Abstract: The absorber tube constitutes a critical component determining the photothermal conversion efficiency in parabolic trough solar collectors. To enhance the overall thermal performance of collector systems, this study proposes an innovative design of metallic absorber tubes integrated with ellipsoidal dimple structures. A systematic numerical investigation was conducted to elucidate the influence of dimple structural parameter β on thermo-hydraulic characteristics under Reynolds numbers（Re） ranging from 10 000 to 50 000. The results demonstrate that ellipsoidal dimples significantly enhance heat transfer performance by inducing boundary layer perturbations and promoting fluid mixing. Optimal single-phase heat transfer occurs at β=60°, exhibiting 11.4~49.6 K reduction in mean wall temperature compared to smooth tubes, accompanied by 75.5%~102.2% improvement in Nusselt number （Nu） and 2.38~3.47-fold increase in friction factor （f）. Comprehensive optimization reveals that β=30° yields peak thermo-hydraulic performance evaluation criterion （PEC） values ranging from 1.12 to 1.38. This research provides novel insights into topology optimization of solar absorber tubes and offers valuable guidance for developing high-efficiency, reliable solar receiver configurations.