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Sunday, July 26, 2020 | History

2 edition of Turbulent friction in eccentric annular conduits found in the catalog.

Turbulent friction in eccentric annular conduits

Robertson, James M.

Turbulent friction in eccentric annular conduits

by Robertson, James M.

  • 320 Want to read
  • 16 Currently reading

Published in Urbana .
Written in English

    Subjects:
  • Turbulence.,
  • Sewerage.

  • Edition Notes

    Statementby James M. Robertson.
    The Physical Object
    Pagination63 p.
    Number of Pages63
    ID Numbers
    Open LibraryOL224130M
    LC Control Numbera 68007936

    gravity, and the type of flow (i.e. laminar or turbulent). Laminar-Turbulent velocity profile transition for flows in concentric Annuli, Parallel Plates and Pipes were modeled numerically by Ogawa et al. () to predict the velocity profile and the pressure gradient. A theoretical analysis by using the method of characteristics for.   In turbulent flow, wall roughness increases the heat transfer coefficient h by a factor of 2 or more [Dipprey and Sabersky ()].The convection heat transfer coefficient for rough tubes can be calculated approximately from the Nusselt number relations such as Eq. 19–81 by using the friction factor determined from the Moody chart or the Colebrook equation.

      In the typical case where the oil density differs from that of the lubricant and skin fluid, there is a net transverse buoyancy force so that the underlying configuration is unlikely to be concentric. A uniform eccentric annular flow generates only axial pressure gradients and cannot support density differences. As previously recognized, 24 G. Pressure-loss form. In a cylindrical pipe of uniform diameter D, flowing full, the pressure loss due to viscous effects Δp is proportional to length L and can be characterized by the Darcy–Weisbach equation: = ⋅ ⋅, where the pressure loss per unit length Δp / L (SI units: Pa/m) is a function of. ρ, the density of the fluid (kg/m 3); D, the hydraulic diameter of the pipe (for a pipe.

    In , Luo and Peden [2] analyzed the eccentric annular flow of non-Newtonian fluids with a new method where an eccentric annulus represented by Newtonian and non-Newtonian fluids in conduits of arbitrary cross-section. And they also studied the turbulent kinetic energy and turbulent .   Friction Factor-Pipe Flow Background for a Liquid Flow Through Annulus Calculator. A liquid flow through annulus calculator spreadsheet uses calculations that are very similar to those for flow through a pipe. The main difference is use of the hydraulic diameter for flow through an annulus in place of the pipe diameter as used for pipe flow.


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Turbulent friction in eccentric annular conduits by Robertson, James M. Download PDF EPUB FB2

A one-layer turbulent eddy-viscosity model is proposed for annular flow. The model is based on the mixing-length approach wherein a damping function is used to account for near wall effects.

Drag reduction effects are simulated with a variable damping parameter in the eddy-viscosity by: 6. Turbulent flow in concentric and eccentric annuli is numerically simulated as part of an investigation aimed at modeling drilled cuttings transport in wellbores.

A numerical code is developed to solve the time-averaged momentum equation wherein the Reynolds stresses Cited by: An extension to annular conduits of the well‐known method of calculating the resistance coefficient for turbulent flow in circular pipes is presented.

The method is new in that it does not borrow any information from laminar flow theory; it gives, therefore, a location for the maximum velocity based only on turbulent flow by: 8. Abstract.

An eccentric annular duct is a prototype element in a number of engineering applications. Numerous modeling and experimental efforts have been made to investigate the details of the flow field and heat transfer characteristics in such kind of ducts [1, 2, 3].Cited by: A broad variety of friction factor correlations for turbulent concentric and eccentric annular flow is available in the literature.

For instance, for the fully eccentric annular turbulent flow of. Turbulent flow in the annular gap between two concentric tubes of 38 and 95 mm diameter at Reynolds number of 79’ is experimentally investigated.

Measurements are conducted using planar particle image velocimetry (PIV) with spatial resolution of 23 \(\upmu \) m/pix and interrogation windows of \(\times \) mm \(^{2}\). turbulent and partly turbulent, may exist at the same Reynolds number but different geometrical configurations (see figure 1).

An eccentric annular duct is a prototype element in a number of engineering applications. Close-packed tubular heat exchangers and coolant channels of nuclear reactor containing clusters of fuel pins are few examples.

In hydraulic engineering, turbulent flow is the most encountered flow regime in closed conduits. Because of the difficulty and complexity of the turbulence mechanism dominated by fluctuations, it is very important to model the turbulence mechanism correctly.

Numerous models are developed by researchers in order to characterize turbulence. Dosunmu and Shah [2] developed a turbulent friction factor correlation that includes wall roughness for straight pipe and annular flow. diameter definition of equivalent diameter for an eccentric annulus provided the best annular of annular conduit.

Studies show that a boundary layer on the inner wall of the annular flow has smaller turbulent kinetic energy than the outer wall for the same volume [2].

This study initially investigates the effect of water flow on the Darcy friction coefficient (hereafter referred to as friction factor or f). Keywor ds: Annular conduit, turbulence, eddies, law of the wall, resistance coefficient, fluid mechanics.

1 Introduction The present paper reports an experimental study of turbulent flow. Also ‘Turbulent Flow’, NACA-TMRehme, K. Pressure drop performance of rod bundles in hexagonal arrangements.

Intl J. Heat Mass Transfer 15 (12), – 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.

15 Concentri Annular Data Plotted in V + vs Y+ 46 c co-ordinates Profil in the 50% Eccentric Annulu ast 0 = 0 4e7 17 Profil in the 50% Eccentric Annulus a 9=t e° 48 18 Profile Perpendicular to the Inner Wall in the 49 s 50% Eccentric Annulus Profile Perpendicular to the Outer Wall in the 50 s 50% Eccentric Annulus.

This paper deals with heat transfer to air (Prandtl number ⋍ ) in fully-developed turbulent flow in an annular passage, the outer boundary of which is insulated. Experiments have been conducted on annuii whose radius ratios are, and over a Reynolds number range 10 –50 The turbulent flow of air through the annular gap between two tubes was studied experimentally, both with the tubes concentric and with the inner tube at eccentricities of 50% and %.

Air velocities were measured using small traversable impact tubes. The shear stresses on the boundaries were studied both by measuring the pressure gradient and by means of a calibrated shear probe attached to. Subsequent editions were published by Hydraulics Research Ltd.

inand by Thomas Telford Ltd. inin both cases with the title Tables for the hydraulic design of pipes and sewers and with Hydraulics Research Ltd as author 2 C.

Colebrook Turbulent flow in pipes, withparticular reference to the transition region between thesmooth and. A Numerical Approach for Modeling of Turbulent Newtonian Fluid Flow in Eccentric Annulus.

Teknik DergiDOI: /tekderg Idowu T. Dosunmu, Subhash N. Shah. Friction Pressure Prediction for Annular Flow of Power Law Fluids. Chemical Engineering Communications(10), DOI: / An analysis is presented of fully developed laminar flow in an eccentric annulus.

An exact solution for the velocity distribution is presented. From this solution may be obtained expressions for loca. Turbulent flow in rough conduits.

The Darcy friction factor for fully turbulent flow (Reynolds number greater than ) in rough conduits can be modeled by the Colebrook–White equation.

Free surface flow. The last formula in the Colebrook equation section of this article is for free surface flow. The approximations elsewhere in this article. laminar and turbulent flow. Friction factor definition based on turbulent flow analysis where.

τ τ µ w wo= (,)rV kρ thus n=6, m=3 and r=3 such that Π i=1,2,3 = 2 w V 8 f ρ τ =, Re VD VDρ µν = =, k/D; or f=f(Re, k/D) where k=roughness height.

For turbulent flow f determined from turbulence modeling since exact solutions not known. Subramanian, R.

and J. J. Azar, "Experimental Study on Friction Pressure Drop for Non-Newtonian Drilling Fluids in Pipes," Paper SPE presented at the SPE International Conference and Exhibition, Beijing, China, November (). Szabo, P. and O. Hassager, "Flow of Viscoplastic Fluids in Eccentric Annular Geometries," J.

Non-Newton. There are six candidate friction factor correlations that would be used for predicting the turbulent flow friction factor for purely viscous non-Newtonian fluids in an eccentric annulus. Appropriate values of geometric parameters ([0]) and ([1]) as formulated by Eq.'s (15) and (16) and turbulent hydraulic diameter ([]=[