CFD Investigation of Vortex Generator Additions to the General Atomics MQ-9 Reaper

摘要

The General Atomics MQ-9 Reaper is widely employed by government agencies around the world. Its many variants have been utilized in combat, as well as areas of scientific research. In this paper, vortex generators are investigated for their effects on the aerodynamic properties of a similar airfoil design. Vortex generators have been proven to delay flow separation and improve flight characteristics, such as reducing stall speed and increasing lift. Vortex generators will be applied to the MQ-9 Reaper airfoil design in an attempt to make such improvements. Four different types of vortex generators were tested: rectangular, delta, rounded, and trapezoidal. Testing was carried out in ANSYS Fluent with vortex generator size, placement, and angle of attack held constant at zero with Reynolds number of 5.8xl06. Results indicate a detrimental effect on lift to drag ratio (L/D), with the four results ranging from a 5.8% to 15.0% decrease in L/D, however delta vortex generators caused an increase in lift. Despite the negative effects, the addition of vortex generators appears to have decreased turbulence along the top surface of the wing. Further research should be conducted to determine vortex generator effects when tested with varying angle of attack and Reynolds number to further decrease stall speeds.