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Article
simulation of dynamic performance of biochemical fermenter

Author: basim O.hasan
Journal: AL-NAHRAIN JOURNAL FOR ENGINEERING SCIENCES مجلة النهرين للعلوم الهندسية ISSN: 25219154 / eISSN 25219162 Year: 2012 Volume: 15 Issue: 1 Pages: 92-107
Publisher: Al-Nahrain University جامعة النهرين

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Article
Heat Transfer Analysis in Annular Two Phase Flow Using Finite Difference Method

Author: Basim. O. Hasan
Journal: Journal of Petroleum Research & Studies مجلة البحوث والدراسات النفطية ISSN: 22205381 Year: 2013 Volume: 124 Issue: 7th Pages: 71-99
Publisher: Ministry of Oil وزارة النفط

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Heat transfer in two phase flow is widely encountered in oil and gas industry in which heat is transported between two phase the fluid and the pipe wall with a rate depending on the hydrodynamic conditions. In present work, theoretical study was carried out to predict the temperature distribution within the liquid layer in annular gas–liquid (air–water) of two phase flow in presence of heat flux under laminar flow conditions. The temperature distribution was evaluated at different values of liquid Reynolds number (ResL), gas Reynolds number (Resg), wall heat flux, and inlet liquid as well as gas temperatures. The finite differences technique was employed to solve the energy equation to obtain the temperature distribution in the liquid layer. Additionally, the effect of Resg and ResL on the liquid layer thickness was investigated and discussed. It was found that the presence of heat flux through the pipe wall leads to an increase in the liquid temperature asymptotically with the axial distance (z) depending on the radial distance (r). The maximum increase occurred in the liquid layers adjacent to the pipe surface layers and the minimum increase was at the interface. The fully developed temperature profile varied with radial distance (r) where the surface layers reached at Lt/d=5. However, the Lt/d for the layers nearest to the interface was less than 5. At a particular (r) and constant Resg, the higher the ResL is, the higher the temperature will be. At a particular ResL and Resg, the liquid layer temperature distribution depends largely on the values of applied heat flux and the gas temperature.


Article
Analysis of Galvanic Corrosion under Mass Transfer Controlled Conditions

Authors: Basim O. Hasan --- Qasim. J.M Slaiman
Journal: Journal of Engineering مجلة الهندسة ISSN: 17264073 25203339 Year: 2007 Volume: 13 Issue: 3 Pages: 1623-1636
Publisher: Baghdad University جامعة بغداد

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Because of practical importance of protecting industrial equipments from galvanic corrosion, the need arises to analyze the effects of variables, such as temperature, velocity, and area fraction of metals on galvanic corrosion in systems under mass transfer control as in seawater (pH=7). For these reasons the galvanic corrosion of Fe-Zn is analyzed to study the influence of Reynolds number, temperature, and area fraction on the galvanic corrosion rates and galvanic corrosion potential under mass transfer control.It is found that galvanic corrosion rate of more active metal (Zn) is increased with Reynolds number while the corrosion rate of more noble metal (Fe) is slightly increased with Re depending on the galvanic potential that depends on the area fraction. Increasing Reynolds number shifts the galvanic potential to more positive values. Also increasing temperature leads to shift the corrosion potential to more negative values and to change the corrosion rate of more active metal (Zn) depending on two parameters oxygen solubility and oxygen diffusivity. As area fraction of more active metal (Zn) increased the galvanic potential is shifted to the negative anodic direction while the corrosion rate for more noble metal is decreased.

بسبب الاهمية التطبيقية لحماية المعدات الصناعية من التاكل الغلفاني ظهرت الحاجة لدراسة وتحليل تأثير بعض العوامل مثل درجة الحرارة وسرعة السائل ومساحة الكاثود والانود على التاكل الغلفاني في الانظمة التي تكون تحت سيطرة انتقال الكتلة(pH=7) كما في ماء البحر.تمت دراسة التاكل الغلفاني لمعدني الحديد والخارصين لمعرفة تاثير عدد رينولد (او السرعة) ودرجة الحرارة ونسبة المساحة في ظروف سيطرة انتقال الكتلة. أظهرت النتائج ان زيادة عدد رينولد يؤدي الى زيادة تأكل المعدن الفعال الانود (Zn ) بصورة رئيسية ويؤثر قليلا على المعدن الاقل فعالية (الكاثودFe) وحسب جهد التاكل الذي يعتمد على نسبة المساحة بين المعدنين. زيادة عدد رينولد يؤدي الى زيادة جهد التاكل الغلفاني بالاتجاه الموجب و زيادة درجة الحرارة تؤدي الى تقليل معدل التاكل الغلفاني وتقليل جهد التاكل الغلفاني(ازاحته بالاتجاه السالب) وازاحته بالاتجاه السالب اما زيادة مساحة المعدن الفعال (Zn) تؤدي الى تقليل الجهد الغلفاني وتقليل تاكل المعدن الاقل فعالية (Fe).


Article
The Influence of Reynolds Number and Temperature on the Mass Transfer Coefficient of the Corroding Pipe

Authors: Basim O. Hasan --- Q.J.M. Slaiman
Journal: Journal of Engineering مجلة الهندسة ISSN: 17264073 25203339 Year: 2005 Volume: 11 Issue: 4 Pages: 741-750
Publisher: Baghdad University جامعة بغداد

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Abstract

Corrosion of carbon steel pipe in aerated O.l N NaCl solution under isothermal turbulent flow conditions (Reynolds number= 15000-113000 and temperature of 30-60°C) is investigated by weight loss method. The effect of Reynolds number and temperature on corrosion rates is experimentally studied and discussed. Corrosion mechanism is analyzed as a mass transfer operation and the corrosion rate is expressed in terms of mass transfer dimensionless groups (Sh and St) and in terms of usual corrosion units. The results of corrosion rates are compared with many proposed models particularly those based on the concept of analogy among mass, heat, and momentum transport by determining experimental friction factor. The capability of these models to express corrosion rates over the investigated range of Re and temperature is examined and discussed. Many of these correlations are adopted to estimate corrosion rates for the considered system. It is found that Reynolds number increases the corrosion rate depending on temperature. Temperature increases the corrosion rate for high and moderate values of Reynolds number. At low Reynolds number the effect of temperature depends on oxygen solubility, oxygen molecular diffusivity, and Reynolds number (or eddy diffusion). Generally, Von Karman and Prandtl- Taylor analogies (based on the experimental friction factor) show good agreement with experimental mass transfer results while Chilton-Colburn analogy exhibits reasonable agreement at low Reynolds number and some overestimation at high Reynolds number.

تم إجراء إختبارات التآكل على إنبوب من الفولاذ الكا ربوني في محلول كلوريد الصوديوم (0.1 عياري) الحاوي على أوكسجين الجو الذائب تحت ظروف الجريان المضطرب بسرع ودرجات حرارة مختلفة (عدد رينولد 15000 الى 113000 ودرجة حرارة من 30oC إلى 65oC) بإستخدام طريقة فقدان الوزن. تمت دراسة مختبرية ومناقشة تأثير عدد رينولد (أو السرعة) ودرجة الحرارة على معدل التآكل وتأثير. تم تحليل عملية التآكل كعملية إنتقال كتلة ووضعت علاقات تجريبية وضعية لحساب معدل التآكل تحت ظروف مختلفة. وقد تم مقارنة النتائج العمليه مع عدة علاقات موضوعة للتعبير عن انتقال الكتله بين الجدار والمائع وخاصة العلاقات المبنية عن التشابه في ميكانيكية الانتقال بين الكتلة والحرارة والزخم لمعرفة امكانية حساب معدل التآكل باستخدام هذه العلاقات. وقد تم اعتماد بعض هذه ألعلاقات للتعبير عن معدل التآكل للنظام المذكور. دلت النتائج على ان زيادة عدد رينولد تؤدي الى زيادة معدل التآكل لكل درجات الحرارة وكذلك تاثير عدد رينولد على معدل التأكل يتغير بتغير درجة الحرارة والزمن. زيادة درجة الحرارة تؤدي الى نى يادة معدل التأكك لقيم عدد رينولد المتوسطة والعالية أما عند قيم عدد رينولد الواطئة فان تاثير درجة الحرارة على معدل التآكل يعتمد على قيمة عدد رينولد. أبدت علاقات (Prandtl-Taylor) و (Von Karman) توافقاً جيدا مع النتائج العملية لكل قيم عدد رينولد. كذلك أبدت علاقة (Chilto1-Colburn) توافقا مع النتائج العملية عند قيم عدد رينولد المنخفضة وأعطت نتائج عالية نسبيا عند قيم عدد رينولد العالية.


Article
Cathodic Protection of Carbon Steel in 0.1N NaCl Solution Under Flow Conditions Using Rotating Cylinder Electrode

Authors: Marwa F. Adul-Jabbar --- Basim O. Hasan
Journal: Journal of Engineering مجلة الهندسة ISSN: 17264073 25203339 Year: 2012 Volume: 18 Issue: 4 Pages: 403-414
Publisher: Baghdad University جامعة بغداد

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Abstract

The effect of applied current on protection of carbon steel in 0.1N NaCl solution (pH=7) was investigated under flow conditions (0-0.262 m/s) for a range of temperatures (35-55°C) using rotating cylinder electrode. Various values of currents were applied to protect steel from corrosion, these were Iapp.= Icorr., Iapp.=2Icorr. and Iapp.=2.4Icorr. under stationary and flow conditions. Corrosion current was measured by weight loss method. The variation of protection potential with time and rotation velocity at various applied currents was assessed. It is found that the corrosion rate of carbon steel increases with rotation velocity and has unstable trend with temperature. The protection current required varies with temperature and it increases considerably when the rotation velocity was increased. The protection potential decreases appreciably (shifts to more negative) with time and with increasing rotation velocity. Also it shifts to more positive with increasing temperature.

لقد تم دراسة تاثير تيارات مسلطة على الفولاذ الكاربوني في محلول تركيز الملح فيه ١,∙ مولاري وتحت ظروف جريان (∙ - ٫٢٦٢. م/ثا) ودرجات حرارة (٣٥­٥٥م°) باستخدام قطب الاسطوانة الدوارة. سلطت قيم مختلفة لتيارات الحماية لحماية الفولاذ الكاربوني من التاكل ، تم تسليط تيار التاكل,ضعف تيار التاكل و٤,٢من تيار التاكل تحت سرع ودرجات حرارة مختلفة ، تم ملاحظة تغير فولتية الحماية مع الوقت ومع السرع في مختلف التيارات المسلطة. وجد ان معدل التاكل للفولاذ الكاربوني يزداد مع السرع ويكون تغيره مع درجات الحرارة غير ثابت وان تيارات الحماية المطلوبة تختلف مع درجات الحرارة وتزداد عند زيادة سرعة الدوران ، وفولتية الحماية تقل (تصبح اكثر سالب) مع زيادة الوقت ومع زيادة السرعة وتصبح أكثر موجب مع زيادة درجات الحرارة.


Article
Turbulent Prandtl Number and its Use in Prediction of Heat Transfer Coefficient for Liquids
استخدام عدد براندتل الاضطرابي لحساب معامل انتقال الحرارة للسوائل

Author: Basim O. Hasan باسم عبيد حسن
Journal: AL-NAHRAIN JOURNAL FOR ENGINEERING SCIENCES مجلة النهرين للعلوم الهندسية ISSN: 25219154 / eISSN 25219162 Year: 2007 Volume: 10 Issue: 1 Pages: 53-64
Publisher: Al-Nahrain University جامعة النهرين

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Abstract

A theoretical study is performed to determine theturbulent Prandtl number (Prt ) for liquids of widerange of molecular Prandtl number (Pr=1 to 600)under turbulent flow conditions of Reynolds numberrange 10000- 100000 by analysis of experimentalmomentum and heat transfer data of other authors. Asemi empirical correlation for Prt is obtained andemployed to predict the heat transfer coefficient forthe investigated range of Re and molecular Prandtlnumber (Pr). Also an expression for momentum eddydiffusivity is developed. The results revealed that thePrt is less than 0.7 and is function of both Re and Praccording to the following relation:Prt=6.374Re-0.238 Pr-0.161The capability of many previously proposed models ofPrt in predicting the heat transfer coefficient isexamined. Cebeci [1973] model is found to give goodaccuracy when used with the momentum eddydiffusivity developed in the present analysis. Thethickness of thermal sublayer decreases withReynolds number and molecular Prandtl number.

تم إجراء دراسة نظرية لتحديد عدد براند تل الاضطرابي( Prt) للسوائل تحت ظروف جريان مضطرب لعدد رينولد من (10000 -100000) وعدد براندتل ألجزيئي من 1 إلى 600 وذلك بتحليل النتائج العملية المستحصلة من دراسات انتقال الزخم وانتقال الحرارة التي اجريت من قبل باحثين آخرين. تم الحصول على علاقة لوصف(Prt) كدالة لعددي رينولد (Re) و برانتل ألجزيئي (Pr) . تم استخدام هذه العلاقة لحساب معامل انتقال الحرارة كما تم الحصول على علاقة تصف الانتشارية الدوامية للزخم . دلت النتائج على إن (Prt) اقل من 0.7 ويتغير مع Re و Pr حسب العلاقة التالية : كذلك تم اختبار إمكانية بعض العلاقات ال (Prt) الموضوعة سابقا من قبل باحثين آخرين لحساب معامل انتقال الحرارة . وجد إن علاقة (Cebeci 1973) تعطي نتائج جيدة إذا استخدمت مع علاقة الانتشارية الدوامية للزخم التي تم الحصول عليها في هذا البحث.


Article
Effect of Salt Content on The Corrosion Rate of Steel Pipe in Turbulently Flowing Solutions
تأثير المحتوى الملحي على معدل التآكل للأنبوب من الفولاذ في ظروف جريان اضطرابي

Author: Dr. Basim O. Hasan باسم عبيد حسن
Journal: AL-NAHRAIN JOURNAL FOR ENGINEERING SCIENCES مجلة النهرين للعلوم الهندسية ISSN: 25219154 / eISSN 25219162 Year: 2010 Volume: 13 Issue: 1 Pages: 66-73
Publisher: Al-Nahrain University جامعة النهرين

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Abstract

The effect of salt content on the corrosionrate of carbon steel pipe in aerated waterunder isothermal turbulent flow conditions(Reynolds number= 15000-110000 andtemperature of 30-60oC) is investigated byweight loss method. The test solutions weredistilled water (one time distilled) and seawater (0.5N NaCl). Also the results of 0.1NNaCl solution obtained by Hasan [2003]were considered. The effect of Reynoldsnumber temperature on the corrosion rateis also studied and discussed. For each run,nine specimens of carbon steel were placedin the test section and the corrosion rate foreach one was determined at every Re andtemperature and the average was taken.The variation of friction factor with Re andtemperature was determined by measuringpressure drop across the test section.The results revealed that the salt contenthas considerable effect on the corrosion ratefor the whole investigated range of Re andtemperature. The highest corrosion rate wasencountered in sea water (3.5% NaCl). Alsodistilled water causes considerable corrosionrate but it is lower than for the whole rangeof Re and temperature. Also it is found thatReynolds number increases the corrosionrate depending on temperature.Temperature affects the corrosion rate bychanging two main parameters, oxygensolubility and diffusivity.

تمت دراسة تأثير المحتوى الملحي للسائل على معدل التآكل للأنبوب من الفولاذ الكاربوني في الماء تحت ظروف جريان اضطرابي (عدد رينولدز 15.000 إلى 110000 ) في درجات حرارة من 30 م - 60م . باستخدام طريقة فقدان الوزن . ثم قياس معدل التآكل في الماء المقطر (مقطر مره واحده) وماء البحر (0.5 N NaCl ) . كذلك تم اعتماد نتائج دراسة الباحث حسن (2003) الخاصة بالتآكل لمعدن الفولاذ الكاربوني في ماء حاوي على 0.1 N من ملح NaCl .كذلك تمت دراسة تأثير السرعة ودرجة الحرارة على معدل التآكل ومناقشة ذلك. في كل تجربة تم استخدام تسعة نماذج من المعدن وقياس معدل التآكل فيها واخذ معدل القيم . اخطر النتائج أن المحتوى المحلي للمحلول يؤثر بشكل كبير على معدل التآكل في كل درجات الحرارة وعند جميع السرع ( أو عدد رينولدز) . وجد أن أعلى معدل تأكل هو في محلول ماء البحر 0.5N . كذلك لوحظ إن زيادة عدد رينولدز تؤدي إلى زيادة معدل التآكل وان درجة الحرارة تؤثر على معدل التآكل بتغيير عاملين هما ذوبانية الأوكسجين ومعامل انتشاره.


Article
Effect of Different Operating Conditions on the Corrosion of Carbon Steel in Oxygenated Sodium Sulphate Solution

Authors: Sara A. Sadek --- Basim O. Hasan
Journal: Journal of Petroleum Research & Studies مجلة البحوث والدراسات النفطية ISSN: 22205381 Year: 2013 Volume: 191 Issue: 9th Pages: 62-89
Publisher: Ministry of Oil وزارة النفط

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Abstract

Carbon steel is a major metal used in manufacturing of the equipments used in petroleum industry and it is subject to different operating conditions causing various corrosion attacks. Corrosion of carbon steel in sodium sulphate solution (Na2SO4) under flow conditions was investigated using rotating cylinder electrode (RCE) for a range of rotation velocity (0 – 2000 rpm) and temperatures (32 - 52 oC). The corrosion rate was determined by using both weight loss method and electrochemical polarization technique (limiting current density). Different salt concentrations were investigated ranged from 0.01 to 0.4 M. The effect of time (or corrosion product formation) and the effect of oxygen concentration through air bubbling in the solution were also investigated and discussed. The results showed that increasing rotational velocity leads to a considerable increase in the corrosion rate represented by limiting current density. The corrosion rate had unstable trend with salt concentrations and temperature. Generally, the corrosion rate decreased appreciably with time due to the formation of corrosion product layer depending on rotational velocity, temperature, and oxygen concentration. It was found that, air pumping through the salt solution leads to a considerable increase in the limiting current density (iL) depending on rotational velocity, temperature, and time.


Article
The Effect of Time and Corrosion Products Formation on CorrosionRate of Carbon Steel Pipe Under Turbulent Flow Conditions

Authors: Shiemaa M. Mahmood --- Basim O. Hasan --- Qasim J. Slaiman
Journal: Iraqi Journal of Chemical and Petroleum Engineering المجلة العراقية للهندسة الكيمياوية وهندسة النفط ISSN: 19974884/E26180707 Year: 2007 Volume: 8 Issue: 4 Pages: 63-71
Publisher: Baghdad University جامعة بغداد

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Abstract

The effect of time (or corrosion products formation) on corrosion rates of carbon steel pipe in aerated 0.1N NaCl solution under turbulent flow conditions is investigated. Tests are conducted using electrochemical polarization technique by determining the limiting current density of oxygen reduction in Reynolds number range of 15000 to 110000 and temperature range of 30 to 60oC. The effect of corrosion products formation on the friction factor is studied and discussed. Corrosion process is analyzed as a mass transfer operation and the mass transfer theory is employed to express the corrosion rate. The results are compared with many proposed models particularly those based on the concept of analogy among momentum, heat, and mass transport. The capability of these models to predict corrosion rates in presence of corrosion products is examined and discussed. It is found that formation of corrosion products with time decreases the corrosion rate (or mass transfer rate) at low Reynolds number and temperature while it increases the corrosion rate at high Re and temperature. It increases momentum transport and this increase depends on temperature,Reynolds number, and corrosion rate. Increasing roughness due to the formation of corrosion products causes overestimation of analogy correlations results by increasing friction factor and decreasing corrosion rate.


Article
Corrosion Inhibition of Carbon Steel under Two Phase Flow (Water-Petroleum) Simulated by Turbulently Agitated System

Authors: Hussein A. Mabmood --- Basim O. Hasan --- Qasim J. M. Slaiman
Journal: Iraqi Journal of Chemical and Petroleum Engineering المجلة العراقية للهندسة الكيمياوية وهندسة النفط ISSN: 19974884/E26180707 Year: 2007 Volume: 8 Issue: 2 Pages: 47-52
Publisher: Baghdad University جامعة بغداد

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Abstract

The corrosion of carbon steel in single phase (water with 0. IN NaCI) and two immiscible phases (kerosene-water) using turbulently agirated system is invest The experiments are carried out for Reynolds number (Re) range of 38000 to 95000 corresponding to rotational velocities from 600 to 1400 rpm using circular disk turbine agitator at 40 C. in two-phase system lest runs are carried out in aqueous phase (water) concentrations of) % vo 5 % vol., 8% vol. and 16% vol. mixed with kerosene at various Re. The effect of Reynolds number (Re), percent of dispersed phase, dispersed drops diameter, and number of drops per unit volume on the corrosion rate is investigated and discussed. Test runs are carried out using two types of inhibitors: sodium nitrite of concentrat ions 20, 40, and 60 ppm and sodium hexapolyphosphate of concentrations 485, 970, and 1940 ppm in a solution containing 8% vol. aqueous phase (water) mixed wi/h kerosene (continuous phase) at 40 °Cfor the whole range qf Re. It was found that increasing Re increases the corrosion rate and the presence of water enhances the corrosion rate by increasing the solution electrical conductivity. For two phase solution containing 8% vol. and /6% vol. of water the corrosion rate was higher than single phase (100 % vol. water). The main parameters that play the major role in determining the corrosion rate in two phase were concentration of oxygen, solution electrical conductivity, and the interfacial area between the two phases (dispersed ond continuous). Sodium nitrite and sodium hexopolyphosphate were found to be fflcient inhibitors in two phase solution for the investigated range of Re.

Keywords

corrosion --- two-phase --- kerosene --- water --- turbulent --- carbon steel.

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