Scopus İndeksli Yayınlar Koleksiyonu / Scopus Indexed Publications Collection

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

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  • Article
    Citation - WoS: 3
    Citation - Scopus: 5
    Constructal Tree-Shaped Designs for Self-Cooling
    (Edizioni ETS, 2016) Yenigün, Onur; Çetkin, Erdal
    In this paper, we show how a plate which is subjected to a heating load can be kept under an allowable temperature. Vascular channels in which coolant fluid flows have been embedded in the plate. Two types of vascular channel designs were compared: radial and tree-shaped. The effects of channel design on the thermal performance for different volume fractions (the fluid volume over the solid volume) are documented. Changing the design from radial to tree-shaped designs decreases the order of pressure drop. Hence increase in the order of the convection coefficient is achieved. However, treeshaped designs do not bath the entire domain. Therefore, we have inserted additional branches at the uncooled regions. Then, we have compared the peak temperatures of radial, traditional tree-shaped and improved tree-shaped designs. The effect of design on the maximum temperature shows that there should be an optimum design for a distinct set of boundary conditions, and this design should be varied as the boundary conditions change. This result is in accord with the constructal law, i.e. the shape should be varied in order to minimize resistances to the flows.
  • Article
    Citation - WoS: 6
    Citation - Scopus: 6
    The Effect of Cavities and T-Shaped Assembly of Fins on Overall Thermal Resistances
    (International Information and Engineering Technology Association, 2017) Çetin, Eylem; Çetkin, Erdal
    In this study, authors show that maximum excess temperature on a heat generating cylindrical solid domain can be minimized with numerically optimized rectangular cavities and T-shaped fins. The effect of the cavities and the fins on overall thermal resistances were compared while their volume fraction in a unit volume element is fixed. Furthermore, the designs correspond to the minimum thermal resistance were uncovered for two types of flows; parallel and cross-flow. The governing equations of the heat transfer and the fluid flow were solved simultaneously in order to show the effects of design on the flow characteristics and the thermal performance. Two-dimensional solution domain was used to uncover the thermal performance in cross-flow case because the flow direction is perpendicular to the heat transfer surface area of the heat generating domain. However, three-dimensional domain was used in parallel flow case because the fluid flows along the outer surface of the heat generating domain. For the cross-flow case, the results show that T-shaped assembly of fins with longer stem and shorter tributaries correspond to the lower peak temperature. In addition, the results also show that there is an optimal cavity shape that minimizes the peak temperature. This optimal shape becomes thinner when the number of the cavities increase. In parallel flow case, fins with thicker and shorter stem and longer tributaries correspond to the minimum excess temperature. In addition, the longer and thinner cavities increase the thermal performance in parallel flow case.