Abstract: A numerical study on the effect of side-dump angle on
fuel droplets sizing and effective mass fraction have been
investigated in present paper. The mass of fuel vapor inside the
flammability limit is named as the effective mass fraction. In the first
step we have considered a side-dump combustor with dump angle of
0o (acrossthe cylinder) and by increasing the entrance airflow velocity
from 20 to 30, 40 and 50 (m/s) respectively, the mean diameter of
fuel droplets sizing and effective mass fraction have been studied.
After this step, we have changed the dump angle from 0o to 30o,45o
and finally 60o in direction of cylinderand also we have increased the
entrance airflow velocity from 20 up to 50 (m/s) with the amount of
growth of 10(m/s) in each step, to examine its effects on fuel droplets
sizing as well as effective mass fraction. With rise of entrance airflow
velocity, these calculations are repeated in each step too. The results
show, with growth of dump-angle the effective mass fraction has
been decreased and the mean diameter of droplets sizing has been
increased. To fulfill the calculations a modified version of KIVA-3V
code which is a transient, three-dimensional, multiphase,
multicomponent code for the analysis of chemically reacting flows
with sprays, is used.
Abstract: In this paper the principle, basic torque theory and design optimisation of a six-phase reluctance dc machine are considered. A trapezoidal phase current waveform for the machine drive is proposed and evaluated to minimise ripple torque. Low cost normal laminated salient-pole rotors with and without slits and chamfered poles are investigated. The six-phase machine is optimised in multi-dimensions by linking the finite-element analysis method directly with an optimisation algorithm; the objective function is to maximise the torque per copper losses of the machine. The armature reaction effect is investigated in detail and found to be severe. The measured and calculated torque performances of a 35 kW optimum designed six-phase reluctance dc machine drive are presented.
Abstract: Electrical discharge machining (EDM) is well
established machining technique mainly used to machine complex
geometries on difficult-to-machine materials and high strength
temperature resistant alloys. In the present research, the objective is
to study the shape of the electrode and establish the application of
liquid nitrogen in reducing distortion of the electrode during
electrical discharge machining of M2 grade high speed steel using
copper electrodes. Study of roundness was performed on the
electrode to observe the shape of the electrode for both conventional
EDM and EDM with cryogenically cooled electrode. Scanning
Electron Microscope (SEM) has been used to study the shape of
electrode tip. The effect of various parameters such as discharge
current and pulse on time has been studied to understand the behavior
of distortion of electrode. It has been concluded that the shape
retention is better in case of liquid nitrogen cooled electrode.
Abstract: Due to environmental concerns, the recent regulation on automobile fuel economy has been strengthened. The market demand for efficient vehicles is growing and automakers to improve engine fuel efficiency in the industry have been paying a lot of effort. To improve the fuel efficiency, it is necessary to reduce losses or to improve combustion efficiency of the engine. VVA (Variable Valve Actuation) technology enhances the engine's intake air flow, reduce pumping losses and mechanical friction losses. And also, VVA technology is the engine's low speed and high speed operation to implement each of appropriate valve lift. It improves the performance of engine in the entire operating range. This paper presents a design procedure of DC motor and drive for VVA system and shows the validity of the design result by experimental result with prototype.
Abstract: To reveal the temperature field distribution of disc
brake in downward belt conveyor, mathematical models of heat
transfer for disc brake were established combined with heat transfer
theory. Then, the simulation process was stated in detail and the
temperature field of disc brake under conditions of dynamic speed and
dynamic braking torque was numerically simulated by using ANSYS
software. Finally the distribution and variation laws of temperature
field in the braking process were analyzed. Results indicate that the
maximum surface temperature occurs at a time before the brake end
and there exist large temperature gradients in both radial and axial
directions, while it is relatively small in the circumferential direction.
Abstract: Internal combustion engines rejects 30-40% of the
energy supplied by fuel to the environment through exhaust gas. thus, there is a possibility for further significant improvement of efficiency with the utilization of exhaust gas energy and its conversion to mechanical energy or electrical energy. The Thermo-Electric
Generator (TEG) will be located in the exhaust system and will make use of an energy flow between the warmer exhaust gas and the external environment. Predict to th optimum position of temperature
distribution and the performance of TEG through numerical analysis.
The experimental results obtained show that the power output significantly increases with the temperature difference between cold
and hot sides of a thermoelectric generator.
Abstract: A theoretical study is conducted to design and explore
the effect of different parameters such as heat loads, the tube size of
piping system, wick thickness, porosity and hole size on the
performance and capability of a Loop Heat Pipe(LHP). This paper
presents a steady state model that describes the different phenomena
inside a LHP. Loop Heat Pipes(LHPs) are two-phase heat transfer
devices with capillary pumping of a working fluid. By their original
design comparing with heat pipes and special properties of the
capillary structure, they-re capable of transferring heat efficiency for
distances up to several meters at any orientation in the gravity field,
or to several meters in a horizontal position. This theoretical model is
described by different relations to satisfy important limits such as
capillary and nucleate boiling. An algorithm is developed to predict
the size of the LHP satisfying the limitations mentioned above for a
wide range of applied loads. Finally, to assess and evaluate the
algorithm and all the relations considered, we have used to design a
new kind of LHP to recover the heat from the exhaust of an actual
Gas Turbine. By finding the results, it showed that we can use the
LHP as a very high efficient device to recover the heat even in high
amount of loads(exhaust of a gas turbine). The sizes of all parts of the
LHP were obtained using the developed algorithm.
Abstract: The purpose of study was to design and construction
the semi-automatic sliced ginger machine for reduce production times
in sheet and slice ginger procedure furthermore, reduced amount of
labor of slides and cutting method. Take consider into clean and safety of workers and consumers. The principle of machines, used 1
horsepower motor, rotation speed of sliced blade 967 rpm, the diameter of sliced dish 310 mm, consists of 2 blades for sheet cutting
ginger and the power from motor which transfer to rotate the sliced blade roller, rotation speed 440 rpm. The slice cutter roller was sliced
ginger from sheet ginger to line ginger. The conveyer could
adjustment level of motors, used to the beginning area that sheet
ginger was transference to the roller for sheet and sliced cutting in next process. The cover of sliced cutting had channel for 1 tuber of
ginger. The semi-automatic sliced ginger machine could produced sheet ginger 81.8 kg/h (6.2 times of labor) and line ginger 17.9 kg/h
(2.5 times of labor) compare with, labor work could produced sheet
ginger 13.2 kg/h and line ginger 7.1 kg/h, and when timekeeper, the
total times of semi auto machine 30.86 kg/h and labor 4.6 kg/h, there
for the semi auto machine was 6.7 times of labor. The semiautomatic
sliced ginger machine convenient, easy for use and
maintain, in addition to reduce fatigue of body and seriousness from
works; must be used high skill, and protection accident in slicing
procedure. Beside, machine could used with other vegetables for
example potato, carrot .etc
Abstract: In this paper, we study the formation control problem
for car-like mobile robots. A team of nonholonomic mobile robots navigate in a terrain with obstacles, while maintaining a desired
formation, using a leader-following strategy. A set of artificial potential field functions is proposed using the direct Lyapunov
method for the avoidance of obstacles and attraction to their designated targets. The effectiveness of the proposed control laws to verify the feasibility of the model is demonstrated through computer simulations
Abstract: This paper presents development of an ignition system using spark electrodes for application in a research explosion vessel.
A single spark is aimed to be discharged with quantifiable ignition energy. The spark electrode system would enable study of flame
propagation, ignitability of fuel-air mixtures and other fundamental characteristics of flames. The principle of the capacitive spark circuit
of ASTM is studied to charge an appropriate capacitance connected across the spark gap through a large resistor by a high voltage from
the source of power supply until the initiation of spark. Different spark energies could be obtained mainly by varying the value of the
capacitance and the supply current. The spark sizes produced are found to be affected by the spark gap, electrode size, input voltage
and capacitance value.
Abstract: Deep cold rolling (DCR) is a cold working process, which easily produces a smooth and work-hardened surface by plastic deformation of surface irregularities. In the present study, the influence of main deep cold rolling process parameters on the surface roughness and the hardness of AISI 4140 steel were studied by using fractional factorial design of experiments. The assessment of the surface integrity aspects on work material was done, in terms of identifying the predominant factor amongst the selected parameters, their order of significance and setting the levels of the factors for minimizing surface roughness and/or maximizing surface hardness. It was found that the ball diameter, rolling force, initial surface roughness and number of tool passes are the most pronounced parameters, which have great effects on the work piece-s surface during the deep cold rolling process. A simple, inexpensive and newly developed DCR tool, with interchangeable collet for using different ball diameters, was used throughout the experimental work presented in this paper.
Abstract: The hydrodynamics behavior of fluid flow in microconverging
plates is investigated analytically. Effects of Knudsen number () on the microchannel hydrodynamics behavior and the
coefficient of friction are investigated. It is found that as increases the slip in the hydrodynamic boundary condition increases.
Also, the coefficient of friction decreases as increases.
Abstract: The common practice of operating S-rotor is in an
open environment; however there are times when the rotor is
installed in a bounded environment and there might be changes in the
performance of the rotor. This paper presents the changes in the
performance of S-rotor when operated in bounded flows. The
investigation was conducted experimentally to compare the
performance of the rotors in bounded environment against open
environment. Three different rotors models were designed, fabricated
and subjected to experimental measurements. All of the three models
were having 600 mm height and 300 mm Diameter. They were tested
in three different flow environments; namely: partially bounded
environment, fully bounded environment and open environment.
Rotors were found to have better starting up capabilities when
operated in bounded environment. Apart from that, all rotors manage
to achieve higher Power and Torque Coefficients at a higher Tip
Speed Ratio as compared to the open environment.
Abstract: In this paper, an artificial neural network simulator is
employed to carry out diagnosis and prognosis on electric motor as
rotating machinery based on predictive maintenance. Vibration data
of the primary failed motor including unbalance, misalignment and
bearing fault were collected for training the neural network. Neural
network training was performed for a variety of inputs and the motor
condition was used as the expert training information. The main
purpose of applying the neural network as an expert system was to
detect the type of failure and applying preventive maintenance. The
advantage of this study is for machinery Industries by providing
appropriate maintenance that has an essential activity to keep the
production process going at all processes in the machinery industry.
Proper maintenance is pivotal in order to prevent the possible failures
in operating system and increase the availability and effectiveness of
a system by analyzing vibration monitoring and developing expert
system.
Abstract: In this present work, the development of an avionics
system for flight data collection of a Raptor 30 V2 is carried out. For the data acquisition both onground and onboard avionics systems are developed for testing of a small-scale Unmanned Aerial Vehicle
(UAV) helicopter. The onboard avionics record the helicopter state
outputs namely accelerations, angular rates and Euler angles, in real time, and the on ground avionics system record the inputs given to
the radio controlled helicopter through a transmitter, in real time. The avionic systems are designed and developed taking into consideration
low weight, small size, anti-vibration, low power consumption, and easy interfacing. To mitigate the medium frequency vibrations
embedded on the UAV helicopter during flight, a damper is designed
and its performance is evaluated. A number of flight tests are carried
out and the data obtained is then analyzed for accuracy and repeatability and conclusions are inferred.
Abstract: This paper focuses on a critical component of the
situational awareness (SA), the control of autonomous vertical flight for tactical unmanned aerial vehicle (TUAV). With the SA strategy,
we proposed a two stage flight control procedure using two autonomous control subsystems to address the dynamics variation
and performance requirement difference in initial and final stages of flight trajectory for a nontrivial nonlinear eight-rotor helicopter
model. This control strategy for chosen model of mini-TUAV has been verified by simulation of hovering maneuvers using software
package Simulink and demonstrated good performance for fast
stabilization of engines in hovering, consequently, fast SA with
economy in energy of batteries can be asserted during search-andrescue
operations.
Abstract: Researches related to standard product model and
development of neutral manufacturing interfaces for numerical
control machines becomes a significant topic since the last 25 years.
In this paper, a detail description of STEP implementation on turnmill
manufacturing has been discussed. It shows requirements of
information contents from ISO14649 data model. It covers to
describe the design of STEP-NC framework applicable to turn-mill
manufacturing. In the framework, EXPRESS-G and UML modeling
tools are used to depict the information contents of the system and
established the bases of information model requirement. A product
and manufacturing data model applicable for STEP compliant
manufacturing. The next generation turn-mill operations
requirements have been represented by a UML diagram. An object
oriented classes of ISO1449 has been developed on Visual Basic dot
NET platform for binding the static information model represented
by the UML diagram. An architect of the proposed system
implementation has been given on the bases of the design and
manufacturing module of STEP-NC interface established. Finally, a
part 21 file process plan generated for an illustration of turn-mill
components.
Abstract: In this study, control performance of a smart base
isolation system consisting of a friction pendulum system (FPS) and a
magnetorheological (MR) damper has been investigated. A fuzzy
logic controller (FLC) is used to modulate the MR damper so as to
minimize structural acceleration while maintaining acceptable base
displacement levels. To this end, a multi-objective optimization
scheme is used to optimize parameters of membership functions and
find appropriate fuzzy rules. To demonstrate effectiveness of the
proposed multi-objective genetic algorithm for FLC, a numerical
study of a smart base isolation system is conducted using several
historical earthquakes. It is shown that the proposed method can find
optimal fuzzy rules and that the optimized FLC outperforms not only a
passive control strategy but also a human-designed FLC and a
conventional semi-active control algorithm.
Abstract: Stress analysis of functionally graded composite plates
composed of ceramic, functionally graded material and metal layers is
investigated using 3-D finite element method. In FGM layer, material
properties are assumed to be varied continuously in the thickness
direction according to a simple power law distribution in terms of the
volume fraction of a ceramic and metal. The 3-D finite element model
is adopted by using an 18-node solid element to analyze more
accurately the variation of material properties in the thickness
direction. Numerical results are compared for three types of materials.
In the analysis, the tensile and the compressive stresses are
summarized for various FGM thickness ratios, volume fraction
distributions, geometric parameters and mechanical loads.
Abstract: This paper presents a model for the evaluation of
energy performance and aerodynamic forces acting on a small
straight-bladed Darrieus-type vertical axis wind turbine depending on
blade geometrical section. It consists of an analytical code coupled to
a solid modeling software, capable of generating the desired blade
geometry based on the desired blade design geometric parameters.
Such module is then linked to a finite volume commercial CFD code
for the calculation of rotor performance by integration of the
aerodynamic forces along the perimeter of each blade for a full period
of revolution.After describing and validating the computational
model with experimental data, the results of numerical simulations
are proposed on the bases of two candidate airfoil sections, that is a
classical symmetrical NACA 0021 blade profile and the recently
developed DU 06-W-200 non-symmetric and laminar blade
profile.Through a full CFD campaign of analysis, the effects of blade
geometrical section on angle of attack are first investigated and then
the overall rotor torque and power are analyzed as a function of blade
azimuthal position, achieving a numerical quantification of the
influence of airfoil geometry on overall rotor performance.