Numerical Investigation of Compressible Fluid in an Eccentric Annulus with Suction and Injection

This study presents a numerical investigation of compressible fluid and heat transfer in a vertically oriented eccentric annulus with moving walls under suction and injection. The flow is assumed Newtonian, laminar, steady, and fully developed. Governing equations are solved under the Boussinesq approximation, applying no-slip conditions on the cylinder walls, while axial conduction and viscous dissipation are neglected. Velocity, temperature, and Nusselt number distributions were obtained numerically using Fluent software for different values. The results show that, under injection, the temperature field shifts toward the outer cylinder wall, whereas under suction, it moves toward the surface of the inner cylinder. Furthermore, when one cylinder wall moves opposite to the Z-axis, the reduction in volumetric flow is compensated by an increase in the pressure gradient and local maximum velocity due to the velocity profile distortion. Increasing the wall speed in the negative z-direction drives the velocity profile toward the stationary wall. In regions where the annular gap is smaller due to eccentricity, the velocity profile approaches the outer wall velocity with a steeper gradient. In the case where the inner cylinder translates along the axis Z while the outer one is fixed, the maximum and minimum heat transfer are observed at the inner and outer walls, respectively. Moreover, an increase in the eccentricity parameter leads to higher Nusselt numbers for both the inner and outer surfaces of the cylinders. Therefore, by varying the controlling parameters investigated in this study, the flow field can be manipulated, and the heat transfer rate can be improved.

کلیدواژه ها:

Eccentric vertical annulus ، Compressible fluid ، Heat Transfer ، Moving walls ، Suction and injection