Free Energy Change of Droplet Formation in a Supersaturated Vapor

Yıl 2016, Cilt: 42 Sayı: 2, 179 - 188, 28.10.2016

Nuretdin Eren , Nihal Buyukcizmeci , Rıza Oğul

Öz

The behavior of the
pure substances during the condensation of liquid droplets in a supersaturated
vapor and, the mechanism of homogeneous nucleation of vapor to liquid droplets
that may occur as a result of large amplitude density fluctuations within the coexistence
line in the metastable region have been investigated. The free energy change
accompanying the formation of a critical water drop is calculated as a function
of droplet radius for various saturation ratios on the basis of Fisher’s model.
It is observed that a geometric term due to the fact that the surface of a drop
relaxes to spherical shape which reduces the total entropy associated with the
surface free energy, produces significant changes in total free energy change
of critical droplet formation.

Anahtar Kelimeler

Supersaturation ratio, droplet formation, saturation density

Süperdoyumdaki Buhar İçinde Damlacık Oluşumunun Serbest Enerji Değişimi

Öz

Süperdoymuş bir buhar içinde damlacık oluşumu sırasında saf bir numunenin
davranışı ve yarı sıvı-gaz faz eğrisi altındaki kararlı bölgedeki büyük
genlikli yoğunluk dalgalanmaları sonucunda buhar fazından damlacıklar oluşumu
süreçleri araştırılmıştır. Fisher modeli temelinde, çeşitli doyma oranları
için, kritik su damlacıklarının oluşumu esnasındaki serbest enerji değişimleri
damlacık yarıçapının bir fonksiyonu olarak hesaplanmıştır. Damlacık yüzeyinin
küresel şekil alması ile yüzey serbest enerjisi ile bağlantılı olan toplam
entropinin azalmasını tanımlayan geometrik terimin kritik damlacık oluşumlarını
tanımlayan toplam serbest enerjide anlamlı değişmelere neden olduğu gözlenmiştir.

Anahtar Kelimeler

Süperdoyma oranı, damlacık oluşumu, doyma yoğunluğu

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