Flow Regime
Flow regime refers to the characteristic behavior of fluid flow within a system, often categorized based on factors such as velocity, density, and viscosity. It helps engineers and technologists understand and predict how fluids will behave under different conditions, enabling the design and optimization of systems such as pipelines, channels, and heat exchangers.
5 Key excerpts on "Flow Regime"
- Tarek Ahmed(Author)
- 2009(Publication Date)
- Gulf Professional Publishing(Publisher)
...p ref It should be pointed out that crude oil and water systems fit into this category. Compressible Fluids These are fluids that experience large changes in volume as a function of pressure. All gases are considered compressible fluids. The truncation of the series expansion, as given by Equation 3-5, is not valid in this category and the complete expansion as given by Equation 3-4 is used. The isothermal compressibility of any compressible fluid is described by the following expression: (3-8) Figures 3-1 and 3-2 show schematic illustrations of the volume and density changes as a function of pressure for the three types of fluids. Figure 3-1 Pressure-volume relationship. Figure 3-2 Fluid density versus pressure for different fluid types. Section 3.2 Flow Regimes Basically, three types of Flow Regimes must be recognized in order to describe the fluid flow behavior and reservoir pressure distribution as a function of time: • Steady-state flow. • Unsteady-state flow. • Pseudosteady-state flow. Steady-State Flow The Flow Regime is identified as a steady-state flow if the pressure at every location in the reservoir remains constant, i.e., does not change with time. Mathematically, this condition is expressed as (3-9) This equation states that the rate of change of pressure p with respect to time t at any location i is 0. In reservoirs, the steady-state flow condition can occur only when the reservoir is completely recharged and supported by strong aquifer or pressure maintenance operations. Unsteady-State Flow The unsteady-state flow (frequently called transient flow) is defined as the fluid flowing condition at which the rate of change of pressure with respect to time at any position in the reservoir is not 0 or constant...
eBook - ePub- James Patrick Abulencia, Louis Theodore(Authors)
- 2011(Publication Date)
- Wiley-AIChE(Publisher)
...PART III FLUID FLOW CLASSIFICATION This part of the book is concerned with Fluid Flow Classification. It contains five chapters and each serves a unique purpose in an attempt to treat nearly all important aspects of fluid motion. From a practical point-of-view, many systems and plants involve the movement of liquids and gases from one point to another; hence, the student and/or practicing engineer is concerned with several key topics in this area including: 1. Chapter 12: Fluid Flow Mechanisms 2. Chapter 13: Laminar Flow 3. Chapter 14: Turbulent Flow 4. Chapter 15: Compressible and Sonic Flow 5. Chapter 16: Two-Phase Flow All receive some measure of treatment in the material contained in this part. CHAPTER 12 FLOW MECHANISMS 12.1 INTRODUCTION When fluids move through a closed conduit of any cross-section, one of two different types of flow may occur. These two flow types are most easily visualized by referring to a classic experiment first performed by Osborne Reynolds in 1883. In Reynolds’ experiment, a glass tube was connected to a reservoir of water in such a way that the velocity of the water flowing through the tube could be varied. A nozzle was inserted in the inlet end of the tube through which a fine stream of colored dye could be introduced. Reynolds found that when the velocity of the water was low, the “thread” of dye color maintained itself throughout the tube. By locating the nozzle at different points in the cross-section, it was shown that there was no mixing of the dye with water and that the dye flowed in parallel, straight lines. At high velocities, it was found that the “line” or “thread” of dye disappeared and the entire mass of flowing water was uniformly colored with the dye...
eBook - ePub- John R. Grace, Xiaotao Bi, Naoko Ellis, John R. Grace, Xiaotao Bi, Naoko Ellis(Authors)
- 2020(Publication Date)
- Wiley-VCH(Publisher)
...Further studies of the regimes of fluidization. Powder Technol. 24: 187–205. 27 Squires, A.M., Kwauk, M., and Avidan, A.A. (1985). Fluid beds: at last, challenging two entrenched practices. Science 230: 1329–1337. 28 Grace, J.R. (1986). Contacting modes and behaviour classification of gas–solid and other two-phase suspensions. Can. J. Chem. Eng. 64: 353–363. 29 Bi, X.T. and Grace, J.R. (1995). Flow Regime maps for gas–solids fluidization and upward transport. Int. J. Multiphase Flow 21: 1229–1236. 30 Papa, G. and Zenz, F.A. (1995). Optimize performance of fluidized-bed reactors. Chem. Eng. Prog. 91 (4): 32–36. 31 Bi, X.T. and Grace, J.R. (1996). Effects of pressure and temperature on Flow Regimes in gas – solid fluidization systems. Can. J. Chem. Eng. 74 (6): 1025–1027. 32 Bi, X.T. (2011). A generalized Flow Regime diagram for fluid-particle vertical transport. In: Proceedings of the 10th Circulating Fluidized Bed Conference (ed. T. Knowlton), 129–136. Sunriver, OR: Engineering Conferences International. 33 Tsukada, M., Nakanishi, D., and Horio, M. (1993). The effect of pressure on the phase transition from bubbling to turbulent fluidization. Int. J. Multiphase Flow 19: 27–34. 34 Kai, T., Murakami, M., Yamasaki, K.I., and Takahashi, T. (1991). Relationship between apparent bed viscosity and fluidization quality in a fluidized bed with fine particles. J. Chem. Eng. Japan 24: 494–500. 35 Kai, T. and Furusaki, S. (1985). Behaviour of fluidized beds of small particles at elevated temperatures. J. Chem. Eng. Japan 18: 113–118. 36 Knowlton, T.M. (1992). Pressure and temperature effects in fluid-particle systems. In: Fluidization VII (eds. O.E. Potter and D.J. Nicklin), 27–46. New York: Engineering Foundation. 37 Rapagna, S., Foscolo, P.U., and Gibilaro, L.G. (1994). The influence of temperature on the quality of gas fluidization. Int. J. Multiphase Flow 20: 305–313. Problems 4.1 A stainless steel fluidized bed column has an internal diameter of 0.5 m...
eBook - ePubIntermittent Rivers and Ephemeral Streams
Ecology and Management
- Thibault Datry, Núria Bonada, Andrew J. Boulton(Authors)
- 2017(Publication Date)
- Academic Press(Publisher)
...If drying continues, hyporheic flows may also cease – Intermittence and drying have major consequences for aquatic ecosystem structure and functioning and so it is important to describe Flow Regimes of IRES. Data from gauging stations can be summarized into hydrological metrics (e.g., variance in frequency, duration, and timing of intermittence) and supplemented by wet-dry mapping, various forms of imagery, and modeling to classify riverine regimes – These classifications show that IRES are globally abundant and that across much of the world, flow intermittence is increasing through climatic drying and greater rates of water extraction 2.2.1 Introduction The Flow Regime of a river is defined as the temporal variability of its discharge, particularly the quantity, timing, and variability in flow (Poff et al., 1997 ; Nilsson and Renöfält, 2008 ; Sauquet et al., 2008). Flow Regimes are generally expressed as statistical generalizations of hydrological phenomena (e.g., seasonal runoff patterns, median annual discharge, mean, and variance of peak flows) at a particular location over multiple years or decades (Thoms and Sheldon, 2000). Alternatively, Flow Regimes may be summarized as probability distribution functions of daily flows (e.g., Doyle et al., 2005) to provide information on average water availability, the extent of discharge fluctuations, and the frequency of high and low flows (Botter et al., 2013). Whatever form is used, information about Flow Regimes is crucial to most research programs and management strategies in rivers because of the central role played by discharge and its temporal variability in governing geomorphology, water quality, and ecology (Box 2.2.1)...
eBook - ePubWell Productivity Handbook
Vertical, Fractured, Horizontal, Multilateral, Multi-fractured, and Radial-Fractured Wells
- Boyun Guo(Author)
- 2019(Publication Date)
- Gulf Professional Publishing(Publisher)
...To analyze the TPR of multiphase oil wells correctly, a multiphase flow model is required. Multiphase flow is much more complicated than single-phase flow due to the variation of Flow Regime (or flow pattern). The fluid distribution changes greatly between different Flow Regimes, which significantly affects the pressure gradient in the tubing. 4.3.1. Flow Regimes At least five Flow Regimes have been identified in gas–liquid two-phase flow. They are bubble, slug, churn, annular, and mist flow. These Flow Regimes occur in a progression displaying increasing gas flow rate for any fixed rate of liquid flow. In bubble flow, the gas phase is dispersed in the form of small bubbles within a continuous liquid phase. In slug flow, small gas bubbles coalesce into larger bubbles that eventually fill the entire pipe cross section. Between the large bubbles are slugs of liquid that contain smaller bubbles of entrained gas. In churn flow, the larger gas bubbles become unstable and collapse, resulting in a highly turbulent flow pattern with both phases dispersed. In annular flow, gas becomes the continuous phase, with liquid flowing in an annulus coating the surface of the pipe and as droplets entrained in the gas phase. In mist flow, dispersed liquid droplets move in the continuous gas phase, forming a relatively homogeneous fluid emulsion. 4.3.2. Liquid holdup In multiphase flow, the volume of pipe occupied by a particular phase is often different from its proportion of the total volumetric flow. This is due to density differences between phases. Gravity causes the denser phases to slip down within the upward flow—that is, the lighter phase rises faster than the denser phase. Because of this, the in-situ volume fraction of the denser phase will be greater than the input volume fraction of the denser phase; the denser phase is “held up” in the pipe relative to the lighter phase...
