NEMLİ VE ZORLANMIŞ TAŞINIMLI KAPALI HACİMLERDE YARIKÜRESEL BUZ SÜBLİMASYONUNUN ANALİTİK İNCELENMESİ

Öz

Gerçek hayatta, buzun belirli koşullar altında süblimleşmesi, düzensiz şekilli buz küplerinin oluşumuyla sonuçlanır. Düzensiz şekilli bu küplerin kapalı alanlardan çıkarılması sırasında küplerin hareket ettiği açıklıklar tıkanabilir. Buz küplerinin şeklinin homojen ve düzgün kenarlı olması için süblimasyon prosesinin derinlemesine analizi gerçekleştirilmelidir. Literatürde küresel buzun süblimleşmesine yönelik analitik bir yöntem bulunmasına rağmen yarım küre şekli çalışılmamıştır. Ayrıca, duvarla sınırlandırılmış bir hacimde buz oluşumu ve süblimleşme aynı anda meydana geliyorsa, yeni yaklaşımlar gereklidir. Bu çalışmada, küresel ve dairesel düz yüzey modellerinin bir kombinasyonu olarak yarım küre şeklindeki bir buz örneğinden süblimleşme için analitik bir yöntem önerilmiştir. Bu yeni analitik yöntemle hesaplanan süblimleşme miktarı, süblimleşmenin bir dizi buz küpü görüntüsünün işlenmesiyle elde edildiği görselleştirme deneyleri ve tartım yapılarak elde edilen sonuçlarla karşılaştırıldı. Hesaplanan değerler ile görselleştirme sonuçlarında ve tartım yapılmış numunelerde gözlemlenen kütle kaybı arasında iyi bir uyum vardır. Elde edilen sonuçlara göre süblimleşme miktarının, süblimleşmeye uğrayan buz küplerinin üzerinden akan havanın hızı, sıcaklığı ve bağıl nemi ile ilişkili olduğu sonucuna varılmıştır.

Anahtar Kelimeler

• Süblimleşme
• görselleştirme
• zamana bağlı kütle transferi
• buz

ANALYTICAL STUDY OF HEMISPHERICAL ICE SUBLIMATION IN ENCLOSURES WITH HUMIDITY AND FORCED CONVECTION

Öz

In real life, sublimation of ice under certain conditions results in non-uniform formation of ice cubes with irregular shapes. During extracting these irregularly shaped cubes from enclosed spaces, the openings through which the cubes move can be plugged. A deep analysis of the sublimation process should be applied to make the shape of the ice cubes homogeneous and smooth-edged. Although there is an analytical method for the sublimation of spherical ice in literature, the hemispherical shape has not been studied. Furthermore, if ice formation and sublimation occur simultaneously within a place confined by a wall, novel approaches are necessary. In the current study, an analytical method has been proposed for the sublimation from a hemispherical ice sample as a combination of the models for the spherical and circular flat surfaces. The sublimation rate calculated by this new analytical method has been compared to the results from the weighing experiments and visualizations where the sublimation over time was measured by processing a series of images of ice cubes. There is a good agreement between the calculated values and the mass loss observed in the visualized images and the weighted samples. Thus, it is concluded that the sublimation rate is correlated with the velocity, temperature, and relative humidity of the air flowing over the ice cubes undergoing sublimation.

Anahtar Kelimeler

• Sublimation
• visualization
• transient mass transfer
• ice

Kaynakça

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