research centers


Search results: Found 29

Listing 1 - 10 of 29 << page
of 3
>>
Sort by

Article
AN EXPERIMENTAL STUDY TO DEVELOP ALUMINUM CORROSION RESISTANCE IN ACIDIC SOLUTION BY DIFFERENT RATIOS OF ADDITIVE ELEMENTS

Author: Awatif Mustafa Ali
Journal: Journal of Engineering and Sustainable Development مجلة الهندسة والتنمية المستدامة ISSN: 25200917 Year: 2019 Volume: 23 Issue: 3 Pages: 158-165
Publisher: Al-Mustansyriah University الجامعة المستنصرية

Loading...
Loading...
Abstract

In this work the corrosion behavior of aluminum alloy includes copper with different ratio is investigated by immersing the specimens in acidic solution (HCL& H_(2 ) 〖SO〗_4) with concentration (5%,10%) then put in furnace at three temperature degree(40,60.80)C^0 and holding for (30)minutes the results showed that increased in (Cu) at alloy contain leads to increase in weight losses while when fixed cupper ratio and increased (Ni) at alloy contain the weight losses decrease .corrosion rate of studied alloy increase in(HCL) solution more than(H_(2 ) 〖SO〗_4) .


Article
Effect of Using Local Insulation Materials on the Indoor Temperature of Residential Buildings at Iraq

Authors: Nassr F. Hussein --- Haqi I. Qatta --- Abdulrahman S. Mahmood Haqi I. Qatta
Journal: Engineering and Technology Journal مجلة الهندسة والتكنولوجيا ISSN: 16816900 24120758 Year: 2019 Volume: 37 Issue: 2 Part (A) Engineering Pages: 37-45
Publisher: University of Technology الجامعة التكنولوجية

Loading...
Loading...
Abstract

Abstract- In this research, a thermal insulation between the two layersof a wall has been used for the residence buildings to reduce the heattransmitted across the walls and thus reducing the power consumptionfor cooling load. A MATLAB program was used to obtain the thermalresponse for various types of walls from the energy sources (solarradiation and ambient temperature) in summer season in Baghdad, Iraq.Local materials used in this study as thermal insulators between the twolayers of walls are: local cane mat, wood sawdust and cork grains.Modeling tests were carried out on June, July and August via usingMatlab program. The simulation results obtained have been comparedfor five different types of walls are: usual wall, thick wall, wallcontaining local cane mat, wall containing wood sawdust and wallcontaining cork grains, which helps in finding the heat flow across thewall where boundary conditions varied according to solar radiation andenvironment thermal load. The results showed that using the wallscontaining of local cane mat, wood sawdust and cork grains can reducethe heat gain by 50%, 44% and 40% respectively, compared with usualwall and thus reduce the power consumption


Article
Enhancement of Heat Transfer using Aluminum Oxide Nanofluid on Smooth and Finned Surfaces with COMSOL Multiphysics Simulation in Turbulent Flow

Authors: Hasan S. Majdi --- Hussein A. Alabdly --- Muayad F. Hamad --- Basim O. Hasan --- et al.
Journal: AL-NAHRAIN JOURNAL FOR ENGINEERING SCIENCES مجلة النهرين للعلوم الهندسية ISSN: 25219154 / eISSN 25219162 Year: 2019 Volume: 22 Issue: 1 Pages: 44-54
Publisher: Al-Nahrain University جامعة النهرين

Loading...
Loading...
Abstract

Both surface extension and nanofluid methods were used to enhance the heat transfer in a double pipe heat exchanger under turbulent flow conditions. Aluminum oxide nanoparticles were used with different concentrations(0.6-3 g/l)in hot water to increase the heat transfer rate on smooth tube and circular fins tube for a range of Reynolds number4240-19790. The simulation was also performed to predict the heat transfer coefficient and temperature profile for selected conditions in which COMSOL Multiphysics is used. The experimental results revealed that the heat transfer enhancement by both circular fin and nanofluid exhibited an increasing trend with Reynolds number and nanofluid concentration. The conjoint effect of Al2O3 of 3 g/l concentration and circular fin provided largest heat transfer enhancement of 53% for the highest Re investigated. Simulation results showed reasonable agreement with the experimental values of heat transfer coefficient. The simulation showed that the presence of nanofluid on finned surface influenced the temperature profile indicating the increased heat transfer rate.


Article
Investigation of R134a Flow Boiling Heat Transfer and Pressure Drop in the Evaporator Test Section of Refrigeration System
استقصاء انتقال الحرارة وانحدار الضغط لغليان مائع التثليج R134a في حالة الجريان في مقطع فحص لمبخر منظومة تجميد

Authors: Zahraa Kareem Yasser زهراء كريم ياسر --- Ahmed J. Hamad أحمد جاسم حمد
Journal: Journal of Engineering مجلة الهندسة ISSN: 17264073 25203339 Year: 2019 Volume: 25 Issue: 1 Pages: 13-31
Publisher: Baghdad University جامعة بغداد

Loading...
Loading...
Abstract

This paper presents an experimental and theoretical analysis to investigate the two-phase flow boiling heat transfer coefficient and pressure drop of the refrigerant R-134a in the evaporator test section of the refrigeration system under different operating conditions. The test conditions considered are, for heat flux (13.7-36.6) kW/m2, mass flux (52-105) kg/m2.s, vapor quality (0.2-1) and saturation temperature (-15 to -3.7) ˚C. Experiments were carried out using a test rig for a 310W capacity refrigeration system, which is designed and constructed in the current work. Investigating of the experimental results has revealed that, the enhancement in local heat transfer coefficient for relatively higher heat flux 36.6 kW/m2 was about 38% compared to 13.7 kW/m2 at constant operating conditions. The enhancement in heat transfer coefficient was about 57% when the mass flux increased from 52 kg/m2.s to 105 kg/m2.s at constant test conditions. The enhancement in the heat transfer coefficient was about 64% when the saturation temperature increased from -8 to -3.7 at fixed refrigerant mass velocity and heat flux. The effect of mass velocity on pressure drop was relatively higher by about 27% than that for heat flux at specified test conditions. The comparison between the experimental and theoretical results has shown an acceptable agreement with an average deviation of 21%.

يقدم هذا البحث تحليلاﹰ تجريبياﹰ ونظرياﹰ لاستقصاء معامل انتقال الحرارة وانحدار الضغط خلال جريان ثنائي الطور في حالة غليان لمائع التثليج R134a في مقطع فحص لمبخر منظومة تجميد تحت ظروف تشغيل مختلفة. ظروف الاختبار التي اعتمدت في هذه الدراسة كانت، عند فيض حراري 36.6-13.7) ) كيلوواطمتر مربع، وفيض كتلي (105-52) كغم/متر مربع. ثانية ونسبة جفاف للبخار (0.2 - 1) ودرجة حرارة تشبع للمائع بين )-15 و -(3.7 درجة مئوية. أجريت الاختبارات باستخدام جهاز أختبار لمنظومة تجميد سعتها 310W والتي صممت ونفذت خلال الدراسة الحالية. أظهرت النتائج التجريبية بان, تحسين معامل انتقال الحرارة الموقعي للفيض الحراري الأعلى نسبيا36.6kW/m2 كان بحدود 38%مقارنة بالفيض13.7kW/m2 عند ظروف تشغيل ثابتة. تحسين معامل انتقال الحرارة عند زيادة قيمة الفيض الكتلي من52 kg/m2.s الى105 kg/m2.s خلال ظروف تشغيل مماثلة كان بنسبة 57%. وكان تحسين قيمة معامل انتقال الحرارة بنسبة64% عند زيادة درجة حرارة التشبع من-8 الى-3.7 عند ثبات قيم الفيض الكتلي والفيض الحراري. تأثير الفيض الكتلي على قيمة انحدار الضغط كان اعلى نسبيا بمقدار27% من تأثير الفيض الحراري عند ظروف الاختبار المعتمدة. مقارنة النتائج التجريبية مع النظرية قد أظهرت


Article
Numerical Investigation on the Thermal Performance of Double Pipe Heat Exchanger Using Different Shapes of Fins

Authors: Wissam H. Khalil --- Asaad K. Ali
Journal: Anbar Journal of Engineering Sciences مجلة الأنبار للعلوم الهندسية ISSN: 19979428 Year: 2019 Volume: 7 Issue: 4 Pages: 326-348
Publisher: University of Anbar جامعة الانبار

Loading...
Loading...
Abstract

In this study, a numerical investigation on the thermo-hydraulic performance of thedouble pipe heat exchanger into heat transfer by different shapes of fins on the outersurface for the inner tube as extended surfaces. The inner and outer diameters of theinner pipe were (16.05 mm), (19.05 mm) respectively, and (34.1 mm), (38.1 mm) for theouter tube. The length of the heat exchanger was (1000 mm). Hot and cold water wereused as the working fluid, where the hot water flows inside of the inner one in counterflow with the cold water which flows in the annulus. The inlet temperature for the hotwater is (75 OC) while it is (30 OC) for the cold. The hot fluid flows at constant ratewhich is (0.1kg/s) while the cold is varied from (0.1 kg/s to 0.2 kg/s).The study wasperform using the known commercial CFD package (ANSYS – FLUNET 15) .Theresults shows that both (rectangular and triangular) fins enhances the heat transfercoefficient compare with the conventional plain tube .The rectangular fins presents anheat transfer enhancement ratio of (61% to 74%). Using of extended surfaces present agood result in saving energy by enhancing the performance of the double pipe heatexchangers used in petroleum industry.


Article
Numerical Study of Fluid Flow and Heat Transfer Characteristics in Solid and Perforated Finned Heat Sinks Utilizing a Piezoelectric Fan
دراسة عددية لخصائص جريان المائع وانتقال الحرارة في مصب حراري صلب ومثقب مجهز بمروحة كهروضغطية

Authors: Ayser Shamil Salman أيسر شامل سلمان --- Mohammed A. Nima محمد عبد الرؤوف نعمة
Journal: Journal of Engineering مجلة الهندسة ISSN: 17264073 25203339 Year: 2019 Volume: 25 Issue: 7 Pages: 83-103
Publisher: Baghdad University جامعة بغداد

Loading...
Loading...
Abstract

Numerical study is adapted to combine between piezoelectric fan as a turbulent air flow generator and perforated finned heat sinks. A single piezoelectric fan with different tip amplitudes placed eccentrically at the duct entrance. The problem of solid and perforated finned heat sinks is solved and analyzed numerically by using Ansys 17.2 fluent, and solving three dimensional energy and Navier–Stokes equations that set with RNG based k−ε scalable wall function turbulent model. Finite volume algorithm is used to solve both phases of solid and fluid. Calculations are done for three values of piezoelectric fan amplitudes 25 mm, 30 mm, and 40 mm, respectively. Results of this numerical study are compared with previous both numerical and experimental studies and give a good agreement. Numerical solution is invoked to explain the behavior of air flow and temperature distribution for two types of circular axial and lateral perforations. For each type, all the results are compared with an identical solid finned heat sink. Perforations show a remarkable enhanced in the heat transfer characteristics. The results achieved enhancement in the heat transfer coefficient about 12% in axial perforation and 25% in the lateral perforation at the maximum fan amplitude.

قدمت هذه الدراسة العددية فكرة للجمع بين مروحة كهرضغطية كمولّد لتدفق هواء مضطرب ومصبات حرارية مزعنفة ذات ثقوب طولية وعرضية. وتم تشغيل مروحة كهرضغطية واحدة بسعات مختلفة وثبتت بشكل مركزي في مدخل مجرى الهواء. تم حل ودراسة تاثير الجريان الناتج عن المروحة على المصبات الحرارية المزعنفة الصلبة والمثقبة وتحليلها عدديًا باستخدام برنامج (Ansys 17.2، فلونت) وحل معادلات ثلاثية الأبعاد ومعادلات Navier – Stokes التي تم ضبطها مع نموذج مضطرب قابل للتطوير يعمل على أساس RNG k−ε باستخدام طريقة (Finite volume) لحل تاثر انتقال الحرارة بجريان المائع. تم حساب ثلاث معدلات لدرجة الحرارة الناتجة من تغيير سعة المروحة الكهرضغطية (25 مم و 30 ملم و 40 ملم) على التوالي. تم مقارنة النتائج المستحصلة من هذه الدراسة العددية بالدراسات العددية والتجريبية السابقة ووجدت موافقة جيدة. تم اجراء الحل العددي لشرح سلوك تدفق الهواء وتوزيع الحرارة لنوعين من الثقوب المحورية والجانبية الدائرية. لكل نوع ، تم مقارنة جميع النتائج الخاصة بالمصبات المثقبة مع مصب بزعانف صلبة ومتطابقة بالابعاد والظروف فظهر تحسناً ملحوظاً في خصائص انتقال الحرارة بنسبة 12% في التثقيب الطولي و 25% في التثقيب المستعرض عند السرعة الاعلى للمروحة.


Article
Influence of Varying Temperature and Concentration on MHD Peristaltic Transport for Jeffrey Fluid with Variable Viscosity through Porous Channel

Authors: Dheia G. Salih Al-Khafajy --- Ahmed A .Hussein Al-Aridhee
Journal: Journal of Al-Qadisiyah for Computer Science and Mathematics مجلة القادسية لعلوم الحاسوب والرياضيات ISSN: 20740204 / 25213504 Year: 2019 Volume: 11 Issue: 3 Pages: Math Page 38-49
Publisher: Al-Qadisiyah University جامعة القادسية

Loading...
Loading...
Abstract

The present paper deals with the peristaltic motion of Jeffrey fluid with varying temperature and concentration through a porous medium in a coaxial uniform circular tube. The fluid is assumed to be non-Newtonian, namely Jeffrey fluid. The inner tube is uniform, while the outer flexible tube has a sinusoidal wave traveling down its wall. The analytical formulas of the velocity and temperature have been obtained in terms of the Bessel function of first and second kinds. The numerical formula of the axial velocity, temperature and concentration are obtained as functions of the physical parameters of the problem (Darcy number, magnetic parameter, thermal Grashof number, Reynolds number, Prandtl number, and Schmidt number) with other physical parameters are obtained. The Influence of physical parameters of the problem on this formula are discussed numerically and illustrated graphically through a set of figures.


Article
A NEW CORRELATION FOR SPECIFIC HEAT OF NORMAL ALKANES (C1-C30) AS A FUNCTION OF TEMPERATURE AND CARBON NUMBER

Author: Ahmed Abdul Hussain Ayash
Journal: Journal of Engineering and Sustainable Development مجلة الهندسة والتنمية المستدامة ISSN: 25200917 Year: 2019 Volume: 23 Issue: 3 Pages: 166-174
Publisher: Al-Mustansyriah University الجامعة المستنصرية

Loading...
Loading...
Abstract

: the paper is about establishing a reliable correlation that can predict specific heat (Cp) of a series of normal alkanes over a wide range of temperatures. High quality experimental measurements reported in the relevant literature were used to verify the accuracy of the developed correlation, including data of heavy n-alkanes up to (n-C30H62). For a fair assessment, all the experimental data used were selected such that are measured at constant pressure. The developed correlation, for the first time, considers the effect of both temperature and carbon number for gas and liquid phase of normal alkanes, ranging from C1 to C30. Interestingly, the results showed that the correlation predicts closely the experimental data with an average relative error (AARE) not exceeding 3.63% for 97 data points.


Article
Determination of Heat and Momentum Fluxes over Baghdad

Authors: Ahmed Fattah Hassoon --- Mustafa Zihraw Mehson
Journal: Al-Mustansiriyah Journal of Science مجلة علوم المستنصرية ISSN: 1814635X Year: 2019 Volume: 30 Issue: 1 Pages: 23-32
Publisher: Al-Mustansyriah University الجامعة المستنصرية

Loading...
Loading...
Abstract

The heat and momentum fluxes have been determined at Al-Mustansiriyah University, Baghdad, Iraq, by using eddy correlation method. It is one of the methods which determines heat and momentum fluxes, it is considered direct and accurate. This method depends on high response instruments like Ultrasonic Anemometer (model: 1590- PK- 020). Observation period is about 53 days for 24 hours in months June, July and August (summer season) from 15/06/2016 to 06//08/2016 and the observations included wind speed and temperature every second. Huge data treated by MATLAB program to calculate heat and momentum fluxes (H and τ). The maximum value of H equals 127.6 Wm-2 in 10:30 at 26/07/2016 and minimum value equals -58.9 Wm-2 in 07:30 at 29/06/2016, as well, the maximum value of τ equals 0.134535 Nm-2 in 15:00 at 03/08/2016 and minimum value equals -0.4649 Nm-2 in 03:00 at 01/07/2016 (negative sign refer also to change in direction flow) . It is found that there is an inverse relationship between H and τ. Fractional drag by wind speed, also deal where Maximum frequency of friction velocity is at unstable conditions.

تم تحديد فيض الحرارة والزخم في الجامعة المستنصرية، بغداد، العراق، بأستخدام طريقة ارتباط الدوامة وهي واحدة من الطرق التي تحدد او تحسب فيض الحرارة والزخم وتعتبر طريقة مباشرة ودقيقة. هذه الطريقة تعتمد على اجهزة ذات استجابة عالية مثل جهاز Ultrasonic (نموذج : 1590- PK- 020) والذي استخدم في الدراسة. مدة الرصد كانت 53 يوم لمدة 24 ساعة خلال الاشهر حزيران وتموز وآب من 15/06/2016 الى 06//08/2016 وتتضمن الرصدات سرعة الرياح ودرجة الحرارة كل ثانية. كذلك تم استخدام برنامج MATLAB لمعالجة البيانات الكبيرة ومن ثم حساب فيض الحرارة والزخم ((H and τ حيث كانت اعلى قيمة لــ H تساوي 127.6 Wm-2 عند الساعة 10:30 في يوم 26/07/2016 واقل قيمة تساوي -58.9 Wm-2 عند الساعة 07:30 في يوم 29/06/2016 كذلك كانت اعلى قيمة لـ τ تساوي 0.134535 Nm-2 عند الساعة 15:00 في يوم 03/08/2016 واقل قيمة تساوي -0.4649 Nm-2 عند الساعة 03:00 في يوم 01/07/2016 ( الاشارة السالبة تشير الى التغير في اتجاه الحركة ) . وقد وجد هنالك علاقة عكسية بين H و τ . السحب الاحتكاكي بواسطة سرعة الرياح تم تناوله ايضا ، حيث كانت اعلى قيم تكرارية للسرعة الاحتيكاكية عند الظروف الغير مستقرة.


Article
Study Of Diffusion Influence Materials Of Copper-ZincSteel On The Hardness And Micro Hardness Under Heat Treatment

Author: Ali Adwan H علي عدوان حمود
Journal: DIYALA JOURNAL OF ENGINEERING SCIENCES مجلة ديالى للعلوم الهندسية ISSN: 19998716/26166909 Year: 2019 Volume: 12 Issue: 3 Pages: 1-7
Publisher: Diyala University جامعة ديالى

Loading...
Loading...
Abstract

Low melting metals like zinc used in this research topromote increasing of diffusion process with presence ofpure powder of copper., this metals have good corrosionresistance in chemical and environmental conditions bymaking thin film to hardening surface of rod of stainlesssteel18/8Ni-Cr under heat treatment condition at 890c aboveeutectic line to reached austerity zone and under this line at0,600c to obtained re-crystallization annealing and 400c0 atsufficient time 90min..chemical composition ,hardness,micro-hardness ,and micro structures were investigated totrack the effectiveness of diffusion zinc-copper melting indifferent s points.

Listing 1 - 10 of 29 << page
of 3
>>
Sort by
Narrow your search

Resource type

article (29)


Language

English (28)

Arabic and English (1)


Year
From To Submit

2019 (29)