Intermittent gas-liquid two-phase flow in helically coiled tubes

Zhu, Guangyu; Yang, Xingtuan; Jiang, Shengyao; Zhu, Hongye

doi:10.1016/j.ijmultiphaseflow.2019.04.013

Cited by 14 publications

(3 citation statements)

References 26 publications

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“…The pump performance is also affected by rotation. At higher rotational speed, centripetal force creates vortices, and pressure gradient and breaks essential airlock [1,[16][17][18]. This might result in a decrease in pressure and lift.…”

Section: Theorymentioning

confidence: 99%

Numerical study of a coil pump and comparison with field measurement

Pandey

Bijukchhe²,

Khanal³

et al. 2023

IOP Conf. Ser.: Mater. Sci. Eng.

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Rural irrigation could be challenging in regions without proper access to electricity. In many remote places of Nepal, where the irrigation takes place in the vicinity of a river stream, a river water pump or coil pump can be used to supply water from the lower river terrain to the field. Water powered coil pump is a reciprocating pump that operates by rotating a coiled tube, by harnessing the power of a flowing river. A comparison in performance of cylindrical and conical shaped coil pumps was done both experimentally as well as numerically in this work. Under the river velocity of 0.9m/s, the maximum discharge at zero lift condition for the conical pump was 11,500 liters/day while for the cylindrical pump it was 8,600 liters/day. However, the conical pump could not generate lift more than 6.5m while the cylindrical pump performed well even at 11m head. The Numerical study was also carried out in order to visualize the flow patterns and compare the performance of the pumps while varying different parameters. The 3D computation domain of the pump for four cases (two cases varying the number of turns and two cases with change in shape) were generated and numerically studied using OpenFOAM. The interaction, being a multiphase case, interFoam solver was used, and to simplify the simulation laminar turbulence model was taken. The pressure and water volume at the outlet in the simulation were measured and compared between different cases. It was observed that the pressure obtained while using a cylindrical pump was 2.52 % more than that while using the conical pump. The outlet pressure was found to be increasing by 35% while increasing the number of turns from 7 to 15 in cylindrical and 42.5% in case of conical coil pump. The volume flow rate was observed to be more frequent in the case of the conical pump. Due to constraints of computational conditions, the experimental setup could not be totally replicated. However, the outcome showed a similar trend as obtained in the experiment. It was found that the cylindrical pump was better for the higher head, whereas the conical pump had shown better results for higher discharge.

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Section: Theorymentioning

confidence: 99%

Numerical study of a coil pump and comparison with field measurement

Pandey

Bijukchhe²,

Khanal³

et al. 2023

IOP Conf. Ser.: Mater. Sci. Eng.

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“…The flow and heat transfer mechanisms of water within the helical tube structure include two-phase flow, asymmetric phase distribution and local dry-out, which have been studied by researchers (Shah, 2019;Zhu et al, 2019;Breitenmoser et al, 2021). Void et al (2014) used hightemperature sodium as the primary side heat source to heat low-temperature water on the secondary side of the H-OTSG.…”

Section: Introductionmentioning

confidence: 99%

Experimental study on helical tubes heat transfer characteristics considering corrosion products

Yulong,

Shuqi,

Xianghui

et al. 2023

Front. Energy Res.

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During the power operation of nuclear reactors, the corrosion products in the secondary circuit will deposit on the inside of Helical-coiled One-Through Steam Generator (H-OTSG) heat transfer tubes and form fouling. The main component of fouling is iron-based oxide, which generates from the heat exchangers made of cast iron. Fouling may change the local heat transfer characteristics of heat transfer tubes, and then affect the safety and economy of reactors. In order to obtain the distribution of fouling thickness and its action mechanism on helical tubes heat transfer characteristics, the heat transfer experiment under small pressurized reactors service environment was conducted. The experimental results indicate: corrosion products mainly deposit on onset of saturated boiling point with the maximum fouling thickness of 50 μm, and induce local wall temperature elevating about 773 K; fouling will increase the thermal equilibrium void fraction and hinder the heat transfer of helical tube, but has little impact on the onset position of saturated boiling point; corrosion products will release and re-deposit near dry-out point because of the flush of high speed vapor, causing the periodic fluctuation of thermal resistance of helical tube.

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“…In addition, often vertical, but not horizontal, helical reactors have been examined, e.g. (Che et al 2020;Colombo et al 2015;Li et al 2017;Liu et al 2015;Mandal and Das 2003;Mansour et al 2020b;Mei et al 2020;Murai et al 2006;Zhu et al 2017Zhu et al , 2019, since accumulation of bubbles in the upper part of the coils is avoided like that. Also micro-channels with Taylor bubble experiments, e.g.…”

Section: Introductionmentioning

confidence: 99%

Experimental characterization of mixing and flow field in the liquid plugs of gas–liquid flow in a helically coiled reactor

2021

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Flow mixing of two miscible liquids with the addition of gas bubbles is a process often found in industrial chemical apparatus for the production of primary matter. The ongoing optimization of such processes also involves the transformation of batch to continuous mode operation. In that case, the use of helically coiled tubes is an interesting alternative, since those reactors have narrow residence time distributions, very good radial mixing properties and excellent mass transfer can be realized between gases and liquids. For these reasons, in this study the mixing of two miscible liquids with addition of air bubbles in gas–liquid flows has been characterized in a horizontal helically coiled reactor in the laminar flow regime at $${\text{Re}}_{{{\text{total}}}} = 300 \ldots 1088$$ Re total = 300 … 1088 . Eight different superficial liquid velocities and five superficial gas velocities were investigated. In order to characterize mixing in the liquid plugs between two bubbles, laser-induced fluorescence of resorufin was used and particle image velocimetry has been employed to characterize the flow field. Pseudo-3D-visualizations of the resorufin concentration and the Q-criterion, representing the mixing efficiency and vorticity, respectively, were established for individual liquid plugs from the time-resolved measurement results. A time-resolved mixing coefficient, as well as a mean mixing coefficient obtained from multiple liquid plugs, is calculated from the fluorescence images for all examined flow conditions. The experimental results clearly show an increase in the mixing coefficient compared to single-phase conditions, caused by the bubbles. However, distinct mixing pattern, depending on the flow structure, can be recognized on different locations inside the liquid plug. Compared to a stationary case without air bubbles, mixing is worse behind the bubbles and increases inside the plug, reaching a maximum mixing coefficient in front of the next bubble. Overall the mixing coefficient is always increased by the presence of the bubbles. Pseudo-3D-visualizations of the Q-criterion and the vorticity show the presence of secondary vortices right in front of the bubbles, shifted to the outer tube walls, and in addition to the steady Dean vortices. In small plugs, these secondary vortices appear in the whole plug and increase the mixing coefficient drastically. Graphical Abstract

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Intermittent gas-liquid two-phase flow in helically coiled tubes

Cited by 14 publications

References 26 publications

Numerical study of a coil pump and comparison with field measurement

Numerical study of a coil pump and comparison with field measurement

Experimental study on helical tubes heat transfer characteristics considering corrosion products

Experimental characterization of mixing and flow field in the liquid plugs of gas–liquid flow in a helically coiled reactor

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