The effect of buoyancy on heat transfer characteristics of supercritical LNG in channels with different cross section shape
In LNG powered ships,supercritical liquefied natural gas(LNG)needs to be gasified before use.The gasific-ation of supercritical LNG is a pseudophase transition process.This study presents a numerical investigation of the local flow and heat transfer performance of supercritical LNG in the pseudophase transition.The main objective is to reveal the effect of buoyancy on the local flow and heat transfer performance in channels with different cross-section shapes.It was found that the cross-section shape has a little impact on the buoyancy factor.On the other hand,the effect of buoyancy on the heat trans-fer performance is concentrated in the liquid-like and pseudo-critical regions.The secondary flow was generated due to the influence of buoyancy and density differences.The distribution and secondary flow of the fluid are affected by the cross-sec-tion shape and buoyancy,which affects the heat transfer performance.In general,the secondary flow improves the heat trans-fer performance between the channel wall and the adjacent fluid.However,due to buoyancy,low-density and high-temperat-ure fluids accumulate at the top of the channel,resulting in deterioration of local heat transfer performance.Because of the different cross-sectional shape of the channel,the distribution of turbulent kinetic energy and the specific heat at constant pressure is different,resulting in differences in heat transfer performance.
supercritical LNGbuoyancysecondary flowturbulent kinetic energy
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