نوع مقاله : مقاله پژوهشی
نویسندگان
بخش مهندسی مکانیک- دانشگاه تربیت مدرس
چکیده
کلیدواژهها
عنوان مقاله [English]
نویسندگان [English]
In the present study, numerical simulation of a turbulent flow and forced convection heat transfer in a pipe partially filled with porous inserts is presented. For this purpose, two arrangements of the porous inserts are considered: (i) cylindrical porous material is inserted in a central arrangement, (ii) an annuli is inserted in the boundary arrangement. Effects of several parameters, such as: porosity, Darcy number, and porous insert thickness on velocity profile, pressure drop and heat transfer are investigated. The obtained results indicate that for Darcy numbers $2times 10^{-4}$,$5times 10^{-4}$, and $10^{-3}$ the certain relative thickness of the porous material at which the heat transfer is maximum at the central arrangement are: 0.9, 0.85, and 0.8, respectively, while, for the boundary arrangement, the maximum value of heat transfer takes place in the whole porous pipe. For Darcy numbers $2times 10^{-4}$, $5times 10^{-4}$, and $10^{-3}$, the certain relative thicknesses of the porous material at which heat transfer is minimum are 0.6, 0.55, and 0.5, respectively. A comparison of the obtained results of the turbulent flow with laminar flow shows that there is more significant variations of corresponding values of the optimum relative thickness, with respect to Darcy number, in the turbulent regime. For the boundary arrangement, minimum heat transfer is achieved at lower relative thicknesses and relative thickness variations are not linear, in comparison with laminar flow.
کلیدواژهها [English]
)