EFFECT OF BLOCKAGE RATIO ON HEAT TRANSFER AND FLOW CHARACTERISTICS OF LAMINAR STEADY FLOW OVER SQUARE CYLINDER

Abstract

Effect of blockage ratio (=B/H) on heat transfer and flow characteristics are investigated for two-dimensional laminar steady flow over a square cylinder (SC) in a confined channel. In the study, while Reynolds number held at Re=40, blockage ratio is changed between =0.125-0.8 values. For numerical calculations, ANSYS CFX 14.0 is used. Effect of blockage ratio on drag coefficient (Cd), friction factor (Cf), dimensionless recirculation length (Lr/B) and average Nusselt number (Nu) values on SC surfaces are investigated. It is found that as the blockage ratio increases drag coefficient (Cd), friction coefficient (Cf), and average Nusselt number (Nu) values increase, but dimensionless recirculation length (Lr/B) values decrease. Equations of drag coefficient (Cd), friction coefficient (Cf), dimensionless recirculation length (Lr/B), and average Nusselt number variation respect to blockage ratio are derived. 

Keywords

• Confined Flow,Square Cylinder,flow characteristics,heat transfer,CFD

KARE SİLİNDİR ÜZERİNDEN LAMİNER SÜREKLİ AKIŞTA BLOKAJ ORANININ ISI TRANSFERİ VE AKIŞ KARAKTERİSTİKLERİNE ETKİSİNİN SAYISAL OLARAK İNCELENMESİ

Abstract

Sınırlandırılmış bir kanal içerisinde yer alan tek kare silindir (KS) üzerinden iki boyutlu laminer sürekli akış için blokaj (=B/H) oranının ısı transferi ve akış karakteristiklerine olan etkisi incelenmiştir. Çalışmada Reynolds sayısı Re=40 değerinde sabit tutulurken blokaj oranı =0.125-0.8 değerleri arasında değiştirilmiştir. Hesaplamalarda ANSYS CFX 14.0 kullanılmıştır. Blokaj oranı etkisinin KS yüzeyleri üzerindeki sürükleme katsayısı (Cd), sürtünme katsayısı (Cf), boyutsuz yeniden birleşme uzunluğu (Lr/B) ve ortalama Nusselt sayısı (Nu) üzerine olan etkileri incelenmiştir. Blokaj oranı arttıkça sürükleme katsayısı (Cd), sürtünme katsayısı (Cf) ve ortalama Nusselt sayısı (Nu) değerlerinin arttığı ancak boyutsuz yeniden birleşme uzunluğu (Lr/B) değerinin azaldığı bulunmuştur. Sürükleme katsayısı (Cd), sürtünme faktörü (Cf), boyutsuz yeniden birleşme uzunluğu (Lr/B) ve ortalama Nusselt sayısı değerlerinin blokaj oranına göre değişimini veren bağıntılar elde edilmiştir.

Keywords

• Sınırlandırılmış Akış,Kare Silindir,Akış Karakteristikleri,Isı Transferi,HAD

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