In order to study the influence of semi-ellipsoid blockage on the flow and heat transfer characteristics of coolant in narrow channels,large eddy simulation was carried out for a semi-ellipsoid blockage with a height of 1/2 of the narrow side width.The time-average velocity field,turbulent kinetic energy and temperature distribution downstream of the blockage are analyzed,and the characteristics of flow and heat transfer near the blockage are studied.The downstream flow field of semi-ellipsoid blockage has obvious three-dimensional characteristics,and there are characteristic regions such as recirculation region brought by the flow around the blockage and the boundary layer separation,shearing layer,main flow region and recovery region.Combined with the time-averaged temperature field and the local Nusselt number(Nu),the influence mechanism of the blockage on the heat transfer in narrow channels is studied.It is found that the local minimum Nu and local high temperature appear in the recirculation region near the side wall of the semi-ellipsoid bottom and the recovery region of the top wall due to the accumulation of hot fluid and the lack of mainstream low temperature fluid.In general,the spanwise influence range of the semi-ellipsoid blockage on the velocity field and temperature field in the narrow channel is 5 times of the semi-diameter range.
Narrow channelSemi-ellipsoid blockageFlow structureHeat transfer inhomogeneity
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