Two-phase countercurrent flow through a bed of packing. VII. Pressure drop at flooding and critical flow rates of both phases in packed bed of spheres

1972 ◽  
Vol 37 (5) ◽  
pp. 1666-1670
Author(s):  
V. Kolář ◽  
Z. Brož
2014 ◽  
Vol 80 (817) ◽  
pp. FE0258-FE0258
Author(s):  
Hideaki HOSOI ◽  
Naoyuki ISHIDA ◽  
Tetsushi HORIBE ◽  
Shigeru SHIMOKAWARA ◽  
Tamotsu CHIBA

Author(s):  
Brian J. Daniels ◽  
Deborah V. Pence ◽  
James A. Liburdy

Single-phase and two-phase flows in microscale fractal-like branching flow networks are studied using a one-dimensional model that includes variable property and developing flow effects. Pressure drop, pumping power, changes in the bulk fluid temperature and a performance parameter are reported for mass flow rates ranging from 25 to 500 g/min and wall heat fluxes from 5 to 40 W/cm2. Two-phase flow through fractal-like flow networks is also compared to flow through a series of parallel channels for identical wall heat fluxes and for flow rates between 25 and 100 g/min. Channel length, height, convective surface area, heat flux and flow rate were the same between the fractal-like and parallel channel array. It was found that single-phase flows through fractal-like flow networks exhibit lower pressure drop and pumping power than do two-phase flows at the same wall heat flux and mass flow rate. The inlet temperature for the single-phase cases is 20°C, whereas the two-phase flow enters as a saturated liquid. The pressure drop and pumping power were always lowest for the fractal-like flow networks compared with the parallel channel arrays for identical heat transfer and flow rates.


2007 ◽  
Author(s):  
Wenhong Liu ◽  
Liejin Guo ◽  
Ximin Zhang ◽  
Kai Lin ◽  
Long Yang ◽  
...  

1985 ◽  
Vol 50 (3) ◽  
pp. 745-757 ◽  
Author(s):  
Andreas Zahn ◽  
Lothar Ebner ◽  
Kurt Winkler ◽  
Jan Kratochvíl ◽  
Jindřich Zahradník

The effect of two-phase flow regime on decisive hydrodynamic and mass transfer characteristics of horizontal-tube gas-liquid reactors (pressure drop, liquid holdup, kLaL) was determined in a cocurrent-flow experimental unit of the length 4.15 m and diameter 0.05 m with air-water system. An adjustable-height weir was installed in the separation chamber at the reactor outlet to simulate the effect of internal baffles on reactor hydrodynamics. Flow regime maps were developed in the whole range of experimental gas and liquid flow rates both for the weirless arrangement and for the weir height 0.05 m, the former being in good agreement with flow-pattern boundaries presented by Mandhane. In the whole range of experi-mental conditions pressure drop data could be well correlated as a function of gas and liquid flow rates by an empirical exponential-type relation with specific sets of coefficients obtained for individual flow regimes from experimental data. Good agreement was observed between values of pressure drop obtained for weirless arrangement and data calculated from the Lockhart-Martinelli correlation while the contribution of weir to the overall pressure drop was well described by a relation proposed for the pressure loss in closed-end tubes. In the region of negligible weir influence values of liquid holdup were again succesfully correlated by the Lockhart-Martinelli relation while the dependence of liquid holdup data on gas and liquid flow rates obtained under conditions of significant weir effect (i.e. at low flow rates of both phases) could be well described by an empirical exponential-type relation. Results of preliminary kLaL measurements confirmed the decisive effect of the rate of energy dissipation on the intensity of interfacial mass transfer in gas-liquid dispersions.


2016 ◽  
Vol 94 ◽  
pp. 422-432 ◽  
Author(s):  
N. Chikhi ◽  
R. Clavier ◽  
J.-P. Laurent ◽  
F. Fichot ◽  
M. Quintard

1988 ◽  
pp. 253-261
Author(s):  
P. Marchot ◽  
M. Crine ◽  
J. C. Cal ◽  
M. Ausloos

Author(s):  
Ashish Kotwal ◽  
Che-Hao Yang ◽  
Clement Tang

The current study shows computational and experimental analysis of multiphase flows (gas-liquid two-phase flow) in channels with sudden area change. Four test sections used for sudden contraction and expansion of area in experiments and computational analysis. These are 0.5–0.375, 0.5–0.315, 0.5–0.19, 0.5–0.14, inversely true for expansion channels. Liquid Flow rates ranging from 0.005 kg/s to 0.03 kg/s employed, while gas flow rates ranging from 0.00049 kg/s to 0.029 kg/s implemented. First, single-phase flow consists of only water, and second two-phase Nitrogen-Water mixture flow analyzed experimentally and computationally. For Single-phase flow, two mathematical models used for comparison: the two transport equations k-epsilon turbulence model (K-Epsilon), and the five transport equations Reynolds stress turbulence interaction model (RSM). A Eulerian-Eulerian multiphase approach and the RSM mathematical model developed for two-phase gas-liquid flows based on current experimental data. As area changes, the pressure drop observed, which is directly proportional to the Reynolds number. The computational analysis can show precise prediction and a good agreement with experimental data when area ratio and pressure differences are smaller for laminar and turbulent flows in circular geometries. During two-phase flows, the pressure drop generated shows reasonable dependence on void fraction parameter, regardless of numerical analysis and experimental analysis.


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