Unsteady Euler analysis of the flowfield of a propfan at an angle of attack

The paper examines the effects of angle of attack of a propfan on the blade loading and details of the flowfield by solving the unsteady three-dimensional Euler equations. The configuration considered is the SR7L propeller at cruise condition and the inflow angles considered are 4.6, 1.6 and -0.4 deg. The results indicate that the blade response is nearly sinusoidal at low inflow angles (1.6 and -0.4 deg) and significant deviations from sinusoidal behavior occur at an inflow angle of 4.6 deg due to the presence of strong shocks on both suction and pressure surfaces of the blade. The detailed flow in the blade passages shows that a shock formed on the suction surface during the highly loaded portion of the revolution extends across the passage to the pressure surface. An increase in inflow angle results in an increase in blade loading on the down-going side and a decrease in loading on the up-going side.