Lift and drag force measurements on basic models of low-speed axial fan blade sections

摘要

This paper presents comparative data on the aerodynamic lift and drag of basic model representations of low-speed axial fan blade sections. Three main types of blades are investigated: flat plate, cambered plate and RAF6-E profiled airfoil. Lift and drag force are measured at three different Reynolds numbers (0.6x10(5), 10(5) and 1.4x10(5)) around the threshold value of 10(5). The measurement data are compared to literature data. The aerodynamic force measurements reveal that, for Reynolds numbers below 10(5), cambered plate blade sections can be superior to airfoil profiles in terms of aerodynamic efficiency, especially in the high-load range. The effect of leading edge bluntness is also investigated. Leaving the leading edge of cambered plates blunt, tends to be uncritical for low Reynolds numbers at angles of attack between 4 degrees and 10 degrees but is critical at angles between 0 degrees and 4 degrees.