Study of hydrodynamics (flow pattern, pressure drop and hold) of viscous oil-water flow through corrugated pipeline in peak configuration experimentally. CFD simulation of hydrodynamics of viscous oil-water flow through a wavy pipeline in peak configuration.
CFD simulation and experimental validation of flow pattern transition during viscous oil-water flow through a
Experimental study of viscous oil-water two-phase flow through an undulated pipeline in peak configuration
CFD simulation of hydrodynamics of viscous oil-water flow through an undulated pipeline in peak configuration
Flow pattern investigation of viscous oil-water flow through an undulated pipeline in valley configuration by
Nomenclature
DO/W&W Dispersion of oil in water and water DW/O Dispersion of water in oil.
P - Plug flow, S - Slug flow, SW - Stratified wave flow, SM - Stratified mixed flow, A - Wispy annular flow, DW/O - Dispersion of water in oil flow, DO/W - Dispersion of of oil in the water stream). -Plug Flow, S-Slug Flow, SW- Stratified Wavy Flow, Mixed Flow SM-Stratified Flow, A-Annular Flow, Dw/o- Water Dispersion in Oil Flow, Do/w-Dispersion of oil to water flow).
List of Tables
Introduction and Literature review
Introduction
In addition to the usual inertia, viscous forces and pressure present in single-phase flow, two-phase flows are also affected by interfacial tension forces, wetting characteristics of the liquid on the pipe wall, and the exchange of momentum between the two phases during the flow. In two-phase flow, the phases can be distributed in different interfacial configurations called flow patterns or flow regimes depending on the operational variables, the physical properties of the fluids, and the geometrical variables of the system.
Hydrodynamics
Schematic description of stratified flow configuration (Rodriguez and Castro, 2014) ('U' is the average axial velocity; 'AO' and 'AW' are the oil and water cross-sectional areas; 'hw' is the water phase height, β is the pipe slope, 'Si', ' Sw' and 'So' are the interface, water and oil wetted perimeters). Force balance on a deformed wave at the oil-water interface (Al-Wahaibi et al. 2007) (where 'Fσ' and 'Fd' are surface and drag forces; 'a' is wave amplitude; 'λ' is wavelength and 'L' is the length of the deformed wave).
Literature review
Flow patterns are strongly influenced by pipe diameter, inlet geometry, and fluid properties (Beretta et al. 1997). It has been observed that smaller pipe diameter promotes slug and annular flow (Mandal et al., 2007).
Aims and objectives
So, the hydrodynamics of the same fluid pair in the horizontal pipeline is studied before the investigation of viscous oil-water flow through corrugated pipes. The same hydrodynamics as the experiments (flow patterns, oil volume fraction, total pressure and velocity profiles) are predicted using 2D simulation in Fluent 6.3 software.
Structure of the thesis
Then the flow patterns are simulated using the VOF model and efforts have been made to understand the volume fraction, pressure and velocity profiles of the separated flow.
Introduction
It consists of a fluid handling system (storage tanks, pumps, rotameters) and three test sections (horizontal, peak configuration, valley configuration) as shown in Fig.
Fluid handling systems
Flow rate measuring devices
Oil flow measurement
Test section
- Peak test section
- Valley test section
- Horizontal test section
The test section consists of an ascending and a descending section between two horizontal sections in sequence in the flow direction. The slope angle is the same for uphill and downhill, which is 5 in magnitude compared to the horizontal. The junction between the upstream and downstream sections is referred to as the downhill elbow, and the junction between the upstream and downstream sections is the uphill elbow.
Experimental procedure
Between EN and TS2, an L/D ratio of 120 is provided to achieve fully developed flow and the same ratio is maintained from test to outlet section to minimize the end effect of the fluids.
Estimation of flow pattern
Conductance probe technique
The schematic representation of this probe (Fig. 2.2a) and a cross-section of the flow configuration (Fig. 2.2b) are shown in Fig. In each circuit, one wire is connected directly to the cathode of the battery and another wire is connected. on the short wire of the LED. The other wire from the LED is connected to one end of the resistor (250 Ohm) and the other end is connected to the anode of the battery (Fig. 3).
Estimation of holdup
Estimation of pressure drop
Contact angle measurement
Then, a drop of oil is carefully placed on a surface already immersed in an aqueous medium (Santos et al. 2006). The image of the oil drop in this setup was captured using a digital camera [DSC-HX100V, Sony].
Computational Fluid Dynamics (CFD) Methodology
The purpose of the grid is to enable the discretization of the Navier-Stokes partial differential equations so that the computer is capable of the required calculations. Another important issue to address when using CFD to model multiphase flow is how to select the multiphase model to be used to calculate the solutions. Appropriate choices must be made for the multiphase model to ensure that the program can use the correct continuity equations and also apply them to fluids in a way that most closely mimics real-life fluid flow.
Mixture Model: Primary and secondary phases are treated as one composite mixture and one momentum equation is solved for the combined phases
Eulerian-Eulerian Model: Primary and secondary phases are treated individually as being continuous and separate momentum equations are solved for each phase
Volume of Fluid (VOF) Model: An Eulerian-Eulerian variation in which the secondary phase is not dispersed within the primary phase but rather there is an interface
- Volume of Fluid (VOF) Approach
- Governing Equations
- Turbulence model
- Initial and boundary condition
- Discretization method
- Convergence criterion
The surface tension can be written in terms of the pressure drop across the surface. From the above equation, it can be seen that the surface tension source term for a cell is proportional to the average density in the cell. After the desired residual value is reached, the current of both phases is monitored to obtain the current pattern.
CFD simulation and experimental validation of flow pattern transition during viscous oil-water flow through
Introduction
Thus, it is necessary to understand the hydrodynamics of oil-water flow in such pipeline networks (corrugated pipeline in the present paper) for the design and proper sizing of downstream separation and other processing facility units. Therefore, the hydrodynamics of oil-water flow in horizontal pipeline is studied before the investigation of viscous oil-water flow through corrugated pipes. This chapter presents the study of various flow patterns during oil-water flow in a horizontal pipeline, particularly the sharp annular flow using a probe probe.
Experimentation
After completing a series of experiments, the water velocity is changed to the next higher value and the same procedure as mentioned above is repeated.
Model development
In the present model, it is assumed that the two fluids share a well-defined interface. Volume of Fluid (VOF) model with k-ε turbulence model is used, which solves a single set of momentum equations for both fluids. The details of the governing equations, treatment of the interface, and initial and boundary conditions are discussed in Chapter 2.
Experimental results
Two types of dispersions are possible: dispersion of oil in water (Do/w) and dispersion of water in oil. A fine oil dispersion is observed at the top, and most of the cross-section of the pipe is occupied by water during the dispersion of oil in the water flow, as shown in figure. At higher oil flow rates, very fine water dispersion is observed. and oil takes up most of the pipe cross-section, as shown in Fig.
Simulated results
- Plug to Slug transition boundary (P-S)
- Slug to Stratified wavy flow transition boundary (S-SW)
- Stratified wavy to mixed flow transition boundary (SW-SM)
- Region of annular flow (A)
The simulated result at these boundary conditions is validated with the experimental images captured at the same flow conditions as shown in Figure. Five different transitions are observed around the annular flow (Figure 3.8): slug, stratified wavy, stratified mixed and dispersion of both. oil and water. The experimental picture of annular flow under the same conditions is also shown in Fig.
Validation
Rows 1, 2, 3, and 4 represent the plug-to-slug, slug-to-stratified-wave, stratified-to-mixed-wave, and annular-flow boundary, respectively. Data points circled around the respective boundary are simulated results of the respective flow regimes. After experimental validation, the model is used to generate useful information about the flow characteristics (volume fraction, pressure, and velocity profile) of a separated flow (ie, stratified wavy, stratified mixed, and ring) which is commonly found in chemicals and petroleum. industries.
Radial distribution of volume fraction, pressure and velocity of a separated flow
- Volume fraction profile
The figure (Fig. 3.13c) depicts maximum pressure at the top interface of annular flow due to higher shear at that interface. In the present work, attempts have been made to understand the radial distribution of velocity for stratified wavy (Fig. 3.14a), stratified mixed (Fig. 3.14b) and annular flow (Fig. 3.14c). Consequently, the velocity is high for water phase and low for oil phase (see Fig. 3.14a,b).
Conclusion
Experimental study of viscous oil-water two-phase flow through a corrugated pipeline in peak configuration.
Introduction
Experimentation
Viewing boxes (VB1 to VB4) are provided in the test sections to minimize the lens effect of the tube material during photography. The test section with peak configuration consists of an uphill (UH) and a downhill section (DH) between two horizontal sections (upstream (US) and downstream (DS) section), in order of flow direction. This experiment was repeated three times to check the reproducibility of the experimental results.
Results and Discussion
- Identification of wispy annular flow and comparison with literature
- Different flow patterns
- Flow pattern maps at four sections and a comparison among them
- Comparison with horizontal flow pattern map
- Effect of viscosity on flow pattern in undulated pipeline
- Effect of undulation (peak configuration) on pressure gradient
The observed flow patterns at four different sections (upstream, uphill, downhill and downstream) of the corrugated pipeline are presented in the form of flow pattern maps (Fig. 4.4a-d, respectively). For this, the upstream peak configuration flow pattern map has been superimposed on the horizontal flow pattern map as shown in Fig. Correspondingly, the transition from stratified mixed to dispersion of oil in the water flow is shifted towards lower oil velocity (0.47 m/s). compared to horizontal flow pattern map (0.53 m/s).
Conclusion
Oil-water flows through sudden contraction and expansion in a horizontal pipe - Phase distribution and pressure drop. Experimental validation of theoretical models in two-phase high viscosity ratio liquid-liquid flows in horizontal and slightly inclined pipes. CFD simulation of the hydrodynamics of viscous oil-water flow through a crested corrugated pipe.
CFD simulation of hydrodynamics of viscous oil-water flow through an undulated pipeline in peak
Introduction
In the petroleum industry, the oil-water two-phase flows are widely found in production processes such as exploration and transportation. In these applications, two-phase flow can attribute different interfacial configurations called flow regimes or patterns, such as plug, slug, wavy, mixed, dispersed and annular flow. The design parameters such as pressure drop, hold-up and flow regimes in a single-phase flow in tubes can be easily modeled.
5. 2 Model Development
- Volume of Fluid (VOF) Approach
- Results and Discussion
- Different flow patterns
- Comparison with horizontal flow pattern map
- Annular flow characteristics
- Conclusion
Similarly, the variation of velocity and oil volume fraction along the positive Y-axis is shown in Figs 5.7b and 5.7c. The variation of the oil volume fraction along the cross section (Fig. 5.7c) helps to find the thickness of the water layer during annular flow. The volume fraction data obtained from the simulation along the peak section shows 10.8% over prediction when compared to the experimental data as shown in Fig. a) Pressure profile (b) Velocity profile (c) Oil volume fraction profile.
P., "Crude oil-natural gas two-phase flow pattern transition boundaries at high pressure conditions," SPE Annual Technical Conference and Exhibition, Paper no. A., "Effect of oil viscosity on the flow structure and pressure gradient in horizontal oil-water flow," Chem. Flow pattern investigation of viscous oil-water flow through a wavy pipeline in valley configuration.
Flow pattern investigation of viscous oil-water flow through an undulated pipeline in valley configuration
Introduction
The hydrodynamics of multiphase flow through a pipeline in undulating or hilly terrain is different from horizontal or inclined flow. A combination of horizontal and inclined (ie a valley configuration) would behave differently than a combination of only horizontal or inclined. Although the hydrodynamics of low-viscosity oil-water flow through hilly terrain and corrugated pipelines has been investigated, the flow behavior of moderately viscous oil-water flow is poorly understood.
Experimentation
Model development
Results and Discussion
- Observed flow patterns
- Flow pattern maps at different sections (US, DH, UH, DS) and a comparison among them
- Validation of simulated results
This flow pattern is called a three-layer or stratified mixed flow pattern as shown in the figure. The flow patterns observed in the four sections (US, UH, DH and DS) during the above mentioned experiments are summarized in graphical form using the surface velocities of oil (USO) and water (USW) as coordinate axes, which is known as the flow pattern map . Then, the experimental flow patterns are also confirmed by overlaying the simulated points on the flow pattern map, as shown in Figure 1 .
Comparison with horizontal flow pattern map
Transition from stratified undulating to stratified mixed (3) and is almost identical to horizontal flow pattern map. But stratified mixing to dispersion of water in oil transition (7) is shifted to a little higher oil velocity. As a whole, stratified mixed region gained more area in the current flow pattern map.
Comparison with literature
As a result, the area under the stratified wave flow (SW) increases in this part. In the present work, patterns of slugs and annular flows (in the valley) are observed, which are not present in the less viscous flow of oil and water (Mandal (2007)). The velocity range of the stratified wavy flow is reduced in this work compared to Mandalov (2007), as the viscosity of their oil is lower.
Conclusion
Abduvayt, P., Manabe, R., Watanabe, T., Arihara, N., 2006. Analysis of oil/water flow tests in horizontal, hilly terrain and vertical pipes. Grassi, B., Strazza, D., Poesio, P., 2008. Experimental validation of theoretical models in high viscosity two-phase liquid-liquid flows in horizontal and gently inclined pipes. Wang, W., Gong, J., Angeli, P., 2011. Investigation of two-phase flow of heavy raw water and related flow characteristics.
Conclusions and Future recommendations
Conclusion
However, the range of fluid velocities for a given flow pattern varies from section to section. Section-wise flow pattern maps are developed and compared with each other and also with literature data to understand the effect of waviness and viscosity on hydrodynamics. The comparison shows that small waviness (5°) has a marginal effect on the flow behavior of the viscous oil-water mixture, and higher viscosity favors the annular, scraped, and dispersed (water-in-oil) flow pattern.
Recommendations for future work
Outcome of the dissertation
