Kare Kesitli Mikrokanallarda Doymuş Kaynamalı Akış Karakteristiklerinin Deneysel İncelenmesi

Yıl 2019, Cilt: 60 Sayı: 694, 50 - 66, 19.03.2019

Burak Markal , Orhan Aydın , Mete Avcı

Öz

Bu çalışmada, her biri 200 µm x 200 µm kanal kesitine (genişlik x yükseklik) sahip yirmi dokuz paralel mikrokanaldan oluşan silikon ısı alıcıda, deiyonize suyun doymuş kaynamalı akış karakteristikleri deneysel olarak incelenmiştir. Üç farklı kütle akısında (51, 65 ve 78 kgm-2s-1) çalışılmış olup; duvar ısı akısı, 44,5 – 62,8 kWm-2 aralığında tutulmuştur. Bu kapsamda, ısı akısı ve kütle akısının iki faz ısı transfer katsayısı ve toplam basınç düşümü üzerindeki etkileri incelenmiştir. Fiziksel mekanizma, ölçümlerle eşzamanlı alınan yüksek hızlı akış görüntüleri yardımıyla irdelenmiştir. Çalışma sonucunda, iki faz ısı transfer katsayısının artan ısı akısı ve kuruluk derecesi ile azaldığı, artan kütle akısı ile arttığı; toplam basınç düşümünün ise, genel karakter olarak, artan ısı akısı ve çıkış kuruluk derecesi ile arttığı ve artan kütle akısı ile azaldığı belirlenmiştir. Ayrıca, akış görüntüleme çalışmalarında, mikrokanallarda kaynamalı akış olayının sanki-periyodik karakterde olduğu gözlemlenmiştir.

Anahtar Kelimeler

Mikrokanal, kaynamalı akış

Destekleyen Kurum

TÜBİTAK

Proje Numarası

113M408

An Experimental Investigation of Saturated Flow Boiling Characteristics in Square Microchannels

Öz

In this study, saturated flow boiling characteristics of deionized water are experimentally investigated in silicon heat sink consisting of twenty nine parallel microchannels with cross sectional dimensions of 200 µm x 200 µm (width x height). Experiments are conducted for three different mass fluxes of 51, 65 and 78 kgm-2s-1, while the wall heat flux ranges from 44.5 – 62.8 kWm-2. In this context, the effects of heat flux and mass flux on the two phase heat transfer coefficient and the total pressure drop are investigated. The physical mechanism is scrutinized through simultaneous high speed flow images taken during measurements. Consequently, two phase heat transfer coefficient decreases with increasing heat flux and vapor quality, and increases with increasing mass flux. The total pressure drop increases with increasing heat flux and exit vapor quality while it decreases with increasing mass flux. From the flow visualization experiments, it is observed that flow boiling phenomenon in microchannels has quasi-periodical characteristics. 

Anahtar Kelimeler

Microchannel, flow boiling

Proje Numarası

113M408

Kaynakça

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