Yazar "Aksoy, Ishak Gokhan" seçeneğine göre listele

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    ADOMIAN DECOMPOSITION METHOD FOR HEAT CONDUCTION IN AN ANNULAR FIN OF HYPERBOLIC PROFILE WITH TEMPERATURE DEPENDENT THERMAL CONDUCTIVITY
    (Turkish Soc Thermal Sciences Technology, 2013) Aksoy, Ishak Gokhan
    The Adomian decomposition method (ADM) is applied to analyze the thermal performance of an annular fin of hyperbolic profile with temperature dependent thermal conductivity. ADM provides the solution in an infinite series with easily computable components. It has been observed that the variation of thermo-geometric fin parameter and the thermal conductivity parameter have a significant effect on the temperature distribution in the fin and its efficiency. For engineering analysis and design, a regression equation is also proposed for fin efficiency as a function of fin radii ratio and thermo-geometric fin parameter. Obtained results are in a good agreement with numerical results of finite difference method (FDM) and exact solution with the constant thermal conductivity.
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    Effect of hot air inclined jet impingement to container for controlling of energy storage of PCM: experimental and numerical investigation
    (Emerald Group Publishing Ltd, 2024) Oztop, Hakan F.; Kiyak, Burak; Aksoy, Ishak Gokhan
    PurposeThis study aims to focus on understanding how different jet angles and Reynolds numbers influence the phase change materials' (PCMs) melting process and their capacity to store energy. This approach is intended to offer novel insights into enhancing thermal energy storage systems, particularly for applications where heat transfer efficiency and energy storage are critical.Design/methodology/approachThe research involved an experimental and numerical analysis of PCM with a melting temperature range of 22 degrees C-26 degrees C under various conditions. Three different jet angles (45 degrees, 90 degrees and 135 degrees) and two container angles (45 degrees and 90 degrees) were tested. Additionally, two different Reynolds numbers (2,235 and 4,470) were used to explore the effects of jet outlet velocities on PCM melting behaviour. The study used a circular container and analysed the melting process using the hot air inclined jet impingement (HAIJI) method.FindingsThe obtained results showed that the average temperature for the last time step at CYRILLIC CAPITAL LETTER EF = 90 degrees and Re = 4,470 is 6.26% higher for CYRILLIC CAPITAL LETTER EF = 135 degrees and 14.23% higher for CYRILLIC CAPITAL LETTER EF = 90 degrees compared with the 45 degrees jet angle. It is also observed that the jet angle, especially for CYRILLIC CAPITAL LETTER EF = 90 degrees, is a much more important factor in energy storage than the Reynolds number. In other words, the jet angle can be used as a passive control parameter for energy storage.Originality/valueThis study offers a novel perspective on the effective storage of waste heat transferred with air, such as exhaust gases. It provides valuable insights into the role of jet inclination angles and Reynolds numbers in optimizing the melting and energy storage performance of PCMs, which can be crucial for enhancing the efficiency of thermal energy storage systems.
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    Nonlinear thermal analysis of serrated fins by using homotopy perturbation method
    (Pamukkale Univ, 2023) Aksoy, Ishak Gokhan
    Thermal analysis of serrated fins which are consist of annular and plain sections are investigated. Serrated fin's thermal conductivity is assumed to change linearly with temperature. Nonlinear differential equations are obtained by applying the energy balance equation for both sections of the serrated fin and these equations are solved by applying homotopy perturbation method. Insulated fin tip, constant fin base temperature and common boundary conditions between the interface of two sections are considered. Serrated fin radii ratio (epsilon), segment height ratio (delta), thermo-geometric fin parameter (psi) and thermal conductivity parameter (beta) effecting the thermal performance and temperature distribution are investigated. The results showed that the homotopy perturbation is a reliable method for the solutions of such nonlinear differential equations. A very good agreement with the homotopy perturbation method and the numerical finite difference method are obtained. It is seen that, serrated fin efficiency lays between annular and rectangular fins and increases with the increase of segment height ratio and thermal conductivity parameter. Such as, fin efficiency values under the condition of epsilon = 2, psi(1) = 1.0 and beta = 0 for delta = 0, 0.5, and 1 are 0.692, 0.718, and 0.762, respectively.
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    A numerical study on the effects of inclination angle and container material on thermal energy storage by phase change material in a thick-walled disc
    (Emerald Group Publishing Ltd, 2024) Kiyak, Burak; Oztop, Hakan Fehmi; Aksoy, Ishak Gokhan
    PurposeThe purpose of this study is to examine the effects of inclination angle on the thermal energy storage capability of a phase change material (PCM) within a disc-shaped container. Different container materials are also tested such as plexiglass and aluminium. This study aims to assess the energy storage capacity, melting behaviour and temperature distributions of PCM with a specific melting range (22 degrees C-26 degrees C) for various governing parameters such as inclination angles, aspect ratios (AR) and temperature differences (Delta T) and compare the melting behaviour and energy storage performance of PCM in aluminium containers to those in plexiglass containers.Design/methodology/approachA finite volume approach was adopted to evaluate the thermal energy storage capability of PCMs. Five inclination angles ranging from 0 degrees to 180 degrees were considered and the energy storage capacity. Also, the melting behaviour of the PCM and temperature distributions of the container with different materials were tested. Two different AR and Delta T values were chosen as parameters to analyse for their effects on the melting performance of the PCM. Conjugate heat transfer problem is solved to see the effects of conduction mode of heat transfer.FindingsThe results of the study indicate that as AR decreases, the effect of the inclination angles on the energy storage capacity of the PCM decreases. For lower Delta T, the difference between the maximum and minimum stored energies was 20.88% for AR = 0.20, whereas it was 6.85% for AR = 0.15. Furthermore, under the same conditions, the PCM stored 8.02% more energy in plexiglass containers than in aluminium containers.Originality/valueThis study contributes to the understanding of the influence of inclination angle, container material, AR and Delta T on the thermal energy storage capabilities of PCM in a novel designed container. The findings highlight the importance of AR in mitigating the effect of the inclination angle on energy storage capacity. Additionally, comparing aluminium and plexiglass containers provides insights into the effect of container material on the melting behaviour and energy storage properties of PCM.