A Study on the Half-Ducted Axial Flow Fan Designed by a Diagonal Flow Fan Design Method

摘要

A study on the half-ducted axial flow fan designed by a diagonal flow fan design method was conducted.The rotor which has NACA65 blades was designed, manufactured, tested experimentally and calculated numerically.For the comparison between the design values and the experimental values at the design flow rate coefficient of Φ =0.264,the experimental values of the pressure rise coefficient ψ and the efficiency η are rather small than the design values, while the experimental value of the torque coefficient τ is almost the same as the design value.However, the experimental value of approximately 0.45 of the maximum efficiency is comparably large value considering for the limitation of the situation of half-ducted.For the comparison between the experimental values and the CFD values at Φ 0.264, the CFD values are almost the same values as the experimental values for all the values of ψ, τ and η.In addition, the tendencies of the CFD values when the flow rate coefficient changes are almost similar as the experimental tendencies, though the flow rate coefficient for the CFD values when ψ or η takes the peak value shifts toward larger flow rate.For the case at rotor outlet at Φ =0.264, three values of the meridional velocity, the tangential velocity and the pitch angle are larger than the design values at the tip side of the radial distribution.On the other hand, the values of the meridional velocity and the tangential velocity are smaller than the design values at the the hub side of the radial distribution.The improvement of the design is prospected for this point, that is, the approach between the design value and the actual flow is prospected if the tangential velocity is assigned small at hub and is assigned large at the tip so as to accord the actual flow in the vortex design of the rotor blade.