Research progress on the hydrodynamic performance of water-air-bubble mixed flows around a ship

Li, Zheng; Zhang, Xiaosong; Wan, Decheng

doi:10.1007/s42241-022-0026-3

Cited by 14 publications

(5 citation statements)

References 92 publications

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“…In water-air two-phase flow, there are many factors that affect water-air mixing (Li et al, 2022). When the turbulent boundary layer develops to the water surface and the flow turbulence reaches a certain intensity, the vortex body near the water surface, jumps out of the water surface to form water droplets or water surface waves.…”

Section: Aeration Concentration Distributionmentioning

confidence: 99%

Aeration strength analysis of overflow weir in siphon well based on numerical simulation of water–air two‐phase flow

Liu,

Lin,

Huang

et al. 2023

River

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The phenomenon of water aeration is serious after the overflow weir in the siphon well at the cooling water circulation system of coastal power plants. At present, designing special hydraulic structures is an effective way to reduce the intensity of aeration. In this paper, three engineering structure schemes were designed, and the three‐dimensional Realizable k–ε turbulence model was used. The volume of fluid method was introduced to capture the free water surface, and the unstructured grid was used to construct the two‐phase turbulent flow field. The aeration concentration and pressure distribution, obtained by numerical simulation, were basically consistent with the physical model test results. The results showed that the flow field at the orifice plates of cases 1 and 2 changed drastically, and the turbulent kinetic energy downstream of the orifice plate decreased with the increase of the number of holes. As for case 3, it showed that the high‐speed water flow fell into the water cushion pool, tumbling and sucking up a lot of air, and the turbulent kinetic energy and Reynolds stress were significantly greater than the other two cases. The hydraulic structure changed the cavitation characteristics of the downflow water, and the sequence of aeration concentration of the horizontal section was case 3 > case 1 > case 2. The aeration concentration was only 9.18%–17.86% in case 2. The aeration concentration at stable time is expressed as a function of the relative water depth y/y90 and the turbulent diffusion coefficient D. The distribution formula of aeration concentration was established, and its validity was verified by literatures. The results of this study will provide a certain reference for in‐depth analysis of water–air mixing motion characteristics, and simultaneously, it will have a guiding significance for the design of siphon well defoaming engineering.

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Section: Aeration Concentration Distributionmentioning

confidence: 99%

Aeration strength analysis of overflow weir in siphon well based on numerical simulation of water–air two‐phase flow

Liu,

Lin,

Huang

et al. 2023

River

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“…4 A large range of white water-air bubble flow can directly affect the hydrodynamic performance of ship from various aspects, and measurements of oxygen bubbles and the air-sea exchange rate can be seen as a tracer for net community biological production in the ocean. 5,6 Microbubbles are also used to detect some underwater or surface activities, such as microbial, 7 undersea cold seep, and natural gas seeps. 8,9 To adequately understand these processes, one of the important aspects is to detect microbubbles and quantify their distribution.…”

Section: Introductionmentioning

confidence: 99%

“…Besides, cavitation microbubbles can increase flow resistance, reduce mechanical efficiency, cause cavitation erosion and great harm to ship propellers, hydraulic machinery, or construction equipment 4 . A large range of white water-air bubble flow can directly affect the hydrodynamic performance of ship from various aspects, and measurements of oxygen bubbles and the air-sea exchange rate can be seen as a tracer for net community biological production in the ocean 5 , 6 . Microbubbles are also used to detect some underwater or surface activities, such as microbial, 7 undersea cold seep, and natural gas seeps 8 , 9 .…”

Section: Introductionmentioning

confidence: 99%

Underwater microbubbles detection and identification based on dark field imaging

Wang,

Sun

et al. 2024

Opt. Eng.

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An underwater microbubbles detection and identification method based on dark field imaging is presented, focusing on measurement of the characteristics of microbubbles with high-resolution image capture. The target microbubbles in sampling volume of interest are illuminated by a laser sheet, which is matched with the depth of field. Images are captured in-focus under an observation angle of 90 deg to implement dark field detection, which suppresses the influence of interferential light, such as backlighting, scattering light, and blur caused by defocus. In this configuration, we propose to measure bubble size based on the distance of peak values of two glare points formed by the diffraction and reflection lights. The modified Resnet18 is employed to recognize the bubble images, and the number of bubbles with different diameters in bubble images is counted by template matching. Experimental results show that this dark field configuration allows high resolution imaging and evaluation of the diameter scale of the microbubbles. The precision of bubble recognition and quantification of bubbles within a certain range achieves more than 90%.

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“…Research on cavity resistance reduction has been conducted by several countries, including the United States, Russia, China, France, Japan, Ukraine, the Netherlands, and others [6][7][8][9][10]. With the introduction of decarbonization regulations such as the Energy Efficiency Design Index, the Energy Efficiency Existing Ship Index, and the Carbon Intensity Indicator, shipowners, ship operators, and charterers are keen to ensure that their ships are as energy-efficient as possible and follow the IMO's decarbonization targets.…”

Section: Introductionmentioning

confidence: 99%

An Experimental Study on the Resistance of a High-Speed Air Cavity Craft

Song

et al. 2023

JMSE

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For the marine industry, resistance reduction can reduce energy consumption and achieve protection of the marine environment. The use of air lubrication to reduce the resistance of ships is one of the most important ways. With this technology, high-speed air cavity crafts show immense potential as they can be utilized in various marine activities, such as emergency rescue, supply, and maritime security. Through experiments, this study presents an in-depth analysis of the effects of bubble chamber pressure and initial stern inclination on the resistance of high-speed air cavity crafts at different speeds. The results show that air pressure has a significant impact on resistance. It was found that as the speed of the ship increased, the resistance reduction effect became more prominent under the same pressure conditions. Moreover, the resistance tended to stabilize when the pressure reached a certain value. In addition to the air pressure, the longitudinal inclination does have an effect on resistance reduction. To achieve better resistance reduction, the initial stern inclination angle should be chosen appropriately. Furthermore, adjusting the angle with speed changes can optimize the resistance reduction effect. This experimental study provides critical support for conducting further research on high-speed air cavity crafts. The findings offer valuable insights into improving hull forms, guiding host selection, and assessing performance.

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Research progress on the hydrodynamic performance of water-air-bubble mixed flows around a ship

Cited by 14 publications

References 92 publications

Aeration strength analysis of overflow weir in siphon well based on numerical simulation of water–air two‐phase flow

Aeration strength analysis of overflow weir in siphon well based on numerical simulation of water–air two‐phase flow

Underwater microbubbles detection and identification based on dark field imaging

An Experimental Study on the Resistance of a High-Speed Air Cavity Craft

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