Türbülanslı Akış Durumunda Isı Kuyusunun İğne Kanatçığının Adım Oranının ve Köşegen Uzunluğunun Konvektif Isı Transferine Etkisi

Abstract

Bu çalışmada, türbülanslı akış rejimi altında ısı kuyusunun termo-hidrolik performansını belirlemek için ısı kuyusu üzerindeki iğne kanatçığın köşegen uzunluğu ve adım oranının etkisi sayısal olarak araştırılmıştır. Genel kanatçık tiplerine kıyasla daha az basınç düşümüne sebep olduğu için iğne kanatçık kullanımı tercih edilmiştir. Geometrik paramtere olarak, adım oranı 0.75 ≤ P/e ≤ 1.1 değiştirilirken, iğne kanatçığın köşe uzunluğu 3 ≤ Lef ≤ 6 olarak değiştirilmiştir. Çalışma aralığı türbulanslı akış rejimi olarak düşünülmüştür (2658 ≤ Re ≤ 7138). Hesaplamalı çalışmada RANS denklemlerini çözmek için low-Re düzeltme modeli ile SST k-ω kullanılarak ANSYS Fluent 2020R2 üzerinde gerçekleştirilmiştir. Termo-hidrolik performansı ifade eden ortalama Nusselt sayısı, Ortalama Darcy sürtünme faktörü ve termal rezistans gibi faktörler detaylıca ele alınmıştır. Ayrıca, akış karakteristiğini detaylıca inceleyebilmek için girdap ve sıcaklık eş eğrileri ve hız akış çizgileri oluşturulmuştur. Genel değerlendirme sonucu olarak, Re=7138’de maksimum konvektif ısı transferi performansı Case 1’e kıyasla %52 oranla Case 12 kullanılarak elde edilmiştir.

Keywords

• Isı kuyusu
• Altıgen iğne kanatçık
• Konvektif ısı transferi
• HAD

Effect of Pitch Ratio and Diagonal Length of Pin Fin of Heat Sink on Convective Heat Transfer for Turbulent Flow Condition

Abstract

In this study, the impact of pitch ratio and diagonal length of pin fin on the heat sink has been numerically investigated to determine the thermo-hydraulic performance of heat sink under turbulent flow regime. Usage of pin fin on the heat sink has been preferred due to less pressure drop in comparison with general fin type. While the pitch ratio has been changed 0.75 ≤ P/e ≤ 1.1, the length of edge of fin has been changed 3 ≤ Lef ≤ 6 as geometric parameters. The working range of the study has been considered as turbulent flow regime (2658 ≤ Re ≤ 7138). The computational study has been carried out on ANSYS Fluent 2020R2 using SST k-ω with low-Re correction model to calculate RANS equations. The factors, which define thermo-hydraulic performance of the study, such as average Nusselt number, average Darcy friction factor, and thermal resistance has been elucidated in detail. Also, to detect flow characteristics comprehensively, the contours have been created for vorticity, temperature, and velocity streamline. As a results of overall assessment of this study, it is concluded that the maximum convective heat transfer performance has been obtained using Case 12 by 52% compared with the Case 1 at Re=7138.

Keywords

• Heat sink
• Hexagonal pin fin
• Convective heat transfer
• CFD.

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