Plakalı Kanatçıklı Isı Değiştiricilerde Kanat Geometrisinin Isı Transferine Olan Etkisinin Üç Boyutlu Sayısal Olarak İncelenmesi

Bu çalışmada, plakalı kanatçıklı ısı değiştiricilerde ısı transferini artırmak için birleşik ısı transferi yaklaşımıyla zikzak (B tipi) ve iç-dış zikzak (C tipi) olmak üzere iki farklı dikdörtgensel kanatçık tipinin ısı transferine olan etkileri ve basınç hesaplamalar, üç boyutlu Navier-Stokes ve enerji denkleminin FLUENT programı kullanılarak çözülmesiyle zamandan bağımsız olarak elde edilmiştir. Çalışma akışkanı olarak hava kullanılmıştır. Çalışmada, paralel ve ters akış şartlarında Reynolds sayısının farklı değerlerinin ve kanatçık yüksekliğinin ısı transfer artışı üzerindeki etkisi ve ayrıca soğuk ve sıcak akışkanların sıcaklık dağılımları da incelenmiştir. Sonuçlar soğuk akışkan sıcaklığının ters akış durumunda iç-dış zikzak kanatçıklı kanalda düz kanala göre kanal çıkışında % 8.4, paralel akış durumunda ise zikzak kanatçıklı kanalda yine düz kanalla karşılaştırıldığında % 7.6' lık artış elde edildiğini göstermektedir.

The Three Dimensional Numerical Investigation of the Effect of Fin Geometry on the Heat Transfer in Plate Fin Heat Exchangers

In the present study, the effects of two different types of rectangular fins with zigzag (B type) and inner-outer zigzag (C type) for heat transfer enhancement with the use of a conjugated heat transfer approach and pressure drops are numerically evaluated in plate fin heat exchangers. The numerical computations are performed by solving a steady, threedimensional Navier-Stokes equation and an energy equation by using Fluent software program. Air is taken as a working fluid. On heat transfer enhancement the effect of different values of Reynolds number and fin heights and also temperature distributions of the hot and cold fluids are investigated for parallel and counter flow in the study. The results show that cold fluid temperature is enhanced by 8.4 % at the exit of the channel with inner-outer zigzag fin for counter flow, it is increased by 7.6 % at the exit of the channel with zigzag fin for parallel flow when compared to channel without fin.

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