Book Volume 2
Numerical Investigation of Turbulent Slot Jets with Various Nanoparticles Shapes
Page: 1-20 (20)
Author: Bouziane Boudraa* and Rachid Bessaïh
DOI: 10.2174/9789815124125123020003
PDF Price: $15
Abstract
In this work, a numerical investigation related to the turbulent forced
convection of a water-Al2O3
nanofluid in slot jets impinging on multiple hot
components fixed on the lower wall, using different nanoparticle shapes (spherical,
blades, bricks, cylindrical and platelets), was carried out. The standard k-ε turbulence
model with wall enhanced treatment and two-phase mixture model were used to
analyze the fluid flow and heat transfer. The outcomes revealed that the increase in the
Reynolds number (Re) and volume fraction of nanoparticles (φ) with all nanoparticle
shapes enhanced the heat transfer rate. The platelets nanoparticle's shape significantly
contributes to increasing the heat transfer rate compared with other forms. Also, we
have found that the two-phase mixture model gives a higher average Nusselt number
(Nu) values compared to the single-phase model, and the maximum values of (Nu) is
located around the last block due to the second jet's dominance (J2) compared to the
first jet (J1). We have compared our results with those found in the literature.
The Experimental Study on a Sweeping Gas Membrane Distillation Unit
Page: 21-29 (9)
Author: Mokhless Boukhriss*, Mohamed Ali Maatoug, Mahdi Timoumi and Nizar El Ouni
DOI: 10.2174/9789815124125123020004
PDF Price: $15
Abstract
This document examines the experimental application of the gas scavenging
membrane distillation (SGMD) process and its advantages and disadvantages. SGMD
is the least used configuration in membrane distillation (MD), and it is more expensive
to build. Scavenging Gas Membrane Distillation (SGMD) is used to treat complicated
solutions with volatile molecules to separate. In this study, heat and mass transport
mechanisms, as well as modeling and simulation studies, are systematically reviewed.
In SGMD, the main operating parameters are supply temperature, supply flow rate, gas
temperature, and gas flow rate. Furthermore, the performance of SGMD is discussed
and highlighted. Potential applications and areas in which SGMD could excel are
mentioned. Finally, future research opportunities in SGMD are identified.
A hollow fiber scavenging gas membrane distillation (SGMD) module is examined in
this study. Our SGMD distillation unit has been modeled by mathematical equations
and simulated by a runtime program on Matlab software to evaluate the effects of heat
transfer and mass transfer. Also, we have found that the heat and mass transfer in our
SGMD desalination system is defined by the temperature evolution in the vaporization
chamber and the inert gas velocity of the gas. The model predicts a small error of 3.6%
with the experimental data reported in the literature, indicating the reliability of
simulated results
Development of Design Processes for Multi-Spindle Drilling using the Neural Network and Expert System
Page: 30-46 (17)
Author: Ayoub Fajraoui* and Kamel Mehdi
DOI: 10.2174/9789815124125123020005
PDF Price: $15
Abstract
This work presents the integration of multilayer neural network with an
expert system for the automatic choice of the design process of multi-spindle drilling
housing. An intelligent design system approach is developed to integrate various
phases of the mechanical process including neural network subclasses and MLANN.
This solution reduces the time during the design preparation process and to improve
production. The automatic choice is carried out in three steps: Firstly, we started with
the formulation of training base experiments of the experts of the field as well as the
necessary knowledge of expertise, and which is among the general criteria for the
choice of the design process. The second step was devoted to the creation of many
multi layers NN1…NNm for the choice of the design mode. The final step is related to
the application of the outputs as results and an input for chaining by the expert system.
This chaining is based on several models based chaining (input data collection) from
the neural network results and processing (output results). The results are the
kinematics schema of the multi spindle drilling housing.
Experimental Investigation of a New Hybrid Solar Collector (PV/T) System
Page: 47-59 (13)
Author: Mohamed Fterich*, Houssam Chouikhi, Hatem Bentaher and Aref Maalej
DOI: 10.2174/9789815124125123020006
PDF Price: $15
Abstract
Solar Energy can be exploited to produce heat and/or electricity. PV/T
panels are a good application to produce both photovoltaic and Thermal energies by
recovering heat lost with a heat removal fluid (water or air). This induces an
improvement of the energetic efficiency of the panel since it is the addition of electrical
and thermal outputs. The object of this work was to design a new hybrid solar collector
based on the superposition of the thermal and electrical functions instead of their
overlay as previously done in most existing systems. Indeed, while thermal energy
production requires high fluid operating temperatures, PV electrical energy production
needs relatively low operating temperatures. The main goals are to study the
effectiveness of our PV/T prototype in terms of thermal energy produced. Moreover,
the present system improves the promotion of agro-food micro-enterprises by the
integration of miniaturized machines with dryers in remote areas where electric
connectivity is not available. In these sites, the farmers can dry the various agricultural
products using the prototype we have realized.
However, we dealt with an experimental analysis to study the influence of external and
internal parameters on the thermal and electrical performance of a photovoltaic thermal
hybrid collector PV/T. The system consists of a photovoltaic-thermal (PV/T) air
collector of 1.37 m2
. A fan was used to force the convection. Based on the experimental
results, it was observed that the thermal and electrical energy was increased when mass
flow rate and solar radiation were increased. The thermal and electrical efficiency
generated by the system was calculated as 65% and 12.5%, respectively. It was also
observed that the outlet air temperature increased.
Theoretical Study of the Effects of Combustion Duration on Engine Performance
Page: 60-83 (24)
Author: Mohamed Brayek*, Amara Ibraim, Mohamed Ali Jemni, Ali Damak, Zied Driss and Mohamed Salah Abid
DOI: 10.2174/9789815124125123020007
PDF Price: $15
Abstract
In this study, a thermodynamic cycle simulation of a four-stroke spark-ignition engine was conducted to predict the engine performance. The single-zone
model was built based on the Wiebe function for the mass fraction burned and
Woschni’s model for the convective heat loss. The first law of thermodynamics was
applied to describe the engine behavior versus the crank angle. These formulas
determine in-cylinder pressure, temperature, mean effective pressure, and effective
power. This study was performed to evaluate the effects of the combustion duration on
the engine performance characteristics. Simulations were carried out on a 98 cm3 four-stroke SI engine set up at 3600 rpm corresponding to the maximum torque (5.7 Nm).
In this study, it was found that under the same operating conditions, accelerating the
combustion does not always increase the power delivered by the engine. The best
engine performance in terms of compromise between heat losses and power delivered
was obtained for the combustion duration corresponding to 60° CA.
Effects of Preheating Temperature and Fuel-Air Equivalence Ratio on Pollution Control in Hydro Carbon Combustion
Page: 84-104 (21)
Author: Rachid Renane*, Rachid Allouche and Nour Abdelkader
DOI: 10.2174/9789815124125123020008
PDF Price: $15
Abstract
Burning fossil fuels produces a great part of our energy production today
and probably it will still do for at least the next few decades. Combustion is
encountered in many practical systems such as heaters, power plants, aeronautic
engines, buildings, etc. The growing expectations on increasing efficiency and reducing
fuel consumption and pollutant emissions make the design of combustion systems
much more complex and the science of combustion a rapidly expanding field.
Comprehension and analysis of complex physical mechanisms start with the study and
control of temperature and species in flame is an important challenge for industrial and
environmental issues. We focus our study on a Kerosene, Methane and Gasoil flame
simulated with detailed chemistry. The mathematical model is based on the enthalpy
conservation between two states, and this model is used with the first law of
thermodynamics to define enthalpies of reaction and adiabatic flame temperatures at
constant pressure [1, 4]. To reach this objective, we must know the products of
complete hydrocarbon combustion and all species of combustion products after
dissociation and their molar fractions and equilibrium equations of dissociation
reactions. Also, we calculate the elementary equilibrium reactions enthalpy and entropy
by using (Bonni Mc Bride et al.) coefficients [2, 3] to compute thermodynamic
functions such as specific heat, enthalpy and molar entropy. The obtained system of
equations is resolved by Newton Raphson method. Among the obtained results are: To
reduce the pollutants (CO2
, CO) and the fuel consumption, the mixture of fuel-air must
be lean, therefore, the equivalence ratio must be lower than the unit. According to this
study, if the fuel consumption is reduced via the equivalence ratio from 1.1 to 0.95, the
combustion temperature remains constant, however, the production of CO will be
reduced by 25%.
Numerical Study of Natural Convection between Two Concentric Ellipses with Different Shapes and Imposed Temperatures
Page: 105-128 (24)
Author: Abderrahmane Horimek*, Farhat Abdelmoumene and Noureddine Ait-Messaoudene
DOI: 10.2174/9789815124125123020009
PDF Price: $15
Abstract
In this work, the laminar natural convection problem for a Newtonian fluid
confined between two concentric ellipses is solved numerically. Two cases of heating
are assumed, an inner wall at high temperature (TH
) and an external one at low
temperature (TC
), then the opposite. Starting from the case of two circles (ellipses with
equal diameters) and arriving at two ellipses, 25 geometries are studied for each type of
heating, which gives 50 geometries in total. The effects of Rayleigh number (Ra),
aspect ratio in addition to the ellipses orientations are investigated. The dynamic and
thermal fields as well as the geometry average Nusselt number calculation
(Nuavg=(Nuavo+Nuavi)/2) are analyzed. Nuavg values are ranked at the end in a descending
order to show which geometry offers the largest heat exchange rate and vice versa, that
is something very useful in practice. It should be noted that a good choice of the
geometry shape may lead to have a more homogeneous thermal field, a result which
goes against the stratifying effect of natural convection that has sometimes to be
avoided.
Theoretical Study of the Geometrical Parameters Effect on the Behavior of a Solar Chimney Power Plant
Page: 129-145 (17)
Author: Haythem Nasraoui*, Zied Driss and Hedi Kchaou
DOI: 10.2174/9789815124125123020010
PDF Price: $15
Abstract
Solar Chimney Power Plant (SCPP) is a large scale setup designed for
generating green power from the thermal solar energy. In this work, a theoretical SCPP
model was developed to study the impact of the main design parameters on the SCPP
performance. Based on the Manzanares prototype, the proposed model was verified and
validated with the experimental data. The thermodynamic characteristics of the SCPP
were analyzed by varying the chimney height, the chimney radius and the collector
radius. Results show that the chimney height presents an important effect of the air
flow behavior. Otherwise, the proposed model has a good agreement to predict the
SCPP performance.
Numerical Investigations of the Effect of Packed Bed Porosity on the Flow Behavior
Page: 146-155 (10)
Author: Hajer Troudi*, Moncef Ghiss, Mohamed Ellejmi and Zoubeir Tourki
DOI: 10.2174/9789815124125123020011
PDF Price: $15
Abstract
Packed columns are considered useful to a great extent in the distillation of
natural gas, and liquid volume fraction is a critical parameter for their design. This
study aimed to develop a geometrical model of a packed column with one cone spray to
simulate the injection. Here, the commercial software FLUENT 6.3 was employed.
CFD simulations using the mixture model coupled with several turbulence models were
used to analyze the porosity effect on the fluid profiles. The results show that the
decrease of the packed porosity resulted in a greater dispersion of the liquid, indicating
the anisotropic behavior in the bed. Furthermore, the effect of different turbulence
models was analyzed in order to study the atomizing of the liquid phase accurately. The
numerical results were obtained to provide further insight into the mechanism of the
distillation with volatile components.
Comparison between a Conventional and a Four-Stage Savonius Wind Rotor
Page: 156-173 (18)
Author: Sobhi Frikha*, Zied Driss and Mohamed Salah Abid
DOI: 10.2174/9789815124125123020012
PDF Price: $15
Abstract
In this study, the influence of the shape on the characteristics of a Savonius
wind rotor was studied in numerical simulations and experimental measurements.
Particularly, we compared the features of the Savonius rotor with a new design rotor
consisting of a four-stage configuration. We used “Solid Works Flow Simulation” to
display the local characteristics in various transverse and longitudinal planes. The
Navier-Stokes equations and the standard k-ε turbulence model were solved in the
numerical model. A finite volume discretization method was applied to solve these
equations. The experimental measurements were conducted in an open wind tunnel to
validate the numerical model.
Subject Index
Page: 174-178 (5)
Author: Zied Driss
DOI: 10.2174/9789815124125123020013
PDF Price: $15
Introduction
This book focuses on cases and studies of interest to mechanical engineers and industrial technicians. The considered applications in this volume are widely used in several industrial fields particularly in the automotive and aviation industries. Readers will understand the theory and techniques which are used in each application covered in each chapter. Volume 2 includes the following topics: Numerical investigation of turbulent slot jets with various nanoparticle shapes Experimental study on a sweeping gas membrane distillation unit Development of design processes for multi-spindle drilling using a neural network and expert systems Experimental investigation of a new hybrid solar collector (PV/t) system Theoretical study of the effects of combustion duration on engine performance Effects of preheating temperature and fuel-air equivalence ratio on pollution control in hydrocarbon combustion Numerical study of natural convection between two concentric ellipses with different shapes and imposed temperatures Theoretical study of the geometrical parameters effect on the behavior of a solar chimney power plant Numerical investigations of the effect of packed bed porosity on the flow behavior Comparison between a conventional and a four-stage Savonius wind rotor The presented case studies and development approaches aim to provide readers with basic and applied information broadly related to mechanical engineering and technology.