scholarly journals Experimental and Numerical Study of Orifice Coefficient of Cargo Tank Design of LNG Vessels

2020 ◽  
Vol 10 (19) ◽  
pp. 6667
Author(s):  
Se-Yun Hwang ◽  
Kwang-Sik Kim ◽  
Ho-Sang Jang ◽  
Jang-Hyun Lee
Keyword(s):  
Numerical Study ◽  
Operating Pressure ◽  
Cfd Analysis ◽  
Storage Tanks ◽  
Insulation System ◽  
Design Factor ◽  
International Regulations ◽  
Computational Fluid Dynamics Cfd ◽  
Tank Design ◽  
Cfd Method

Liquid cargo storage tanks of liquefied natural gas (LNG) carriers are designed by strict standards to maintain the cryogenic state (−163 °C). For most LNG cargo storage tanks, it is mandatory to install a system that can safely store leaked fluid for 15 days in the case of leakage of liquid cargo due to crack of the insulation system. To ensure safety, it is necessary to predict the amount of LNG spilling from the cracks in the insulation panels. Although international regulations are provided, they rely on a conservative and consistent coefficient. In this study, experimental and numerical methods were applied to examine the design factor used to predict the flow rate in the tank design process. To check the amount of leakage that occurs under pressure conditions of LNG tanks, an experiment was conducted using crack specimens and pressure containers filled with water. In order to simulate the leakage of LNG, the amount of leakage was predicted using the Computational Fluid Dynamics (CFD) method. The distribution of leakage quantity was investigated according to the shape of the crack through the pressure vessel experiment and the analysis. Through CFD analysis, the leakage rate of LNG was calculated for each operating pressure condition through the crack. Finally, the results of this study examined the need to identify and reconsider the coefficients due to international guidelines and other factors in calculating orifice coefficients applied to the design of LNG tanks.

scholarly journals Numerical study of flow characteristics on wing airfoil eppler 562 with whitcomb winglet variations

2018 ◽  
Vol 204 ◽  
pp. 04009
Author(s):  
S.P Setyo Hariyadi ◽  
Sutardi ◽  
Wawan Aries Widodo ◽  
Muhammad Anis Mustaghfirin ◽  
Arifandi Rachmadiyan
Keyword(s):  
Fluid Flow ◽  
Numerical Study ◽  
Fuel Efficiency ◽  
Flow Characteristics ◽  
Lower Surface ◽  
Computational Fluid Dynamics Cfd ◽  
Fluid Flow Characteristics ◽  
Conducting Research ◽  
Cfd Method ◽  
Wing Airfoil

Winglet is a tool used to improve the efficiency of aircraft and UAV performance by preventing fluid flow jump from lower surface to upper surface at wingtip. The addition of this winglet resulted in improved lift and reduction of drag force from the aircraft wing or UAV. From Whitcomb's research, it was found that the use of winglet on a full size airplane can increase fuel efficiency by 7%. The research led to the idea of conducting research on fluid flow characteristics on the UAV wing with the Eppler 562 airfoil combined with the whitcomb winglet. This numerical study was conducted using the Computational Fluid Dynamics (CFD) method based on the advantages of using this simulation that can review the fluid flow in macroscopic way. This study is provide accurate fluid flow visualization results and can improve the performance of the wings when compared with wings without winglet (plain wing). Wing with the Eppler 562 airfoil combined with the whitcomb winglet results reduction in rotating motion that makes velocity components as opposed to lift.

scholarly journals Numerical Study on Wave-Ice Interaction in the Marginal Ice Zone

2020 ◽  
Vol 9 (1) ◽  
pp. 4
Author(s):  
Tiecheng Wu ◽  
Wanzhen Luo ◽  
Dapeng Jiang ◽  
Rui Deng ◽  
Shuo Huang
Keyword(s):  
Sea Ice ◽  
Numerical Study ◽  
Test Results ◽  
Towing Tank ◽  
Marginal Ice Zone ◽  
Computational Fluid Dynamics Cfd ◽  
Numerical Research ◽  
Ice Floes ◽  
Cfd Method ◽  
Six Degree Of Freedom

The effect of waves on ice sheet is critical in the marginal ice zone (MIZ). Waves break large sea ice into small pieces and cause them to collide with each other. Simultaneously, the interaction between sea ice and waves attenuates these waves. In this study, a numerical research is conducted based on a computational fluid dynamics (CFD) method to investigate the response of single ice floe to wave action. The obtained results demonstrate that the sea ice has a violent six degree of freedom (6DoF) motion in waves. Ice floes with different sizes, thicknesses, and shapes exhibit different 6DoF motions under the action of waves. The heave and surge response amplitude operator (RAO) of the sea ice are related to wavelength. Furthermore, the overwash phenomenon can be observed in the simulation. The obtained results are compared with the model test in the towing tank based on artificial ice, and they agree well with test results.

A numerical analysis on different-generation prototypes of ventricular assist device

2019 ◽  
Vol 10 (05) ◽  
pp. 1950029
Author(s):  
Ali Tavakoli Golpaygani ◽  
Kamran Hassani ◽  
Alireza Karimi ◽  
Amin Nokhbe Zaeim
Keyword(s):  
Ventricular Assist Device ◽  
Numerical Study ◽  
Heart Diseases ◽  
Shear Stresses ◽  
Assist Device ◽  
Ventricular Assist ◽  
Curved Blade ◽  
Concurrent Study ◽  
Computational Fluid Dynamics Cfd ◽  
Cfd Method

The ventricular assist device (VAD) assists the patients with heart diseases for limited and prolonged periods. This device synchronizes with normal heart activities to help foster its performance. Consequently, its sensitive design requires high accuracy. The pumps are the essential part of every VAD which should operate in wide ranges of flow and pressure. As there are various types of VAD under different designs, it is neither practical nor plausible to experimentally/clinically investigate their performances. Therefore, in the concurrent study, a numerical study was carried out on four different generation prototypes of VAD pumps for reaching an optimum design. Using computational fluid dynamics (CFD) method, the software derived, showed and streamlined the flow field shear stress both inside the VAD and its blades. Furthermore, the vortices and flow rate-pressure curves were observed. The results showed that the curved blade pumps operate better compared to that of the straight blade types, concerning the provision of enough pressure and less damage to the red blood cells. The results have implications not only for comparing different types of VAD designs but also for understanding the resulted shear stresses and pressures as a result of the blade’s structure.

Numerical Study on Pressure Difference of Valve Core in Vertical Pilot-Control Globe Valve

2017 ◽  
Author(s):  
Zhi-xin Gao ◽  
Fu-qiang Chen ◽  
Jin-yuan Qian ◽  
Zhi-jiang Jin
Keyword(s):  
Pressure Difference ◽  
Numerical Study ◽  
Orifice Diameter ◽  
Inlet Velocity ◽  
Before And After ◽  
Computational Fluid Dynamics Cfd ◽  
Cfd Method ◽  
Globe Valve ◽  
Opening And Closing ◽  
Core Displacement

Vertical pilot-control globe valve (VPCGV) is a novel globe valve that costs little driving energy and responds quickly. In VPCGV, the opening and closing forces are related to the pressure difference before and after the valve core. In this paper, parameters that have influences on pressure difference such as orifice diameter, valve core displacement, and inlet velocity are thoroughly investigated by computational fluid dynamics (CFD) method. It is found that pressure difference increases with the raising of inlet velocity and the diminishing of valve core displacement, and middle-sized orifice diameter is the best in VPCGV. Furthermore, the correlation between pressure difference and inlet velocity is obtained, which can be beneficial for the selection of VPCGV under certain conditions.

CFD Analysis of Gear Windage Losses: Validation and Parametric Aerodynamic Studies

2011 ◽  
Vol 133 (3) ◽  
Author(s):  
Matthew J. Hill ◽  
Robert F. Kunz ◽  
Richard B. Medvitz ◽  
Robert F. Handschuh ◽  
Lyle N. Long ◽  
...  
Keyword(s):  
Experimental Data ◽  
Spur Gear ◽  
Mitigation Strategies ◽  
Test Facility ◽  
Cfd Analysis ◽  
Physical Mechanisms ◽  
Computational Fluid Dynamics Cfd ◽  
Cfd Method ◽  
Cfd Analyses ◽  
Good Agreement

A computational fluid dynamics (CFD) method has been applied to gear configurations with and without shrouding. The goals of this work have been to validate the numerical and modeling approaches used for these applications and to develop physical understanding of the aerodynamics of gear windage loss. Several spur gear geometries are considered, for which experimental data are available. Various canonical shrouding configurations and free spinning (no shroud) cases are studied. Comparisons are made with experimental data from open literature, and data recently obtained in the NASA Glenn Research Center Gear Windage Test Facility, Cleveland, OH. The results show good agreement with the experiment. The parametric shroud configuration studies carried out in the Glenn experiments and the CFD analyses elucidate the physical mechanisms of windage losses as well as mitigation strategies due to shrouding and newly proposed tooth contour modifications.

Numerical Study of a Flap Rudder Based on Turbulence Model LES

2011 ◽  
Vol 88-89 ◽  
pp. 240-243 ◽  
Author(s):  
Shu Guang Wu ◽  
Hean Liu
Keyword(s):  
Fluid Dynamics ◽  
Turbulence Model ◽  
Numerical Study ◽  
Boundary Layer Separation ◽  
Eddy Simulation ◽  
Large Eddy ◽  
Fluctuation Range ◽  
Computational Fluid Dynamics Cfd ◽  
Cfd Method ◽  
Two Sides

The flap rudder flow field at Re 1.4×106 is calculated using computational fluid dynamics (CFD) method. Large eddy simulation (LES) turbulence model is adopted. The results shows that boundary layer separation phenomenon appears in flap after the gap, and as angle of flap (AOF) is increased, the separation tends to asymmetry, the pressure fluctuation range is becomes higher. There is no eddy in gap when AOF is 0°, but as AOF increases, the eddy in gap appears because of the pressure difference between two sides of the rudder.

Effect of Vortex Induced Vibration on a Paired-Column Semisubmersible Platform

2015 ◽  
Vol 15 (08) ◽  
pp. 1540019 ◽  
Author(s):  
Agbomerie Charles Odijie ◽  
Jianqiao Ye
Keyword(s):  
Fluid Dynamics ◽  
Vortex Shedding ◽  
Numerical Study ◽  
Incidence Angle ◽  
Maximum Amplitude ◽  
Weather Conditions ◽  
Cfd Analysis ◽  
Computational Fluid Dynamics Cfd ◽  
Rectangular Columns ◽  
Effect Of Surface

This paper describes a numerical study of the effect of vortex induced movement (VIM) on the hull of a paired-column semisubmersible (pc-semi) platform in relation to the column geometric properties. A computational fluid dynamics (CFD) analysis was carried out and vortex shedding was observed. The response of the square and rectangular columns hull configuration was investigated using ANSYS AQWA and the maximum amplitude was observed to be almost the same for both geometry, but it occurred at different range of reduced velocity Vr. The effect of surface wave and flow incidence angle were investigated for extreme and regular weather conditions, and it was found that VIM occurred at 2 ≤ Vr ≤ 12.

scholarly journals Design and Numerical Study of the Novel Manifold Header for the Evacuated Tube Solar Collector

Energies ◽  
2020 ◽  
Vol 13 (10) ◽  
pp. 2450
Author(s):  
Martin Beer ◽  
Radim Rybár ◽  
Michal Cehlár ◽  
Sergey Zhironkin ◽  
Peter Sivák
Keyword(s):  
Numerical Study ◽  
Cfd Analysis ◽  
The Novel ◽  
Design Elements ◽  
Serial Connection ◽  
Final Design ◽  
Computational Fluid Dynamics Cfd ◽  
Evacuated Tube ◽  
Prototype Phase ◽  
Selection Of

The presented paper dealt with the concept of an innovative manifold header for evacuated tube solar collectors. The proposed concept eliminates the drawbacks of conventional manifold headers, especially the serial connection of heat pipes that operate under uneven conditions. The advantage of the proposed design of the manifold header is also an increase in the heat exchange surface and the possibility of conducting the heat transfer media flow in a parallel flow arrangement, which increases the overall efficiency. The concept of the manifold header was evaluated on five variations of design with the use of the computational fluid dynamics (CFD) analysis. The results of the CFD analysis confirmed the functionality of the concept and also enabled the selection of the most suitable design elements, which were incorporated into the final design of a manifold header in the pre-prototype phase of manufacturing.

Load Characteristics of Steel and Concrete Tubular Members Under Jet Fire: An Experimental and Numerical Study

2010 ◽  
Author(s):  
Jeong Hyo Park ◽  
Bong Ju Kim ◽  
Jung Kwan Seo ◽  
Jae Sung Jeong ◽  
Byung Keun Oh ◽  
...  
Keyword(s):  
Cfd Simulation ◽  
Numerical Study ◽  
Fire Load ◽  
Adiabatic Wall ◽  
Fire Engineering ◽  
Ansys Cfx ◽  
Design Values ◽  
Computational Fluid Dynamics Cfd ◽  
Load Characteristics ◽  
Set Up

The aim of this study was to evaluate the load characteristics of steel and concrete tubular members under jet fire, with the motivation to investigate the jet fire load characteristics in FPSO topsides. This paper is part of Phase II of the joint industry project on explosion and fire engineering of FPSOs (EFEF JIP) [1]. To obtain reliable load values, jet fire tests were carried out in parallel with a numerical study. Computational fluid dynamics (CFD) simulation was used to set up an adiabatic wall boundary condition for the jet fire to model the heat transfer mechanism. A concrete tubular member was tested under the assumption that there is no conduction effect from jet fire. A steel tubular member was tested and considered to transfer heat through conduction, convection, and radiation. The temperature distribution, or heat load, was analyzed at specific locations on each type of member. ANSYS CFX [2] and Kameleon FireEx [3] codes were used to obtain similar fire action in the numerical and experimental methods. The results of this study will provide a useful database to determine design values related to jet fire.

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