Drag reduction in two-phase annular-mist flow of air and water

AIChE Journal ◽  
1976 ◽  
Vol 22 (3) ◽  
pp. 615-617 ◽  
Author(s):  
Nicholas D. Sylvester ◽  
James P. Brill
Keyword(s):  
Drag Reduction ◽  
Two Phase ◽  
Mist Flow

Determination of specific interfacial areas in swirled two-phase flow

1983 ◽  
Vol 48 (3) ◽  
pp. 842-853
Author(s):  
Kurt Winkler ◽  
František Kaštánek ◽  
Jan Kratochvíl
Keyword(s):  
Interfacial Area ◽  
Liquid Volume ◽  
Upward Flow ◽  
Two Phase ◽  
Flow Rates ◽  
Mist Flow ◽  
Interfacial Areas ◽  
Correlation Parameters ◽  
Flow Components

Specific gas-liquid interfacial area in flow tubes 70 mm in diameter of the length 725 and 1 450 mm resp. containing various swirl bodies were measured for concurrent upward flow in the ranges of average gas (air) velocities 11 to 35 ms-1 and liquid flow rates 13 to 80 m3 m-2 h-1 using the method of CO2 absorption into NaOH solutions. Two different flow regimes were observed: slug flow swirled annular-mist flow. In the latter case the determination was carried out separately for the film and spray flow components, respectively. The obtained specific areas range between 500 to 20 000 m3 m-2. Correlation parameters are energy dissipation criteria, related to the geometrical reactor volume and to the static liquid volume in the reactor.

Pressure drop and drag reduction in two-phase non-newtonian slug flow

1976 ◽  
Vol 54 (1-2) ◽  
pp. 111-114 ◽  
Author(s):  
Lambert Otten ◽  
Abdelrahman S. Fayed
Keyword(s):  
Pressure Drop ◽  
Drag Reduction ◽  
Slug Flow ◽  
Two Phase

An Experimental Study of Mist/Air Film Cooling With Fan-Shaped Holes on an Extended Flat Plate—Part II: Two-Phase Flow Measurements and Droplet Dynamics

2017 ◽  
Vol 140 (4) ◽  
Author(s):  
Reda Ragab ◽  
Ting Wang
Keyword(s):  
Flow Behavior ◽  
Data Rate ◽  
Main Flow ◽  
Shear Stresses ◽  
Two Phase ◽  
Flow Measurements ◽  
Droplet Dynamics ◽  
Mist Flow ◽  
Film Layer ◽  
Upper Boundary

A phase Doppler particle analyzer (PDPA) system is employed to measure the two-phase mist flow behavior including flow velocity field, droplet size distribution, droplet dynamics, and turbulence characteristics. Based on the droplet measurements made through PDPA, a projected profile describing how the air–mist coolant jet flow spreads and eventually blends into the hot main flow is prescribed for both cylindrical and fan-shaped holes. The mist film layer consists of two layers: a typical coolant film layer (cooling air containing the majority of the droplets) and a wider droplet layer containing droplets outside the film layer. Thanks to the higher inertia possessed by larger droplets (>20 μm in diameter) at the injection hole, the larger droplets tend to shoot across the coolant film layer, resulting in a wider droplet layer than the coolant film layer. The wider droplet layer boundaries are detected by measuring the droplet data rate (droplet number per second) distribution, and it is identified by a wedge-shaped enclosure prescribed by the data rate distribution curve. The coolant film layer is prescribed by its core and its upper boundary. The apex of the data rate curve, depicted by the maximum data rate, roughly indicates the core region of the coolant film layer. The upper boundary of the coolant film layer, characterized by active mixing with the main flow, is found to be close to relatively high values of local Reynolds shear stresses. With the results of PDPA measurements and the prescribed coolant film and droplet layer profiles, the heat transfer results on the wall presented in Part I are re-examined, and the fundamental mist-flow physics are analyzed. The three-dimensional (3D) droplet measurements show that the droplets injected from the fan-shaped holes tend to spread wider in lateral direction than cylinder holes and accumulate at the location where the neighboring coolant film layers meet. This flow and droplet behavior explain the higher cooling performance as well as mist-enhancement occurs between the fan-shaped cooling holes, rather than along the hole's centerline as demonstrated in the case using the cylindrical holes.

Experimental Study of DRA for Vertical Two-Phase Annular Flow

2009 ◽  
Vol 131 (2) ◽  
Author(s):  
R. L. J. Fernandes ◽  
B. A. Fleck ◽  
T. R. Heidrick ◽  
L. Torres ◽  
M. G. Rodriguez
Keyword(s):  
Pressure Gradient ◽  
Drag Reduction ◽  
Production Rate ◽  
Annular Flow ◽  
Liquid Holdup ◽  
Two Phase ◽  
High Production Rate ◽  
High Production ◽  
Feasibility Test ◽  
Main Effects

Experimental investigation of drag reduction in vertical two-phase annular flow is presented. The work is a feasibility test for applying drag reducing additives (DRAs) in high production-rate gas-condensate wells where friction in the production tubing limits the production rate. The DRAs are intended to reduce the overall pressure gradient and thereby increase the production rate. Since such wells typically operate in the annular-entrained flow regime, the gas and liquid velocities were chosen such that the experiments were in a vertical two-phase annular flow. The drag reducers had two main effects on the flow. As expected, they reduced the frictional component of the pressure gradient by up to 74%. However, they also resulted in a significant increase in the liquid holdup by up to 27%. This phenomenon is identified as “DRA-induced flooding.” Since the flow was vertical, the increase in the liquid holdup increased the hydrostatic component of the pressure gradient by up to 25%, offsetting some of reduction in the frictional component of the pressure gradient. The DRA-induced flooding was most pronounced at the lowest gas velocities. However, the results show that in the annular flow the net effect will generally be a reduction in the overall pressure gradient by up to 82%. The findings here help to establish an envelope of operations for the application of multiphase drag reduction in vertical flows and indicate the conditions where a significant net reduction of the pressure gradient may be expected.

Moisture Fraction Measurements for Two-Phase Mist Flow Using High-Sensitivity Capacitance Sensors

1997 ◽  
Vol 117 (3) ◽  
pp. 353-365 ◽  
Author(s):  
Michael F. Dowling ◽  
Jason D. Wartell ◽  
Sheldon M. Jeter ◽  
Said I. Abdel-Khalik
Keyword(s):  
High Sensitivity ◽  
Two Phase ◽  
Mist Flow

Drag Reduction of Gas-Liquid Two-Phase Flow in Steel Pipes with Different Inclination Geometry

2012 ◽  
Vol 433-440 ◽  
pp. 463-470
Author(s):  
Lei Liu ◽  
Xin Feng Guo ◽  
Qiu Yue Guo ◽  
Hui Qing Fan ◽  
Zhu Hai Zhong
Keyword(s):  
Drag Reduction ◽  
Two Phase Flow ◽  
Vertical Section ◽  
High Energy ◽  
Phase Flow ◽  
Two Phase ◽  
Steel Pipes ◽  
Horizontal Pipes ◽  
Reduction Efficiency ◽  
Reduction Characteristics

It is significant to make researches on drag reduction in two-phase transport pipeline because two-phase flow has high energy dissipation. API X 52 steel pipe with diameter of 40mm is used in this paper to simulate pipeline with different inclination geometry including horizontal, up-inclined and vertical sections. The up-inclined section has an inclination angle of eight degree. Experiments and theoretical analysis are carried out to study the drag reduction characteristics of gas-liquid two-phase flow in these three sections. The drag reducing agents used here is polyacrylamide. It is found that two-phase drag reduction varies with pipe inclination geometry. The largest drag reduction efficiency occurs in horizontal pipes and which is up to seventy percent. Drag reduction efficiency in up-inclined section is up to sixty percent. Drag reduction in vertical section is the lowest and which can be up to about thirty percent. A mechanistic drag reduction model is proposed to predict drag reduction in gas-liquid two-phase flow. The results predicted are in good agreement with the experiment data.

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