seismic performance of
double thin-wall piers is superior to hollow thin wall
pillar, on the basis of the fact that double thin-wall piers
contains more than hollow thin wall pillar low-frequency
vibration frequency in sectional characteristic and pier
under the condition of high basic agreement, which is easily
causing to frequency dispersion. |
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