scholarly journals Experimental Research on Hydraulic Collecting Spherical Particles in Deep Sea Mining

Energies ◽  
2018 ◽  
Vol 11 (8) ◽  
pp. 1938 ◽  
Author(s):  
Guocheng Zhao ◽  
Longfei Xiao ◽  
Tao Peng ◽  
Mingyuan Zhang
Keyword(s):  
Flow Field ◽  
Deep Sea ◽  
Economic Benefits ◽  
Spherical Particles ◽  
Vertical Force ◽  
Incipient Motion ◽  
Force Coefficient ◽  
Suction Force ◽  
Suction Flow ◽  
Force Characteristics

Hydraulic collecting is the key technology in deep sea mining and dredging engineering. It determines economic benefits of the project and environmental issues. However, mechanistic studies of hydraulic collecting are rarely described. In this study, the mechanism of collecting spherical particles is researched by dimensional analysis and experimental study. The experimental system is established to carry out three kinds of tests including 253 different test cases. The empirical model of collecting performance prediction is established by the tests of vertical force characteristics and vertical incipient motion characteristics of particles in suction flow field. The results show that the vertical suction force coefficient (Cvs) decreases exponentially with the ratio of bottom clearance to diameter of the particle (h/d), increases linearly with the ratio of diameter of the suction pipe to diameter of the particle (D/d), and is nearly independent of Reynolds number (Re). The empirical formula of vertical force and criterion-formula of vertical incipient motion of particles are obtained with the maximum tolerance less than 15%. The phenomenon that the vortex could help strengthen the suction force was observed in the tests. In addition, the characteristics of suction flow field were obtained by flow visualization tests, and applied to explain the force characteristics of particles in the suction flow field.

Shape Effect of Polymetallic Nodules on Suction Forces and Flow Field During Seabed Hydraulic Collection

2021 ◽  
pp. 1-21
Author(s):  
Guocheng Zhao ◽  
Haining Lu ◽  
Longfei Xiao ◽  
Jingchao Hu
Keyword(s):  
Flow Field ◽  
Time History ◽  
Basic Research ◽  
Shape Effect ◽  
Detached Eddy Simulation ◽  
Field Methods ◽  
Dye Tracing ◽  
Suction Force ◽  
Polymetallic Nodule ◽  
Suction Flow

Abstract Turbulent suction pipe flow around a near-wall ellipsoid nodule, as basic research of polymetallic nodule hydraulic collection, is investigated numerically and experimentally in this paper. Seven ellipsoids with axe ratios (a/b) ranging from 1 to 2 are considered as nodule models to reveal the shape effect on the characteristics of suction forces and suction flow field. Methods of particle image velocimetry (PIV) and dye tracing were used to visualize the suction flow field. The results indicate that: (1) suction force coefficients increase with a/b; (2) the shape effect is more significant in the cases with smaller ratios of bottom clearance to semi-thickness of the ellipsoid (h/c); (3) the weak vortex shedding in suction flow results in small-amplitude fluctuations of time-history suction forces; (4) the detached-eddy simulation (DES) method based on shear stress transport (SST) model is validated to be accurate and feasible for predicting the suction forces and suction flow field. It is expected to provide references for the design of nodule pick-up devices and to help us further understand the mechanism of hydraulic collection.

Research on the influence of the suction force on spherical particles in suction flow

2021 ◽  
Author(s):  
Junhong Li ◽  
Qinghui Lai ◽  
Wei Su ◽  
Yuerong Xie ◽  
Zhaoguo Zhang
Keyword(s):  
Spherical Particles ◽  
Suction Force ◽  
Suction Flow

scholarly journals Analysis of the Effect of Payment Mechanism on Exploitation of Polymetallic Nodules in the Area

Minerals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 221
Author(s):  
Yan Li ◽  
Chang Liu ◽  
Sihan Su ◽  
Mengdan Li ◽  
Shaojun Liu
Keyword(s):  
Deep Sea ◽  
Mineral Resources ◽  
Economic Benefits ◽  
Rate Of Return ◽  
Internal Rate Of Return ◽  
Financial Model ◽  
Payment Mechanism ◽  
Advantages And Disadvantages ◽  
Internal Rate ◽  
Payment Mechanisms

The international seabed area (i.e., the “Area”) is rich in mineral resources. According to the United Nations Convention on the Law of the Sea (UNCLOS) and the relevant implemented agreements, in 2012, the International Seabed Authority (ISA) began to develop the regulations for the exploitation of mineral resources in the Area. The most important part of the regulations involves determining the distribution of benefits from the exploitation of mineral resources in the Area between the ISA and the contractors. The establishment of a financial model to evaluate the economic benefits and compare the distribution scheme was the basic method relied on in the current study of payment mechanism. According to the characteristics of the exploitation project of mineral resources in the Area, the discounted cash flow method was selected to construct the financial model. Taking China’s deep-sea mineral resources development project in the Area as the background, the main parameters of the model were determined. A comparative study of similar financial models with Massachusetts Institute of Technology (MIT) and other foreign countries was carried out, in addition to a sensitivity analysis of parameters. On the basis of the assurance that the contractor’s internal rate of return was not lower than the level of the land mining enterprise, the financial model was used to calculate the internal rate of return and the revenue of royalty under different payment mechanisms and rates. The advantages and disadvantages of different payment mechanisms in the exploitation of mineral resources in the area were analyzed. Lastly, the possible impacts of deep-sea polymetallic nodule mining on Terrestrial metal markets were highlighted.

A High Resolution Simulation of a Single Shock-Accelerated Particle

2021 ◽  
Author(s):  
W. Curtis Maxon ◽  
Tanner Nielsen ◽  
Nicholas Denissen ◽  
Johnathan D. Regele ◽  
Jacob McFarland
Keyword(s):  
Flow Field ◽  
Cost Effective ◽  
Pressure Effects ◽  
Heat Diffusion ◽  
Spherical Particles ◽  
Navier Stokes ◽  
Exact Equation ◽  
Arbitrary Lagrangian Eulerian ◽  
Particle Laden Flows ◽  
Drag Models

Abstract Particle drag models, which capture macro viscous and pressure effects, have been developed over the years for various flow regimes to enable cost effective simulations of particle-laden flows. The relatively recent derivation by Maxey and Riley has provided an exact equation of motion for spherical particles in a flow field based on the continuum assumption. Many models that have been simplified from these equations have provided reasonable approximations; however, the sensitivity of particle-laden flows to particle drag requires a very accurate model to simulate. To develop such a model, a 2D axisymmetric Navier-Stokes direct numerical simulation of a single particle in a transient, shock-driven flow field was conducted using the hydrocode FLAG. FLAG's capability to run arbitrary Lagrangian-Eulerian hydrodynamics coupled with solid mechanic models makes it an ideal code to capture the physics of the flow field around and in the particle as it is shock-accelerated -- a challenging regime to study. The goal of this work is twofold: to provide a validation for FLAG's Navier-Stokes and heat diffusion solutions, and to provide a rationale for recent experimental particle drag measurements.

Orientational Distributions of a Ferromagnetic Spherocylinder Particle in a Simple Shear Flow

2002 ◽  
Author(s):  
Masayuki Aoshima ◽  
Akira Satoh ◽  
Geoff N. Coverdale ◽  
Roy W. Chantrell
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Shear Flow ◽  
Flow Field ◽  
Simple Shear ◽  
Applied Magnetic Field ◽  
Spherical Particles ◽  
Simple Shear Flow ◽  
Microstructure Formation ◽  
Base Liquid

A ferrofluid is a suspension of ferromagnetic spherical particles in a base liquid (1), and is well known as a functional fluid which responds to an external magnetic field to give a large increase in the viscosity. Such a significant increase in the viscosity is due to the fact that chain-like clusters are formed owing to magnetostatic interactions between particles in an applied magnetic field. The microstructure formation offers a large resistance to a flow field that gives rise to a significant increase of the apparent viscosity (2).

Two-dimensional pressure field and backflow in the annular skirt of vortex gripper

2020 ◽  
pp. 095440622097404
Author(s):  
Jianghong Zhao ◽  
Xin Li
Keyword(s):  
Flow Field ◽  
Pressure Distribution ◽  
Local Stress ◽  
Vortex Chamber ◽  
Physical Contact ◽  
Two Dimensional ◽  
Stress Concentrations ◽  
Suction Force ◽  
Maximum Value ◽  
Gap Height

The vortex gripper is a kind of pneumatic noncontact gripper that does not produce a magnetic field and heat. It can grip a workpiece without physical contact, which avoids any unintentional damage such as mechanical scratches, local stress concentrations, frictional static electricity, and surface stains. This study focused on the two-dimensional pressure distribution field on a workpiece surface under the vortex gripper. Theoretical, experimental, and computational fluid dynamics results were combined to study the backflow phenomenon in the annular skirt, which can decrease the gripper’s suction force after the maximum value is reached. First, the pressure distribution in the annular skirt was theoretically modeled. A comparison with the experimental results showed that increasing the gap height between the gripper and workpiece generates a circumferentially asymmetrical flow field in the skirt. Based on this, it was hypothesized that an airflow in the circumferential direction may exist. The experimental data and simulation results were analyzed under large gap height conditions to observe the backflow in detail and it was found that an uneven pressure distribution with positive and negative pressure regions generated by the uneven flow is the root cause of the backflow. Finally, the effect of the backflow on the flow field in two different flow regions (in the annular skirt and inside the vortex chamber) was analyzed and the reason why the suction force of the vortex gripper has a maximum value was determined.

A calculation of cricket ball trajectories

2010 ◽  
Vol 224 (9) ◽  
pp. 1947-1958 ◽  
Author(s):  
C J Baker
Keyword(s):  
Reynolds Number ◽  
Limited Range ◽  
Force Coefficient ◽  
Number Range ◽  
Force Coefficients ◽  
Cricket Ball ◽  
Complex Ball ◽  
Full Solution ◽  
Supercritical Flows ◽  
Force Characteristics

While a number of past investigations have measured the aerodynamic forces on cricket balls, in general these forces have not been used to calculate the trajectories of balls between bowler and batsman. This article presents such a calculation. It begins with the full trajectory equations as developed for the study of debris flight in extreme windstorms, which are adapted for the cricket ball case. A collation of earlier experimental data is then presented for drag and side force coefficients on cricket balls. From these data, which show considerable scatter, a small number of generic force characteristics are derived for use in the trajectory equations. These characteristics have constant force coefficients in the subcritical and supercritical Reynolds number regions, and a transition between these two regions with a variable gradient. An approximate analysis of the trajectory equations results in very simple forms for the trajectories in the sub- and supercritical Reynolds number regimes, which reveal the governing dimensionless parameters of the problem, and enable the effect of crosswinds to be quantified. The predicted parabolic profiles are in agreement with some very simple calculations carried out by earlier investigators, revealing the limited range of validity of such calculations, and with the limited real bowling trajectories that have been observed. A full solution of the trajectory equations is then presented for the generic force coefficient characteristics, and a study of trajectories through the Reynolds number range is carried out. In the transition region between sub- and supercritical flows, complex ball trajectories are shown to be possible.

Aerodynamic Performance Investigation under the Influence of Heavy Rain of a NACA 0012 Airfoil for Wind Turbine Applications

2012 ◽  
Vol 6 (6) ◽  
pp. 1228-1235
Author(s):  
Eleni C. Douvi ◽  
Dionissios P. Margaris
Keyword(s):  
Flow Field ◽  
Wind Turbine ◽  
Heavy Rain ◽  
Aerodynamic Characteristics ◽  
Aerodynamic Performance ◽  
Spherical Particles ◽  
Discrete Phase Model ◽  
Two Phase ◽  
Naca0012 Airfoil ◽  
The Impact

The study of the prediction of the flow field and aerodynamic characteristics of a NACA0012 airfoil in simulated heavy rain, using a computational fluid dynamics code is presented. The simulation of rain is accomplished by using the two-phase flow Discrete Phase Model, which is available in the CFD code. Spherical particles are tracked through the two-dimensional, incompressible air flow field over a NACA0012 airfoil, at a simulated rain rate of 1000 mm/h and operating at Reynolds numbers Re=1×106 and Re=3×106. To validate the CFD developed model, the results are compared with well-established and published experimental data, showing good agreement. The aim of the work was to show the behavior of the airfoil at these conditions and to establish a verified solution method. Lift and drag coefficients are computed at various angles of attack in both dry and wet conditions and the results are compared to show the effects of rain at airfoil performance. The impact of rain on wind turbine performance is also analyzed. It is concluded that rain causes degradation of aerodynamic performance, especially lift is decreased and drag is increased.

ANALYSIS OF THE WATER IMPACT OF SYMMETRIC WEDGES WITH A MULTI- MATERIAL EULERIAN FORMULATION

2021 ◽  
Vol 154 (A4) ◽  
Author(s):  
S Wang ◽  
C Guedes Soares
Keyword(s):  
Pressure Distribution ◽  
Impact Velocity ◽  
Pressure Coefficient ◽  
Time History ◽  
Maximum Pressure ◽  
Vertical Force ◽  
Force Coefficient ◽  
Explicit Finite Element ◽  
Eulerian Formulation ◽  
The Impact

The two-dimensional hydrodynamic problem of a symmetric wedge vertically impacting in calm water is analysed by using an explicit finite element method based on a multi-material Eulerian formulation. The slam-induced loads on wedges with different deadrise angle at a constant velocity are calculated, including pressure distribution, maximum pressure coefficient, force coefficient and time history of vertical force, which are compared with available theoretical and analytical results. The time evolution of pressure distribution and free surface elevation are presented. Furthermore, the effects of impact velocity are investigated. It shows that this method is capable of predicting the local slamming loads, and as well assessing the effects of the deadrise angle and the impact velocity on the slamming pressure for the wedge-shape section.

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