Effect of Different Dimpled Fin Configurations and Angles on Entropy Generation, Flow Behavior, and Thermal Performance

Abstract

Recent studies highlight that flow in tubes with dimpled fins provides significant thermal performance improvement. Although the variety of these fins comes to the fore today, there is no comprehensive study on which geometry provides better performance. In this study, the heat transfer, entropy generation, and performance effects of dimpled fins with 6 different geometries and 17 different configurations, machined on a smooth tube and having the same surface area, were numerically analysed under steady-state, thermally and hydrodynamically developing flow conditions. Water has been considered as working fluid and it flowed under laminar conditions (1000≤Re≤2000). According to obtained results, the cube-shaped dimpled fins arranged as parallel to flow (CuDT/C) exhibit the highest average Nusselt number, with increases of 95.21%, 176.25%, and 272.13% for Re=1000, 1500, and 2000, respectively, compared to smoot tube. It has been determined that CuDT/C increases the performance evaluation criterion at the rates of 65.94%, 115.96%, and 176.79% for Re=1000, 1500, and 2000, respectively.

Keywords

• Different dimpled fin types
• Entropy generation
• Laminar flow regime
• Performance evaluation criterion
• Thermo-hydraulic performance

Farklı ÇukurlKanat Konfigürasyonları ve Açılarının Entropi Üretimi, Akış Davranışları ve Termal Performans Üzerindeki Etkisi

Abstract

Son yapılan çalışmalar, çukurlu kanatçıklara sahip kanallardaki akışın önemli ölçüde termal performans iyileştirmesi sağladığını vurgulamaktadır. Ancak günümüzde bu kanat çeşitliliği öne çıkmasına rağmen, hangi geometrinin daha iyi performans sağladığına dair kapsamlı bir çalışma bulunmamaktadır. Bu çalışmada, düz boru üzerinde işlenmiş ve aynı yüzey alanına sahip 6 farklı geometri ve 17 farklı konfigürasyonuna sahip çukur kanatların, ısı transferi, entropi üretimi ve performans etkileri, sürekli durum, ısıl ve hidrodinamik olarak gelişen akış koşullarında sayısal olarak analiz edilmiştir. Çalışma akışkanının su olduğu ve laminer koşullar altında (1000≤Re≤2000) akışın gerçekleştiği varsayılmıştır. Elde edilen sonuçlara göre akışa paralel olarak düzenlenmiş küp şekilli çukur kanatlar (CuDT/C), en yüksek ortalama Nusselt sayısını sağlamıştır ve düz kanal ile kıyaslandığında Re=1000, 1500 ve 2000 için sırasıyla %95,21, %176,25 ve %272,13 artışlar kaydedilmiştir. CuDT/C’nin performans değerlendirme kriterini Re=1000, 1500 ve 2000 için sırasıyla %65,94, %115,96 ve %176,79 oranlarında artırdığı belirlenmiştir.

Keywords

• Entropi üretimi
• Farklı çukur kanat tipleri
• Laminer akış rejimi
• Performans değerlendirme katsayısı
• Termo-hidrolik performans.

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