不同光学边界条件强化石墨烯-乙二醇纳米流体吸收器的集热性能

Enhancement of heat collection properties of graphene-ethylene based nanofluid absorbers under different optical boundary conditions

通过改变集热器光学边界条件来改善集热器内部温度场的均匀性,从而有效提升集热器的光热转化效率。研究结果表明:在不同的光学边界条件下,乙二醇基石墨烯纳米片纳米流体具有不同的温度场分布以及不同的集热效率;以乙二醇作为工作流体时,顶部、底部和侧面3种光照模式下集热器光热转化效率分别为27.52%,33.64%和33.25%;以乙二醇基石墨烯纳米片纳米流体作为集热工质,最高集热器光热转化效率分别为59.68%(顶部光照模式,质量分数为0.003%),69.66%(底部光照模式,质量分数为0.005%),60.48%(侧面光照模式,质量分数为0.003%);将石墨烯纳米流体作为集热工质时,集热器光热转化效率提升近1倍。

A method was proposed to improve the uniformity of the internal temperature field of the collector by changing the optical boundary conditions of the collector,thereby effectively improve photothermal conversion efficiency of the collector.The results show that ethylene glycol-based graphene nanosheet nanofluids have different temperature field distributions and different absorber efficiencies under different optical boundary conditions.When ethylene glycol is used as the working fluid,the photo-thermal conversion efficiencies of collector in the top,bottom,and side lighting modes are 27.52%,33.64%,and 33.25%,respectively.Using ethylene glycol-based graphene nanosheet nanofluid as the heat absorption medium,the maximum photothermal conversion efficiency of the collector in the top irradiation mode is 59.68%(0.003%,mass fraction),and the maximum efficiency is 69.66%(0.005%,mass fraction)in the bottom irradiation mode,up to 60.48%(0.003%,mass fraction)in side irradiation mode.The photothermal conversion efficiency of the heat collector is improved by about 100%when graphene nanofluid is used as a heat absorption medium.