The maximum figure of Merit (FMmax) is the most important index for a rotor which indicates the greatest hover efficiency the rotor can achieve. However, it cannot reflect the rotor's ability to keep a high Figure of Merit (FM) in certain blade load ranges. Therefore a new concept, the hover hold ability (HHA) of roltor is defined in this paper. In order to describe the distribution of vortices on a blade more accurately, the lifting-surface is used in the blade aerodynamic model. To take into consideration different airfoils, vortices of a blade are set on the middle line of an airfoil. Based on the free-wake model, a calculation method of rotor performance is established which includes the lifting-surface model, rigid blade flap equation, airfoil dynamics stall model and second-order time accurate algorithm. The model rotor FM with different tip Mach numbers (Matip) is calculated and compared with test results to validate the precision of the method. Compared with the free-wake model which includes a lifting-line model, more accurate FM of rotor is attained. Finally, the influence of critical rotor design parameters on rotor hover performance is analyzed, and new laws for the effect of design parameters on rotor hover hold ability are obtained.
TAN Jianfeng, WANG Haowen, LIN Changliang
. Analysis of Influence of Rotor Parameters on Rotor Hover Performance by Lifting-Surface and Free Wake Method[J]. ACTA AERONAUTICAET ASTRONAUTICA SINICA, 2012
, 33(2)
: 249
-257
.
DOI: CNKI:11-1929/V.20111031.1056.003
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