EXPERIMENTAL AND NUMERICAL STUDY ON HEAT TRANSFER PERFORMANCE OF SQUARE, CYLINDRICAL AND PLATE HEAT SINKS IN EXTERNAL TRANSITION FLOW REGIME

Öz

Geometrical optimization of heat sinks with square, cylindrical and plate fins for heat transfer increase is numerically analyzed in transition regime external flow. The relations between the thermal characteristics of fins and boundary conditions such as free-stream velocity are investigated. Experimental studies are performed by using manufacturable fins to validate the numerical model. Heat transfer correlations are derived in order to determine average heat transfer coefficients over a certain range of both Reynolds number and non-dimensional geometric parameters like spanwise and streamwise spacings. Confidence level of the experimental work is demonstrated by uncertainty analysis. Cylindrical fins are observed to be approximately 4.5% superior to ones with square and plate profiles in terms of maximum base plate temperature.

Anahtar Kelimeler

• CFD
• external flow
• fin
• heat sink
• transition regime
• heat transfer correlation

DIŞ GEÇİŞ AKIŞI REJİMİNDE KARE, SİLİNDİR VE PLAKA ISI KUYULARI İÇİN ISI TRANSFER PERFORMANSI ÜZERİNE DENEYSEL VE SAYISAL ÇALIŞMA

Öz

Kare, silindir ve plaka kanatçıklı ısı kuyularının ısı transferi artışına yönelik geometrik en iyileştirilmeleri geçiş rejimindeki dış akışta sayısal olarak incelenmiştir. Serbest akış hızı gibi sınır koşulları ile kanatçık termal karakterizasyonu arasındaki ilişkiler araştırılmıştır. Sayısal modeli doğrulamak için üretilebilir kanatçıklar kullanılarak deneysel çalışmalar gerçekleştirilmiştir. Ortalama ısı transfer katsayısını belirlemek üzere, hem belirli bir Reynolds sayısı hem de akış yönü ile akışa dik doğrultudaki boyutsuz geometrik parametrelerin aralığı dikkate alınarak ısı transferi korelasyonları elde edilmiştir. Deneysel çalışmanın güvenilirliği belirsizlik analizi ile gösterilmiştir. Taban plakası en yüksek sıcaklığının, silindir kanatçıklı ısı kuyusunda diğerlerine göre yaklaşık %4.5 oranında daha düşük çıktığı gözlemlenmiştir.

Anahtar Kelimeler

• HAD
• Dış Akış
• Kanatçık
• Isı Kuyusu
• Geçiş Rejimi
• Isı Transfer Korelasyonu

Kaynakça

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