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

Compact Model of Slug Flow in Microchannels

2007 ◽  
Author(s):  
Dong Rip Kim ◽  
Jae-Mo Koo ◽  
Chen Fang ◽  
Julie E. Steinbrenner ◽  
Eon Soo Lee ◽  
...  
Keyword(s):  
Pressure Drop ◽  
Liquid Water ◽  
Slug Flow ◽  
Flow Behavior ◽  
Contact Angles ◽  
Proton Exchange ◽  
Force Balance ◽  
Compact Model ◽  
Two Phase ◽  
Coverage Ratio

This paper presents a theoretical investigation of the movement of liquid droplets and slugs in hydrophobic microchannels and develops a compact model for this type of two-phase flow. This model is used in the prediction of pressure drop and liquid water coverage ratio, key parameters in the operation of Proton Exchange Membrane Fuel Cells (PEMFC), the primary motivation for this work. A semi-empirical, periodic-steady two-phase separated flow compact model is formulated to characterize the slug flow behavior. The momentum equation includes the effects of acceleration, friction and surface tension on the pressure drop. The model considers spatial changes in slug velocity through the use of a force balance formulation. The model uses a departure scheme that computes slug size and shape at entrainment. The steady state slug flow compact model is capable of predicting liquid water coverage ratio and pressure drop using liquid and gas flow rates and advancing/receding triple point contact angles as its only inputs. The results indicate that the pressure drop increases as the droplet formation frequency increases.

Frictional Pressure Drop of Gas-Newtonian and Gas-Non Newtonian Slug Flow in Vertical Pipe

2011 ◽  
Vol 9 (1) ◽  
Author(s):  
Subrata Kumar Majumder ◽  
Sandip Ghosh ◽  
Gautam Kundu ◽  
Arun Kumar Mitra
Keyword(s):  
Pressure Drop ◽  
Slug Flow ◽  
Amyl Alcohol ◽  
Newtonian Liquid ◽  
Vertical Pipe ◽  
Two Phase ◽  
Vertical Column ◽  
Frictional Pressure Drop ◽  
Liquid Systems ◽  
Phase Pressure

Experimental study on two-phase pressure drop in a vertical pipe with air-Newtonian and non-Newtonian liquid in slug flow regime has been carried out within a range of gas and liquid flowrate of 0.5×10-4 to 1.92×10-4 m-3/s and 1.6×10-4 to 6.7×10-4 m3/s respectively. In the present study air and four types of liquids such as water, amyl alcohol, glycerin (two different concentrations), and CMC (Sodium Carboxymethyl Cellulose) are used. The present data were analyzed by two-phase friction method. To predict the two-phase pressure drop, correlations have been developed with Newtonian and non-Newtonian liquid. A general correlation was also developed to predict the two-phase pressure drop in a vertical column of diameter 0.01905 m and 3.4 m height combining both the Newtonian and non-Newtonian liquid systems.

Pressure drop of two-phase liquid-liquid slug flow in square microchannels

2018 ◽  
Vol 191 ◽  
pp. 398-409 ◽  
Author(s):  
Agnieszka Ładosz ◽  
Philipp Rudolf von Rohr
Keyword(s):  
Pressure Drop ◽  
Slug Flow ◽  
Liquid Slug ◽  
Two Phase ◽  
Phase Liquid

A Flow Model for Two-Phase Slug Flow in Horizontal Tubes

1961 ◽  
Vol 83 (4) ◽  
pp. 613-618 ◽  
Author(s):  
E. S. Kordyban
Keyword(s):  
Pressure Drop ◽  
Flow Pattern ◽  
Slug Flow ◽  
Flow Model ◽  
Simplified Model ◽  
Two Phase ◽  
Frictional Pressure Drop ◽  
Horizontal Tubes

The paper presents a construction of a simplified model approximating the actual observed flow pattern. The resulting expressions for frictional pressure drop are found to agree fairly well with the author’s data for steam and water and the data for air and water of other investigators. The similarity with a portion of the Chenoweth-Martin correlation appears to present a logical explanation for the applicability of that correlation to slug flow.

Surface Tension Effects on Liquid Flow in Small Plastic Tubes When Gas Bubbles are Present

2005 ◽  
Vol 219 (8) ◽  
pp. 853-857 ◽  
Author(s):  
M. R. Myers ◽  
H. M. Cave ◽  
S. P. Krumdieck
Keyword(s):  
Surface Tension ◽  
High Pressure ◽  
Pressure Drop ◽  
Liquid Flow ◽  
Slug Flow ◽  
Small Diameter ◽  
Gas Bubbles ◽  
Flow Regimes ◽  
Liquid Slug ◽  
Two Phase

Two-phase intermittent gas and liquid slug flow in small diameter glass and plastic tubes was studied. Two distinct flow regimes and the transition phenomena were identified. A modified Hagen-Poiseuille relation was derived to describe the extremely high pressure drop due to the surface tension effects of pinned slug flow.

The Visualization of Flow Boiling in a Uniformly Heated Micro Capillary Tube

2006 ◽  
Author(s):  
X. H. Yan ◽  
J. Z. Xu ◽  
D. W. Tang
Keyword(s):  
Pressure Drop ◽  
Slug Flow ◽  
Annular Flow ◽  
Capillary Tube ◽  
Flow Boiling ◽  
Bubbly Flow ◽  
Flow Patterns ◽  
Phase Flow ◽  
Two Phase ◽  
Inner Diameter

This work presents experiments on the visualization of flow boiling of water in a horizontally placed and uniformly heated micro capillary tube. Three micro capillary tubes of quartz glass with inner diameters of 520, 315 and 242 μm are prepared. Experiments are performed with deionized water over a mass flux range from 39.3 to 362.5kg/m2s, and the inlet temperatures of 30, 45, and 60 °C respectively. By a video system with microscope and high-speed camera, the vapor-water two-phase flow’s patterns are recorded and analyzed. It has been found that periodic change of two-phase flow patterns and dramatic fluctuations of pressure drop occur in the micro capillary tubes. A new arch flow pattern, liquid film evaporating, and liquid droplet have been observed firstly. Bubbly flow has not been observed during our visual experiments for the inner diameter of 242 μm, the flow patterns are only made up of single liquid phase flow and two-phase elongate slug flow. The main flow regimes in these micro-tubes are single-liquid flow, slug flow, and annular flow with liquid film surrounded in the micro-tube with inner diameter of 520 and 315μm. Trends of pressure drop and flow patterns’ transition are compared and the results show that the increasing process of pressure drop is approximately in the single-liquid flow and bubbly flow, while the decreasing process of pressure drop is in the state of annular flow.

Drag Reduction in Three Distinctly Different Fluid Systems

1981 ◽  
Vol 21 (06) ◽  
pp. 663-669 ◽  
Author(s):  
Thomas R. Sifferman ◽  
Robert A. Greenkorn
Keyword(s):  
Pressure Drop ◽  
Drag Reduction ◽  
Polymer Solution ◽  
Flow Rate ◽  
Polymer Solutions ◽  
Tap Water ◽  
Smooth Wall ◽  
Two Phase ◽  
Fluid Systems ◽  
Flow Systems

Abstract Drag reduction was observed in three distinctly different flow systems-dilute polymer solutions, two-phase solid/liquid suspensions, and three-phase immiscible liquid/liquid flow with suspended solids - in relatively large-diameter pipes (0.027, 0.038, and 0.053 m). Galvanized pipes presented a rough wall, while glass provided a smooth wall and allowed for flow visualization. provided a smooth wall and allowed for flow visualization. By drag reduction, we mean that, for the same flow rate, there is less pressure drop per length of pipe than for the base fluid flowing, alone.Three polymers-sodium carboxymethylcellulose (CMC). polyethylene oxide (POLYOX(TM)), and guar gum) (Jaguar(TM)) were mixed with water to form solutions of various concentrations (from 0.001 to 0.3 wt%). Two nominal concentrations (5 to 10%) of silca sand also were suspended with either tap water or some of the polymers. Finally, white mineral oil and either tap water or polymer solutions were tested. Sand also was added to the oil system.Drag reductions of up to almost 80% were obtained for both the polymer systems and the oil system. Sand suspensions had a maximum of about 35% drag reduction in tap water. However, greatest reductions (more than 90% were attained with the polymer/sand suspensionsSince the sand in the polymer solutions reduced the drag even more than the polymers alone, it may be that the drag mechanism is additive and even may be the same type for both polymers and suspensions.Drag reduction occurs in the region near the wall and could occur in an intermediate layer zone that allows an effective slip velocity to result. Polymers showed significant deviation from the Newtonian velocity profiles.Less power was required to pump the polymers than water alone. Viscosity and normal stress data were obtained also. Introduction There are many interesting engineering applications of drag-reduction phenomena. For many flow situations in conduits, the use of a drag reduction agent (normally a viscoelastic soluble polymer) increases flow rate for the same pressure drop in diverse systems. Such as storm sewers, drilling operations, fire fighting, irrigation and living systems. External flows can be improved around ships and torpedoes. Proper design of solid/fluid systems to take advantage of the drag reduction associated with suspended solids can be used in transporting coal, raw sewage, and sediment. In two-phase liquid/liquid situations, such as hydraulic fracturing of oil wells and transportation of liquid petroleum. drag reduction associated with annular immiscible or emulsion flow can be used to advantage where exceptionally large reductions in pressure for a given flow rate result for viscous oils and water.To design systems to take advantage of lower energy requirements at the same flow rate, data are necessary (1) from systems large enough that diameter effects are absent, (2) at flow rates of sufficient velocity that the phenomena are present, and (3) on different systems phenomena are present, and (3) on different systems with varying physical properties. Such data re necessary to develop correlations, to understand flow mechanisms, and to develop mathematical models-all of which are necessary to interpolate and extrapolate the data for design of such flow systems. Previously, this type of data has not been available.Drag reductions is defined, at a given flow rate, as the pressure drop for a given system minus the pressure drop pressure drop for a given system minus the pressure drop for the base fluid divided by the pressure drop for the base fluid.In this paper, we report observations of drag-reduction phenomena in three distinctly different flow systems: (1) phenomena in three distinctly different flow systems:single-phase water, oil, and dilute polymer-water solutions;two-phase oil/water, oil/polymer solution, water/sand, and polymer solution/sand; andthree-phase oil/water/sand and oil/polymer solution/sand. The data were collected in 0.027- and 0.053-m Schedule 40 galvanized pipe and a 0.038-m-ID smooth-wall glass pipe. pipe. SPEJ P. 663

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