TY - JOUR TI - Experimental study on heat transfer and flow characteristics of two kinds of porous metal foam tubes filled with water AU - Wang Guiqing AU - Qi Cong AU - Pan Yuhang AU - Li Chunyang JN - Thermal Science PY - 2018 VL - 22 IS - 12 SP - 497 EP - 505 PT - Article AB - This paper presents an experimental study on the flow structures in turbulent Rayleigh-Benard convection with surfactant solutions. The shadowgraph visualization was used to obtain the plumes and the velocity field was measured using particle image velocimetry. The results show that the size of plumes in surfactant solution case is larger than that in Newtonian fluid case and it needs more time for surfactant solution case to start convection. The large-scale circulation fails to form in surfactant solution case and the convection velocity is smaller. A decrease of the measured Nusselt number is observed in surfactant solution case. The phenomena are caused by the shear-shinning and elastic characteristics of surfactant solution.