NANO-GÖZENEKLİ ZARLARDAN GERÇEKLEŞEN BUHARLAŞMANIN MOLEKÜLER DİNAMİK SİMÜLASYONLARI KULLANILARAK MODELLENMESİ

Yıl 2019, Cilt: 39 Sayı: 1, 91 - 99, 30.04.2019

Yiğit Akkuş

Öz

Nano-gözenekli yapılardan gerçekleşen buharlaşma, yüksek ısı akısına sahip elektronik cihazların ısıl yönetimindeki büyük potansiyeli nedeniyle teorik ve deneysel olarak geniş çapta incelenmektedir. Fakat moleküler/atomik seviye bir modelleme yönteminin eksikliği sebebiyle, sıvı-gaz arayüzeyinde gerçekleşen taşınımın temellerinin anlaşılabilmesi mümkün olamamaktadır. Bu çalışmada, uygun periyodik sınır koşullarının kullanımı sayesinde nano-gözenekli bir zarı betimleyebilen bir tekil nano-gözenekten gerçekleşen buharlaşmayı modelleyen bir hesaplama düzeneği oluşturulmuştur. Artan ısı yükleri altında, buharlaşan menisküsün şekli ve konumu gözlenmiş ve farklı buharlaşma rejimleri (çivilenmiş ve çekilen) tanımlanmıştır. Genel olarak bilinenin aksine, menisküsün çekilme sırasında kendi şeklini değiştirdiği keşfedilmiş ve bu duruma sebep olan fiziksel mekanizma açıklanmıştır. Nano-gözeneğin ısı uzaklaştırabilme kabiliyeti, farklı çalışma koşulları altında incelenmiştir. Yazarın bilgisine göre, bu çalışma, hem sıvı hem de buhar akışı ile ilgili olan sürekli-olmayan-ortam etkilerini göz önüne alarak nano-gözenekli bir zardan buharlaşmayı modelleyen ilk girişimdir. Sunulan yöntem, nano-gözenekli zarlardan gerçekleşen buharlaşmanın moleküler/atomik seviyede modellenebilmesinin önünü açmaktadır.

Anahtar Kelimeler

Buharlaşma, nano-gözenekli zar, moleküler dinamik simülasyonu, buharlaşan menisküsün kendi şeklini değiştirmesi

MODELING OF EVAPORATION FROM NANOPOROUS MEMBRANES USING MOLECULAR DYNAMICS SIMULATION

Öz

Evaporation from nanoporous structures is widely studied theoretically and experimentally due to its huge potential in thermal management of high heat flux electronic devices. Yet a fundamental understanding of liquid-vapor interfacial transport is lacking due to the absence of a molecular/atomic level modeling framework. In the current study, a computational setup is constructed to model the steady-state, continuous evaporation from a single nanopore, which is analogous to a nanoporous membrane due to the utilization of proper periodic boundary conditions. Under increasing heat loads, shape and position of the evaporating meniscus are observed, and different evaporation regimes (pinning and receding) are identified. An uncommon, self-regulation of the meniscus during receding is discovered and the underlying physical mechanism is elucidated. Heat removal ability of the nanopore is examined in response to different operating conditions. To the best of the author knowledge, the current study is the first attempt to model the evaporation from a nanoporous membrane incorporating non-continuum effects associated with the both liquid and vapor flows. The methodology presented opens up an avenue for the molecular/atomic level modeling of evaporation from nanoporous membranes.

Anahtar Kelimeler

Evaporation, nanoporous membrane, molecular dynamics simulation, self-regulation of an evaporating meniscus

Kaynakça

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