Scopus İndeksli Yayınlar Koleksiyonu / Scopus Indexed Publications Collection

Permanent URI for this collectionhttps://hdl.handle.net/11147/7148

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COAR Access Rights: search.filters.coarAccessRights.open accessSubject: search.filters.subject.Heat exchangers

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Now showing 1 - 4 of 4
  • Article
    Citation - WoS: 7
    Citation - Scopus: 9
    Effects of Thermal Dispersion on Heat Transfer in Cross-Flow Tubular Heat Exchangers
    (Springer Verlag, 2012) Sano, Y.; Kuwahara, F.; Mobedi, Moghtada; Nakayama, A.
    Effects of thermal dispersion on heat transfer and temperature field within cross-flow tubular heat exchangers are investigated both analytically and numerically, exploiting the volume averaging theory in porous media. Thermal dispersion caused by fluid mixing due to the presence of the obstacles plays an important role in enhancing heat transfer. Therefore, it must be taken into account for accurate estimations of the exit temperature and total heat transfer rate. It is shown that the thermal dispersion coefficient is inversely proportional to the interstitial heat transfer coefficient. The present analysis reveals that conventional estimations without consideration of the thermal dispersion result in errors in the fluid temperature development and underestimation of the total heat transfer rate. © Springer-Verlag 2011.
  • Article
    Citation - WoS: 18
    Citation - Scopus: 24
    Forced Convection Heat Transfer Inside an Anisotropic Porous Channel With Oblique Principal Axes: Effect of Viscous Dissipation
    (Elsevier Ltd., 2010) Mobedi, Moghtada; Çekmer, Özgür; Pop, Ioan
    An analytical study on laminar and fully developed forced convection heat transfer in a parallel-plate horizontal channel filled with an anisotropic permeability porous medium is performed. The principal axis of the anisotropic porous medium is oriented from 0 to 90 degrees. A constant heat flux is applied on the outer wall of the channel. Both clear (Newtonian) fluid and Darcy viscous dissipations are considered in the energy equation. Directional permeability ratio parameter A* is defined to combine both the effect of the dimensionless permeability ratio parameter K*=(K 1/K2) and orientation angle φ into one parameter. The effects of the parameter A*, the Darcy number Da and the modified Brinkman number Br* on the heat transfer and fluid flow characteristics in the channels are investigated and presented in graphs. The obtained results show that the parameters A*, Da and Br* have strong effects on the dimensionless normalized velocity and temperature profiles as well as on the Nusselt number. It is found that for a particular value of A*, called as critical value Acr*, the external heat applied to the surface of the channel is balanced by the internal heat generation due to viscous dissipation and the bulk mean temperature approaches the wall temperature. Hence, the Nusselt number approaches infinity for the critical values A cr*. © 2010 Elsevier Masson SAS. All rights reserved.
  • Article
    Citation - WoS: 15
    Citation - Scopus: 17
    Heat 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, Zafer
    A 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.
  • Article
    Citation - WoS: 101
    Citation - Scopus: 132
    Effect 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, Zafer
    In 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.