8 research outputs found
CHARACTERISTICS OF HEAT TRANSFER AND PRESSURE DROP IN A CHEVRON-TYPE PLATE HEAT EXCHANGER WITH Al2O3-WATER NANOFLUIDS
No full textIn this study, heat transfer and pressure drop characteristics have been experimentally investigated by using Al2O3-water nanofluids in the chevron-type plate heat exchanger. The purpose of the experiments was to determine the heat transfer coefficient and pressure drop for different flow rates of 90, 120, 150, 180, 240, and 300 kg/h and different volume concentrations of 0.25%, 0.5%, 0.75%, and 1% of the nanofluids. The Nusselt number of the nanofluids increased with the increasing volume concentration and flow rate at constant hot water flow rate and constant inlet temperatures. The increase in the Nusselt number is 42.4% when compared to distilled water at the maximum volume concentration and Reynolds number (600 <= Re <= 1900) in the nanofluids plate heat exchanger. It has been concluded that nanofluids enhanced the heat transfer significantly and pressure drops at the maximum volume concentration and the Reynolds number increased by between 6.4% and 8.4% compared to distilled water
Numerical Investigation of Forced Convection Heat Transfer Performance of Al2O3 Water Nanofluids in Plate Heat Exchanger Channel
No full textComputational investigation of the velocity and temperature fields in corrugated heat exchanger channels using RANS based turbulence models with experimental validation
No full textÖzçelik, Güven (Arel Author)The characteristics of convective heat transfer and friction factor for periodic corrugated channels are investigated numerically. In the numerical study, the finite volume method (FVM) is used. Three different Reynolds averaged numerical simulation (RANS) based turbulent models, namely the k-omega, the shear stress transport (SST) model and the transition SST model are employed and compared with each other. Experimental results obtained from a previous study are used for the assessment of the numerical results. Investigations are performed for air flowing through corrugated channels with an inclination angle of 30 degrees. The Reynolds number is varied within the range 2,000 to 11,000, while keeping the Prandtl number constant at 0.70. Variations of the Nusselt number, Colburn factor, friction factor and goodness factor with the Reynolds number are studied. Effects of the corrugation geometry and channel height are discussed. The overall performances of the considered turbulence model are observed to be quite similar. The SST model is observed to show a slightly better overall performance
Application of artificial neural network to predict specific fuel consumption and exhaust temperature for a Diesel engine
No full textThe ability of an artificial neural network model, using a back propagation learning algorithm, to predict specific fuel consumption and exhaust temperature of a Diesel engine for various injection timings is studied. The proposed new model is compared with experimental results. The comparison showed that the consistence between experimental and the network results are achieved by a mean absolute relative error less than 2%. It is considered that a well-trained neural network model provides fast and consistent results, making it an easy-to-use tool in preliminary studies for such thermal engineering problems. (c) 2005 Elsevier Ltd. All rights reserved
Application of artificial neural network to predict specific fuel consumption and exhaust temperature for a Diesel engine
No full textThe ability of an artificial neural network model, using a back propagation learning algorithm, to predict specific fuel consumption and exhaust temperature of a Diesel engine for various injection timings is studied. The proposed new model is compared with experimental results. The comparison showed that the consistence between experimental and the network results are achieved by a mean absolute relative error less than 2%. It is considered that a well-trained neural network model provides fast and consistent results, making it an easy-to-use tool in preliminary studies for such thermal engineering problems. (c) 2005 Elsevier Ltd. All rights reserved
Relationship Between Mean Platelet Volume and Varicocele: A Preliminary Study
No full textOBJECTIVE To examine the relationship between the mean platelet volume (MPV) and varicocele to clarify the etiopathogenesis of varicocele. METHODS MPV levels were measured in 60 varicocele subjects (group I) and 57 healthy controls (group II) from 2009-2010. Ages were similar between the 2 groups. The diagnosis of varicocele was based on the findings from both physical examination and color Doppler ultrasound. RESULTS The average patient age at the time of examination was 28.12 +/- 6.4 years in group I and 28.10 +/- 5.8 in group II. MPV levels were statistically significantly higher in group I than in group II (P < .001). Positive correlations were found between MPV and varicocele grade as between MPV and diameter of left spermatic vein (P < .05). CONCLUSION The increase in MPV is independent of the disease, and the increase in varicocele grade is associated with higher MPV in varicocele patients. On the basis of the importance of the vascular component in the pathophysiology of varicocele, we would suggest conducting more studies with platelets in varicocele patients. UROLOGY 79: 1048-1051, 2012. (C) 2012 Elsevier Inc
Mawlawi sulûk according to the Jazeera-i Mathnawi̇ and its commentaries
No full textDoktora Tezi. YÖK Tez Merkezi No: 383593Bu çalışmada XVI. Yüzyıl Mevlevî şeyhlerinden Yûsuf Sîneçâk'ın Cezîre-i Mesnevî Adlı seçkisi ve şerhlerine göre Mevlevî Sülûkü incelenmiştir. Çalışma, bir giriş, üç bölüm ve eklerden oluşmaktadır. Giriş bölümünde, çalışmanın amacı, kapsamı ve kaynaklarının yanısıra Mesnevî'nin irşâd yönü ve XVI. Yüzyıla kadar Mesnevî üzerine yapılmış olan çalışmalar incelenmiştir. Birinci bölüm Yûsuf Sîneçâk'a tahsis edilmiştir. Burada müellifin hayatı, eserleri, tasavvufî kişiliği ve etkileri incelenmiştir. İkinci bölüm, çalışmanın çerçevesi olan Cezîre-i Mesnevî ve şerhlerinin incelenmesine tahsis edilmiştir. Burada Osmanlı telif geleneğine değinilerek, telif türlerinden "metin" ve "şerh" konusu incelenmiş, Osmanlı'da Mesnevî şerhlerinin genel özellikleri ele alınmıştır. Cezîre-i Mesnevî ve şerhleri ise genel olarak; yazılış sebepleri ve temel özellikleri bağlamında incelenmiş, nüshaları tesbit edilmiştir. Üçüncü bölüm, Mevlevî sülûküne tahsis edilmiştir. Burada öncelikle çeşitli başlıklar altında "sülûk" konusu ele alınarak incelenmiştir. Mevlevî sülûkü ise müellifin izlediği sülûk tertibine riâyetle, vatan-ı aslîyi talep, tezkiye, tasfiye ve aşk süreçleri sıralamasına göre incelenmiştir. Ekler bölümünde, Sîneçâk Dede'nin, Abdülbâki Gölpınarlı'nın Mevlânâ'dan Sonra Mevlevîlik adlı eserinde yer almayan bir kaç şiirine yer verilmiştir. Ayrıca Sîneçâk Dede'nin kabrinin iki ve son türbedâr Muhammed İslamoğlu'nun bir fotoğrafına yer verilmiştir.In this study, one of the XVI. Century Mawlawi sheikhs, Yusuf Sînechak's collection called Jazeera-i Mathnawi and according to its commentaries Mawlawi Sulûk/spiritual journey have been studied. The study consists of an introduction, three chapters and appendixes. In the introduction, in addition to the aim, scope and resources of the study; the guidance aspect of the Mathnawi and works on it authored until the XVI. Century have been examined. First chapter has been allocated to Yûsuf Sînechâk. The life, works and the sufistic personality of the author have been studied here. Second chapter has been allocated to the examination of Jazeera-i Mathnawi and its commentaries, which compromises the framework of the study. Mentioning the Ottoman authoring tradition here, we have reviewed the issues of "text" and "commentary" among the authoring types and dealt with the general aspects of Mathnawi commentaries during the Ottoman Era. Jazeera-i Mathnawi and its commentaries have been generally examined in terms of underlying reasons of authoring and its basic features, in addition to determining its editions. Third chapter has been assigned to the Mawlawî Sulûk. First, the issue of "sulûk" has been studied under various headings. Then, Mawlawi Sulûk has been studied according to the sulûk contexture of the author in the order of the processes of "demanding the main homeland", "clearance", "purification", and "love". In the appendixes chapter, several poems of Sînechâk Dede, which don't exist in Abdulbaki Golpinarli's work called "Mevlânâ'dan Sonra Mevlevîlik" have been included. Moreover, two photos of Sînechâk Dede's grave and a photo of the last tomb keeper, Muhammed İslamoglu, have been included
