The present study involves experimental analysis of the modified Closed Wet Cooling Tower (CWCT) based on first and second law of thermodynamics, to gain a deeper knowledge in this important field of engineering in Iraq. For this purpose, a prototype of CWCT optimized by added packing under a heat exchanger was designed, manufactured and tested for cooling capacity of 9 kW. Experiments are conducted to explore the effects of various operational and conformational parameters on the towers thermal performance. In the test section, spray water temperature and both dry bulb temperature and relative humidity of air measured at intermediate points of the heat exchanger and packing. Exergy of water and air were calculated by applying the exergy destruction method on the cooling tower. Experimental results showed a significant performance improvement when using packing on the CWCT. It can be observed that the thermal efficiency for the CWCT with packing under a heat exchanger and CWCT with packing above the heat exchanger are approximately 40% and 25% higher than that of the CWCT without packing respectively. As another part of the experiment results, it is indicated that the exergy destruction is directly proportional to air flow rate, cooling water flow rate, inlet cooling water flow rate and inlet Air Wet Bulb Temperature (AWBT) whereas, it is inversely proportional with spray water flow rate. In comparison with the cooling capacity of the tower, it was found that the exergy destruction approximately less than 20%. Exergy efficiency behavior is inversely proportional with the behavior of the exergy destruction. Empirical correlations are obtained to predict water film heat transfer coefficient and air-water mass transfer coefficient considering the influences of operational parameters.
أهمية البحث والحاجة إليه :
يعد نسيان المثيرات المعلوماتية التي يتعلمها أو يطلع عليها الفرد في حياته من المشكلات التي يعاني منها الأفراد في جميع مناحي الحياة وليس في مجال الدراسة الأكاديمية فحسب. وبالتالي فان هناك حاجة ملحة ومهمة لابتداع طرائق ووسائل وإمكانيات يمكن عن طريقها التقليل من نسيان المثيرات المعلوماتية المختلفة التي يتعلمها الفرد في حياته اليومية.
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Among the metaheuristic algorithms, population-based algorithms are an explorative search algorithm superior to the local search algorithm in terms of exploring the search space to find globally optimal solutions. However, the primary downside of such algorithms is their low exploitative capability, which prevents the expansion of the search space neighborhood for more optimal solutions. The firefly algorithm (FA) is a population-based algorithm that has been widely used in clustering problems. However, FA is limited in terms of its premature convergence when no neighborhood search strategies are employed to improve the quality of clustering solutions in the neighborhood region and exploring the global regions in the search space. On the
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Due to the importance of the word and because it is the basic building block from which speech is formed, it has become the subject of the attention of many scholars, ancient and modern
The objective of the research is to find the best method to estimate rice crop through out evaluating the applied methods of stratified random sampling .By using different sorts of sampling estimators, a comparison was held among the variances of the mean for simple random sampling, stratified random sampling(var()) and separate regression estimator. The results indicate that the separate regression estimator give best estimations. The approximate cum.f4/5 method was used to determine the optimum stratum boundaries, new strata was put and then var () was calculated .In comparison with strata used nowadays in central statistical organization, the new strata led to obvious decrease in the variance. The stratified mean wa
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أن هذه الدراسة هي دراسة نظرية اهتمت بتقديم مدخل معاصر لمنظمات الأعمال، يمكن أن يعتمد علية من أجل تحقيق الريادة و البقاء. وذلك من خلال اعتماد مدخل الهدم الخلاق و تقديم أنموذج قادر على التفاعل مع البيئة بكل ما تقدمه من فرص وتحديات.
وتم تقسيم هذه الدراسة إلى ثلاثة مباحث،تناول المبحث الأول منهجية الدراسة. وبينما تناول المبحث الثاني توضيح مفهوم الهدم الخلاق والعناصر المكونة لهذا المدخل وأخيراً
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Ibn Khaldun is one of the best Arab Muslims scientists who participated in establishing Arabic Muslims heritage in all different disciplines & directions specially in sociology, neurological & his political theories which showed the development of Arabic philosophy in all scientific disciplines specially his introduction
Abook of alzmkchri (AL-Mefsal) considers one of the most book familiarities among grammarians whom begin to explain it importance kitab AL-Takhmair for Khwarizmi separated opinions in grammatical schools that dealt with.
Arabic humanity heritage had considered as a treasure of artistic, literary aspects, which is full of energies to embody investment by suitable historical ideology.
Theatre, art can be used, corresponded to make special essay reflecting a desire to establish cultural notification.
السياسة الداخلية لعراق ما بعد الانتخابات 2010 دراسة في الثوابت والمتغيرات
The historian, Professor Dr. Abdullah Al-Fayyad, left a huge legacy of knowledge product that scholars and stakeholders benefited from in the field of Islamic historical and modern studies,