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15 pages, 10734 KiB

Open AccessArticle

Study on the Adsorption Performance of a Vortex Suction Cup under Varying Diameters of Underwater Structure Tubes

by Qinyun Tang, Ying Du, Zhaojin Liu, Shuo Zhang, Qiang Zhao, Yingxuan Li, Liquan Wang, Tong Cui and Gang Wang

J. Mar. Sci. Eng. 2024, 12(4), 662; https://doi.org/10.3390/jmse12040662 - 17 Apr 2024

Viewed by 1950

Abstract

In certain precision work scenarios, underwater robots require the ability to adhere to surfaces in order to perform tasks effectively. An efficient and stable suction device plays a pivotal role in the functionality of such underwater robots. The vortex suction cup, distinguished by its uncomplicated design, high suction efficiency, and capability for non-contact adhesion, holds significant promise for integration into underwater robotic systems. This paper presents a novel design for a vortex suction cup and investigates its suction force and torque when encountering surfaces with varying curvature radii using Computational Fluid Dynamics (CFD) simulations and experimental testing. These findings offer valuable insights for the development of robots capable of adapting to underwater structures of different dimensions. Results from both experiments and simulations indicate that reducing the curvature radius of the adhered surface results in a decrease in suction force and an increase in torque exerted on the suction cup. As the adhered surface transitions from flat to a curvature radius of 150 mm, the adhesion force of our proposed vortex suction cup decreases by approximately 10%, while the torque increases by approximately 20% to 30%. Consequently, the adhesion efficiency of the suction cup decreases by about 25% to 30%. Full article

(This article belongs to the Section Ocean Engineering)

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29 pages, 26385 KiB

Open AccessArticle

Study on the Optimal Design for Cavitation Reduction in the Vortex Suction Cup for Underwater Climbing Robot

by Yibing Zhao, Canjun Yang, Yanhu Chen, Jia Li, Siyue Liu and Guoyun Ye

J. Mar. Sci. Eng. 2022, 10(1), 70; https://doi.org/10.3390/jmse10010070 - 6 Jan 2022

Cited by 12 | Viewed by 3196

Abstract

In order to adhere to the wall stably in an underwater environment, a vortex suction cup that injects high-pressure water inside via two axisymmetrically side-distributed inlets to create a negative pressure area in the center is the necessary component for the underwater climbing robot (UCR). However, the suction force of this vortex suction cup is reduced and periodically unstable due to unstable cavitation. The aim of this paper is to propose a cavitation reduction optimization method for vortex suction cups and to verify the effectiveness of the optimization. Analyses of this vortex flow, including streamlines, pressure, and cavitation number fluctuations, were carried out by the introduced computational fluid dynamics (CFD) simulating methods based on the multiphase RNG

k - ε

model to study the periodic fluctuations of the suction force of the original suction cup and the optimized ones. Force measurement and vortex observation experiments were conducted to compare the suction force of the original vortex suction cup and the optimized suction cup, as well as the cavitation and pressure fluctuation phenomenon. Results of simulation and experiments prove the existence of the effect of vortex cavitation on the suction performance and verify the rationality of optimization as well. Full article

(This article belongs to the Section Ocean Engineering)

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15 pages, 33686 KiB

Open AccessArticle

Enhanced Non-Contact Grip Force and Swirl Stability by a Combined Venturi–Vortex Air Head

by Yung Hoon Lee, Joon Hyun Kim and Jaeyong Sung

Materials 2021, 14(23), 7123; https://doi.org/10.3390/ma14237123 - 23 Nov 2021

Cited by 3 | Viewed by 2658

Abstract

A combination of the venturi module and the vortex cup was proposed to solve vortex instability and to enhance grip capacity. Mounting a venturi suction pad inside the vortex cup improved vacuum generation efficiency. When the vortex cup properly maintained the non-contact air gap and generated an equivalent vacuum to achieve a sealing effect around the open gap of the suction pad, the combined head improved grip capacity and stabilized the non-contact environment. Furthermore, the flow patterns around the venturi chamber and the swirl inside the vortex cup were analyzed based on the design elements of each module. In a module that integrated some of the venturi’s features internally, increased air consumption of the vortex cup was required than that of the venturi. However, it supported a wide range of non-contact grips. The coupled model effectively protected the vacuum suction features of the venturi suction pad in all non-contact environments in that range. Full article

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