Effect of wall roughness in turbulent pipe flow of a pseudoplastic crude oil: An evaluation of pipeline field data

Hemeida, Adel M.

doi:10.1016/0920-4105(93)90039-h

Cited by 7 publications

(3 citation statements)

References 7 publications

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“…The results quantified the delay in transition from laminar to turbulent flow caused by shear-thinning, the suppression of turbulent fluctuations, and the drag reduction at high Reynolds numbers. Hemeida (8) presented an equation for estimating the thickness of the laminar sublayer in turbulent pipe flow of pseudoplastic fluids and validated the friction factors against the reported correlations and field measurements. It was found that the hydraulically smooth pipes can be used to determine the pressure loss in the tested pipeline because the thickness of the laminar sublayer was greater than the average roughness height.…”

Section: Introductionmentioning

confidence: 82%

Computational Fluid Dynamics Investigation of Turbulence Models for Non-Newtonian Fluid Flow in Anaerobic Digesters

Wu¹

2010

Environ. Sci. Technol.

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In this paper, 12 turbulence models for single-phase non-newtonian fluid flow in a pipe are evaluated by comparing the frictional pressure drops obtained from computational fluid dynamics (CFD) with those from three friction factor correlations. The turbulence models studied are (1) three high-Reynolds-number k-ε models, (2) six low-Reynolds-number k-ε models, (3) two k-ω models, and (4) the Reynolds stress model. The simulation results indicate that the Chang-Hsieh-Chen version of the low-Reynolds-number k-ε model performs better than the other models in predicting the frictional pressure drops while the standard k-ω model has an acceptable accuracy and a low computing cost. In the model applications, CFD simulation of mixing in a full-scale anaerobic digester with pumped circulation is performed to propose an improvement in the effective mixing standards recommended by the U.S. EPA based on the effect of rheology on the flow fields. Characterization of the velocity gradient is conducted to quantify the growth or breakage of an assumed floc size. Placement of two discharge nozzles in the digester is analyzed to show that spacing two nozzles 180° apart with each one discharging at an angle of 45° off the wall is the most efficient. Moreover, the similarity rules of geometry and mixing energy are checked for scaling up the digester.

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Section: Introductionmentioning

confidence: 82%

Computational Fluid Dynamics Investigation of Turbulence Models for Non-Newtonian Fluid Flow in Anaerobic Digesters

Wu¹

2010

Environ. Sci. Technol.

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“…Thus, Torrance (1963) and Szilas et al (1981) have incorporated a small correction to account for pipe roughness in their expressions for the turbulent fl ow of power-law and Bingham plastic fl uids; under fully turbulent conditions, it is assumed that the value of the friction factor is determined only by pipe roughness and rheological properties, and is independent of the Reynolds number. However, in view of the fact that laminar sub-layers tend to be somewhat thicker for non-Newtonian fl uids than that for Newtonian liquids, the effect of pipe roughness is likely to be small for time-independent fl uids ( Bowen, 1961 ;Hemeida, 1993 ;Wojs, 1993 ). Despite this, Govier and Aziz (1982) recommend the use of the same function of relative roughness for time-independent fl uids as for Newtonian systems.…”

Section: Effect Of Pipe Roughnessmentioning

confidence: 99%

Flow in Pipes and in Conduits of Non-circular Cross-sections

Chhabra

Richardson

2008

Non-Newtonian Flow and Applied Rheology

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“…">Literature OverviewIn the past years, many scholars studied the effect of wall roughness on the flow in pipes, fans, compressors, microchannels. In order to study the effect of wall roughness in turbulent pipe flow, Hemeida [17] developed an equation for estimating the thickness of the laminar sublayer in turbulent pipe flow of pseudoplastic fluids and found that the turbulent pipe flow could be divided into two regions: smooth wall and rough wall turbulence. The roughness Reynolds number was used to determine the smooth wall turbulence and rough wall turbulence regions.…”

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confidence: 99%

Influence of Critical Wall Roughness on the Performance of Double-Channel Sewage Pump

Zhang

Wang

et al. 2020

Energies

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The numerical method on a double-channel sewage pump was studied, while the corresponding experimental result was also provided. On this basis, the influence of wall roughness on the pump performance was deeply studied. The results showed that there was a critical value of wall roughness. When the wall roughness was less than the critical value, it had a great influence on the pump performance, including the head, efficiency, and shaft power. As the wall roughness increased, the head and efficiency were continuously reduced, while the shaft power was continuously increased. Otherwise, the opposite was true. The effect of wall roughness on the head and hydraulic loss power was much smaller than that on the efficiency and disk friction loss power, respectively. With the increase of wall roughness, mechanical efficiency and hydraulic efficiency reduced constantly, leading to the decrement of the total efficiency. With the increase of flow rate, the effect of wall roughness on the head and efficiency gradually increased, while the influence on the leakage continuously reduced. The influence of the flow-through component roughness on the pump performance was interactive.Energies 2020, 13, 464 2 of 20 Literature OverviewIn the past years, many scholars studied the effect of wall roughness on the flow in pipes, fans, compressors, microchannels. In order to study the effect of wall roughness in turbulent pipe flow, Hemeida [17] developed an equation for estimating the thickness of the laminar sublayer in turbulent pipe flow of pseudoplastic fluids and found that the turbulent pipe flow could be divided into two regions: smooth wall and rough wall turbulence. The roughness Reynolds number was used to determine the smooth wall turbulence and rough wall turbulence regions. Kandlikar [18] studied the roughness effects at microscale-reassessing Nikuradse's experiments on liquid flow in rough tubes, and found that Nikuradse's work was revisited in light of the recent experimental work on roughness effects in microscale flow geometries. Li et al. [19] studied the influence of the internal surface roughness of the nozzle on cavitation erosion characteristics of submerged cavitation jets from the aspects of erosion intensity and erosion efficiency; it could be concluded that excessive smooth surface was not conducive to the formation of cavitation bubbles, leading to an attenuated intensity of cavitation erosion, while excessive rough surface caused much energy dissipation and led to divergent jets, resulting in a significant reduction of erosion intensity. According to the experimental results, there existed an optimum inner surface roughness value to achieve the strongest aggressive cavitation erosion capability for submerged cavitating jets. Tang et al. [20] analyzed the existing experimental data in the literature on the friction factor in microchannels. The friction factors in stainless steel tubes were much higher than the theoretical predictions for tubes of conventional size. This discrepancy resulted from the large rel...

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Effect of wall roughness in turbulent pipe flow of a pseudoplastic crude oil: An evaluation of pipeline field data

Cited by 7 publications

References 7 publications

Computational Fluid Dynamics Investigation of Turbulence Models for Non-Newtonian Fluid Flow in Anaerobic Digesters

Computational Fluid Dynamics Investigation of Turbulence Models for Non-Newtonian Fluid Flow in Anaerobic Digesters

Flow in Pipes and in Conduits of Non-circular Cross-sections

Influence of Critical Wall Roughness on the Performance of Double-Channel Sewage Pump

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