Liquefied natural gas(LNG)is a kind of clean energy,and many LNG-powered vessels have been de-signed and built around the world.However,LNG introduces the potential risk of leakage and explosion accidents;thus,it is n...Liquefied natural gas(LNG)is a kind of clean energy,and many LNG-powered vessels have been de-signed and built around the world.However,LNG introduces the potential risk of leakage and explosion accidents;thus,it is necessary to conduct safety assessments on the layout of typical facilities during the initial design stage.In this paper,an on-deck LNG fuel area model is established by employing the computational fluid dynamics(CFD)method according to an LNG-powered Aframax oil tanker.The distri-bution of potential dangerous areas on the concentration field and temperature field is presented under leakage and diffusion accident conditions with vent masts of different heights.The results show the fol-lowing:the gas concentration rises rapidly at the initial stage of leakage and tends to stabilize after a certain period;the leakage and diffusion trend of light gas is basically the same as that of heavy gas,and the lowest heavy gas and light gas temperature on the deck between the storage tank and the upper building is-7.9 C and 4.7°C,respectively,when the venting mast leakage point is at the height of 6 m;and the higher the mast leakage point is,the more safe the ship design.For safety considerations,the height of the venting mast designed in this paper should not be lower than the height of the LNG storage tank,which is 10 m.展开更多
Nowadays the development of green ship technology requires the vibration and noise control of oceangoing ships. The three-dimensional hydroelasticity theory of ships was previously extended to include the effect of fl...Nowadays the development of green ship technology requires the vibration and noise control of oceangoing ships. The three-dimensional hydroelasticity theory of ships was previously extended to include the effect of fluid compressibility. This enables the dynamic responses and the acoustic radiations of a ship excited by onboard machineries or fluid fluctuation loads to be predicted. In this paper the hydroelastic analysis and sonoelastic analysis methods are fixrther incorporated with the Green＇s function in the Pekeris ocean hydro-acoustic waveguide model to work out a three-dimensional sonoelastic analysis method for ships in the ocean hydro-acoustic environment. As examples, the sound radiations of a floating elastic spherical shell excited by a concentrated force and a traveling LNG ship excited by the propeller induced pulsating forces acting on the wetted bottom plate of the stem in the shallow sea environment are predicted. The influences of the free surface and the sea bed on the generalized hydrodynamic coefficients and the acoustic pressure distributions in fluid domain are illustrated and discussed.展开更多
基金The authors express their gratitude to the Na-tional Natural Science Foundation of China(Grant No.41976194)the Shanghai Engineering Research Center of Marine Renew-able Energy(Grant No.19DZ2254800)of China for their financial support of this study.
文摘Liquefied natural gas(LNG)is a kind of clean energy,and many LNG-powered vessels have been de-signed and built around the world.However,LNG introduces the potential risk of leakage and explosion accidents;thus,it is necessary to conduct safety assessments on the layout of typical facilities during the initial design stage.In this paper,an on-deck LNG fuel area model is established by employing the computational fluid dynamics(CFD)method according to an LNG-powered Aframax oil tanker.The distri-bution of potential dangerous areas on the concentration field and temperature field is presented under leakage and diffusion accident conditions with vent masts of different heights.The results show the fol-lowing:the gas concentration rises rapidly at the initial stage of leakage and tends to stabilize after a certain period;the leakage and diffusion trend of light gas is basically the same as that of heavy gas,and the lowest heavy gas and light gas temperature on the deck between the storage tank and the upper building is-7.9 C and 4.7°C,respectively,when the venting mast leakage point is at the height of 6 m;and the higher the mast leakage point is,the more safe the ship design.For safety considerations,the height of the venting mast designed in this paper should not be lower than the height of the LNG storage tank,which is 10 m.
文摘Nowadays the development of green ship technology requires the vibration and noise control of oceangoing ships. The three-dimensional hydroelasticity theory of ships was previously extended to include the effect of fluid compressibility. This enables the dynamic responses and the acoustic radiations of a ship excited by onboard machineries or fluid fluctuation loads to be predicted. In this paper the hydroelastic analysis and sonoelastic analysis methods are fixrther incorporated with the Green＇s function in the Pekeris ocean hydro-acoustic waveguide model to work out a three-dimensional sonoelastic analysis method for ships in the ocean hydro-acoustic environment. As examples, the sound radiations of a floating elastic spherical shell excited by a concentrated force and a traveling LNG ship excited by the propeller induced pulsating forces acting on the wetted bottom plate of the stem in the shallow sea environment are predicted. The influences of the free surface and the sea bed on the generalized hydrodynamic coefficients and the acoustic pressure distributions in fluid domain are illustrated and discussed.
