Experimental and computational analysis of microscale shrouded coaxial rotor in hover

Experimental and computational studies of the hovering performance of microcoaxial shrouded rotors were carried out. The ATI Mini Multi-Axis Force/Torque Transducer system was used to measure all six components of the force and moment. Meanwhile, numerical simulation of flow field around rotor was carried out using sliding mesh method and multiple reference frame technique by ANASYS FLUENT. The computational results were well agreed with experimental data. Several important factors, such as blade pitch angle, rotor spacing and tip clearance, which influence the performance of shrouded coaxial rotor are studied in detail using CFD method in this paper. Results shows that, evaluated in terms of Figure of Merit, open coaxial rotor is suited for smaller pitch angle condition while shrouded coaxial rotor is suited for larger pitch angle condition. The negative pressure region around the shroud lip is the main source of the thrust generation. In order to have a better performance for shrouded coaxial rotor, the tip clearance must be smaller. The thrust sharing of upper- and lower-rotor is also discussed in this paper.