Study on Numerical Simulation of Jacket Launching Progress

Abstract

Jacket type structures are widely used in shallow waters. The size of a jacket is determined by the dimensions of the deck and piles, as well as the environment loads. The jackets are usually transported with barges to the operation water after they have been fabricated in the shipyard, then the jackets slip into the water. Launch operation is the most hazardous stage during the installation of a jacket. The main purpose of this study is to evaluate the physical modeling test results for the launch, and compared to those of numerical simulation. It is found that there are some differences between the numerical simulations and physical model tests. The scale effect cannot be ignored in the prediction of the jacket launching process. The model test is based on the Froude similarity law, and the effect of Reynolds number is neglected. The drag coefficient depending on the Reynolds number plays a crucial role in determining the launch process. With different Reynolds number, the structure has different hydrodynamic force that results to different pitch angle, heave, launch time, acceleration and so on. Thus, a scale effect emerges when we convert the results of a wave basin model test to the prototype scale. This study also includes a sensitivity analysis about some key parameters in the launch process, such as initial barge trim and draft, frictions between barge and jacket.

Study on Flow Characteristics of Hydraulic Suction of Seabed Ore Particles

“…Jin et al [32] used floating experiment to study the minimum lifting velocity, established a formula for the floating velocity and determined that the minimum lifting velocity should be twice the floating velocity of the particles. Xiong et al [33] used analytical CFD-DEM to simulate the settling and floating motion of spherical particles in vertical pipe and obtained the equations of motion of the particles, revealing the relationship between particle size and floating velocity. Pougatch et al [34] proposed a numerical model of three-phase flow in upward gas lift pipe and studied the influence of pipe diameter on lifting efficiency.…”

“…Relevant scholars have studied the algorithm application of coarse particle numerical simulation. Xiong et al [33] resolved the CFD-DEM method and compared it with experiments to analyze the feasibility for studying solid-liquid two-phase flow of large particles. Mohammad et al [35] used a rigorous procedure combining CFD (computational fluid dynamics) and bidirectional FSI (fluid-structure interaction) programs to investigate the effect of sliding on the behavior of a sliding bearing system operating with non-Newtonian lubricants, demonstrating that more realistic results can be obtained using the CFD-FSI approach.…”

“…The CFD-DEM model is mainly used for numerical calculation [32,35]. Previous studies have been conducted on the velocity distribution and particle wake of individual particles collected in vertical pipelines, and research on particle motion characteristics mainly focused on pipelines [31][32][33][34][35][36]. Quantitative studies of single particle suction mainly focus on the influence of size design on particle stress coefficient, including the relationship between h/d, D/d, particle density ρ, particle Froude number Fr and vertical suction number C vs [23][24][25][26][27].…”

Study on Collection Performance of Hydraulic Polymetallic Nodule Collector Based on Solid–Liquid Two-Phase Flow Numerical Simulation

“…Lim et al [15] analyzed the flow field characteristics with outflow discharge from a collecting device in deep seawater while gathering manganese nodules through computational fluid dynamics simulation. Xiong et al [16] adopted the CFD-DEM method to establish a solid-liquid two-phase flow model in which a single particle leaves the ground and enters the lifting pipe under the action of suction from the vertical pipe. Through this, the flow field and motion state of the single particle was explored.…”

Separation of Azeotropic Systems by Distillation-Crystallization Coupling Process

“…All this system separation depends on overhead crystallization, namely increase one level solid-liquid equilibrium on top of distillation column [7,8] . Nevertheless, for the azeotropic systems whose heavy component has a relatively high condensation point, such as, methanol and dimethyl carbonate, cyclohexanol and cyclohexanone [9,10] , the tower kettle effluent must be separating with crystallization, the function of the strengthening mass transfer can be incarnated to the DCC process. Whereas, the research report for this type technological process is very less.…”