Yazar "Aktas, Arif Emre" seçeneğine göre listele

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    An optimization study on thermo-hydraulic performance arrays of circular and diamond shaped cross-sections in periodic flow
    (Pergamon-Elsevier Science Ltd, 2021) Erdinc, Mehmet Tahir; Aktas, Arif Emre; Kuru, Muhammet Nasif; Bilgili, Mehmet; Aydin, Orhan
    In this study, thermo-hydraulic characteristics of arrays of circular and diamond shaped cross-sections in periodic flow are investigated numerically. The main purpose of this study is to configure diamond shaped cross-sections in order to obtain better thermal performance compared to circular shaped cross-section. The optimization frameworks are constructed by using multi-objective genetic algorithm (MOGA) for both circular and diamond shaped cross-sections to obtain maximum heat transfer and minimum pressure drop while keeping the mass flow rate constant. The study can be divided into two parts: Firstly, an optimization study is carried out to achieve an optimum design for the circular type. Later, a new optimization scheme is constructed where the optimum design of circular type's heat transfer and pressure drop values are given as constraints. Thus, the optimization algorithm seeks better thermal performances with respect to the circular one. Moreover, optimum designs are illustrated graphically and given in the tabular form. Compared to circular geometries, it is found that the average Nusselt number of diamond shaped geometry can be increased by 10.11%, while pressure drop and volume of diamond shaped geometries are reduced by 11.90% and 52.76%, respectively.
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    Öğe
    Numerical investigation of flow and heat transfer in axially-finned in-line tube banks
    (Taylor & Francis Inc, 2025) Kuru, Muhammet Nasif; Yilmaz, Alper; Aktas, Arif Emre; Erdinc, Mehmet Tahir
    Numerical analysis of heat and fluid flow over tube bank heat exchangers with axial fins is performed in this work. Finite volume method is used to solve the governing equations numerically. Simulations are carried out in the range of 400-1500 Reynolds number. To ensure the numerical model reliability, unfinned in-line tube bank is simulated and compared with results from the literature. It is shown that the results are in accordance with the experimental studies in the literature. Heat transfer and pressure loss computations are carried out for four different axial and transversal pitch ratios; namely, $$s_L<^>{\rm{*}} = 3$$sL & lowast;=3 and $$s_T<^>{\rm{*}} = 1.5$$sT & lowast;=1.5, $$s_L<^>{\rm{*}} = 3$$sL & lowast;=3 and $$s_T<^>{\rm{*}} = 2$$sT & lowast;=2, $$s_L<^>{\rm{*}} = 5$$sL & lowast;=5 and $$s_T<^>{\rm{*}} = 1.5$$sT & lowast;=1.5, $$s_L<^>{\rm{*}} = 5$$sL & lowast;=5 and $$s_T<^>{\rm{*}} = 2$$sT & lowast;=2. Air and water are used as working fluids for determined mass flow rates where Prandtl numbers are 0.7 and 7, respectively. Moreover, velocity streamlines and temperature contours along the flow field are given. Effects of axial ($$s_L<^>{\rm{*}}$$sL & lowast;) and transversal ($$s_T<^>{\rm{*}}$$sT & lowast;) pitch ratios and fin lengths on the average Nusselt number and friction factor are also presented in graphical forms. It is found that the maximum average Nusselt number is observed at Re = 1500 for the pitch ratios of $$s_L<^>{\rm{*}} = 5$$sL & lowast;=5 and $$s_T<^>{\rm{*}} = 1.5$$sT & lowast;=1.5 where fin length equals to 2D mm. Besides, adding axial-fins to in-line tube bank results in a decrement in friction factors.
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    Öğe
    Optimizing the tube geometry to enhance thermohydraulic performance of tube bank heat exchanger
    (Elsevier France-Editions Scientifiques Medicales Elsevier, 2023) Aktas, Arif Emre; Kuru, Muhammet Nasif; Erdinc, Mehmet Tahir; Aydin, Orhan; Bilgili, Mehmet
    In this study, optimum design parameters of circular, diamond and enhanced shaped geometries for staggered tube banks are explored utilizing a multi-objective genetic algorithm (MOGA-II). For given three geometries, two step optimization studies are compared: (1) circular and diamond shaped geometries, (2) diamond and enhanced shaped geometries. Steady, incompressible, and turbulent flow around three-dimensional numerical models is solved using finite volume method. Initially, using literature experimental data numerical results are validated for circular and diamond geometries. In the optimization studies, maximization of heat transfer and minimization of required pumping power are preferred as objective functions. The results of optimization studies are demonstrated graphically. Furthermore, velocity and temperature distribution for the optimum cases are illustrated. The results of first step optimization studies exhibited that diamond shaped tube bank shows higher heat transfer rate than circular one for the same given volume (156%). Besides, as a result of second step optimization studies, optimal enhanced shaped geometry showed 0.59% higher heat transfer rate, 21.73% lower pumping power requirement and 9.65% lower total tube bank volume than optimal diamond shaped one.