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Mixed convection in an obstructed cavity with heated horizontal walls is investigated in this work. Brinkman-Forchheimer-extended Darcy model is utilized to describe the flow characteristics within a porous medium for different angles of attack with respect to the forced convection. Numerical results are obtained for a wide range of Grashof numbers (102–109), Reynolds numbers (102–105), Darcy numbers (10−6–10−1), and aspect ratios (0.25–2). Effects of the pertinent physical parameters are investigated in terms of the flow and temperature fields, as well as Nusselt number distributions. The presented results show that the Darcy number plays a significant role on the flow and thermal fields and the Nusselt number distributions for different flow configurations. For an inclined flow, the vertical velocity component is substantially diminished within a narrow entrance section near the inlet boundary. It is shown that as the aspect ratio increases the thickness of the thermal boundary layer increases, resultin...

The spherical titanium nanopowder is prepared by induction plasma technology, according to scanning electron microscope, oxygen-azote mensuration equipment and inductive coupled plasma emission spectrometer, the morphology and chemical constitution of titanium nanopowder are characterized. With the processing parameters of the induction plasma technology are chosen, the average diameter of nanopowder is 25.4 nm, and spheroidization degree is almost 100%. Meanwhile, the result of chemical constitution shows that the induction plasma technology has no obvious influence on the content of impurity element such as C, Fe, Ni, Cr and Al but reduce the oxygen content of Ta nanopowder.