Scopus İndeksli Yayınlar Koleksiyonu / Scopus Indexed Publications Collection
Permanent URI for this collectionhttps://hdl.handle.net/11147/7148
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Conference Object Si-Geothermometry Applied for the Interpretation of Three-Components Mixtures in Marine Geothermal Systems -Exploration of the Gülbahce Geothermal Field, Western Anatolia/ Turkey(Wydawnictwo Uczelniane Politechniki Szczecinskiej, 2000) Giese, L.B.; İlken, Zafer; Çetiner, Levent; Yıldırım, NazımThe geothermal field of Gülbahce is located in western Anatolia/Turkey near Izmir. The University of Izmir IYTE is building-up a campus there. A pre-study was done to investigate whether the campus can be supplied with geothermal heat. Based on hydrogeochemical data, mixing calculations and a modified version of the SiO2-enthalpy diagram were applied to evaluate the reservoir temperature of three-components-mixtures. The temperature of the mixed outcrop water is 35°C. It consists of geothermal sea water, freshwater, and cold sea water. The fraction of freshwater was estimated to be 8%, The contents of Li and Si were interpreted to be generated by the reservoir temperature of 60°C in minimum - lower limit for low-temperature space heating - but to be maybe more than 100°C. This geothermal resource seems to be suitable, but exploitation will be difficult. One production well should satisfy the heat supply. Problems with scaling and corrosion are expected.Article Citation - WoS: 12Citation - Scopus: 16Numerical Optimization of a Fin-Tube Gas To Liquid Heat Exchanger(Elsevier Ltd., 2012) Bilir, Levent; İlken, Zafer; Erek, AytunçThe influence of plate fin, fin tube and protrusion parameters on heat transfer and pressure drop characteristics of a finned tube gas to liquid heat exchanger is examined in this study. The optimization of plate fin, fin tube and protrusion dimensions as well as protrusion locations on plate fin surface is performed numerically using a computational fluid dynamics (CFD) program named "Fluent". The dimensions of the plate fin of a commercially available combi boiler apparatus heat exchanger are taken as basic dimensions. As the first step, the best plate fin and fin tube geometry is determined. Secondly, the best dimensions for three different protrusions (balcony, winglet and imprint) and their most suitable locations on the plate fin surface are found. Finally, the cumulative effects of several combinations of these three protrusions on the plate fin surface are analyzed. The placement combinations of protrusions are decided according to the results obtained for the individual effect of each protrusion. The fin named as I5B2W3 is found to be the most efficient fin among the investigated cases. A comparison with a numerical and computational study is also performed to validate the numerical results of the present study. © 2011 Elsevier Masson SAS. All rights reserved.Article Citation - WoS: 15Citation - Scopus: 17Heat Transfer and Pressure Drop Characteristics of Fin-Tube Heat Exchangers With Different Types of Vortex Generator Configurations(Begell House Inc., 2010) Bilir, Levent; Özerdem, Barış; Erek, Aytunç; İlken, ZaferA fin-and-tube heat exchanger with three different types of vortex generators is investigated in this study in order to observe the effects of these vortex generators on heat transfer and pressure drop characteristics. The individual as well as the cumulative influences of the vortex generators on the performance of a heat exchanger are examined. The numerical analyses are performed using a computational fluid dynamics (CFD) program named "Fluent". Firstly, each vortex generator type is placed at four different locations on the fin to determine its best location in terms of heat transfer and pressure drop values. After the determination of the best location on the fin for a vortex generator of each type, two different models with all three types of vortex generators are created and analyzed numerically. The investigation of the cumulative effect of three different vortex generators is the novelty of the study. The results of the study show that the use of three different vortex generators together increases heat transfer rate with a moderate increase in pressure drop value. The comparison of the present study results with an experimental and numerical study showed also a good agreement. © 2010 by Begell House, Inc.Other Citation - WoS: 1Citation - Scopus: 1Erratum To "total Solidification Time of a Liquid Phase Change Material Enclosed in Cylindrical/Spherical Containers" [applied Thermal Engineering 25 (10) (2005) 1488-1502] (doi:10.1016/J.applthermaleng.2004.10.005)(Elsevier Ltd., 2007) Bilir, Levent; İlken, ZaferRefers To Levent Bilir, Zafer İlken Total solidification time of a liquid phase change material enclosed in cylindrical/spherical containers Applied Thermal Engineering, Volume 25, Issue 10, July 2005, Pages 1488-1502Article Citation - WoS: 84Citation - Scopus: 96Total Solidification Time of a Liquid Phase Change Material Enclosed in Cylindrical/Spherical Containers(Elsevier Ltd., 2005) Bilir, Levent; İlken, ZaferThis study investigates the inward solidification problem of a phase change material (PCM) encapsulated in a cylindrical/spherical container with a third kind of boundary condition. The governing dimensionless equations of the problem and boundary conditions are formulated and solved numerically by using enthalpy method with control volume approach. The problem is solved many times for different values of the affecting parameters and data sets are obtained for dimensionless total solidification time of the PCM. These data sets are then used to derive correlations which express the dimensionless total solidification time of the PCM in terms of Stefan Number, Biot Number and Superheat Parameter.Article Citation - WoS: 152Citation - Scopus: 172Experimental and Numerical Investigation of Thermal Energy Storage With a Finned Tube(John Wiley and Sons Inc., 2005) Erek, Aytunç; İlken, Zafer; Acar, Mehmet AliA latent heat thermal energy storage system using a phase change material (PCM) is an efficient way of storing or releasing a large amount of heat during melting or solidification. It has been determined that the shell-and-tube type heat exchanger is the most promising device as a latent heat system that requires high efficiency for a minimum volume. In this type of heat exchanger, the PCM fills the annular shell space around the finned tube while the heat transfer fluid flows within the tube. One of the methods used for increasing the rate of energy sto rage is to increase the heat transfer surface area by employing finned surfaces. In this study, energy storage by phase change around a radially finned tube is investigated numerically and experimentally. The solution of the system consists of the solving governing equations for the heat transfer fluid (HTF), pipe wall and phase change material. Numerical simulations are performed to investigate the effect of several fin parameters (fin spacing and fin diameter) and flow parameter (Re number and inlet temperature of HTF) and compare with experimental results. The effect of each variable on energy storage and amount of solidification are presented graphically.Article Citation - WoS: 101Citation - Scopus: 132Effect of Geometrical Parameters on Heat Transfer and Pressure Drop Characteristics of Plate Fin and Tube Heat Exchangers(Elsevier Ltd., 2005) Erek, Aytunç; Özerdem, Barış; Bilir, Levent; İlken, ZaferIn this study, the influences of the changes in fin geometry on heat transfer and pressure drop of a plate fin and tube heat exchanger are investigated, numerically. A computational fluid dynamics (CFD) program called Fluent is used in the analysis. The segment of one tenth of fin is used in the modeling, due to symmetrical condition. The results of heat transfer, static, and total pressure drop values of ten different fins are tabulated and the normalized values of them are, also, given for the comparison of the models. The distance between fins is found to have a considerable effect on pressure drop. It is observed that placing the fin tube at downstream region affects heat transfer positively. Another important result of the study is that increasing ellipticity of the fin tube increases the heat transfer while it, also, results in an important reduction in pressure drop.