KENARLARINDA ISINMIŞ EŞKENAR ÜÇGEN ENGEL ÇİFTİ BULUNAN DİKEY BİR KANALDAKİ KARIŞIK TAŞINIM ISI TRANSFERİNİN ARTIRILMASININ İNCELENMESİ

Öz

Bu çalışmada, birbirine paralel dikey levhalar üzerinde ikişer tane olmak üzere simetrik şekilde toplamda dört tane eşkenar üçgen geometrili sabit ısı akılı elektronik engel bileşenlerinin bulunduğu bir kanalda karışık taşınımla ısı transferi ve engeller etrafındaki akışkan hareketi sayısal olarak araştırılmıştır. Sayısal inceleme, zamandan bağımsız, laminer ve iki boyutlu olarak süreklilik, momentum ve enerji denklemlerinin Ansys-Fluent bilgisayar programı kullanılarak çözülmesiyle yapılmıştır. Akışın kanal içerisindeki ısınmış engel elemanlarına yönlendirilmesi amacıyla kanalın üst giriş yüzeylerine 30o, 45o ve 60o açılarında akış yönlendirici kanatçıklar yerleştirilmiştir. Kanalın engel elemanı hariç diğer yüzeyleri ve akış yönlendiriciler adyabatiktir. Kanalda çalışma akışkanı olarak 293 K giriş sıcaklığında su kullanılmıştır. Çalışmadaki Reynolds sayısı (Re) değerleri 100, 300 ve 500 iken; değiştirilmiş Richardson sayısı (Ri*) aralığı 50-150 ve Akış Geçiş Mesafesi (AGM) oranları 2 ve 4 olarak alınmıştır. Çalışmanın sonuçları, literatürdeki deneysel ve sayısal sonuçlarla karşılaştırıldığında oldukça uyumlu oldukları görülmüştür. Ri*=50, Re=100 ve AGM=4 için 60o açılı kanalda elde edilen Num değerinin AGM=2’deki değerinden %32,88 daha fazla olduğu belirlenmiştir. Ayrıca, AGM=2, Re=500 ve Ri*=150 için kanatçıksız durumla kıyaslandığında 30o, 45o ve 60o açılı kanatçıklı durumlarda ∆p değerlerinin sırasıyla %9,06, %9,04 ve %9,66 daha yüksek oldukları bulunmuştur.

Anahtar Kelimeler

• Karışık taşınım
• Kanatçık
• Richardson sayısı
• Eşkenar üçgen engel
• Isı transferi

Investigation of the Increase of Mixed Convection Heat Transfer In A Vertical Channel with Warmed Equilateral Triangular Obstacle Pair on Edges

Öz

In this study, mixed convection heat transfer and fluid movement around the obstacles were numerically investigated in a channel where electronic barrier components have a total of four equilateral triangular geometries with constant heat flux, two symmetrically on parallel vertical plates. Using the Ansys-Fluent computer program, a numerical analysis was carried out by solving steady, laminar and twodimensional continuity, momentum and energy equations. Flow-directing fins were placed on the upper entrance surfaces of the channel at angles of 30o, 45o and 60o to direct the flow to the heated obstacle elements in the channel. Except for the obstacle element, other surfaces of the channel and flow directors are adiabatic. Water with an inlet temperature of 293 K was used as the working fluid in the channel. While the Reynolds number (Re) values in the study were 100, 300 and 500; the modified Richardson number (Ri*) range was taken as 50-150 and the Flow Transition Distance (FTD) ratios were taken as 2 and 4. The study's results were compared with the experimental and numerical results in the literature and found to be quite compatible. For Ri*=50, Re=100 and AGM=4, the Num value obtained in the 60o-angle channel was 32.88% higher than in AGM=2. Additionally, ∆p values were found to be 9.06%, 9.04% and 9.66% higher in cases with 30o, 45o and 60o angle fins, respectively, compared to the case without fins for FTD=2, Re=500 and Ri*=150.

Anahtar Kelimeler

• Mixed convection
• Fin
• Richardson number
• Equilateral triangle obstacle
• Heat transfer

Kaynakça

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