Dikdörtgensel Engellerin Dairesel Oluklu bir Kanalın Isıl-Hidrolik Özellikleri Üzerindeki Etkilerinin Sayısal Olarak İncelenmesi

Öz

Bu çalışmada dairesel oluklu bir kanalın alt yüzeyine farklı açılar ve yüksekliklerde yerleştirilen dikdörtgensel engellerin kanalın ısıl-hidrolik özelliklerine olan etkisi sayısal olarak incelenmiştir. Analizler için 500x10 mm boyutlarında üç bölümden oluşan (yukarı akış, oluklu ve aşağı akış) bir kanal kullanılmıştır. Engeller kanal yüzeyine üç farklı açı (β=45°, 90° ve 135°) ve üç farklı yükseklikte (h/H=0,1, 0,25 ve 0,5) yerleştirilmiştir. Süreklilik, momentum ve enerji denklemlerinin çözümleri k-ε türbülans modeli kullanılarak Ansys-Fluent sonlu hacimler yöntemi ile gerçekleştirilmiştir. Akış alanına ait türbülans kinetik enerji (TKE) konturları ile ortalama Nusselt sayısı (Nu), sürtünme faktörü (f), basınç düşüşü (ΔP) ve performans değerlendirme kıstas sayısı (PEC) değerleri Reynolds sayısının (Re) 5000-20000 aralığı için elde edilmiştir. En yüksek termal-hidrolik performans h/H=0,1, β=45° kanal modeli için elde edilmiştir. Bu durum PEC değerlerine göre en düşük performansa sahip h/H=0,5, β=135° modele kıyasla %26,19 daha fazladır.

Anahtar Kelimeler

• Dikdörtgensel engeller
• Isı transferi artırma
• Oluklu kanal akışı
• PEC sayısı

Numerical Investigation of the Effects of Rectangular Obstacles on the Thermal-Hydraulic Properties of a Circular Corrugated Channel

Öz

In this study, the effect of rectangular obstacles, placed at different angles and heights on the bottom surface of a circular corrugated channel, on the channel’s thermal-hydraulic properties was investigated numerically. For analysis, a 500x10 mm dimensional channel, consisting of three sections (upstream, corrugated, and downstream), was used. The obstacles were placed on the canal surface at three different angles (β=45°, 90° and 135°) and at three different heights (h/H=0.1, 0.25 and 0.5). The solutions of the continuity, momentum and energy equations were performed using the k-ε turbulence model by means of the Ansys-Fluent finite volume method. For the flow field, the turbulent kinetic energy (TKE) contours, the average Nusselt number (Nu), friction factor (f), pressure drop (ΔP) and performance evaluation criterion number (PEC) values were obtained for the Reynolds number (Re) 5000-20000 range. The highest thermal-hydraulic performance was obtained for the h/H=0.1, β=45° channel model. This is 26.19% higher than the h/H=0.5, β=135° model with the lowest performance according to PEC values.

Anahtar Kelimeler

• Corrugated channel flow
• Heat transfer enhancement
• PEC number
• Rectangular obstacles

Kaynakça

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