Axial dispersion of the liquid phase in vertical tubular contactors with static mixers

1986 ◽  
Vol 51 (9) ◽  
pp. 1925-1932 ◽  
Author(s):  
Marie Fialová ◽  
Karl-Heinz Redlich ◽  
Kurt Winkler
Keyword(s):  
Liquid Phase ◽  
Single Phase ◽  
Flow System ◽  
Axial Dispersion ◽  
Cocurrent Flow ◽  
Phase Flow ◽  
Static Mixer ◽  
Two Phase ◽  
Static Mixers ◽  
Phase Water

Axial dispersion characteristics in the liquid phase have been determined for three selected types of static mixers using the impulse response technique in a vertical tubular contactor for single phase (water) and two phase (water-air, cocurrent flow arrangement) systems. The character of the measured dependences for individual types of static mixers has been found different and also corresponding values of axial dispersion have been found significant. From the stand point of axial dispersion the behaviour of the static mixer under the two phase flow has been found different from its behaviour in the single phase flow system.

Axial Mixing in a Novel Perforated Plate Bubble Column

2010 ◽  
Vol 8 (1) ◽  
Author(s):  
S. Dhanasekaran ◽  
T. Karunanithi
Keyword(s):  
Flow Condition ◽  
Single Phase ◽  
Two Phase Flow ◽  
Liquid Velocity ◽  
Bubble Column ◽  
Axial Dispersion ◽  
Phase Flow ◽  
Two Phase ◽  
Dispersion Number ◽  
Superficial Liquid Velocity

This investigation reports the experimental and theoretical results carried out to evaluate the axial dispersion number for an air-water system in a novel hybrid rotating and reciprocating perforated plate bubble column for single phase and two phase flow conditions. Axial dispersion studies are carried out using stimulus response technique. Sodium hydroxide solution is used as the tracer. Effects of superficial liquid velocity, agitation level and superficial gas velocity on axial dispersion number were analyzed and found to be significant. For the single phase (water) flow condition, it is found that the main variables affecting the axial dispersion number are the agitation level and superficial liquid velocity. When compared to the agitation level, the effect of superficial liquid velocity on axial dispersion number is more predominant. The increase in superficial liquid velocity decreases the axial dispersion number. The same trend is shown by agitation level but the effect is less. The rotational movement of the perforated plates enhances the radial mixing in the section; hence, axial dispersion number is reduced. For the two phase flow condition, the increase in superficial liquid velocity decreases the axial dispersion number, as reported in the single phase flow condition. The increase in agitation level decreases the axial dispersion number, but this decreasing trend is non-linear. An increase in superficial gas velocity increases the axial dispersion number. Correlations have been developed for axial dispersion number for single phase and two phase flow conditions. The correlation values are found to concur with the experimental values.

Thermofluid Characteristics of Two-Phase Microgap Coolers

2007 ◽  
Author(s):  
Dae W. Kim ◽  
Emil Rahim ◽  
Avram Bar-Cohen ◽  
Bongtae Han
Keyword(s):  
Heat Transfer ◽  
Numerical Model ◽  
Pressure Drop ◽  
Single Phase ◽  
Flow Boiling ◽  
Phase Flow ◽  
Dissolved Gas ◽  
Single Phase Flow ◽  
Two Phase ◽  
Phase Water

The thermofluid characteristics of a chip-scale microgap cooler, including single-phase flow of water and FC-72 and flow boiling of FC-72, are explored. Heat transfer and pressure drop results for single phase water are used to validate a detailed numerical model and, together with the convective FC-72 data, establish a baseline for microgap cooler performance. Experimental results for single phase water and FC-72 flowing in 120 μm, 260 μm and 600 μm microgap coolers, 31mm wide by 34mm long, at velocities of 0.1 – 2 m/s are reported. “Pseudo-boiling” driven by dissolved gas and flow boiling of FC-72 are found to provide significant enhancement in heat transfer relative to theoretical single phase values.

Numerical Study of the Single-Phase and Two-Phase Flow in a Centrifugal Pump

2013 ◽  
Vol 307 ◽  
pp. 215-218
Author(s):  
Te Ba ◽  
Arthur Teck Bin Lim ◽  
Chang Wei Kang
Keyword(s):  
Centrifugal Pump ◽  
Single Phase ◽  
Transient Flow ◽  
Two Phase Flow ◽  
Numerical Study ◽  
Flow Simulation ◽  
Phase Flow ◽  
Two Phase ◽  
Normal Mass ◽  
Phase Water

The paper presents the numerical investigation of a radial flow centrifugal pump with 2D curvature blade geometry. The geometry is based on the experimental equipment by Anagostopulos. Single phase (water) flow is modeled with a normal mass flow rate and rotation speed. Pressure distribution and fluid streamlines are evaluated and visualized. An extension of the model to transient flow and two-phase flow simulation has been done to see the effect of impeller rotation and gas entrainment in the centrifugal operation procedure.

Measurements of single-phase and two-phase flows in a vertical pipe using ultrasonic pulse Doppler method and ultrasonic time-domain cross-correlation method

2013 ◽  
Vol 35 (3) ◽  
Author(s):  
Tat Thang Nguyen ◽  
Hiroshige Kikura ◽  
Ngoc Hai Duong ◽  
Hideki Murakawa ◽  
Nobuyoshi Tsuzuki
Keyword(s):  
Time Domain ◽  
Cross Correlation ◽  
Single Phase ◽  
Ultrasonic Pulse ◽  
Phase Flow ◽  
Beam Diameter ◽  
Vertical Pipe ◽  
Two Phase ◽  
Ultrasonic Time ◽  
Pulse Doppler

Ultrasonic Velocity Profile (UVP) method for measurement of single-phase and two-phase flow in a vertical pipe has recently been developed in the Laboratory for industrial and Environmental Fluid Dynamics, Institute of Mechanics, VAST. The signal processings of the UVP method include the ultrasonic pulse Doppler method (UDM)and the ultrasonic time-domain cross-correlation (UTDC) method. For two-phase flow, simultaneous measurements of both liquid and gas are enabled by using a multi-wave ultrasonic transducer (multi-wave TDX). The multi-wave TDX is able to emit and receive ultrasound of two different center frequencies of 2 MHz and 8 MHz at the same time and position. 2 MHz frequency with beam diameter 10 mm is exploited for measurement of gas. 8 MHz one with beam diameter 3 mm is used for liquid. Measurements have been carried out for laminar and turbulent single-phase flows and bubbly counter-current two-phase flows in two flow loops using two vertical pipes of 26 mm inner diameter (I.D.) and 50 mm I.D. respectively. Based on the measured results, assessment of each method is clarified. Applicability of each method for different conditions of pipe flow has been tested. Suggestions for application of the two methods have been recommended.

Axial dispersion in the liquid phase in a horizontal two-phase tube reactor

1991 ◽  
Vol 56 (6) ◽  
pp. 1249-1252
Author(s):  
Marie Fialová ◽  
Ctirad Verner ◽  
Lothar Ebner
Keyword(s):  
Liquid Phase ◽  
Flow Regimes ◽  
Basic Flow ◽  
Axial Dispersion ◽  
Two Phase ◽  
Tube Reactor

The characteristics of axial dispersion in the liquid phase were measured for two basic flow regimes in a horizontal two-phase tube reactor. The data obtained indicate that in some flow regions, axial dispersion can be quite significant.

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