Filtreler

2013 - 20162
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Yazar: Karakaya, Hakan × WoS Q: Q1 ×

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  • Küçük Resim
    Öğe
    Heat transfer and exergy loss in conical spring turbulators
    (Elsevier, 2013-05) Karakaya, Hakan; Durmuş, Aydın
    It would be misleading to consider only the construction costs of heat exchangers in their design because high service costs during their service life may also greatly increase total costs. Therefore energy saving aspects are very important in the design, construction and operation of the heat exchangers. For this reason, various active or passive methods have been sought to save energy by increasing the heat transfer coefficients in the cold and warm fluid sides in the heat exchangers. Conical spring turbulators (CST) are devised in this study. Performances of heat transfer and pressure drop in a pipe with the CST are experimentally examined for the CSTs’ angle (θ) of 30°, 45° and 60° in Reynolds number (Re) range of 10,000–34,000. Heat transfer, pressure loss and exergy analysis were made for the conditions with and without turbulators and compared to each other. Some empirical correlations expressing the results were also derived and discussed.
  • Küçük Resim
    Öğe
    Drying of sweet basil with solar air collectors
    (Elsevier, 2016-08) Karakaya, Hakan; Durmuş, Aydın; Fevzi, Gülçimen
    In this study, sweet basil was dried and its drying parameters were investigated experimentally and theoretically by using newly developed solar air collectors. Proper temperatures were chosen to dry sweet basil and experiments were carried out at different flow rates. At the end of drying experiments, it was determined that total mass of sweet basil decreased from 0.250 kg to 0.029 kg. In drying sweet basil, dimensionless moisture ratios were decreased rapidly to 300 min for 0.012 kg/s, 360 min for 0.026 kg/s, and 450 min for 0.033 kg/s. It was observed that the efficiency of collector was increased at the same rate with air flow changed between 29 and 63%. Among the models in the literature, Page Model was found to suit best for drying sweet basil. Furthermore, a novel mathematical model rendering more valid results for sweet basil and leafy products was developed.