The friction factor–Reynolds number relation for the steady flow of pseudoplastic fluids through rectangular ducts. Part II. Experimental results

AIChE Journal ◽  
1965 ◽  
Vol 11 (2) ◽  
pp. 212-216 ◽  
Author(s):  
John A. Wheeler ◽  
Eugene H. Wissler
Keyword(s):  
Reynolds Number ◽  
Friction Factor ◽  
Steady Flow ◽  
Experimental Results ◽  
Pseudoplastic Fluids ◽  
Number Relation

Measurements of Resistance of Individual Square-Mesh Screens to Oscillating Flow at Low and Intermediate Reynolds Numbers

2003 ◽  
Vol 125 (5) ◽  
pp. 851-862 ◽  
Author(s):  
Ray Scott Wakeland ◽  
Robert M. Keolian
Keyword(s):  
Reynolds Number ◽  
Friction Factor ◽  
Steady Flow ◽  
Oscillation Amplitude ◽  
Low Frequency ◽  
Reynolds Numbers ◽  
Oscillating Flow ◽  
Pressure Losses ◽  
Approach Velocity ◽  
Flow Resistances

Measurements are reported of pressure losses across single screens subjected to low-frequency oscillating flow for 0.002≲Red≲400, where Red is Reynolds number based on wire diameter and peak approach velocity. Several correlation methods are examined. Extensive comparisons are made between present oscillating-flow results and previous reports of the resistance of screens to steady flow. Defining oscillating results in terms of peak amplitudes, the oscillating and steady-flow resistances are found to be the same, including behavior in the intermediate Reynolds number region that departs from correlations of the form ARe−1+B. The friction factor is also found to depend on Reynolds number, but not independently on oscillation amplitude, over the range of conditions measured.

Experiments on laminar flow in curved channels of square section

1971 ◽  
Vol 48 (3) ◽  
pp. 417-422 ◽  
Author(s):  
J. A. Baylis
Keyword(s):  
Reynolds Number ◽  
Numerical Analysis ◽  
Laminar Flow ◽  
Friction Factor ◽  
Experimental Results ◽  
Radius Of Curvature ◽  
Dean Number ◽  
Rectangular Section ◽  
Curved Channels ◽  
Channel Dimension

Recently Cheng & Akiyama (1970) published a numerical analysis of laminar flow in curved channels of square and rectangular section. Experimental results are presented here for flow in curved channels of square section. The channels were toroidal in shape, and the flow was driven electromagnetically. Various ratios of the channel dimension d to the channel radius of curvature, R, were used to investigate the dependence of friction factor, f, on the Dean number K, and the Reynolds number, Re. For 5 × 102 < K < 7 × 104 the formula (fRe) = 1·51 K½ was found to fit all the results, although R/d was varied from 17·5 down to the low value of 1·75. At lower values of K the analysis of Cheng & Akiyama was approximately validated.

Numerical and Experimental Analysis of Turbulent Flow in Corrugated Pipes

2010 ◽  
Vol 132 (7) ◽  
Author(s):  
Henrique Stel ◽  
Rigoberto E. M. Morales ◽  
Admilson T. Franco ◽  
Silvio L. M. Junqueira ◽  
Raul H. Erthal ◽  
...  
Keyword(s):  
Reynolds Number ◽  
Pressure Drop ◽  
Turbulent Flow ◽  
Friction Factor ◽  
Turbulence Models ◽  
Reynolds Numbers ◽  
Velocity Magnitude ◽  
Geometric Configurations ◽  
Corrugated Surfaces ◽  
Friction Factors

This article describes a numerical and experimental investigation of turbulent flow in pipes with periodic “d-type” corrugations. Four geometric configurations of d-type corrugated surfaces with different groove heights and lengths are evaluated, and calculations for Reynolds numbers ranging from 5000 to 100,000 are performed. The numerical analysis is carried out using computational fluid dynamics, and two turbulence models are considered: the two-equation, low-Reynolds-number Chen–Kim k-ε turbulence model, for which several flow properties such as friction factor, Reynolds stress, and turbulence kinetic energy are computed, and the algebraic LVEL model, used only to compute the friction factors and a velocity magnitude profile for comparison. An experimental loop is designed to perform pressure-drop measurements of turbulent water flow in corrugated pipes for the different geometric configurations. Pressure-drop values are correlated with the friction factor to validate the numerical results. These show that, in general, the magnitudes of all the flow quantities analyzed increase near the corrugated wall and that this increase tends to be more significant for higher Reynolds numbers as well as for larger grooves. According to previous studies, these results may be related to enhanced momentum transfer between the groove and core flow as the Reynolds number and groove length increase. Numerical friction factors for both the Chen–Kim k-ε and LVEL turbulence models show good agreement with the experimental measurements.

A Combined Packed-Bed Friction Factor Equation: Extension to Higher Reynolds Number with Wall Effects

AIChE Journal ◽  
2013 ◽  
Vol 59 (3) ◽  
pp. 703-706 ◽  
Author(s):  
Luke D. Harrison ◽  
Kyle M. Brunner ◽  
William C. Hecker
Keyword(s):  
Reynolds Number ◽  
Friction Factor ◽  
Packed Bed ◽  
Wall Effects ◽  
Bed Friction ◽  
Factor Equation

Thermal Performance Assessment of Turbulent Flow Through Dimpled Tubes

2010 ◽  
Author(s):  
Pornchai Nivesrangsan ◽  
Somsak Pethkool ◽  
Kwanchai Nanan ◽  
Monsak Pimsarn ◽  
Smith Eiamsa-ard
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Friction Factor ◽  
Heat Transfer Rate ◽  
Thermal Performance ◽  
Transfer Rate ◽  
Staggered Arrangement ◽  
Plain Tube ◽  
Pitch Ratio ◽  
Surface Patterns

This paper presents the heat transfer augmentation and friction factor characteristics by means of dimpled tubes. The experiments were conducted using the dimpled tubes with two different dimpled-surface patterns including aligned arrangement (A-A) and staggered arrangement (S-A), each with two pitch ratios (PR = p/Di = 0.6 and 1.0), for Reynolds number ranging from 9800 to 67,000. The experimental results achieved from the dimpled tubes are compared with those obtained from the plain tube. Evidently, the dimpled tubes with both arrangements offer higher heat transfer rates compared to the plain tube and the dimpled tube with staggered arrangement shows an advantage on the basis of heat transfer enhancement over the dimpled tube with aligned arrangement. The increase in heat transfer rate with reducing pitch ratio is due to the higher turbulent intensity imparted to the flow between the dimple surfaces. The mean heat transfer rate offered by the dimpled tube with staggered arrangement (S-A) at the lowest pitch ratio (PR = 0.6), is higher than those provided by the plain tube and the dimpled tube with aligned arrangement (A-A) at the same PR by around 127% and 8%, respectively. The empirical correlations developed in terms of pitch ratio (PR), Prandtl number (Pr) and Reynolds number, are fitted the experimental data within ±8% and ±2% for Nusselt number (Nu) and friction factor (f), respectively. In addition, the thermal performance factors under an equal pumping power constraint of the dimple tubes for both dimpled-surface arrangements are also determined.

Heat Transfer And Pressure Drop Of An Angled Discrete Turbulator At Elevated Reynolds Numbers Up To 900,000

2021 ◽  
pp. 1-29
Author(s):  
Sam Ghazi-Hesami ◽  
Dylan Wise ◽  
Keith Taylor ◽  
Peter Ireland ◽  
Étienne Robert
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Pressure Drop ◽  
Friction Factor ◽  
Rectangular Channel ◽  
Reynolds Numbers ◽  
Enhance Heat Transfer ◽  
Near Surface ◽  
Number Range ◽  
Smooth Channel

Abstract Turbulators are a promising avenue to enhance heat transfer in a wide variety of applications. An experimental and numerical investigation of heat transfer and pressure drop of a broken V (chevron) turbulator is presented at Reynolds numbers ranging from approximately 300,000 to 900,000 in a rectangular channel with an aspect ratio (width/height) of 1.29. The rib height is 3% of the channel hydraulic diameter while the rib spacing to rib height ratio is fixed at 10. Heat transfer measurements are performed on the flat surface between ribs using transient liquid crystal thermography. The experimental results reveal a significant increase of the heat transfer and friction factor of the ribbed surface compared to a smooth channel. Both parameters increase with Reynolds number, with a heat transfer enhancement ratio of up to 2.15 (relative to a smooth channel) and a friction factor ratio of up to 6.32 over the investigated Reynolds number range. Complementary CFD RANS (Reynolds-Averaged Navier-Stokes) simulations are performed with the κ-ω SST turbulence model in ANSYS Fluent® 17.1, and the numerical estimates are compared against the experimental data. The results reveal that the discrepancy between the experimentally measured area averaged Nusselt number and the numerical estimates increases from approximately 3% to 13% with increasing Reynolds number from 339,000 to 917,000. The numerical estimates indicate turbulators enhance heat transfer by interrupting the boundary layer as well as increasing near surface turbulent kinetic energy and mixing.

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