Karakterisisasi lapisan film jatuh (FLF) pada dinding dalam tabung vertikal oleh pengumpan pusar secara eksperimen dan simulasi CFD

Yazid Bindar, Rusdi Wijisaksono

Abstract


Falling liquid film characterization in the inside wall of vertical tube using whirl feeder through experiment and  CFD simulation

Falling Liquid Film (FLF) from swirl feed holes were characterized through experiment and Computational Fluid Dynamic (CFD) simulation. The falling liquid film is quantified by its thickness. The effect of liquid flow rate, physical properties and diameter of swirl holes are successfully correlated to form a model that is based on the liquid film theory. The FLF dimensionless thickness linearly relates to power functions of Reynolds and Galilea numbers. The minimum mass flow increases with the size of the swirl holes. The minimum Reynolds number of the inlet does not change with swirl hole sizes. The CFD investigations were conducted using k-turbulent model and multi phase system. Falling film thickness was calculated using axial velocity data resulted from CFD investigation. Calculated falling film thickness using CFD method  agrees very well with measured one for both systems. Combination between physical and CFD experiments has the advantages in determining the critical diameter of the swirl hole that still produce good FLF characteristics.

Keywords: CFD Simulation, Falling film, Film Layer, Stripper

 

Abstrak

Lapis anfilm jatuh (FLF) yang dihasilkan oleh pengumpan pusar dikarekterisasi secara percobaan dan simulasi Computational Fluid Dynamics (CFD). Karakter FLF yang dikuantifikasi adalah ketebalannya. Karakter FLF dipengaruhi diameter lubang pusar, laju alir cairan, danjenis cairan. Pengaruh laju alir, sifat fisik dan ukuran lubang pusar terhadap ketebalan FLF dimodelkan dalam bentuk persamaan tidak berdimensi. Ketebalan FLF tak berdimensi mempunyai korelasi pangkat dengan bilangan Reynolds dan bilangan Galilleo. Ini didukung oleh konsep teoritisnya. Karakter­ karakter lain dari FLF yang dikaji adalah nilai bilangan Reynold minimum untuk pembentukan FLF dan diameter maksimum lubang pusar yang diizinkan. FLF pada rejim laminar beriak dan rejim turbulen lebih tebal dari FLF pada rejim laminer tak beriak. Simulasi CFD dilakukan dengan menggunakan model turbulent k- dan sistem multi fasa campuran gas dan cair. Simulasi CFD memiliki kemampuan yang sangat lengkap untuk perkiraan nilai karakter FLF pada semua posisi tiga dimensinya. Hasil perkiraan ketebalan FLF dengan simulasi CFD berada dalam rentang nilai hasil percobaan. Kombinasi percobaan dan simulasi CFD untuk karakterisasi FLF ternyata sangat efektif dengan pendekatan percobaan yang sederhana dan murah

Kata kunci: Falling film, Lapisan film, Simulasi CFD, Stripper

 


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DOI: http://dx.doi.org/10.5614/jtki.2006.5.3.2

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