As an efficient natural selection nutrient transport system,biomimetic leaf hierarchical porous structure has unique advantages in material transportation and energy transfer.Biomimetic leaf hierarchical porous struct...As an efficient natural selection nutrient transport system,biomimetic leaf hierarchical porous structure has unique advantages in material transportation and energy transfer.Biomimetic leaf hierarchical porous structure has been widely used in solar thermochemical reactions,photocatalysis,and energy storage.To improve the thermal efficiency and reduce the power consumption,the authors introduce the idea of bionic leaf hierarchical porous structure packed-bed latent heat thermal energy storage(LHTES)system.Under the same porosity,the diameter of the PCM capsules is designed to change along the flow direction to optimize the thermal performance.The effects of velocity on temperature distribution,pressure drop,liquid fraction,and thermal storage capacity of the conventional uniform model and bionic leaf hierarchical porous model are analyzed.The results show that the bionic leaf hierarchical porous structure can thin the thickness of the thermocline,reduce the pressure drop,increase the heat transfer area,and improve the thermal response of the packed-bed compared with the conventional uniform model.The maximum increases of liquid fraction and completion rate are 36.6%and 20.3%with pressure drop reduction of 25 Pa,respectively.The maximum decrease of the above-melting point(MP)thermocline is 51.7%as well.These results provide suggestions to optimize the packed-bed LHTES system and improve its thermal performance under practical conditions.展开更多
基金This work was supported by the National Key R&D Program of China(No.2018YFA0702300)the National Natural Science Foundation of China(Grant No.52076064)the Taishan Scholars of Shandong Province(tsqn201812105).
文摘As an efficient natural selection nutrient transport system,biomimetic leaf hierarchical porous structure has unique advantages in material transportation and energy transfer.Biomimetic leaf hierarchical porous structure has been widely used in solar thermochemical reactions,photocatalysis,and energy storage.To improve the thermal efficiency and reduce the power consumption,the authors introduce the idea of bionic leaf hierarchical porous structure packed-bed latent heat thermal energy storage(LHTES)system.Under the same porosity,the diameter of the PCM capsules is designed to change along the flow direction to optimize the thermal performance.The effects of velocity on temperature distribution,pressure drop,liquid fraction,and thermal storage capacity of the conventional uniform model and bionic leaf hierarchical porous model are analyzed.The results show that the bionic leaf hierarchical porous structure can thin the thickness of the thermocline,reduce the pressure drop,increase the heat transfer area,and improve the thermal response of the packed-bed compared with the conventional uniform model.The maximum increases of liquid fraction and completion rate are 36.6%and 20.3%with pressure drop reduction of 25 Pa,respectively.The maximum decrease of the above-melting point(MP)thermocline is 51.7%as well.These results provide suggestions to optimize the packed-bed LHTES system and improve its thermal performance under practical conditions.
