In view of the high thermal conductivity of graphene, adding graphene to silicone oil to form nanofluids is expected to enhance thermocapillary convection and the efficiency of heat transfer under the microgravity conditions. In the present study, graphene nanofluid thermocapillary convection in a two-dimensional rectangular cavity was investigated numerically, in which the two-phase mixture model was used to simulate the nanoparticles-fluid mixture flow, the influences of volume fraction of nanoparticles and cavity aspect ratio on the flow characteristics and heat transfer performance were discussed. The results show that with the volume fraction of graphene increases, thermocapillary convection intensity decreases at both ends of the cavity, and the thermocapillary convection in the central cavity increases first and then weakens; meanwhile, the temperature gradient of free surface at both ends of the cavity increases, and the free surface velocity increases first and then decreases with increasing volume fraction of graphene. The intensity of thermocapillary convection to be increased to the maximal value at α_p of 3 vol% and then reduced. The peak heat flux on the hot wall of the cavity gradually shifts from the upper part to the lower part with increasing volume fraction of graphene, meanwhile, and the Nusselt number of the hot wall surface of the cavity gradually decreases. Thermocapillary convective heat transfer intensity of the cavity hot wall increases with the decrease of the aspect ratio.

鉴于石墨烯的高导热性，将石墨烯添加到硅油中形成纳米流体有望增强微重力条件下的热毛细对流和传热效率。本研究对二维矩形腔内石墨烯纳米流体热毛细管对流进行了数值研究，其中采用两相混合物模型模拟纳米颗粒-流体混合物流动、纳米颗粒体积分数和腔长径比的影响对流动特性和传热性能进行了讨论。结果表明，随着石墨烯体积分数的增加，腔体两端的热毛细对流强度降低，中心腔内的热毛细对流先增加后减弱；同时，腔体两端自由表面的温度梯度增大，自由表面速度随着石墨烯体积分数的增加先增大后减小。热毛细对流强度增加到最大值α _p为 3 vol%，然后降低。随着石墨烯体积分数的增加，腔体热壁上的峰值热通量逐渐从上部向下部移动，同时腔体热壁面的努塞尔数逐渐减小。型腔热壁的热毛细管对流传热强度随着纵横比的减小而增大。