Design and development of an Air Supply Unit for Circulation Control Wing-based UAVs

The main contribution of this paper is the design, development and evaluation of a light-weight Air Supply Unit (ASU) and its associated speed controller, suitable for use in Circulation Control Wings (CCW) of small-scale Unmanned Aerial Vehicles (UAVs). An iterative process, presented here, is used to optimize the design of the centrifugal compressor for the ASU through extensive simulation. The implemented speed controller provides the necessary mass flow rate on-demand by maintaining a fixed velocity ratio (Vjet=V∞) thereby reducing the power penalties associated with operating the ASU continuously. The ASU/controller system is evaluated by integrating with a CCW plenum design capable of distributing air evenly across the span and measuring the Vjet at the slot exit in a laboratory environment. Results obtained demonstrate a close match between experimental tests and simulation in all cases considered. In particular, the velocity at the slot (Vjet) is measured to be 24.5 m/s, which provides sufficient velocity to accomplish Circulation Control during both take off and cruise flight for the purposes of this research.

1. Nomenclature

Pressure (Pa)

Wing span (mm)

Gas constant

Moment Coefficient of Blowing

Slot height (mm)

Cross-section area (m²)

Mass flow rate (kg/s)

Mach number -

Density (kg/m³) Velocity of the jct (m/s)

Ratio of specific heat Free stream velocity (m/s)

Diameter (mm)

Height (mm)

Blade angle (degrees)

Vane thickness (mm)

Speed (rpm)

Prewhirl angle (degrees)

Angular velocity (rpm)

Tanzential velocity (m/s)

Absolute velocity -(m/s).

Desired (m/s)

Radius (mm)

Gravitational constant

a

Speed of sound (m/s)