فهرست نشریات علمی دسترسی آزاد ایران

This study presents a numerical analysis of a laminar, steady, and fully developed Newtonian flow and heat transfer within a vertical concentric annulus under a no‑slip boundary condition. Initially, the concentric cylindrical walls are assumed to be stationary, and the effect of key parameters is analyzed. Axial conduction in the wall and viscous dissipation are neglected in this model. The walls of the concentric annulus contain perforations that enable suction and injection of fluid into the gap between the two cylinders. Appropriate boundary conditions were applied, and the ANSYS Fluent software was utilized to obtain numerical results. Variations of velocity, temperature, and inner wall Nusselt number were analyzed for different suction and injection rates, along with dimensionless temperature distributions and radius ratios, under conditions involving movement of the inner and outer walls. The findings show that when a wall moves along the z‑axis, an increase in its speed causes the velocity field near the moving wall to shift and reduces the peak velocity magnitude. In contrast, if the wall moves against the z‑axis direction, the overall flow rate drops, which is offset by an increase in the pressure‑driven velocity gradient. For S<0, the volumetric flow rate increases, causing a rise in temperature in the region adjacent to the heated inner wall. For S>0, the opposite trend is observed: the fluid velocity near the inner wall increases, and higher S values lead to enhance the Nusselt number of the inner wall.