scholarly journals Flow Pattern Phenomena Incorporated into a Model for Pressure Losses in Air�Water Heterogeneous Mixture Flow in Horizontal Minichannels

2021 ◽  
Author(s):  
Chengyi Ma ◽  
Jerry K. Keska
Keyword(s):  
Flow Pattern ◽  
Heterogeneous Mixture ◽  
Mixture Flow ◽  
Pressure Losses

Incorporated Flow Patterns Into a Model of Two-Phase Heterogeneous Mixture Flow in Microchannels

2006 ◽  
Author(s):  
Jerry K. Keska
Keyword(s):  
Mathematical Model ◽  
Flow Pattern ◽  
Two Phase Flow ◽  
Full Range ◽  
Flow Patterns ◽  
Phase Flow ◽  
Heterogeneous Mixture ◽  
Two Phase ◽  
Mixture Flow ◽  
Pressure Losses

In the two-phase or multiphase flow of such heterogeneous mixture like gas-liquid many more independent parameters are involved, thereby making this process more complicated and less transparent for understanding, mathematical modeling and simulating or calculating of such parameter like the length pressure gradient. In two-phase flow, there is a very complicated and random phenomenon of flow patterns, which needs to be quantitatively and accurately incorporated. Unfortunately, nowadays, a method of how to measure flow patterns is not available. And, also there is a need for mathematical models with quantitatively incorporated flow patterns in full range of flow. It is understandable that in all such cases any reasonable attempt to define and incorporate quantitatively this phenomenon in mathematical model will be beneficial. Recognizing these challenges this paper will present an approach to incorporate flow pattern phenomenon into the two-phase flow model by (1) developing a mathematical model for pressure losses in two-phase flow based on in-situ parameters, (2) developing and defining a flow pattern coefficient, which incorporates the flow pattern phenomena, and (3) present the developed mathematical model with the incorporation of flow patterns, which demonstrated significant increase of accuracy of calculations based on conducted experimental research on air-water twophase mixture flow in a horizontal square microchannel.

Model of Two-Phase Heterogeneous Mixture Flow in a Microchannel With Incorporated Flow Patterns

2005 ◽  
Author(s):  
Jerry K. Keska
Keyword(s):  
Mathematical Model ◽  
Flow Pattern ◽  
Two Phase Flow ◽  
Full Range ◽  
Flow Patterns ◽  
Calculation Model ◽  
Phase Flow ◽  
Heterogeneous Mixture ◽  
Two Phase ◽  
Mixture Flow

In the two-phase or multiphase flow of such heterogeneous mixture like gas-liquid there is a very complicated and random phenomenon of flow patterns, which needs to be quantitatively and accurately, incorporated. Unfortunately, a model with quantitatively incorporated flow patterns in full range of concentration or method of how to measure flow patterns is not available. Recognizing these challenges this paper will present an approach to incorporate flow pattern phenomenon into the two-phase flow calculation model by (1) developing a mathematical model for pressure losses in two-phase flow based on in-situ parameters, (2) developing and defining a flow pattern coefficient, which incorporates the flow pattern phenomena, and (3) present the developed mathematical model with the incorporation of flow patterns, which demonstrated significant increase of accuracy of calculations based on conducted experimental research on air-water two-phase mixture flow in a horizontal square microchannel.

A Study on the Blade Shape Influence on Flow Distribution and Performance in Centrifugal Compressor Rotors

1990 ◽  
Author(s):  
Raffaele Tuccillo ◽  
Adolfo Senatore
Keyword(s):  
Flow Pattern ◽  
Boundary Layers ◽  
Centrifugal Compressor ◽  
Flow Distribution ◽  
Aircraft Engine ◽  
Pressure Losses ◽  
Compressor Rotor ◽  
Blade Shape ◽  
Shape Influence ◽  
And Performance

The authors present an analysis of the flow through a centrifugal compressor rotor. A quasi-3D flow model evaluates the interaction of the meridional and blade-to-blade solution, so as to determine the flow pattern inside an inviscid region. A further interaction is then considered between the non-viscous flow and the boundary layers which grow along the end-walls and the blade surfaces. This makes it possible both to determine a more realistic flow condition, because of the blockage effects exerted by the boundary layers, and to estimate the total pressure losses related to the momentum thickness. Examples are presented for a compressor of an aircraft engine. The influence of blade shape on the above described phenomena is analyzed, starting from the actual rotor geometry and making a parametric study of the alterations in flow pattern produced by changes in meridional blade shape, inlet and outlet flow areas, and splitter blades. The analysis will provide a basis for future activities involving the use of optimizing techniques for the final choice of the blade characteristics.

Numerical Modeling of Pressure Losses Caused by Bends in Pneumatic Conveying Pipeline

2009 ◽  
Author(s):  
Jie Cui
Keyword(s):  
Numerical Modeling ◽  
Pressure Drop ◽  
Flow Pattern ◽  
Pressure Loss ◽  
Pressure Field ◽  
Pneumatic Conveying ◽  
Laboratory Measurements ◽  
Pressure Losses ◽  
Flow Information ◽  
Parametric Studies

Pneumatic conveying pipelines are widely employed in many industries to transport granular solids. Use of bends with various turning radii in these pipelines is mandatory and it is well known that the bends cause a loss of energy which results in an additional pressure drop. The pressure loss associated with various bends in pneumatic conveying pipelines was studied numerically. The numerical modeling results were validated against laboratory measurements, and parametric studies were performed to examine various factors that affect the pressure loss caused by bends in pneumatic conveying pipelines. Since the numerical results supply flow information at every location in the pipeline, the flow pattern and pressure field of air and pellet were resolved in detail to investigate the mechanism of the pressure loss in such systems.

Pressure Loss Due to Hydraulic Transport of Large Solid Particles in Vertical Pipes Under Pulsating Flow Conditions

2021 ◽  
Vol 143 (6) ◽  
Author(s):  
Sotaro Masanobu ◽  
Satoru Takano ◽  
Shigeo Kanada ◽  
Masao Ono
Keyword(s):  
Pressure Loss ◽  
Solid Particles ◽  
Hydraulic Transport ◽  
Vertical Pipe ◽  
Mining System ◽  
Mixture Flow ◽  
Pressure Losses ◽  
Proposed Model ◽  
Calculation Results ◽  
The One

Abstract It is important to predict the pressure loss due to hydraulic transport of large solid particles for the design of subsea mining system. The mixture flow in the lifting pipe is expected to be unsteady in the actual mining system. The authors develop the one-dimensional mathematical model to predict the pressure loss of pulsating mixture flow in a static vertical pipe assuming that the flow in the pipe is fully developed. The experiment on hydraulic transport of solid particles was carried out to obtain the data for the investigation of the effects of flow fluctuation on pressure loss in a static vertical pipe. In the experiment, alumina beads and glass beads were used as solid particles, and the experimental parameters were mixture velocity, solid concentration, pulsating period, and pulsating amplitude. The proposed model was validated by a comparison with experimental data. Furthermore, we calculated the pressure losses due to hydraulic transports of polymetallic sulfide ores and manganese nodules using the proposed model. The calculation results showed that the fluctuating component in pulsating mixture flow should be considered for the design of lifting system and that the homogeneous mixture model could not be applied to the prediction of the pressure loss unless the mixture concentration is low and the pulsating period is short.

Modeling of Vertical Core-Annular Flows and Application to Heavy Oil Production

2001 ◽  
Vol 123 (3) ◽  
pp. 194-199 ◽  
Author(s):  
Jose´ W. Vanegas Prada ◽  
Antonio C. Bannwart
Keyword(s):  
Pressure Drop ◽  
Flow Pattern ◽  
Heavy Oil ◽  
Room Temperature ◽  
Single Phase ◽  
Laboratory Data ◽  
Mixture Flow ◽  
Frictional Pressure Drop ◽  
Artificial Lift ◽  
Oil Flow

The use of core-annular flow pattern may be attractive as an artificial lift method in heavy oil wells. This flow pattern can be induced by the lateral injection of relatively small quantities of water, in order to get a lubricated oil core along the pipe. Frictional pressure drop measurements for upward vertical core flow in a 1-in. pipe, using a 17.6-Pa.s, 963-kg/m3 oil and water at room temperature reported a decrease by over 1000-fold with respect to single-phase oil flow, being comparable to the flow of water alone in the pipe at mixture flow rate. The total pressure drop was reduced by over 45-fold. The frictional pressure drop model proposed includes both irreversible and buoyancy terms. The model was adjusted to fit our data and shows excellent agreement with laboratory data available.

scholarly journals Flow pattern and pressure drop for oil–water flows in and around 180° bends

2021 ◽  
Vol 3 (1) ◽  
Author(s):  
Paul Onubi Ayegba ◽  
Lawrence C. Edomwonyi-Otu ◽  
Abdulkareem Abubakar ◽  
Nurudeen Yusuf
Keyword(s):  
Pressure Drop ◽  
Pressure Gradient ◽  
Flow Pattern ◽  
Phase Inversion ◽  
Superficial Velocity ◽  
Pressure Losses ◽  
Water Flows ◽  
Oil Water ◽  
Velocity Pressure ◽  
Mixture Velocity

AbstractPressure drop and flow pattern of oil–water flows were investigated in a 19-mm ID clear polyvinyl chloride pipe consisting of U-bend with radius of curvature of 100 mm. The range for oil and water superficial velocities tested was $$0.04 \le U_{{{\text{so}}}} \le 0.950 \;{\text{m/s}}$$ 0.04 ≤ U so ≤ 0.950 m/s and $$0.13 \le U_{{{\text{sw}}}} \le 1.10 \;{\text{m/s}}$$ 0.13 ≤ U sw ≤ 1.10 m/s , respectively. Measurements were carried out under different flow conditions in a test section that consisted of four different parts: upstream of the bend, at the bend and at two redeveloping flow locations after the bend. The result indicated that the bend had limited influence on downstream flow patterns. However, the shear forces imposed by the bend caused some shift flow pattern transition and bubble characteristics in the redeveloping flow section after the bend relative to develop flow before the bend. Generally, pressure gradient at all the test sections increased with both oil fraction and water superficial velocity and there was a sharp change of pressure gradient profile during phase inversion. The transition point where phase inversion occurred was always within the range of $$0.4 \le U_{{{\text{sw}}}} \le 0.54 \;{\text{m/s}}$$ 0.4 ≤ U sw ≤ 0.54 m/s . Pressure losses differed at the various test sections, and the difference was strongly linked to the superficial velocity of the phases and the flow pattern. At high mixture velocity, pressure losses at the redeveloping section after the bend were higher than that at the bend and that for fully developed flows. At low mixture velocity, pressure losses at the bend are higher than in the straight sections. Pressure drop generally decreased with level of flow development downstream of the bend.

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