Propeller aerodynamic performance by vortex-lattice method

Abstract

It is inappropriate to apply classical propeller theories to design an advanced turboprop (ATP). In this paper, the vortex-lattice method is applied to rotating blades. It is assumed that the flow is inviscid and incompressible. However, the compressibility effect is included in the calculations through the Prandtl-Glauert similarity rule. The other properties characteristics of an ATP, i.e., the effect of displacement velocities, the interference effect between blades, and the effect of flow deflection by a spinner and nacelle, are introduced into the calculations. Powers, thrusts, and efficiencies of two kinds of ATP, SR-1 and SR-3, are obtained and compared with experimental values. The numerical values show that they agree well with the experimental results of SR-1. However, the former is larger than those of SR-3. This is consistent with the calculations by Hamilton Standard. The principal reason for this difference is that the portion of the blade near the tip is distorted by centrifugal force. Using this method, the ATP performance can be calculated accurately below Mach 0.6. However, the transonic wing theory should be applied for performance estimates at Mach 0.7-0.8.