Numerical Investigation by Applying Microballoon Actuators on High-Altitude Propeller

Abstract

Microballoon actuators as a potential active flow control device have been studied for years. However, most studies have relied on experimental methods to investigate its effects. In this paper, we utilized the numerical method of steady-state RANS to explore the feasibility of applying microballoon actuators to suppress flow separation on a wing section and a high-altitude propeller. The geometric design, including shapes and positions for microballoons, is introduced, and these microballoons are fully resolved for the numerical models to better assess the influence of sensitive parameters. The turbulent model used in simulations is well validated in comparison with experimental data. In the wing section model, computational results show that at $Re=2\times {10}^5$, placing nonrotation microballoons close to the separation point can suppress separation bubbles and decrease drag by 12% before the stall angle of attack. In the propeller model, computational results show that placing a microballoon actuator array with a proper dimension and position on the blade can also effectively suppress the crossflow separation appearing at the trailing edge. At a rotational speed of 450 rpm, the efficiency enhancement can reach a maximum of 1.6%.