Laminar Flow in Curved Pipes

Ito, Haruko

doi:10.1002/zamm.19690491104

Cited by 114 publications

(5 citation statements)

References 10 publications

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“…The curves (a) and (b) correspond to Hasson's [79] (Equation ( 21)) and Van Dyke's [81] (Equation ( 24)) correlations, respectively. The measured De cr values indicating the onset of turbulence were found to agree fairly well with Ito's [73] (Equation ( 12)) and Srinivasan et al's [74] (Equation ( 13)) correlations for prediction of the critical Re values. It is clear from the left plot of Figure 4 that, with the exception of Van Dyke's correlation (24), the pressure drop predictions based on correlations (21) and (27) are in very good agreement with Liu et al's [36] experimental data for small helical pitch.…”

Section: Pressure Dropsupporting

confidence: 79%

“…Figure 11 shows the axial velocity profiles for various De values as compared with a straight pipe in the θ = 0 (left plot) and θ = 90 • planes (right plot). The numerically obtained friction factor for fully developed flow was also found to match Ito's [73] experimental measurements reasonably well. However, their numerical temperature profile along the θ = 0 plane did not reproduce the experimental profile that was reported by Mori and Nakayama [83] in the inside region (see their Figure 11).…”

Section: Numerical Simulations: Laminar Flowsupporting

confidence: 68%

“…The experimental measurements correspond to a test facility built at the SIET laboratories in Piacenza, Italy, which reproduces the helically coiled Steam Generator of the IRIS nuclear reactor [16]. The left frame of Figure 6 shows their measured Darcy friction factors for varying Re in the laminar regime, i.e., for Re 3200, where they are compared with Ito's [73] correlation. The predicted value of Re ≈ 3200 marks a first discontinuity and initiates a regime with lower friction factor up to Re ≈ 5000.…”

Section: Heat Transfermentioning

confidence: 99%

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Fluid Flow in Helically Coiled Pipes

Sigalotti,

Alvarado-Rodríguez,

Rendón

2023

Fluids

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Helically coiled pipes are widely used in many industrial and engineering applications because of their compactness, larger heat transfer area per unit volume and higher efficiency in heat and mass transfer compared to other pipe geometries. They are commonly encountered in heat exchangers, steam generators in power plants and chemical reactors. The most notable feature of flow in helical pipes is the secondary flow (i.e., the cross-sectional circulatory motion) caused by centrifugal forces due to the curvature. Other important features are the stabilization effects of turbulent flow and the higher Reynolds number at which the transition from a laminar to a turbulent state occurs compared to straight pipes. A survey of the open literature on helical pipe flows shows that a good deal of experimental and theoretical work has been conducted to derive appropriate correlations to predict frictional pressure losses under laminar and turbulent conditions as well as to study the dependence of the flow characteristics and heat transfer capabilities on the Reynolds number, the Nusselt number and the geometrical parameters of the helical pipe. Despite the progress made so far in understanding the flow and heat transfer characteristics of helical pipe flow, there is still much work to be completed to address the more complex problem of multiphase flows and the impact of pipe deformation and corrugation on single- and multiphase flow. The aim of this paper is to provide a review on the state-of-the-art experimental and theoretical research concerning the flow in helically coiled pipes.

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Section: Pressure Dropsupporting

confidence: 79%

Section: Numerical Simulations: Laminar Flowsupporting

confidence: 68%

Section: Heat Transfermentioning

confidence: 99%

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Fluid Flow in Helically Coiled Pipes

Sigalotti,

Alvarado-Rodríguez,

Rendón

2023

Fluids

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“…ciency significantly [31,32], but in the case of the human nose the bends are localized to the connecting regions, while the main nasal cavity is rather straight. We show in the SI that the overall function of the nose is only slightly affected by the bent geometry, consistent with numerical simulations [33].…”

Section: Geometric Constraints Imply Labyrinth-like Shapesmentioning

confidence: 99%

Physical and geometric constraints shape the labyrinth-like nasal cavity

Zwicker

Ostilla–Mónico

Lieberman

et al. 2018

Proc. Natl. Acad. Sci. U.S.A.

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The nasal cavity is a vital component of the respiratory system that heats and humidifies inhaled air in all vertebrates. Despite this common function, the shapes of nasal cavities vary widely across animals. To understand this variability, we here connect nasal geometry to its function by theoretically studying the airflow and the associated scalar exchange that describes heating and humidification. We find that optimal geometries, which have minimal resistance for a given exchange efficiency, have a constant gap width between their side walls, while their overall shape can adhere to the geometric constraints imposed by the head. Our theory explains the geometric variations of natural nasal cavities quantitatively, and we hypothesize that the trade-off between high exchange efficiency and low resistance to airflow is the main driving force shaping the nasal cavity. Our model further explains why humans, whose nasal cavities evolved to be smaller than expected for their size, become obligate oral breathers in aerobically challenging situations.

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“…Dean [2,3] was the first to investigate the hydrodynamics of a curved channel flow, and a single parameter, the Dean number was defined to characterize the flow phenomena of Newtonian fluids in a curved channel. It o [4] investigated the steady laminar flow in a curved channel with circular cross-section, and derived a formula for the friction factor of the curved channel. Berger et al [5] comprehensively reviewed the study of the flow of Newtonian fluids in curved pipes.…”

Section: Introductionmentioning

confidence: 99%