Half-ducted fan and ducted fan have been designed and numerically analyzed for investigating the radial flow effect on the overall performance and the three dimensional flow field in design. Based on quasi-three dimensional flow theory, the meridional flow was calculated by adopting the radial balance equations, while the calculation of the blade to blade flow was obtained by 2D cascade data with the correction by a potential flow theory. Two types of axial flow fan were designed. One is the full ducted case as if it was in the straight pipe and another is the half-ducted case with the radial inflow and outflow. The previous experimental results of authors were used to decide the inclinations of both the inflow and outflow. And the circular arc blade with equal thickness was adopted. The numerical results indicate that both of the designed fans can reach the specified efficiency and also the efficiency surpasses more than 11%. Furthermore, the static pressure characteristic of half-ducted fan is much better than that of ducted fan. In comparison of the three dimensional internal flow of these two fans, the improvement of the flow angle at inlet and outlet, the distributions of velocity in the flow field and the pressure distributions on the blade surfaces can be achieved more successfully in accordance with the design intension on consideration of flow angle in design. The conclusion that half-ducted design with considering radial inflow and outflow is feasible and valid in comparison with ducted design for axial flow fans has been obtained at the end of the paper.
Cite this paper
P. Liu, Y. Oka, Y. Kinoue, N. Shiomi, T. Setoguchi and Y. Jin, "Design of Half-Ducted Axial Flow Fan Considering Radial Inflow and Outflow," Open Journal of Fluid Dynamics, Vol. 3 No. 2, 2013, pp. 1-8. doi: 10.4236/ojfd.2013.32A001.
 M. Zangeneh, “A Compressible Three-Dimensional Design Methhod for Radial and Mixed Flow Turbomachinery Blades,” International Journal of Numerical Methods in Fluids, Vol. 13, No. 5, 1991, pp. 599-624.
 M. Zangeneh, “Inverse Design of Centrifugal Compressor Vaned Diffusers in Inlet Shear Flows,” ASME Transactions on Journal of Turbomachinery, Vol. 118, No. 2, 1996, pp. 385-393. doi:10.1115/1.2836653
 M. Zangeneh, A. Goto and H. Harada, “On the Design Criteria for Suppression of Secondary Flows in Centrifugal and Mixed Flow Impellers,” ASME Transactions on Journal of Turbomachinery, Vol. 120, No. 4, 1998, pp. 723-735. doi:10.1115/1.2841783
 W. T. Tiow and M. Zangeneh, “A Novel 3D Inverse Method for the Design of Turbomachinery Blades in Rotational Viscous Flow: Theory and Applications,” Task Quarterly, Vol. 6, No. 1, 2002, pp. 63-78.
 J. Vad, A. R. A. Kwedikha, et al., “Aerodynamic Effects of Forward Blade Skew in Axial Flow Rotors of Controlled Vortex Design,” Proceedings of the Institution of Mechanical Engineers, Part A: Journal of Power and Energy, Vol. 221, No. 7, 2007, pp. 1011-1023.
 S. J. Gallimore, J. J. Bolger, et al., “The Use of Sweep and Dihedral in Multistage Axial Flow Compressor Blading—Parts 1 and 2,” ASME Transactions on Journal of Turbomachinery, Vol. 124, No. 4, 2002, pp. 521-541.
 J. Vad and F. Bencze, “Three-Dimensional Flow in Axial Flow Fans of NonFree Vortex Design,” International Journal of Heat and Fluid Flow, Vol. 19, No. 6, 1998, pp. 601-607. doi:10.1016/S0142-727X(98)10004-8
 N. Shiomi, Y. Kinoue and T. Setoguchi, “Experimental Study on Flow Fields with Vortex in a Semi-Opened Propeller Fan,” Turbomachinery, Vol. 40, No. 11, 2012, pp. 688-696.
 N. Shiomi, Y. Kinoue and T. Setoguchi, “Three Dimensional Velocity Fields at Rotor Outlet of a Semi-Opened Propeller Fan,” Turbomachinery, Vol. 40, No. 4, 2012, pp. 218-225.
 R. A. Novak, “Streamline Curvature Computing Procedures for Fluid-Flow Problems,” ASME Transactions on Journal of Engineering for Power, Vol. 89, No. 2, 1967, pp. 478-490. doi:10.1115/1.3616716
 M. Inoue, T. Ikui, Y. Kmada and M. Tashiro, “A Quasi Three-Dimensional Design of Diagonal Flow Impellers by Use of Cascade Data,” Proceeding of 10th Symposium of IAHR, Tokyo, 28 September-2 October1980, pp. 403-414.