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Article
Numerical Study of Heat Transfer Enhancement in Heat Exchanger Using AL2O3 Nanofluids
دراسة عددية لتحسين انتقال الحرارة داخل مبادل حراري باستخدام نانو اوكسيد الالمنيوم-الماء

Author: Hussein Talal Dhaiban حسين طلال ذيبان
Journal: Journal of Engineering مجلة الهندسة ISSN: 17264073 25203339 Year: 2016 Volume: 22 Issue: 4 Pages: 98-115
Publisher: Baghdad University جامعة بغداد

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Abstract

In this study, the flow and heat transfer characteristics of Al2O3-water nanofluids for a range of the Reynolds number of 3000, 4500, 6000 and 7500 with a range of volume concentration of 1%, 2%, 3% and 4% are studied numerically. The test rig consists of cold liquid loop, hot liquid loop and the test section which is counter flow double pipe heat exchanger with 1m length. The inner tube is made of smooth copper with diameter of 15mm. The outer tube is made of smooth copper with diameter of 50mm. The hot liquid flows through the outer tube and the cold liquid (or nanofluid) flow through the inner tube. The boundary condition of this study is thermally insulated the outer wall with uniform velocity at (0.2, 0.3, 0.4 and 0.5 m/s) at the cold loop and constant velocity at (0.5 m/s) at the hot loop.The results show that the heat transfer coefficient and Nusselt number increased by increasing Reynolds number and particle concentration. Numerical results indicate that the maximum enhancement in Nusselt number and heat transfer coefficient were 9.5% and 13.5% respectively at Reynolds number of 7100 and particles volume fraction of 4%. Results of nanofluids also showed a good agreement with the available empirical correlation at particles volume fractions of 1%, 2% and 3%, but at volume fractions of 4% a slight deviation is obtained.

تمت عددياً دراسة خواص الجريان وانتقال الحرارة لمائع نانو اوكسيد الالمنيوم-الماء لمدى من عدد رينولدز 3000, 4500, 6000 و 7500 مع مدى من التركيز الحجمي لللدقائق من 1%, 2%, 3% و 4%. يتألف جهاز الاختبار من دورة باردة ودورة حارة مع جريان متعاكس للمائع داخل انبوب مزدوج متحد المركز بطول متر واحد. الانبوب الداخلي مصنوع من النحاس الاملس بقطر يعادل 15 مليمتر. والأنبوب الخارجي مصنوع من النحاس الاملس بقطر يعادل 50 مليمتر. جريان المائع الساخن خلال الانبوب الخارجي وجريان المائع البارد (او النانوي) خلال الانبوب الداخلي. الشروط الحدودية لهذه الدراسة هي السطح الخارجي معزول مع سرع متغيرة (0.2, 0.3 , 0.4 و 0.5)مثا للدورة الباردة وسرعة ثابتة (0.5 )مثا للدورة الساخنة. النتائج تبين ان معامل انتقال الحرارة وعدد نسيلت تزداد بزيادة عدد رينولد ومعامل التركيز الحجمي . والنتائج العددية تمثلت بأعلى نسبة تحسين لعدد نسلت ومعامل انتقال الحرارة ب 9.5% و 13.5% على التوالي عند عدد رينولد 7100 ومعامل التركيز الحجمي للجزيئات 4%.كذلك النتائج بينت توافق جيد مع معادلة عددية عند معامل التركيزالحجمي للجزيئات 1%, 2% و 3% ولكن بمعامل الكسر الحجمي 4% حدث اختلاف بسيط .


Article
EXPERIMENTAL STUDY OF WICK STRUCTURE MATERIAL AND SCREEN MESH ON HEAT PIPE PERFORMANCE
دراسة عملية لهيكل المواد النسيجية على اداء الانبوب الحراري

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Abstract

An experimental study has been done on heat pipe 1000mm length and 25.4mm diameter. Evaporator section is formed by adopting a coil heater over 240mm from one side of heat pipe length. The condenser section is formed by adopting a water jacket over 300mm from the other end of heat pipe length. The working fluids used is R-134a. The used wick structure is of square meshes of (Bronze150*150, Bronze200*200 and Copper145*145). The wick structure is formed by turning the square mesh layer six times to form an internal circumference for heat pipe inner diameter. The supplied power over evaporator (20, 30, 40 and 60)W. Thermal conductivity of Copper is 401W/m.Co and Bronze is 51.2 W/m.oC . It is found that the thermal conductivity has no effect on the heat pipe performance. But mesh screen size affected the performance the heat pipe and increases the temperature along the heat pipe.

اجريت دراسة عملية لأنبوب حرارة بطول (1000mm) وقطر(25.4mm) . يتكون المبخر من خلال وضع مسخن حراري على طول (240mm) من الطول الكلي لأنبوب الحراري من أحد طرفيه بينما يكون المكثف من خلال وضع جيب مائي على طول (300mm) من طول الأنبوب . كان مائع التشغيل المستخدم (R134a). بينما كانت المواد النسيجية المستخدمة هي (برونز 150x150 ,برونز200x200 و نحاس 145x145) تم تشكيل المواد النسيجية عن طريق لفها ستة لفات لتكون القطر الداخلي لانبوب الحرارة. القدرة المجهزة للمبخر(20, 30, 40, and 60W) مع كل نوع من المواد النسيجية. الموصلية الحرارية للنحاس (401W/m.oC) وللبرونز(51.2W/m.oC). لقد وجد بأن الموصلية الحرارية لا تؤثر على أداء الأنبوب الحراري. لكن التشبيك النسيجي له تأثير واضح فكلما زاد التشبيك النسيجي انخفض أداء الأنبوب وارتفعت درجة الحرارة على طول الأنبوب .


Article
EXPERIMENTAL AND NUMERICAL STUDY OF THE HEAT TRANSFER COEFFICIENTS OF DOUBLE PIPE HELICALLY COILED HEAT EXCHANGER
دراسة عملية وعددية لمعامل انتقال الحرارة لمبادل حراري مكون من ملف حلزوني مزدوج الانبوب

Authors: Ammar A. Hussain --- Ali S. Golam
Journal: Journal of Engineering and Sustainable Development مجلة الهندسة والتنمية المستدامة ISSN: 25200917 Year: 2016 Volume: 20 Issue: 6 Pages: 81-102
Publisher: Al-Mustansyriah University الجامعة المستنصرية

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Abstract

This work introduces an experimental and numerical study of the heat transfer coefficients of double pipe helically coiled heat exchanger. It tested for both parallel and counter flow arrangements. Water is used as working fluid in inner tubes side and annulus tube side. The mass flow rate has range between (0.032 - 0.0721) kg/s for cold water while hot water is kept constants at (0.0724 kg/s). Also the range of inlet temperatures of cold and hot water are (20 - 25°C), and (40 - 70 °C), respectively. All experiments performed at the Dean Number for annulus tubes side range of (1250 - 1700). The study directed to focus on influencing the inlet mass flow rate of annulus tubes-side, and inlet temperatures of inner tubes-side over the effectiveness, axial temperature distribution of heat exchanger, efficiency and heat transfer coefficient. All experimental data performed at the steady-state conditions. The results show that the mass flow rate ratio ((m_r ) ̇) effects the axial temperature distribution of heat exchanger also, the effectiveness and efficiency decreased by increasing mass flow rate ratio. Likewise, comparisons between numerical and experimental results have been made. Empirical correlations between the Nusselt Number with Dean and Prandtl Numbers for the annulus tube have been found.

يقدم هذا العمل دراسة عملية وعددية لمعامل انتقال الحرارة لمبادل مزدوج الانبوب ملفوف بشكل حلزوني. جرى الاختبار للجريان المتوازي والمتعاكس. تم استعمال الماء كسائل تشغيل من جانب الانبوب الداخلي والحلقي. نسب التدفق تتراوح بين 0.072 kg/s) - 0.032) للماء البارد بينما للماء الحار يبقى ثابت عند (0.0724 kg/s) . مدى درجات الحرارة لدخول الماء البارد والحار تتراوح بين ( (20 - 25 °Cو ( (40 - 70 °Cوعلى التوالي. كل الاختبارات اجريت لاعداد دين (De ) من جانب الانبوب الحلقي تتراوح بين (1250 - 1700). تركز الدراسة على تأثير كل من معدل التدفق للانبوب الحلقي ودرجة الحرارة للانبوب الداخلي على شكل توزيع درجات الحرارة المحوري داخل المبادل, وفعالية وكفاءة المبادل, ومعامل انتقال الحرارة. تظهر النتائج ان لنسبة التدفق ((m_r ) ̇) تأثير واضح على شكل توزيع درجات الحرارة المحورية للمبادل. وتؤثر زيادتها سلبا على فعالية وكفاءة المبادل. تم مقارنة النتائج العددية والعملية . تم ايجاد معادلة تجربيية لربط عدد نسلت من جانب الانبوب الخارجي بكل من عدد برانتل وعدد دین .


Article
Influence of Heat Treatment on Wear and Hardness Properties of MWCNTs Reinforced Epoxy nanocomposites.
تأثير المعاملة الحرارية على خاصية البلى والصلادة لمتراكبات أنابيب الكاربون النانوية المدعمة براتنج الايبوكسي

Authors: Khalid R. Al-Rawi خالد رشاد الراوي --- Noor H. Madhi نور هاشم ماضي
Journal: Iraqi Journal of Science المجلة العراقية للعلوم ISSN: 00672904/23121637 Year: 2016 Volume: 57 Issue: 4C Pages: 2891-2897
Publisher: Baghdad University جامعة بغداد

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Abstract

Nanocomposite of carbon nanotube add to epoxy resin material of weight fraction ( 0.25, 0.5, 0.75 1.0, 1.25, 1.5, 1.75 , 2 & 2.5 wt. % ) were fabricated by dispersing within an epoxy resin using a Ultrasound machine followed by mechanical stirring. The samples were heat treated at temperature ( 80 °C for 3 hrs) The mechanical properties of the composites were investigated. Wear and hardness properties measurements indicated higher wear rate and hardness with increasing concentration of MWCNTs . The MWCNTs significantly improved the wear resistance and hardness when compare than the pure epoxy. These note show too after heat treatment of composite with ( 80 oC for 3 hrs ).

تم تحضير متراكب نانومتري من مادة الايبوكسي مضاف اليه انابيب الكاربون النانوية متعدد الجدران وبنسب وزنية (0.25 ,0.5 , 1.75 , 1 , 1.25 , 1.5 , 1.75 , 2 , 2.5 ) % بتفريق داخل راتنج الإيبوكسي باستخدام جهاز الموجات فوق الصوتية متبوعاً بالتحريك الميكانيكي . العينات تعرضت لمعاملة في درجة حرارة (80 درجة مئوية ولمدة 3 ساعات) وتم التحقيق في الخواص الميكانيكية للمركبات . قياسات خصائص البلى والصلادة لمتراكب النانومتري أشارت إلى معدل أعلى للبلى والصلادة مع زيادة تركيز انابيب الكاربون النانوية . اضافة الكاربون النانوي ادى الى تحسين كبير في مقاومة البلى)التأكل ) والصلادة مقارنة بعينات الايبوكسي النقي . وكذلك تظهر بعد المعالجة الحرارية للعينات عند (80 درجة مئوية ولمدة 3 ساعات) .


Article
Effect of adding Betaine to the diet inWater Intake Pattern of Japanese quail exposed to heat stress
تأثير اضافة البيتين Betaineالى العليقة في نمط استهلاك الماء لطير السمان الياباني المعرض للإجهاد الحراري

Authors: عقيل يوسف الشكري --- فاضل رسول الخفاجي --- علي فرعون الجبوري
Journal: Euphrates Journal of Agriculture Science مجلة الفرات للعلوم الزراعية ISSN: 38752072 Year: 2016 Volume: 8 Issue: 1 Pages: 64-73
Publisher: Al-kasim University جامعة القاسم الخضراء

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Abstract

This study was conducted at the poultry farm -Animal Department of Resources College Agriculture -AlQasim Green University, from 17/10/2014 To 4/12/2014 to investigate the effect of supplement Betaine to the diet on Water Intake Pattern during entire day and 3, 4, 5, and 6 weeks of Japanease quailthat exposed to heat stress.The trial was started at the age of 8 daysandthree hundred unsexed birds were used . Birds were raised in cages and randomly distributed into 5 treatments with 3 riplicates for each treatment and , 20 birds eachriplicate. Birds were exposed to the cyclic temperature (29-36.5-31.5)˚C . Treatments were as follows:T1: Control treatment (without supplementation) T2 : Diet supplemented with 500 mg betaine /kg diet . T3 : Diet supplemented with 1000 mg betaine /kg diet .T4 : Diet supplemented with 1500 mg betaine /kg diet .T5 : Diet supplemented with 2000 mg betaine /kg diet .The results:showed thatWater consumption for 24 hours by birds of T5 at 3rd and 4th weeks was significantly higher as compared with other treatments whileat 5th and 6th weeks, birds of T5 were superior compared with those of T1 and T2 .

اجريت هذه الدراسة في حقل الطيور الداجنة التابع لقسم الثروة الحيوانية , كلية الزراعة / جامعة القاسم الخضراء . للمدة من 2014/10/17 ولغاية 2014/12/4 , للتحري عن تأثير البيتين المضاف الى العليقة في نمط استهلاك الماء خلال يوم كامل وللأسابيع 3 , 4 ,5 و6 لطائر السمان الياباني المعرض للإجهاد الحراري . بدأت التجربة من عمر 8 يوم واستخدم في التجربة 300 طائر سمان ياباني غير مجنس , ربيت الطيور في بطاريات , وقسمت الطيور عشوائيا الى 5 معاملات بواقع 3 مكرر لكل معاملة و20 طير لكل مكرر , عرضت الطيور الى درجة حرارة دورية ( 29- 36.5-(31.5 م˚ والمعاملات على النحو الاتي : (T1) : عليقة اساسية من دون اضافة البيتين . ( T2) : عليقة اساسية + بيتين بتركيز 500 ملغم / كغم علف .(T3) : عليقة اساسية + بيتين بتركيز 1000 ملغم / كغم علف . (T4) : عليقة اساسية + بيتين بتركيز 1500 ملغم / كغم علف. (T5) : عليقة اساسية + بيتين بتركيز 2000 ملغم / كغم علف . وكانت النتائج على النحو الاتي : حصل تفوق معنوي لطيور المعاملة T5 على باقي المعاملات في استهلاك الماء ليوم كامل في الاسبوعين 3 و4 وتفوقت المعاملة T5 على المعاملتين T1 و T2 في الاسبوعين 5 و6 .


Article
Entransy Dissipation of Shell and Double Concentric Tubes Heat Exchanger

Authors: Basma Abbas Abdulmajeed --- Zena Fallah Abdulah
Journal: Iraqi Journal of Chemical and Petroleum Engineering المجلة العراقية للهندسة الكيمياوية وهندسة النفط ISSN: 19974884/E26180707 Year: 2016 Volume: 17 Issue: 2 Pages: 7-14
Publisher: Baghdad University جامعة بغداد

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Abstract

The concept of entransy dissipation was determined for new type of heat exchanger (shell and double concentric tubes heat exchanger). Three parameters, hot oil flow rate, temperature of inlet hot oil and pressure drop of system were investigated with this concept (entransy dissipation). The results showed that the value of entransy dissipation of oil and of system which represents the summation of entransy dissipation of both oil and water increased with increasing the flow rate of hot oil and these values were larger when cold water flow rate was doubled. Also they were increased with increasing the hot oil inlet temperature at a certain flow rate of hot oil. Furthermore, the pressure drops for hot oil in both shell side and inner tubes side was constant and increased according to the increase of its flow rate. At different hot oil flow rate and a certain hot oil inlet temperature, the entransy of hot oil was increased with its pressure drop. In order to keep up with modern technology, infrared thermography camera was used in order to measure the temperatures which were higher than the temperatures obtained by thermocouples. For that reason the entransy dissipation was determined with lower values compared with their values obtained by using thermocouples.


Article
Study the Effect of the Flow on the Performance of a shell and Tube Type Heat Exchanger Using Experimental Design Technique

Authors: Zuher Hassan Abdullah --- Saad Sami Farhan --- Thamer K. Salem
Journal: Tikrit Journal of Engineering Sciences مجلة تكريت للعلوم الهندسية ISSN: 1813162X 23127589 Year: 2016 Volume: 23 Issue: 2 Pages: 38-45
Publisher: Tikrit University جامعة تكريت

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Abstract

In the current research an experimental study was done to show the effect of pulse flow on the effectiveness of shell and tube type heat exchanger. the study was in the case of steady and pulse flows with a changing mass flow rate of hot water flowing inside the pipes of the heat exchanger for the range between (0.0273-0.0819 kg / s) at fix mass flow rate of cold water that flows through the shell and on the outer surface of the pipes when (0.0416 kg / s), to obtain pulsing a used was solenoid valve. The research aims to measure the percentage effect of independent factors which were presenting the mass flow rate of hot water, flow type and the surrounding environment conditions of the experimental side upon shell and tube type heat exchanger performance using experimental design technique at the significant level (0.05).The results derived from the experimental tests showed that pulse flow leads to increase internal heat transfer coefficient (hi) comparing with its value in the steady flow and the highest increase was by (9.75%) at a mass flow rate of hot water (0.0416 kg / s) and increases the overall heat transfer coefficient (U), where the highest percentage was by )4.68%) at a mass flow rate of hot water (0.0416kg/s). The results also showed increasing both the number of transmitted units (NTU) and the effectiveness of the shell and tube type heat exchanger ( ) in the case of pulse flow of its value in the steady flow and the highest percentage of increase occurring was (4.75%) and (1.85%), respectively, and at the mass flow rate of hot water (0.0416 kg / s). Percentage effect of mass flow rate of hot water was (97%, 97.42%, 95.5%, 99.48%) and the percentage effect of each flow type and the errors were (2.8%, 2.25%, 2.44%, 0.4%) and (0. 2, 0.33%, 2.06%, 0.12) respectively.


Article
Study the effect of thermal change in some biochemical parameters in male rats infected with diabetes mellitus experimentally
دراسة التغيرات الحرارية المختلفة على بعض المعايير المناعية في الجرذان البيض المصابة تجريبياً بداء السكري

Author: Ihsan Raisan Ibrahim أحسان ريسان الركابي
Journal: journal of al-qadisiyah for pure science(quarterly) مجلة القادسية للعلوم الصرفة (فصلية). ISSN: 19972490 Year: 2016 Volume: 1 Issue: 21 Pages: 10-23
Publisher: Al-Qadisiyah University جامعة القادسية

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The current study aimed to knowing the effect of different temperatures degrees for different periods on some biochemical parameters on diabetes rats. Two experiments were carried out, the first is hyperthermia 80 rats (40 healthy and 40 infected) were divided into five groups( each group subdivided into: 8 health and 8 infected). First group considered as a control group exposed to normal temperature (21 ± 2) c °, the second, third , fourth group exposed to high temperature (40 ± 2) ° C and divided two groups infected and healthy for one hour, the third group: offered to degree (40 ± 2) ° C for one, tow, four hours respectively. Secondary experiment is hypothermal it was designed in same design of first experiment and temperature used was (5 ± 2) ° CThe results showed significant increase (P <0.05) in the level of glucose, cholesterol , triglycerides ,lipoproteins and GOT in healthy group and infected and in GPT in healthy group exposed to high temperature. All group showed significant increase in all infected parameter (P <0.05) compared whit healthy group in one hour period. Unless HDL which suffered from decrease.. As at increased exposure to two hours, he got the same results in the previous period except significant increase (P <0.05), which happened in the level triglycerides and VLDL in the group exposed to low temperature and decrease, which happened in LDL a infected group exposed to low temperature compared with healthy group In the period of four hours the results were similar that in the period one hour except the significant decrease (P <0.05) in cholesterol and HDL and GOT in the group exposed to low temperature compared with healthy group Levels of glucose and ALP and GOT increased in healthy animals and infected in groups expose low temperature, also HDI In LDLV significantly increase in group exposed to high temperatures, there was significantly differences in levels of cholesterol and triglycerides and HDL in the group exposed to high temperature also LDLV in group exposed to low temperature. Depending on period of of exposure

The current study aimed to knowing the effect of different temperatures degrees for different periods on some biochemical parameters on diabetes rats. Two experiments were carried out, the first is hyperthermia 80 rats (40 healthy and 40 infected) were divided into five groups( each group subdivided into: 8 health and 8 infected). First group considered as a control group exposed to normal temperature (21 ± 2) c °, the second, third , fourth group exposed to high temperature (40 ± 2) ° C and divided two groups infected and healthy for one hour, the third group: offered to degree (40 ± 2) ° C for one, tow, four hours respectively. Secondary experiment is hypothermal it was designed in same design of first experiment and temperature used was (5 ± 2) ° CThe results showed significant increase (P <0.05) in the level of glucose, cholesterol , triglycerides ,lipoproteins and GOT in healthy group and infected and in GPT in healthy group exposed to high temperature. All group showed significant increase in all infected parameter (P <0.05) compared whit healthy group in one hour period. Unless HDL which suffered from decrease.. As at increased exposure to two hours, he got the same results in the previous period except significant increase (P <0.05), which happened in the level triglycerides and VLDL in the group exposed to low temperature and decrease, which happened in LDL a infected group exposed to low temperature compared with healthy group In the period of four hours the results were similar that in the period one hour except the significant decrease (P <0.05) in cholesterol and HDL and GOT in the group exposed to low temperature compared with healthy group Levels of glucose and ALP and GOT increased in healthy animals and infected in groups expose low temperature, also HDI In LDLV significantly increase in group exposed to high temperatures, there was significantly differences in levels of cholesterol and triglycerides and HDL in the group exposed to high temperature also LDLV in group exposed to low temperature. Depending on period of of exposure


Article
Theoretical Study of Refrigerant Injection Technology Effect on Heat Pump Cycle Performance

Authors: Abdul Hadi N. Khalifa --- Johain J. Faraj --- Hayder K. Hasan
Journal: Engineering and Technology Journal مجلة الهندسة والتكنولوجيا ISSN: 16816900 24120758 Year: 2016 Volume: 34 Issue: 14 Part (A) Engineering Pages: 2727-2738
Publisher: University of Technology الجامعة التكنولوجية

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Abstract

A 5 ton heat pump system with R22 was improved by Liquid Pressure Amplification (LPA) and refrigerant injection technologies. Three approaches for refrigerant injection were used. The first one was by mixture injection in suction line through accumulator; the second one was by liquid refrigerant injection through discharge line, while the third was a hybrid injection, in which vapour and liquid refrigerant were injected both simultaneously. For both approaches two and three LPA technique was used. The range of volume ratio of injected mixture and liquid was 1 to 7%, and 1 to 10% respectively, and in the hybrid injection, the volume ratio of injected mixture was 1 to 3% and for injected liquid was as mentioned above. The following improvement in cycle performance factors were achieved, for mixture injection 5.33%, for liquid injection 29.4%, and 33.45% for hybrid injection. The effect of condensing pressure on the cycle performance was studied also in this work.


Article
Effect of Heat Treatment Parameters on Microstructure and Mechanical Properties of (Aisi1005) Steel

Authors: Hassanen L. Jaber --- R. k. Salim, --- Ashraf S. Fahad
Journal: University of Thi-Qar Journal for Engineering Sciences مجلة جامعة ذي قار للعلوم الهندسية ISSN: 26645564/26645572 Year: 2016 Volume: 7 Issue: 2 Pages: 46-55
Publisher: Thi-Qar University جامعة ذي قار

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Abstract

This study aims to investigate tensile properties and work hardening behavior of dual phase(DP) steels. A series of DP steels containing ferrite and martensite with different volumefractions of martensite (Vm) were produced by intercritical heat treatment. Microstructuralinvestigations, hardness test, and tensile test were carried out. The experimental results showedthat dual phase steels at 760oc and 10s have excellent mechanical properties in terms of tensilestrength, ductility and fracture energy. A further increase in Vm was found to increase tensilestrengths and ductility. The increasing and then decreasing trend in tensile strength is in contrastto the law of mixture. These unusual behaviors are discussed and explained. Work hardeningbehavior was analyzed in terms of Holloman analysis.

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