Experimental Thermal and Fluid Science ( IF 3.2 ) Pub Date : 2021-07-26 , DOI: 10.1016/j.expthermflusci.2021.110485 Thomas Jaroslawski 1 , Maxime Forte 1 , Jean-Marc Moschetta 2 , Gregory Delattre 1 , Erwin R. Gowree 2
An experimental investigation on the flow topology over a rotor operating at low Reynolds numbers is presented. The feasibility of laminar to turbulent transition experiments over small rotors is demonstrated. Phase-locked infrared thermography coupled with simultaneous force and torque measurements were used to study a three bladed rotor with a NACA0012 aerofoil section set at a uniform angle of incidence of 10. Boundary layer transition was forced using two-dimensional (2D) and three-dimensional (3D) roughness elements, placed at approximately 5% and 28% of the rotor blades chord. In the 3D roughness configurations once the critical roughness Reynolds was attained the streaks downstream developed into fully turbulent wedges. For the current rotor configuration, it was found that the state of the boundary layer can significantly affect its performance, with the non-optimal forcing of laminar to turbulent transition generally resulting in a loss of performance when compared to the smooth reference rotor case.
中文翻译:
低雷诺数转子上边界层过渡的表征
介绍了在低雷诺数下运行的转子上的流动拓扑结构的实验研究。证明了在小转子上进行层流到湍流过渡实验的可行性。锁相红外热成像结合同步力和扭矩测量被用于研究三叶转子,其 NACA0012 翼型截面设置为 10°的均匀入射角. 使用二维 (2D) 和三维 (3D) 粗糙度元素强制边界层过渡,放置在转子叶片弦的大约 5% 和 28% 处。在 3D 粗糙度配置中,一旦达到临界粗糙度雷诺数,下游的条纹就会发展成完全湍流的楔形。对于当前的转子配置,发现边界层的状态会显着影响其性能,与平滑的参考转子情况相比,层流到湍流过渡的非最佳强制通常会导致性能损失。