scholarly journals The Effect of Variations of Flow from Tributary Channel on the Flow Behavior in a T-Shape Confluence

Processes ◽  
2020 ◽  
Vol 8 (5) ◽  
pp. 614
Author(s):  
Aliasghar Azma ◽  
Yongxiang Zhang
Keyword(s):  
Fluid Transport ◽  
Flow Behavior ◽  
Surface Profile ◽  
Main Channel ◽  
Turbulence Energy ◽  
Side Channel ◽  
Head Losses ◽  
Flow Parameters ◽  
Separation Plate ◽  
Transport Channels

Channel confluences are of the common structures in fluid transport channels. In this study, a series of numerical simulations were performed, utilizing a 3D code to investigate the reaction of the flow parameters and vortical structure to the variations in flow discharge and its Froude number from both main channel and tributary branch in a T-shape junction. The code was calibrated with the experimental data. Parameters, including the velocity, the turbulence energy, stream surface profile, head losses, and the transverse flow motions, were considered in different situations. It was concluded that increasing the ratio of discharge of flow from side-channel to the main channel (Q*) increased the area and power of the recirculation zone, as well as the width of separation plate downstream of the confluence, while it reduced the area of the stagnation zone (or the wake vortex) within the side-channel. It was also indicated that increasing the discharge ratio from side-channel resulted in an increase in the upstream water level in the main channels, which was dependent on the upstream discharge.

scholarly journals Tributary Channel Width Effect on the Flow Behavior in Trapezoidal and Rectangular Channel Confluences

Processes ◽  
2020 ◽  
Vol 8 (11) ◽  
pp. 1344
Author(s):  
Aliasghar Azma ◽  
Yongxiang Zhang
Keyword(s):  
Recirculation Zone ◽  
Flow Behavior ◽  
Rectangular Channel ◽  
Maximum Velocity ◽  
Main Channel ◽  
Channel Width ◽  
Width Ratio ◽  
Geometrical Shape ◽  
Eddy Simulation ◽  
Flow Parameters

Channel confluences happen commonly in water transport networks and natural rivers. Utilizing a 3D CFD code, a series of numerical simulations were performed using a large eddy simulation turbulence model to investigate the effect of the variations in tributary channel width and the transverse geometrical shape of the main channel on the flow parameters and vertical structure in a T-shape confluence. The code was calibrated using the experimental data from the literature. Flow parameters were considered in ratios of tributary width to the main channel width in trapezoidal and rectangular channels. Results indicate that decreasing the width ratio of the tributary channel to the main channel significantly affects the flow structure in the confluence. Generally, it increases the width and length of the main recirculation zone. It also increases the maximum velocity near the bed, especially in cases with a trapezoidal shape. Besides, it highly affects the structure and formation of the recirculation zone in trapezoidal channels.

A Unique Approach in Modelling Flow in Tight Oil Unconventional Reservoirs With Viscous, Inertial and Diffusion Forces Contributions

2021 ◽  
Author(s):  
Mohammed Aldhuhoori ◽  
Hadi Belhaj ◽  
Bisweswar Ghosh ◽  
Ryan Fernandes ◽  
Hamda Alkuwaiti ◽  
...  
Keyword(s):  
Fluid Flow ◽  
Fluid Transport ◽  
Synthetic Data ◽  
Diffusion Term ◽  
Flowing Fluid ◽  
New Model ◽  
Forchheimer’S Equation ◽  
Low Viscosity ◽  
Flow Parameters ◽  
Unique Approach

Abstract A model for single-phase fluid flow in tight UCRs was previously produced by modifying the flow Forchheimer’s equation. The new modification addresses the fluid transport phenomena into three scales incorporating a diffusion term. In this study, a new liner model, numerically solved, has been developed and deployed for a gas huff and puff project. The new model has been numerically validated and verified using synthetic data and huff and puff case study. Ideally, the new model suits fluid flow in tight UCRs. The modified Forchheimer’s model presented is solved using the MATLAB numerical method for linear multiphase flow. For the huff & puff case, very simple profiles and flow dynamics of the main flow parameters have been established and a thorough parametric analysis and verifications were performed. It has been observed that the diffusion system becomes more prominent in regulating flow velocity with low permeability of the formation rock and low viscosity of the flowing fluid. The findings indicate a behavioral alignment with a previous hypothesis that matches actual reservoir behavior.

Interaction Between Impeller and Volute of Pumps at Off-Design Conditions

1986 ◽  
Vol 108 (1) ◽  
pp. 12-18 ◽  
Author(s):  
J. A. Lorett ◽  
S. Gopalakrishnan
Keyword(s):  
Analytical Solution ◽  
Flow Behavior ◽  
Cyclic Variation ◽  
Test Results ◽  
Flow Parameters ◽  
Pump Output ◽  
Simplifying Assumptions ◽  
Radial Thrust ◽  
Relative Flow ◽  
Good Agreement

In a centrifugal pump of volute type, the respective characteristics of the impeller and the volute are such that at only one operating point can the flow parameters be constant along the length of the volute. At off-design conditions the mismatching of characteristics causes variations of velocity and pressure along the periphery of the impeller. This in turn forces cyclic variation of the flow in the impeller channels, introduces variations of the inlet incidence and contributes significantly to the direction and the magnitude of the radial thrust. Furthermore, below a certain pump output, a complete flow reversal occurs over a part of the impeller periphery, thus explaining the onset of recirculation. The paper describes the calculation approach used to derive this aspect of the flow behavior. Because of difficulties in obtaining a closed analytical solution, a step by step computation is employed. Beginning with arbitrarily chosen conditions at the volute tongue, the program computes the flow parameters for following segments, using the continuity and the momentum equations, until the exit from the last segment is reached. The inherent unsteadiness of the relative flow in the impeller is explicitly accounted for. Since the inflow and the velocity in the first segment depend upon the exit conditions of the last, the initial input must be modified, and the computation repeated, until the values are compatible with the exit conditions. In spite of several simplifying assumptions, the results of the calculations show very good agreement with published test results.

scholarly journals On the MHD Casson Axisymmetric Marangoni Forced Convective Flow of Nanofluids

Mathematics ◽  
2019 ◽  
Vol 7 (11) ◽  
pp. 1087 ◽  
Author(s):  
Anum Shafiq ◽  
Islam Zari ◽  
Ghulam Rasool ◽  
Iskander Tlili ◽  
Tahir Saeed Khan
Keyword(s):  
Differential Equations ◽  
Convective Flow ◽  
Flow Behavior ◽  
Marangoni Effect ◽  
Casson Fluid ◽  
Linear Ordinary Differential Equations ◽  
Metallic Particles ◽  
Flow Parameters ◽  
Forced Convective Flow ◽  
The Impact

The proposed investigation concerns the impact of inclined magnetohydrodynamics (MHD) in a Casson axisymmetric Marangoni forced convective flow of nanofluids. Axisymmetric Marangoni convective flow has been driven by concentration and temperature gradients due to an infinite disk. Brownian motion appears due to concentration of the nanosize metallic particles in a typical base fluid. Thermophoretic attribute and heat source are considered. The analysis of flow pattern is perceived in the presence of certain distinct fluid parameters. Using appropriate transformations, the system of Partial Differential Equations (PDEs) is reduced into non-linear Ordinary Differential Equations (ODEs). Numerical solution of this problem is achieved invoking Runge–Kutta fourth-order algorithm. To observe the effect of inclined MHD in axisymmetric Marangoni convective flow, some suitable boundary conditions are incorporated. To figure out the impact of heat/mass phenomena on flow behavior, different physical and flow parameters are addressed for velocity, concentration and temperature profiles with the aid of tables and graphs. The results indicate that Casson fluid parameter and angle of inclination of MHD are reducing factors for fluid movement; however, stronger Marangoni effect is sufficient to improve the velocity profile.

Study of Flow Behavior in a Vibrating Pipe on Offshore Platform

2003 ◽  
Author(s):  
Dezhong Li ◽  
Ning Mei ◽  
Jian Su
Keyword(s):  
Flow Behavior ◽  
Offshore Platform ◽  
Polynomial Method ◽  
Flow Parameters ◽  
Pressure Distributions ◽  
Incompressible Viscous Flow ◽  
Fluid Properties ◽  
Oscillating Fluid Mechanics ◽  
The Mathematical Model ◽  
Good Agreement

The purpose of this paper is to study flow behavior in a vibrating pipe on offshore platform. The mathematical model of unsteady, incompressible, viscous flow in a vibrating pipe is established according to the basic theory of oscillating fluid mechanics. The governing equations of flow are decomposed into a system for steady flow and another for flow oscillation, with the equations of the differential coefficients of flow parameters solved by using the parametric polynomial method. Velocity and pressure distributions are obtained for different flow conditions. Numerical results indicate that the flow behavior in the vibrating pipe on offshore platform is strongly affected by fluid properties and the pipe structure. A good agreement is obtained when comparing the results with the variational solution in constant cross-section, which shows that the method proposed in this work is effective for studying flow behavior in a vibrating pipe on offshore platform.

Computational Modeling and Experimental Investigation of Static Straight-Through Labyrinth Seals

2008 ◽  
Author(s):  
Alexandrina Untaroiu ◽  
Christopher P. Goyne ◽  
Costin D. Untaroiu ◽  
Houston G. Wood ◽  
Robert Rockwell ◽  
...  
Keyword(s):  
Experimental Data ◽  
Flow Behavior ◽  
Optimization Techniques ◽  
Bulk Flow ◽  
Numerical Code ◽  
Cfd Modeling ◽  
Leakage Flow ◽  
Dynamic Coefficients ◽  
Seal Design ◽  
Flow Parameters

To design highly efficient and stable turbomachines, engineers require accurate methods to model seal flows and calculate clearance-excitation forces generated by the eccentric position of the rotor. One of the most widely used methods to predict leakage flow and dynamic coefficients is the use of computer codes developed based on bulk flow theory. In recent years, computational fluid dynamics (CFD) modeling is increasingly being recognized as an accurate assessment tool for flow parameters and dynamic coefficients evaluation as compared to the bulk flow codes. This paper presents computational and experimental investigations that were carried out to calculate flow parameters in a stationary straight-through model labyrinth seal. The main objective of this study is to explore the capabilities of Ansys-CFX, a commercially available state of the art 3D numerical code, to accurately model compressible flow through the seals. The flow behavior is analyzed using CFD and the flow parameters calculated by CFD are validated against experimental data taken for the same seal configuration. The integrated values of leakage flow rates estimated from the computational results agree with the experimental data within 7.6%. This study serves as a benchmark case that supports further efforts in applying CFD analysis in conjunction with automatic design optimization techniques for seals used for compressible media. It was shown that optimization algorithms combined with CFD simulations have good potential for improving seal design.

Flow Behavior With an Oscillating Motion of the Impinging Jet in a Dump Diffuser Combustor

1994 ◽  
Author(s):  
Shinji Honami ◽  
Takaaki Shizawa ◽  
Atsushi Sato ◽  
Hideki Ogata
Keyword(s):  
High Speed ◽  
Reynolds Shear Stress ◽  
Flow Behavior ◽  
Vortex Formation ◽  
Impinging Jet ◽  
Video Camera ◽  
Sudden Expansion ◽  
Laser Doppler Velocimeter ◽  
Turbulence Energy ◽  
Oscillating Motion

The paper presents the flow behavior with an oscillating motion of an impinging jet upon a flame dome head and its reattachment to the casing wall, when a distorted flow is provided at the inlet of the dump diffuser combustor. Laser Doppler Velocimeter was used for the measurements of the time-averaged flow within a sudden expansion region. Surface pressure fluctuation survey on the flame dome head and flow visualization by a smoke wire technique with a high-speed video camera were conducted from the view point of the unsteady flow feature of the impinging jet. There exists the high vorticity region at the jet boundary resulting in the production of the turbulence kinetic energy. In particular, higher vorticity is observed in the higher velocity side of the jet. The jet near the dome head has the favorable characteristics about the flow rate distribution into the branched channel. Reynolds shear stress and turbulence energy are remarkably produced near the reattachment region. The jet has an oscillating motion near the dome head with asymmetric vortex formation at the jet boundary.

Marangoni Asymmetrical Instability in a T-Junction Microchannel With an Open Outlet

2012 ◽  
Author(s):  
Zhenhai Pan ◽  
Hao Wang
Keyword(s):  
Heat Transfer ◽  
Flow Rate ◽  
Marangoni Number ◽  
Marangoni Convection ◽  
Main Channel ◽  
The Other ◽  
Side Channel ◽  
Single Vortex ◽  
Steady Convection ◽  
Critical Intensity

The Marangoni convections in microchannels are of interest in various applications such as heat transfer, material and microfluidics. In this paper, the Marangoni asymmetrical instability at a T-junction in a microchannel is investigated. The T-junction is formed by a main channel which water going through and a side channel which is open to the ambient. A convex meniscus is formed in side channel near the T-junction, evaporating/volatizing into the ambient. The consumption of water due to the evaporation is compensated by the supply from the main channel. It is found that for weak evaporations, the evaporation-induced Marangoni convections are symmetrical. However, when the evaporation reaches a critical intensity, the symmetrical Marangoni convection becomes unstable and evolves into an asymmetrical one, with one single vortex under the meniscus. More interestingly, the vortex creates a steady convection through the main channel from its one end to the other, just like a pump. The pumping flow rate is found linearly correlated with the Marangoni number at the T-junction.

A Runge-Kutta Approach for the Analysis of Spatially Varied Flow

1994 ◽  
Vol 22 (4) ◽  
pp. 279-282
Author(s):  
P. W. France
Keyword(s):  
Open Channel ◽  
Numerical Technique ◽  
Surface Profile ◽  
Main Channel ◽  
Trial And Error ◽  
Side Weir ◽  
Step Procedure ◽  
Simple Alternative ◽  
Difference Form ◽  
Runge Kutta

Steady spatially varied flow has a non-uniform discharge in an open channel resulting from the addition or diminution of water along the course of the flow. The longitudinal water surface profile is normally found by expressing the appropriate general equation in finite difference form and solving using a trial and error step-by-step procedure. In this paper a simple alternative method is presented using a Runge-Kutta fourth-order numerical technique. The method is applied to a channel side weir where the discharge in the main channel is decreasing in the direction of flow.

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