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Article
Electrode Consumption Simulation for Shielded Metal Arc Welding in Virtual Welding Training System

Authors: Raheem Kh. Al-Sabur --- Qais A. Rishack
Journal: Basrah Journal for Engineering Science مجلة البصرة للعلوم الهندسية ISSN: Print: 18146120; Online: 23118385 Year: 2014 Volume: 14 Issue: 2 Pages: 56-61
Publisher: Basrah University جامعة البصرة

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Abstract

One of the major problems in industry are new welding trainees cost, it drains the budget of many companies, particularly in industrialized countries, through raw material costs for preparation, welding wires, electric and fumes in addition to time spent. Recently a new technique was appeared; it is called virtual welding training system (VWTS) to reduce the training cost. In the present work a VWTS technique was built, a simulation of electrode motion is upgraded by using LVDT to represent the welding arc length while a DC motor with gearbox connect to the steel rode is used to represent welding electrode consumption. A 2D graphs with touch screen monitor are used to represent welding process. All sensors were calibrated to generate a VWTS. Accepted results obtained in training new welding trainees in the shielded metal arc welding (SMAW) training.

Keywords

Virtual welding --- electrode simulator --- SMAW --- LVDT --- VWTS


Article
Study of the Condenser Performance in Al-Nassiriyah Thermal Power Plant

Authors: Khalid N. Hassan --- Qais A. Rishack --- Ahmed K. Mohammed
Journal: University of Thi-Qar Journal for Engineering Sciences مجلة جامعة ذي قار للعلوم الهندسية ISSN: 26645564/26645572 Year: 2011 Volume: 2 Issue: 3 Pages: 95-112
Publisher: Thi-Qar University جامعة ذي قار

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Abstract

This paper includes a study of the performance of Al-Nassiriyah thermal power plant condenser. Which includes a calculations of the main variables of condenser (heat transfer, condensation rate, overall heat transfer coefficient and vapour pressure) by applying two dimensional mathematical model and depending on the empirical equations of heat transfer.Comparison was made between the theoretical results for Al-Nassiriyah thermal power plant condenser before operation it (standard power plant) with practical data which taken from the plant for the second unit in year 2007. The comparison showed that there was a largedifference between theoretical results and the values taken from the plant as a result to the effect of operation conditions.


Article
A Numerical simulation of emissions of pollutants from industrial chimney

Authors: Saleh I. Najim --- Qais A. Rishack --- Alaa H. Mohammed
Journal: Basrah Journal for Engineering Science مجلة البصرة للعلوم الهندسية ISSN: Print: 18146120; Online: 23118385 Year: 2014 Volume: 14 Issue: 2 Pages: 1-12
Publisher: Basrah University جامعة البصرة

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Abstract

The prediction of the concentration fields of pollutants released to the atmosphere is a key factor in assessing possible environmental damages caused by industrial emissions. To solve the concentration equation for gaseous or particulate effluents it is necessary to know as accurately as possible the velocity field and turbulence intensities at the atmospheric boundary layer in the region of interest. A two dimensional mathematical model based on the equations of fluid mechanics along with a modified non-isotropic k-ε turbulence model are employed to calculate the flow and dispersion at the atmospheric micro scale (distances of the order of kilometers).Results of investigation are obtained by using the finite volume method (FVM) to solve the average Navier Stock equations coupling with turbulent k- ε model. The calculation was carried out for plume flow from the industrial chimney with different plume velocities, wind velocities and heights of stack. The equations of model are solved with SIMPLE schemes.FLUENT program used to show the results of the plume flow at the variable parameters of wind and plume velocities and heights of stack, the code is applied to simulate several cases of flow and dispersion. Comparisons against experimental results show that the non-isotropic turbulence model has better ability to foresee the plume dispersion than the standard k- ε, in which the non-isotropic character of turbulence is relevant. The computational results show that the plume path and concentrations are correctly predicted by the numerical model


Article
Theoretical and Experimental Study of the Intake Manifold Effect on the SI Engine Performance

Authors: Qais A. Rishack --- Sadoun F. Dakhil --- Mohammed K. Obaid
Journal: Basrah Journal for Engineering Science مجلة البصرة للعلوم الهندسية ISSN: Print: 18146120; Online: 23118385 Year: 2014 Volume: 14 Issue: 2 Pages: 200-215
Publisher: Basrah University جامعة البصرة

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Abstract

This work uses different shapes of intake manifold for study the effect on a single cylinder four stroke gasoline engine. A numerical simulation of the flow achieved through five intake manifold designs, using 3D Computational Fluid Dynamic (CFD) software package FLUINT (6.3.). Accordingly, the three-dimensional resolution of Navier-Stokes equations in conjunction with the standard k-ε turbulence model is undertaken to provide knowledge of the air movement nature and examining the intake manifold optimal geometry. Five cases of intake manifold are examined experimentally in order to produce a comprehensive and realistic data set. These data are in the form of engine performance, exhaust gas products and relative AFR for each case separately under different engine speeds. Exhaust gas analyzer type (Infragas-209) is used in the present work to measure exhaust gas concentrations and relative air/fuel ratio ( ). The results were obtained in this investigation showed that a Simulate numerically and experimentally is capable to select the optimized intake system geometry with reliability. Velocity is highest near the outer wall at increased the curvature ratio and pressure is highest near the inner wall at increased the curvature ratio. The secondary flow increases when the engine speeds and curvature ratio increase because of increasing the pressure difference between the inner wall and the outer wall. The effect of these parameters explained on the swirl air movement and tumble inside the cylinder are increasing by increase the engine speed and γ respectively. The increasing in the engine speed and the optimum selection of the manifold which designed enhanced the mixing of the fuel with air. The results showed that the optimized manifold 135º- NE (case 5) due to enhance AFR, fuel consumption and exhaust emissions are improved.

Keywords


Article
Modeling of Pollutants Prediction from Fuel Burning in Oil and Gas Refineries
نمذجة التنبؤ بالملوثات من احتراق الوقود في مصافي النفط والغاز

Authors: Qais A. Rishack --- Salih E.Najim --- Rafid M. Hannun --- Nick Syred
Journal: Engineering and Technology Journal مجلة الهندسة والتكنولوجيا ISSN: 16816900 24120758 Year: 2013 Volume: 31 Issue: 18 Part (A) Engineering Pages: 69-87
Publisher: University of Technology الجامعة التكنولوجية

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Abstract

Oxides of nitrogen (NO + NO2 , (NOx)) are emitted from refineries, not only contribute to the production of photochemical smog at ground level but also cause damage to plant life and add to the problem of acid rain. The small amounts of prompt NO produced in the furnace chambers and oil refineries because the formation of NOx can be attributed to four distinct chemical kinetic processes: thermal NOx formation, prompt NOx formation, fuel NOx formation, and intermediate N2O. In this paper, the portions of pollutants that resulted in fuel burning (liquid or gas) in oil and gas refinery were studied by modeling of emitted gases in furnace chamber. The case study at Nassiriya power plant with different loads (70 – 210) MW was studied. The method of finite volume was studied to predict the pollutant portions by using FLUENT computer code (FLUENT is one of largest codes of computer programs which solve thousands of flow and combustion cases. The case study was drawn graphically then imported to solve by FLUENT). These types of pollution species are NOx and SOx as the important air pollutant influenced the human health. The numerical analysis in calculating the pollutants of chamber gave the findings of crude oil emission in combustion is higher than that at using gaseous fuel. So, the methods of decreasing NOx and SOx pollution by water injection and exhaust gas recirculation are used in refinery operation were presented

تنبعث أكاسيد النيتروجين (NO + NO2) من المصافي، وتساهم ليس فقط في إنتاج الضباب الدخاني الكيميائي الضوئي على مستوى سطح الأرض ولكن أيضا تسبب ضررا على الحياة النباتية وتضاف إلى مشكلة الأمطار الحمضية. يعزى تكون كميات صغيرة من أكاسيد النيتروجين في غرف الفرن ومصافي النفط إلى أربعة عمليات حركية كيميائية منفصلة هي: تكون أكاسيد النيتروجين الحرارية، تكون أكاسيد النيتروجين الفورية ، تكون أكاسيد النيتروجين من الوقود، و(N2O) الوسطية. في هذا البحث، تمت دراسة مكونات الملوثات التي نتجت عن حرق الوقود السائل أو الغاز في مصفاة النفط والغاز والتي درست بنمذجة الغازات المنبعثة في غرفة الفرن. وقد درست حالة الدراسة في محطة توليد كهرباء الناصرية بأحمال مختلفة (70-210 MW). ودرست الحالة بطريقة الحجم المحدد للتنبؤ بنسب الملوثات باستخدام برنامج الكمبيوتر (FLUENT) والذي هو واحد من أكبر البرامج لحل الاف الحالات للجريان والاحتراق. اعتمدت دراسة الحالة بيانيا ثم استيرادها للحل بواسطة(FLUENT) هذه الأنواع من عناصر التلوث هي أكاسيد النيتروجين وأكاسيد الكبريت هي من اهم ملوثات الهواء التي تؤثر على صحة الإنسان. أعطى التحليل العددي في حساب الملوثات في غرفة الاحتراق نتائج لانبعاثات احتراق النفط الخام أعلى من ذلك في استخدام الوقود الغازي. لذلك، قدمت الدراسة استخدام أساليب خفض أكاسيد النيتروجين وأكاسيد الكبريت الملوثة عن طريق حقن المياه وإعادة تدوير غاز العادم عند تشغيل المصفى.


Article
Analysis of Turbulent Free Convection in Enclosure with Conductive Partitions
تحليل الحمل الاضطرابي الحر داخل حيز بوجود حواجز موصلة للحرارة

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Abstract

A numerical method is presented to investigate the turbulent free convection inside an enclosure with partitions. The conductive partitions were located at the bottom wall. The Navier-Stokes and energy equations besides to the kinetic and dissipation equations were discretized by using a finite volume method. The solution of these equations was made via constructing a Fortran 90 computer program. The turbulence in the flow was modeled by using a k-ε model. The obtained results show that the conductive partitions represented a key factor for enhancing the rate of heat transfer. Also the results showed that the partitions height has more effect on enhancing the rate of heat transfer compared with the partitions thickness. The height of partitions were ranged from 0.25≤ h ≤ 0.65 and the width from 0.07 ≤ w ≤ 0.13. The enclosure was partially heated and the range of the considered values of Rayleigh number was up to 1014. The maximum rate of heat transfer is enhanced by 35% with increasing partitions height up to h= 0.65.

تم استخدام طريقة عددية لدراسة الحمل الاضطرابي الحر داخل حيز يحتوي على عوائق. تم تثبيت العوائق على الجزء السفلي المعزول. معادلات نافير- ستوكس ومعادلة الطاقة بالإضافة الى معادلات الطاقة الحركية للاضطراب ومعدل تبددها تم تحويلها الى معادلات جبرية باستخدام طريقة الحجم المحدد ومن ثم تم حلها بتصميم برنامج حسابي بلغة فورتران 90. تأثير الاضطراب على الجريان تمت نمذجته باستخدام موديل الاضطراب (k-ε). اوضحت النتائج التي تم الحصول عليها ان العوائق الموصلة للحرارة مثلت عاملاً ذو تأثير مباشر على تحسين معدل انتقال الحرارة وتبين ايضاً ان طول هذه العوائق له تأثير اكبر على تحسين معدل انتقال الحرارة مقارنة بسمك هذه العوائق. تراوح استخدام العوارض المستخدمة بين 0.25≤ h ≤ 0.65 بينما تراوح العرض بين 0.07 ≤ w ≤ 0.13 والحيز كان مسخن جزئياً واجريت الدراسة الحالية لقيم مختلفة من عدد رايليه وصلت الى 1014. اعلى معدل لانتقال الحرارة تم تحسينه بنسبة 35% عند زيادة ارتفاع الحاجز الى h= 0.65.

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