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.

[1]  J. Gordon Leishman,et al.  Free-Wake Analysis of Tandem, Tilt-Rotor and Coaxial Rotor Configurations , 1996 .

[2]  Daniel J. Inman,et al.  Nondimensional Modeling of Ducted-Fan Aerodynamics , 2012 .

[3]  Thomas J. Mueller,et al.  An overview of micro air vehicle aerodynamics , 2001 .

[4]  D. Pines,et al.  Challenges Facing Future Micro-Air-Vehicle Development , 2006 .

[5]  Yang Wang,et al.  Modeling and Hovering Attitude Control of a Prototype Tandem Ducted Fan Vehicle , 2015, J. Intell. Robotic Syst..

[6]  Timothy E. Lee,et al.  Design and Performance of a Ducted Coaxial Rotor in Hover and Forward Flight , 2010 .

[7]  Yue Ma,et al.  Modelling and hovering control of a novel multi-tandem ducted fan vehicle , 2015, 2015 International Conference on Unmanned Aircraft Systems (ICUAS).

[8]  Yibo Zhang,et al.  Comprehensive nonlinear modeling and attitude control of a novel tandem ducted fan vehicle , 2016, 2016 IEEE International Conference on Aircraft Utility Systems (AUS).

[9]  Krzysztof Sibilski,et al.  Comparative Evaluation of Power Requirements for Fixed, Rotary, and Flapping Wings Micro Air Vehicles , 2007 .

[10]  Peretz P. Friedmann,et al.  Application of Vortex Methods to Coaxial Rotor Wake and Load Calculations , 2017 .

[11]  Vinod K. Lakshminarayan,et al.  Computational investigation of micro-scale coaxial rotor aerodynamics in hover , 2010 .

[12]  S. J. Newman,et al.  Principles of Helicopter Aerodynamics – Second edition J.G. Leishmann Cambridge University Press, The Edinburgh Building, Shaftesbury Road, Cambridge, CB2 2RU, UK. 2006. 826pp. Illustrated. £65. ISBN 0-521-85860-7. , 2007, Aeronautical Journal.

[13]  Oh Joon Kwon,et al.  Detailed Aerodynamic Analysis of a Shrouded Tail Rotor Using an Unstructured Mesh Flow Solver , 2004 .

[14]  Jason Louie Pereira,et al.  Hover and wind-tunnel testing of shrouded rotors for improved micro air vehicle design , 2008 .

[15]  Chao Huo,et al.  Experimental Analysis of the Aerodynamics of Long-Shrouded Contrarotating Rotor in Hover , 2015 .

[16]  Jean-Marc Moschetta,et al.  Aerodynamic Analysis of a Multi-Mission Short-Shrouded Coaxial UAV: Part III { CFD for Hovering Flight , 2008 .

[17]  Chao Xu.  CFD investigation into propeller spacing and pitch angle for a ducted twin counter rotating propeller system , 2015 .

[18]  Thomas J. Mueller.  Computation of Aerodynamic Characteristics of a Micro Air Vehicle , 2001 .

[19]  H Zhao,et al.  Development of a dynamic model of a ducted fan VTOL UAV , 2009 .

[20]  J. Gordon Leishman,et al.  An Optimum Coaxial Rotor System for Axial Flight , 2008 .

[21]  Chinnapat Thipyopas,et al.  Experimental and Computational Evaluation of Small Microcoaxial Rotor in Hover , 2011 .

[22]  Yue Bai,et al.  An experimental investigation on aerodynamic performance of a coaxial rotor system with different rotor spacing and wind speed , 2013 .

[23]  Mark D. Maughmer,et al.  Experimental Analysis of Power Requirements for Fixed-, Flapping-, and Rotary-Wing Micro Air Vehicles , 2014 .

[24]  Konstantinos Karamolegkos.  Ducted tail rotor perfomance prediction using CFD , 2014 .

[25]  Roger Barènes,et al.  Revisiting Froude’s Theory for Hovering Shrouded Rotor , 2015 .

[26]  C. Thipyopas,et al.  Aerodynamic Analysis of a Multi-Mission Short-Shrouded Coaxial UAV: part II - Translation Flight , 2010 .