F2 - INTRODUCTION Packed beds are containers filled with...

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INTRODUCTION Packed beds are containers filled with tiny particles (e.g. sand, berl-saddles or glass particles). The pressure drop can occur across the packed bed when a fluid is passed through that bed. Void fraction is the volume fraction of the paced bed without including the packing material. In addition, it is a part of the bed available for fluid flow through the channels formed between the packing. There is important relation between the pressure drops and flowrates. Namely, pressure drops increase as the flowrate increases and vices versa. The objective of this experiment is to measure the pressure drop through packed beds. THEORITICAL BACKGROUND D p,e is defined as: For sphere: (1) φ is defined as: D p,e = φ D s,p where φ ≤ 1 (2) Packed bed Reynold’s number is defined as: (3) Vα is the fluid velocity throug the bed (no packings are present) and equal to the flowrate divided by the cross sectional area of the bed: V α = Q/A (4) Packed bed friction factor (f p ) is defined as: (5) Correlations: In the turbulent range of Re p ≥ 1000 the friction factor for flow through packed beds is described be the Burke Plummer equation, which is based on experimental data. f p = 1.75 (6) In the laminar range of Rep ≤ 10 the friction factor is described by the Karman – Kozeny equation: ( 29 D D D D e p = × = 2 3 , 6 / 6 π ( 29 η ε ρ - = 1 Re , V D e p p ( 29 L V P D f e p p - = 1 3 ,
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f p = 150/ Re p (7) The Ergun equation is an equation applying to the whole range of Reynold’s number. It is simply the sum of eq. 6 and eq. 7:
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F2 - INTRODUCTION Packed beds are containers filled with...

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