Abstract The contribution of this thesis is to improve the understanding of flame dynamics in the gas turbine combustor. The dynamic of diffusion flame or the flicker of a flame, as they are called in the research community is an important physical parameter associated with the characteristics of a combustion process. The flicker frequency of a flame reflects its oscillation of radiation, pressure and other characteristics, and plays an important role in flame structure, radiation field and energy efficiency. In addition, flickering frequency could be an indication of flame instability. It is therefore important to be able to measure the flicker of a flame in order to achieve an in depth understanding of the fundamental aspects of combustion processes and to develop a technique suitable for advanced flame monitoring in electrical power generation, gas turbine, boiler, and etc... To understand the phenomena related to thermoacoustic, a simple Rijke-type tube combustor was built and studied. Extensive experimental results, as well as theoretical analyses related to the Rijke tube is presented in this project. The results, attributable to both the analyses and the experiments, help explain all the phenomena affecting the acoustic pressure in the combustor. The conclusion is that there are three separate yet related physical processes affecting the acoustic pressure in the tube. To understand this parameter, a simple system was built and studied. Extensive experimental results are presented in this project to measure a flicker signal. In order to begin to understand what flicker parameter is, it was necessary to collect and analyze the light signal produced by light cell from burner which operates on diffusion flame, the chosen method for data collection was a light data acquisition system, the acquired light signal was then analyzed with Lab VIEW software, the software’s main feature is that it was capable of defining the light signal in many parameters, the most important of which were: power spectrum, cross correlation and the light wave shape. The power spectrum gave a concise presentation of the main frequencies which constituted the flicker signals, and their relative amplitudes. this was very helpful in determining the frequency of the diffusion flame (flicker signal).flame height and flame lift off also have been studied in this project. Finally applied this technique and all this Procedures at alkhoms power plant gas turbine combustor and then we compare the results with other technique like CCD camera and Photomultiplier we option the same results with cheaper devices
محمد عمران محمد (2013)

عند تطبيق سياسات الصيانة تواجه المؤسسات الصناعية والخدمية على حدا سواء تحدى ألا وهو ماهى طريقة الصيانة المثلى والسياسة الأفضل الواجب إتباعها لصيانة النظام بالأخذ في الاعتبار التكاليف ؟ بكلمات أخرى ماهى السياسة المثلى للصيانة التي تحقق التوازن بين تقليل الأعطال والحفاظ على النظام في أحسن الظروف التشغيلية وبأقل تكلفة ممكنة للصيانة.لذلك تشكل تكلفة الصيانة دورا هاما قي عملية المفاضلة عند اختيار وتخطيط سياسات الصيانة. إن حساب تكاليف الصيانة لاى نظام من بداية تشغيله إلى نهاية عمره الافتراضي له أهمية كبيرة للمؤسسة الصناعية ، حيث يضمن لمتخذي القرار حسن التصرف في مصادر رؤؤس الأموال وهذا الأمر مهم جدا خصوصا للدول النامية نظرا لمحدودية توفر إمكانياتها . لذلك يقدم البحث نموذج رياضي مطور لتقدير التكاليف الإجمالية لسياسات الصيانة المتبعة أو المقترحة لنظام ما على طول العمر الافتراضي له ، تقدير عدد الأعطال التي يتعرض لها النظام، تقدير تكلفة المواد المطلوبة لعمليات الصيانة ، تقدير العدد الأمثل لمرات إجراء الصيانة الوقائية بكل فترة من فترات عمر النظام ، ومن خلال البحث نقوم بدراسة وتحليل تأثير العناصر المختلفة للصيانة على معايير الأداء . أيضا يعطى النموذج الرياضي المطور الوقت الأمثل لإجراء العمرة لمعدات النظام بدلا من السياسة التقليدية المتبعة ببعض المؤسسات الصناعية في الدول النامية والتي تعتمد فقط على إجراء عمرة لمعدات النظام بعد فترات زمنية ثابتة بغض النظر عن حالة النظام ومدى احتياجه فعليا لتجديد معداته .ويدعم البحث بدراسة تحليلية وعملية لنظام محطة نقل الطاقة الكهربائية بالشركة العامة للكهرباء كمثال للدراسة . Abstract Through implementation of the maintenance policies, companies face challenge with respect to system maintenance cost, which is how to keep the system in good working condition at low maintenance cost? Thus the tradeoff process between cost and performance of the system plays an important role in the selection of the maintenance policies.This research is intended to achieve the optimum maintenance policies, and to achieve the leverage between system performance and life cycle maintenance cost. It focused on accomplishing the following points:Developing a mathematical model to evaluate maintenance policies through life cycle of the system.Assessing the impact of maintenance parameters on system performance measures.Using the developed model to determine the appropriate overhauling times for the industrial enterprises, actually when the equipments should be overhauled, instead the traditional way, that is performed based on fixed number of years. The model works based on criteria's are set by enterprise's decision makers, such that if the system exceeds certain number of breakdowns through its life cycle, then system must be overhauled. This thing helps the companies saving money. Using appropriate performance measures to evaluate how well the system meets its goals based on the applied maintenance policy. Practical and analytical study of power transmission station's equipments in general electrical company of Libya was presented as a case study.
عماد مختار المصراتي (2009)

Abstract In spite of their widely-spread use across the globe, the domestic solar water heaters are still subject to essential, technical difficulties that need to be deeply studied. Such technical impediments are latent in how appropriate to each other the different, mutually-dependent components of the system are; and how appropriate they are to the prevailing meteorological conditions of the application site which is still under research and development. This thesis presents a clear-cut, straightforward mathematical model that determines the basic factors influencing such systems, and, in specific, discusses the optimum design month as well as the optimum tilt angle of the solar collector, bearing in mind the contribution of the energy obtained to meet the targeted load. Furthermore, the study considers the required thermal capacity that should be provided by the solar collector. To avoid assumptions that could be unjustified in practice, and to get as precise results as possible, the study was thoroughly based on normalized mathematical parameters. In the case where the total demand for energy used in water heating is to be fully satisfied by the solar energy system, provided that the required temperature of the heated water is 45oC and consumption is 100 (litre/day) per person for a given house, the results of the study concluded that according to the climate information of Tripoli city, 32.68°N latitude, the optimum design month is December, the optimum tilt angle is 75°, and the solar collector area fulfilling the following specifications: Glazed type, Fr () = 0.58, and Fr UL= 4.00 (W/m2oC) is 2.83 square meters. On the other hand, the results suggest an optimum tilt angle of 50°, which is the same angle obtained by the traditional technique, and solar collector area of 1.6 square meters if up to 80% of demand is to be covered by solar energy.
علاء بلقاسم العلوني (2010)