Numerical Study on Parametrical Design of Long Shrouded Contra-Rotating Propulsion System in Hovering

Authors: Chao. Huo, Roger. Barènes, Jérémie. Gressier, Gilles.Grondin

Abstract:

The parametrical study of Shrouded Contra-rotating Rotor was done in this paper based on 2D axisymmetric simulations. The calculations were made with an actuator disk as double rotor model. It objects to explore and quantify the effects of different shroud geometry parameters mainly using the performance of power loading (PL), which could evaluate the whole propulsion system capability as 5 Newtontotal thrust generationfor hover demand. The numerical results show that:The increase of nozzle radius is desired but limited by the flow separation, its optimal design is around 1.15 times rotor radius, the viscosity effects greatly constraint the influence of nozzle shape, the divergent angle around 10.5° performs best for chosen nozzle length;The parameters of inlet such as leading edge curvature, radius and internal shape do not affect thrust great but play an important role in pressure distribution which could produce most part of shroud thrust, they should be chosen according to the reduction of adverse pressure gradients to reduce the risk of boundary separation.

Keywords: Axisymmetric simulation, parametrical design, power loading, Shrouded Contra-Rotating Rotor.

Digital Object Identifier (DOI): doi.org/10.5281/zenodo.1063401

References:

[1] Black, D., "Shrouded Propellers- A Comprehensive Performance Study", AIAA 68-994, Oct.1968;
[2] Kruger, W., "On Wind Tunnel Tests and Computations Concerning the Problem of Shrouded Propellers", NACA TM No.1202, Feb.1949;
[3] Cycon, J., "Sikorsky Aircraft UAV Program",Vertiite, V.38, No.3, May. 1992;
[4] Lipera, L., "The Micro Craft iSTAR Micro Air Vehicle: Control System Design and Testing", AHS57th Annual Forum, May 2001;
[5] Kailash, K., "Ducted Fan or Shrouded Rotor Aerodynamics and its Applications in VTOLMiniature Aerial Vehicles", AE 416 project,Dec.2005;
[6] Tayor, R., "Experimental Investigation of the Effects of some Shroud Design Variables onthe Static Thrust Characteristics of a Small Scale Shrouded Propeller Submerged in a Wing",NACA, Jan.1958;
[7] Jason Pereira, et al, "Performance and Surface Pressure Measurements on A MAV-ScaleShrouded Rotor in translational flight", American helicopter Society International, May 1-3, 2007;
[8] Fleming, J., "Improving Control System Effectiveness for Ducted Fan VTOL UAVs Operating inCrosswinds", AIAA Paper, 2003-6514;
[9] Dyer,K., "Aerodynamic Study of a Small, Ducted VTOL Aerial Vehicle", M.S Thesis, MassachusettsInsitute of Technology, Jun.2002;
[10] Hui When Zhao, and CeesBil, "Aerodynamic Design and Analysis of a VTOL Ducted-FanUAV", 26th AIAA Applied Aerodynamics Conference, August 18-21, 2008;
[11] Andy Ko., "Ducted Fan UAV Modeling and Simulation in Preliminary Design", AIAA Modeling and Simulation Technologies Conference and Exhibit, Aug 20-23,2007;
[12] Hui, W. Z., Bil, C. and Bok, H. Y., "Computational Fluid Dynamics Calculations on Preproduction Ducted Fan VTOL UAV for Stability andControl",3rd Australasian Unmanned Air Vehicles Conference, 9 - 12 March, 2009.