Preferred Language
Articles
/
alkej-347
Experimental and Numerical Research on Flow-Induced Vibration in Valves
...Show More Authors

Abstract  

All central air conditioning systems contain piping system with various components, sizes, material, and layouts. If such systems in operating mode, the flow in piping system and its component such as valves can produce severe vibration due to some flow phenomenon’s. In this research, experimental measurements and numerical simulation are used to study the flow-induced vibration in valves. Computational fluid dynamics (CFD) concepts are included with one-way and two-way fluid-structure interaction concepts by using finite element software Package (ANSYS 14.57). Detection analysis is performed on flow characteristics under operation conditions and relations with structural vibration. Most of real geometrical, operational, and boundary conditions are simulated to obtain best similarity with real operation conditions. Comparisons performed between experimental data and numerical results (one-way and two-way simulation) to verify the results. The main conclusion was drawn from the study that the dominant source of vibration for valve is the water pulsation in addition to amount of water hammering. In addition, the main source of water pulsation in globe valve is the vortex shedding and pressure difference between upstream and downstream of valve. The vibration amplitude was increased with increasing flow rate until to be maximum when the flow rate around 30% and then decreased until flow rate reaches to around 85% and then trends to be constant.

Keywords: Flow-induced vibration, vortex shedding, pressure pulsation, valve, finite element, ANSYS, fast Fourier transform (FFT).

Crossref
View Publication Preview PDF
Quick Preview PDF
Publication Date
Tue Feb 14 2023
Journal Name
Journal Of Educational And Psychological Researches
Vocabulary Learning Strategies Employed by English as Foreign Language Students at NBU University
...Show More Authors

ABSTRACT

Learning vocabulary is a challenging task for female English as a foreign language (EFL) students. Thus, improving students’ knowledge of vocabulary is critical if they are to make progress in learning a new language. The current study aimed at exploring the vocabulary learning strategies used by EFL students at Northern Border University (NBU). It also aimed to identify the mechanisms applied by EFL students at NBU University to learn vocabulary. It also aimed at evaluating the approaches adopted by EFL female students at Northern Border University (NBU) to learn a language. The study adopted the descriptive-analytical method. Two research instruments were developed to collect data namely, a survey qu

... Show More
View Publication Preview PDF
Publication Date
Wed Dec 04 2024
Journal Name
المكتب العربي للمعارف
إدراة الصراع بين القوى الإقليمية في آسيا بعد 2011 (الصين والهند وروسيا واليابان )انموذجاً
...Show More Authors

تعيش قارة آسيا حالة فريدة تكاد تقترب من حالة أوروبا قبل الحرب العالمية الثانية، فالقارة حاليا تحتوي على العديد من القوى الإقليمية الفاعلة أبرزها الصين وروسيا والهند واليابان، أما القوى الإقليمية الفاعلة في نطاق نظمها الإقليمية الفرعية نجد من أهمها الكوريتين (الشمالية والجنوبية)، وباكستان، وإيران وغيرها، ووجه الاختلاف عن أوروبا هو أن آسيا منطقة شاسعة جغرافياً، وكل نظام إقليمي فرعي فيها هو نظام قاري بحد ذات

... Show More
Publication Date
Mon Nov 12 2018
Journal Name
Arab Science Heritage Journal
عمارة عمارة المشهد الحسيني المقدس في ضوء رسومات المطراقي زادة (941ه/1534م) " دراسة تحليلية "
...Show More Authors

   The drawings of The travelers artist is important historical document and sources for  important information about The most of The city and building and different Islamic art which idling  because of different causes like wars and destruction or natural causes and disasters like eruptions and earthquakes and floods  which we cannot make a clear form about the buildings  mapping in later period .

View Publication Preview PDF
Publication Date
Mon Dec 01 2008
Journal Name
Journal Of Economics And Administrative Sciences
قياس وتحليل تفاعل عمل المضاعف والمعجل في الاقتصاد العراقي باستخدام نموذج المستخدم – المنتج الديناميكي
...Show More Authors

The individual average income is considered one of the most used criteria for the distinguishing between the developed and the developing countries, for this reason the efforts of economic development has been construed on increasing the average national income, the investment expenditures is considered one of the basic foundations for economic development operation which lead to the expanding the prodection power of the economy, and increasing the level of national income in an averages greaten than the primary expenditures due to the work and interaction between the multiplier and the accelerator. But the ability of the economic sectors in the generation of national income as a result of the primary expenditures is different fr

... Show More
View Publication Preview PDF
Crossref
Publication Date
Tue Sep 13 2022
Journal Name
جامعة بغداد/ كلية التربية للعلوم الصرفة - ابن الهيثم
اثر انموذج تسريع التعلم في تحصيل مادة الرياضياتوالتفكير المحوري لدى طالبات الصف الثالث المتوسط
...Show More Authors

Publication Date
Thu Jun 01 2023
Journal Name
Baghdad Science Journal
Estimation of Parameters for the Gumbel Type-I Distribution under Type-II Censoring Scheme
...Show More Authors

This paper aims to decide the best parameter estimation methods for the parameters of the Gumbel type-I distribution under the type-II censorship scheme. For this purpose, classical and Bayesian parameter estimation procedures are considered. The maximum likelihood estimators are used for the classical parameter estimation procedure. The asymptotic distributions of these estimators are also derived. It is not possible to obtain explicit solutions of Bayesian estimators. Therefore, Markov Chain Monte Carlo, and Lindley techniques are taken into account to estimate the unknown parameters. In Bayesian analysis, it is very important to determine an appropriate combination of a prior distribution and a loss function. Therefore, two different

... Show More
View Publication Preview PDF
Scopus Crossref
Publication Date
Wed Sep 25 2019
Journal Name
Journal Of The College Of Education For Women
كنائس وأديرة بغداد في العصر العباسي ودورها الإجتماعي والإقتصادي والثقافي (132- 656هـ/ 749- 1258م)
...Show More Authors

اقيمت الكنائس على جانبي مدينة بغداد الغربي(الكرخ) والشرقي(الرصافة)، أما الأديرة فقد انشئت في موضع مدينة بغداد قبل بنائها وبعد البناء حافظ البعض منها على مكانته وانشئ البعض الآخر، في جانبيها الغربي(الكرخ) والشرقي(الرصافة)، وهو ما سنركز عليه في بحثنا عن كنائس وأديرة بغداد لمختلف الطوائف المسيحية فيها، فضلاً عن تسليط الضوء على دورها الإجتماعي والإقتصادي والثقافي، وإن كان محدوداً جداً وقاصراً على الأديرة أكثر

... Show More
View Publication Preview PDF
Publication Date
Wed Mar 30 2022
Journal Name
College Of Islamic Sciences
ما خالف به الامامُ ابن السبكي الامامَ الامدي في تشنيف المسامع باب القياس انموذجا
...Show More Authors

The idea of ​​the research at first was to find out about the rare occurrence, which is the occurrence of a violation in the same madhhab and between two Shafi’i scholars such as Al-Amadi and Ibn Al-Subki. The scholarly had some brief and then moved on to the fundamentalist violations that occurred between them in the syllabus of the hearing within the chapter on analogy exclusively. The diffuse division (within the sounding and division) of the observer and the debates, or is it confined to the beholder without the debates, Imam Al-Amadi sees the inadmissibility of analogy with the reasons, while Imam Ibn Al-Subki argues that it is permissible, and Imam Al-Amdi sees that the widespread division is an argument for the observer (Muj

... Show More
View Publication Preview PDF
Crossref
Publication Date
Tue Dec 15 2020
Journal Name
Alustath Journal For Human And Social Sciences
مستويات التفكير الهندسي لدى طلبة قسم الرياضيات في كلية التربية/ابن الهيثم - جامعة بغداد
...Show More Authors

رمت الدراسة التعرف بمستويات التفكير الهندسي لدى طلبة قسم الرياضيات في كلية التربية / ابن الهيثم - جامعة بغداد، ولتحقيق هدف الدراسة تم اعتماد مقياس الحربي(2003) المعد على البيئة السعودية ويتكون من (25)  فقرة موزعه على خمسة مستويات وهي (المستوى البصري ، التحليلي ، شبه الاستدلالي، الاستدلالي، المجرد وبلغت عينة الدراسة (206) طلاب من طلبة قسم الرياضيات في كلية التربية- ابن الهيثم بجامعة بغداد تم اختيارهم بالطريقة ال

... Show More
View Publication Preview PDF
Crossref
Publication Date
Thu Jul 01 2021
Journal Name
مجلة اداب ذي قار
دور الفضائيات الموجهة الناطقة بالعربية في تشكيل معارف واتجاهات الجمهور العراقي ازاء البرلمان العراقي
...Show More Authors