Numerical Investigation On Two-way Fluid-structure Coupling Effect Of Flow Channel Insert And Heat Transfer Enhancement Of Liquid Metal Blanket

Fusion energy is a renewable energy with a wide source of raw materials,huge energy and less pollution.Blanket is one of the most important parts in the fusion reactor and it is the key component of energy conversion.As one of the most potential blanket,Dual Coolant Lead Lithium Blanket attracted much attention from scholars.Because of the magnetohydrodynamic effects of liquid metals,there is always a high MHD pressure drop in the DCLL blanket,which has a great effect on the stress of blanket structure.At the same time,the suppression of strong magnetic field makes the liquid metal flow become laminar in the channel,which suppresses the heat transfer of liquid metal in the channel,leading to overheating in the local area of the channel,and bringing unsafe factors to the blanket structure.Therefore,it is of great significance to study the working conditions of DCLL channel and heat transfer enhancement technology for the structure safety and energy conversion efficiency of the blanket.The two-way fluid-structure coupling calculation not only considers the influence of the flow field on the solid,but also considers the influence of the solid deformation on the flow field.Therefore,compared with one-way fluid-structure coupling calculation,the results of two-way fluid-structure coupling calculation is closer to the actual situation of simulation object.one-way and two-way coupling numerical calculations are carried out for DCLL channels respectively.The results show that when DCLL channel is working,the equivalent stress of channel FCI is mainly concentrated at the channel entrance,the center of FCI and the edge of FCI along the flow direction.The pressure value obtained by two-way coupling is 6.6%higher than that obtained by one-way coupling.Due to the influence of the flow field pressure difference,the deformation of FCI is mainly concentrated in the first half,and the deformation obtained by two-way coupling is 6%higher than that obtained by one-way coupling deformation.Secondly,the influence of the wall conductivity,the triangle rib,the vortex generator and the twisted tape on the flow and heat transfer characteristics of liquid metal in the DCLL channel are studied.The results show that for DCLL channel without FCI,insulating strips will decrease the temperature of the area near the insulating strip wall of the channel by up to 15K.When the magnetic field strength increases to 1.5T,the enhanced heat transfer factor of channel with insulating strip at Y=0.13m decreases to 0.67times of the channel without insulating strip when the magnetic field strength is 0.5T.The enhanced heat transfer factor of the channel will reach to 5 with triangle rib,while the pressure drop and friction of the channel is only 1.12 times and 1.102 times than that of the no-rib channel.Vortex generator will enhance the heat transfer on the channel wall and reduce the outlet temperature.The mean square error of the outlet temperature and average outlet temperature of the channel with vortex generator was 0.9407 times and 0.9962 times of the original channel,respectively.The average outlet temperature and the outlet enthalpy flow rate of channel with twisted tape are 0.998 times and 0.983 times of the original channel.And the mean square deviation of outlet temperatureσ_T is 0.862 times of the original channel.The wall heat transfer performance enhancement factor with twisted tapeη=1.68.For FCI channels,conductive strips make the temperature distribution in the Y direction of the channel more uniform.And when the velocity of the channel is slow,the heat transfer of the channel will enhance,however,heat transfer in local area of the channel will be inhibited with the increase of velocity.Moreover,the maximum heat transfer efficiency of the channel with horizontal conducting strip is 1.13times than that of the channel without conducting strip when the inlet velocity reaches 1m/s.For channel with vertex generator,the average outlet temperature and the outlet enthalpy flow rate of the channel is0.9996 times and 0.9995 times of the original channel.The outlet maximum temperature of channel with twisted tape decreased from 1020K to 930K.Also,the average temperature and the enthalpy at the outlet were 1.022 times and 1.002 times than that of the original channel.And the mean square deviation of outlet temperatureσ_T was only 0.586 times of the original channel.