Marine Propeller Design Method based on Lifting Line Theory and Lifting Surface Correction Factors

Abstract

In the present paper, a marine propeller design method has been presented based on lifting line theory and lifting surface correction factors. The developed method has been applied for the propeller whose blade outline is symmetrical about the mid- chord and the mean line chosen is parabolic which is also symmetrical about the mid-chord. So no pitch correction is necessary. Only camber correction is required. The blade outline has been chosen symmetric to avoid cavitation. The pitch and camber has been determined by the requirement that the designed load distribution to be obtained. The method has been used for wake adapted propeller with an adaptation of the vortex lattice method. Assumption about the loading is that the circulation goes to zero at hub and tip in both lifting line and lifting surface calculation. Also in lifting surface calculation, the circulation goes to zero at L.E and T.E. For the calculation of induced velocity at any point in the flow field, the Biot-Savart law has been used. The pitch has been calculated in lifting line program. Trial and error method has been followed for the program.