2 edition of **On the velocity fields in eccentric annuli** found in the catalog.

On the velocity fields in eccentric annuli

T W. Ricker

- 171 Want to read
- 20 Currently reading

Published
**1968**
by American Society of Mechanical Engineers
.

Written in English

**Edition Notes**

Statement | [by]T.W. Ricker,N. W. Wilson, J. H. T. Wade. |

Contributions | Wilson, N W., Wade, J H T., American Society of Mechanical Engineers. |

The Physical Object | |
---|---|

Pagination | 7p. |

ID Numbers | |

Open Library | OL20663783M |

The laminar eccentric annular flow of non-Newtonian fluids is analyzed with a new method where an eccentric ammulus is represented by an infinite number of concentric annuli with variable outer radii. increase on the axial and tangential velocity at the narrowest gap, which have positive effects on the cuttings removal process. Keywords: drill pipe rotation, eccentric annuli, CFD. INTRODUCTION With the discovery of new oil fields, the horizontal drilling process became an attractive process, due to the increase of the contact area of.

Estimation of pressure losses and deposition velocities is vital in the hydraulic design of annular drill holes in the petroleum industry. The present study investigates the effects of fluid velocity, fluid type, particle size, particle concentration, drill string rotational speed, and eccentricity on pressure losses and settling conditions using computational fluid dynamics (CFD). Reynolds-averaged modeling is performed for polymer-induced drag reduction (DR) fluid at the fully developed turbulent regime in a concentric annulus by using the commercial code, numerical approach adopted in this study relies on a modified k–ε– v 2 ¯ –f model to characterize the turbulence and the finitely extensible nonlinear elastic-Peterlin (FENE-P) constitutive.

Velocity Profiles: For an eccentric annulus, the coordinate system was centred at the inner tubing axis and used to define the conventional planes for velocity profile analysis. A cross section of the annular geometry and the grid arrangement for a typical numerical calculation are shown in Figure 7. • A comparison is made between the concentric and eccentric annuli. • The data presented herein may be useful for those who want to outline the hydrodynamics characteristics for this kind of devices and fluids, therefore, avoiding a great effort for achieving a high number of experiments.

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Velocity profiles, and the viscosity profiles are compared to widely used substitutes: the average velocity and the apparent viscosity, respectively. A correlation based on the model generated data is developed that permits for an easy calculation of the frictional pressure losses in eccentric annuli.

An eccentric annulus is characterized by the eccentric angle of the inner cylinder, φ. To study the effect of eccentric angle on the natural convection characteristics in an eccentric annulus, computations were carried out for R = 2, ɛ =Pr =Ra = 10 4, Da = and E cc = at various φ for cases 1 and 2 (T i * > T o *).The eccentricity, E cc, is definied as E cc = E/D i.

The geometry of the eccentric annulus is shown in Fig. inner pipe of radius R rotates with angular velocity ω relative to a stationary outer pipe of radius R 0; e is the eccentricity.

To describe the nonlinear viscosity of the fluid between eccentric cylinders, the concept of fluidity developed by Kutateladze et al. is used. They define fluidity ϕ(τ) as the reciprocal of the viscosity Cited by: For eccentric annuli with small e* and r*, the Nusselt numbers are approximately the same as those for the corresponding concentric annuli for small x*.

With increasing e* and r*, the deviation between Nusselt numbers of eccentric and concentric annuli starts at smaller and smaller values of x*. Vilenskii et al. [] also presented fully. Developing turbulent flow in concentric annuli: An analytical and experimental study. Wärme- und Stoffübertragung4 (3), DOI: /BF D.

Roy, U. Gangopadhay. Turbulent friction factor and velocity profile in smooth by: This research work presents results obtained from the simulation of natural convection inside a concentric hexagonal annulus by using the lattice Boltzmann method (LBM).

The fluid flow (pressure and velocity fields) inside the annulus is evaluated by LBM and a finite difference method (FDM) is used to get the temperature filed. The isothermal and no-slip boundary conditions (BC) on the.

ents, in concentric and eccentric annuli, of flows of different non-Newtonian fluids, evaluating their ef-fects on the hydrodynamics of these systems.

Further-more, it is also important to evaluate velocity fields in order to identify areas of preferential flows and stagnation zones, because they directly affect the. However for eccentric annuli, flow field cannot be axisymmetric anymore and the velocity distribution depends highly on the level of buoyancy.

When forced convection is dominant, the peak of velocity happens in the widest part of the cross section (θ = −90).

An experimental investigation of primary and secondary velocity for turbulent flow in eccentric annuli. The Canadian Journal of Chemical Engineering, Vol. 49, Issue. 2, p. The Canadian Journal of Chemical Engineering, Vol.

49, Issue. 2, p. The solution is in excellent agreement with the two published limiting cases of slip flow through concentric annuli and no-slip flow through eccentric annuli. It is shown that for a fixed aspect ratio, fully eccentric channels sustain the maximum average velocity (flow rate) under the same pressure gradient and slip conditions.

Laminar combined convection of non-Newtonian fluids in vertical eccentric annuli, in which the inner and outer walls are held at different constant temperatures is considered and a new economical method of solution for the three-dimensional flow in the annulus is developed.

Assuming that the ratio of the radial to the vertical scale, ε, is small, as occurs frequently in many industrial. Velocity profiles from experimental (Nouri and Whitelaw) and numerical investigation (Neto et.

al) in concentric and eccentric annuli in comparison to own CFD results. There is good agreement between our numerical simulation and the data of Nouri and Whitelaw [ 18 ] and Neto et al.

[ 17 ] for the concentric case. Flow visualization, laser Doppler velocimetry and planar and stereoscopic particle image velocimetry were used to investigate the isothermal velocity field along an eccentric annular channel with a diameter ratio of and an eccentricity of for a Reynolds number of A two-dimensional model is derived of the displacement flows that occur during primary cementing of oil and gas wells.

The displacement geometry is a long narrow eccentric annulus, between the casing and the rock formation. The model consists of a series of first-order convection equations for the fluid concentrations and a quasi-linear Poisson-type equation for the stream function.

This approximation leads to a two-dimensional model to determine the three components of the velocity field in a cross-section of the annulus.

The model presented in this work takes into account the variation of the eccentricity along the well; a more appropriate description of the geometric configuration of directional wells.

Experimental data for the eccentric annuli experiments covered the radius ratio of andwith the eccentricity parameter range from 0 to The energy equation for a fully developed temperature profile and constant heat flux was integrated numerically, using assumed fully developed velocity and thermal diffusivity profiies based.

The problem of the simultaneously developing turbulent flow and heat transfer in concentric annuli was studied from an integral viewpoint, based on a modified model for the eddy diffusivity of momentum together with a new ratio of eddy diffusivities obtained from experiment.

Viscosity profiles predicted for an eccentric annulus show how misleading the widely used single-value apparent viscosity term can be for non-Newtonian fluids. Profiles of velocity and viscosity in concentric and varying eccentric annuli are presented in 3-D and 2.

One of the earliest studies of Newtonian flow in eccentric annuli was that of Piercy et al, who presented analytical solution for laminar velocity field. Using bipolar coordinate transformation, Snyder and Goldstein14 obtained expressions for friction factor and circumferential wall shear stress distributions in eccentric annuli.

Reynolds number range varied f to 66, Axial mean velocity profile was found to be following the universal wall law (u + = y +) in the viscous sublayer (y + 30).

Radial position of zero shear stress and maximum velocity were found to. Velocity profiles were measured for a Newtonian glycerol/water mixture and a non-Newtonian oil field spacer fluid in eccentric annuli using the stroboscopic flow visualization [email protected]{osti_, title = {Laminar mixed convection in a horizontal eccentric annulus}, author = {Choudhury, D and Karki, K}, abstractNote = {Laminar fluid flow and heat transfer phenomena in cylindrical annuli are encountered in various applications.

The purpose of this paper is to present a numerical study of laminar mixed convection in horizontal eccentric annuli.Experimental data for the eccentric annuli experiments covered the radius ratio of andwith the eccentricity parameter range from 0 tomore» The energy equation for a fully developed temperature profile and constant heat flux was integrated numerically, using assumed fully developed velocity and thermal diffusivity profiies based.