Table of content

Iraqi journal of mechanical and material engineering

المجلة العراقية للهندسة الميكانيكية وهندسة المواد

ISSN: 20761819
Publisher: Babylon University
Faculty: Engineering
Language: Arabic and English

This journal is Open Access

About

Iraqi journal for mechanical and material engineering is a refereed scientific journal published quarterly by the engineering college/ university of Babylon. It deals with high quality researches in fields of mechanical and material engineering.

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Contact info

Journal E-mail:
j.mec_mat_eng@yahoo.com
Babylon university/Babylon/Iraq P.O.Box(4)
Tel:++96430245387.(1155)

Table of content: 2008 volume:8 issue:2

Article
ETHANOL AS AN OCTANE ENHANCER FOR THE COMMERCIAL GASOLINE FUELS

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Abstract

Considering pollution problems today, investigations have been concentrated on lowering the concentration of toxic components in combustion products. A gasoline lead additive at a concentration of 0.6 g/l is used to provide a gasoline with an octane number of 98. In many countries methyl tertiary butyl ether (MTBE) is used instead of lead to produce gasoline with the same octane number. Presently, 15% by volume of MTBE is added to unleaded gasoline to provide a gasoline with an octane number of 98. However, the leaded gasoline is still used in many countries. The purpose of this research is to experimentally study the possibility of using ethanol as a lead / MTBE replacement for spark ignition engines fuels. The effect of ethanol addition to unleaded gasoline on the research octane number, performance and pollutant emission of the spark ignition engine is studied. A Ricardo E6/US engine is used in this study. Results showed that the use of 15.% by volume of ethanol is a good alternative for replacing lead or MTBE in gasoline fuel and the resulted blended fuel satisfies the global specifications. The results of the standard ASTM methods showed that with increasing the ethanol content, the research octane number of the blended fuel increases, while the Reid vapor pressure of the blended fuel initially increases to a maximum value at 10 % by volume ethanol and then decreases. The results also showed that the addition of ethanol, (from 0% to 30% by volume), increases the break power, break thermal efficiency and break specific fuel consumption, and reduces NOx, CO, and HC emissions. The higher useful compression ratio, which produced maximum break power, is directly proportional to ethanol percentage in the blended fuel.


Article
HEAT AND MASS TRANSFER DURING AIR DRYING OF FRUITS

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Abstract

This study included air drying of a single le kernel of fruits (apple, apricot or grape) which is taken as a sphere. Convective heat and mass transfer takes place between the sample surface and its drying environment; while, unsteady heat conduction and moisture diffusion take place within the drying body without phase change for liquid (evaporation occurs at the surface only). The mass, energy conservation equations was solved by using the finite difference technique. A set of empirical correlations have been employed to determine the product properties which assumed to be changed during drying process like (thermal conductivity, specific heat and coefficient of moisture diffusion) and other properties was assumed to be constant through the process as (the coefficients of heat and mass transfer and the density). The results showed that the product temperature is increased and its moisture content will decrease during the drying process. The numerical results were compared with experimental results and showed good agreement.


Article
THERMAL ANALYSIS OF TRANSIENT OPERATION OF A SMALL SCALE REFRIGERATION SYSTEM

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Abstract

An unsteady- state model of vapor compression refrigeration system is presented. Thermal and flow processes occurring in a small-scale refrigeration system have been discussed. A theoretical description of the processes in the system components has been proposed in order to develop a theoretical model of the entire system. Components model include the heat exchangers (condenser and evaporator), expansion valve and compressor. For the condenser and evaporator mathematical model, assume two approaches for homogenous refrigerant, the first approach is the lumped model and the second is distributed model. Experimental investigations are carried out on the laboratory scale system model RCT/EV. The results obtained from the two models prediction are in a good agreement with the experimental results. The system approaches its final steady-state operating condition in a few minutes.


Article
BUCKLING ANALYSIS OF STRINGER STIFFENED COMPOSITE CYLINDER

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Abstract

Buckling, a distinguished word appears in the most failure case of the more sensitive applications such as cylinder. Buckling analysis presents the most important once in which huge helpful information (the failure modes, types of failure, and critical failure load respectively) must be taken in the considerations in the design of any structure. In this paper, buckling analysis was done on stiffened composite cylindrical shell to obtain the critical load and modes of failure under different conditions. The mathematical formulation of the problem was achieved by the ANSYS (Analysis System) finite element program. Effects of some parameters (fiber orientation, skin thickness, and elastic material properties) were studied. A numerical program includes all above features written in APDL (Ansys Parametric Design Language) was achieved.


Article
Drag Force Reduction of Flowing Crude Oil by Polymers Addition
تقليل قوة الاعاقة لجريان النفط الخام بإضافة البوليمرات

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Abstract

Studying of effect polymers addition on drag force for flowing crude oil are presented. Two types of Iraqi crude oil have been studied namely, Karkok crude oil with API=35.8 and Basrah crude oil with API=31.2 . Three types of linear polymers (poly isobutylene PIB150K, PIB90K and poly isoprene PIP) are used, the polymers are injected through pumping system at different concentrations rounded between (10-50) ppm with temperatures range of 30o to 50oC. Several experiments were carried out to determine the best concentration of polymer which is satisfied lowest drag force on of crude oil flow rate .The results show that the best execution are realization for PIB150K at 30 ppm and 45oC for two types of crude oil.

Keywords

: Crude Oil --- Polymer --- Drag Force


Article
STRUCTURAL DESIGN OF SERPENTINE GAS CHANNEL IN FUEL CELL
التصميم البنيوي للقناة الغازية الملتفة في خلية الوقود

Authors: Nawras H. Mostafa Qusay R. Al-Hagag
Pages: 162-176
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Abstract

Fuel and oxidant gas delivery plate, or fuel cell plate, is a key component of a Proton Exchange Membrane (PEM) fuel cell. To develop low-cost and high performance fuel cell plates, advanced computer modeling and finite element structure analysis are used as useful tools for the optimization of the plates at the early design stage.In a fuel cell application, these fuel cell plates are routinely heated up to 80oC with structure pressure loads. The temperature induced thermal stresses is found to be much higher that the structure loading stress. Thus, the thermal stresses plays a key role in the structure design and optimization of the plates.To carry out the analysis, a model of the serpentine plate is analyzed using finite element analysis model for both linear and nonlinear elasticity analysis. Design optimization is applied to minimize the maximum stress within the plate, subject to constraint with both geometry and material parameters as design variables. The study reveals the characteristics of the printed plates, and provides guidelines for the structure and material design of the fuel cell plate.


Article
تأثير اضافة الكروم على الصفات الميكانيكية للمادة المركبة ذات الاساس شبه المعدني (NiAl-Al2O3)

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Abstract

In this investigation NiAl-based composites containing a dispersion of Al2O3 particles are prepared by sintering technique at 1350°C for 90 min. in an argon atmosphere. Intermetallic compound NiAl was prepared from a mixture of nickel and aluminum powders by using reactive sintering technique at 600°C for 12 Hrs. in an argon atmosphere. To improve the ductility of NiAl three weight percents of Cr (3.5, 4, 4.5 wt %) were added to the composite (NiAl-Al2O3). Series of experiments showed that: - adding of (Al2O3) to (NiAl) leads to increase its compressive strength and its hardness but with a decrease in its ductility; - adding Cr to the intrmetallic composite (NiAl-Al2O3) leads to increase its compressive strength and its hardness with an ability to improve its ductility. An addition of (4.5 wt% Cr) to the composite containing (10wt%Al2O3) led to improve the compressive strength by (25%), hardness by (9%) and ductility by (94%) in comparison with that containing no Cr.


Article
STUDY OF PERFORMANCE OF S.I.E. WORKED WITH SUPPLEMENTARY METHANE TO LPG
دراسة أداء محرك اشتعال بالشرارة يعمل باضافة الميثان للغاز النفطي المسال

Authors: Miqdam T. Chaichan
Pages: 185-196
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Abstract

This paper include study of performance of single cylinder, 4-stroke spark ignition Ricardo E6, with variable compression ratio, spark timing and equivalence ratio, worked by supplemented methane to LPG. The speed of 25 rps and higher useful compression ratio were chosen in studying the effect of wide range of equivalence ratios and spark timing. The results showed that HUCR for mixture of two gases was differ from mixture ratio to other. The brake power when operated with LPG was higher than when it was working with methane, and when mixing two fuels the brake power decreased and became lower than that when working with LPG. The equivalence ratio at which the brake power got its highest value was between (Ø=1-1.2) when mixing the two fuels. The results showed that it can be worked with very lean equivalence ratios with supplementary methane, the indicated thermal efficiency increased also, and the brake specific fuel consumption reduced when methane volumetric ratio increased.


Article
تحسين الاستقرارية الحرارية لسبائك

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Abstract

It is well established that Aluminum and its alloys are widely used in aerospace industries, for their good mechanical and physical properties. In addition, to reliable toughness and low density which is the prime importance factor in selecting materials for aerospace industries. Duralumin (Al-4% Cu) is one of these important alloys and it is one of (2XXX) series where Copper is the major alloying element. However, in spite of its high strength, it has low thermal stability, which imposes limitations on Airplanes speeds, from which Air frame is made. This work represents an attempt to improve thermal stability. Several techniques were adopted to evaluate the role of thermo-mechanical treatments and alloying elements. Results show an interesting behaviour and significant improvement in properties.

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