Porous metallic structures such as Kelvin cells have attracted increasing attention due to their high surface-to-volume ratio and design flexibility, making them promising candidates for lightweight and efficient heat exchangers. While previous studies have primarily focused on isotropic or single-directional flow configurations, research on the thermohydraulic behavior of anisotropic Kelvin structures under oblique flow conditions—a common operating condition in practical applications—remains scarce. In this study, three-dimensional numerical simulations were conducted on ellipsoidal Kelvin cells with flow orientation angles ranging from 0° to 90°. The results indicate that the pressure drop generally increases with the tilt angle, rising by 87.7% at 90° compared to 0°, owing to enlarged frontal area, increased tortuosity, and stagnation effects. In contrast, the heat transfer coefficient rises significantly with angle and reaches its maximum at 60°, showing an enhancement of more than threefold relative to 0°. Analysis of velocity and temperature fields reveals that oblique jets and secondary flows disrupt boundary layers and enlarge fluid–solid contact areas, thereby strengthening convective mixing. The overall performance ratio ( j/f ) peaks at 60°, with an improvement of approximately 268%, confirming that moderate inclination provides the optimal balance between heat transfer enhancement and flow resistance. These findings fill a critical research gap and provide mechanistic insights and design guidance for optimizing anisotropic porous media heat exchangers.
Yiqiang et al. (Wed,) studied this question.