Effects of propeller separation and onset flow condition on the performance of quadcopter propellers

Abstract

This study aims to enhance the understanding of multirotor flows by deploying numerical simulations to investigate the effects of propeller separation and onset flow conditions on the performance of quadcopter propellers. Two configurations were tested: a dual propeller setup, with propellers spaced perpendicular to the direction of onset flow, and a quadcopter setup. Both configurations used high washout propellers similar to those found on commercially available quadcopters. The dual propeller setup tested four separation distances over three onset flow conditions. The separation distances tested were L/R = 2.2, 2.8, 3.6, and 5.2, and the flow conditions were still air, 5 m/s laminar onset flow, and 5 m/s onset flow with 15 % turbulence intensity. The quadcopter analysis was conducted for the same three flow conditions, with the four propellers spaced at an L/R of 2.8. The L in L/R is given as the hub-to-hub distance between propellers and R is the propeller radius. The dual propeller simulations indicate that the separation distance of propellers spaced perpendicular to the flow direction has a minimal effect on propeller performance. Comparing the dual propeller results to results from past studies suggests that the degree of propeller washout has a significant effect on the degree of wake interaction between adjacent propellers in still air and will therefore influence the performance of the propellers. The quadcopter simulations indicate that propeller pairs experience noticeable changes in performance when an onset flow is applied parallel to the propeller spacing and the velocity of this onset flow has a greater influence on propeller performance than the flow's turbulence intensity.