15 Ben Glass Altaeros Energies, Inc. ben.glass@altaerosenergies.com www.altaerosenergies.com
Altaeros Energies
Development Process for Buoyant Airborne Wind Turbines
Ben Glass (Speaker Chris Vermillion)Altaeros Energies
Altaeros Energies is developing a buoyant airborne wind tur-bine for remote power applications. The Altaeros 30, current-ly under development, will deploy within remote communi-ties and industrial sites that currently rely on diesel for most of their power needs. By deploying from two standard ship-ping containers and operating up to 2000ft above ground, the Altaeros 30 simplifies the logistics and installation costs of traditional renewables in remote locations, while delivering more net energy, ultimately reducing diesel consumption by up to 60% in a wind-diesel hybrid configuration.
Altaeros’ buoyant shell is designed to incorporate sufficient lifting gas volume to stay aloft in light winds while providing aerodynamic lift and passively stable flight characteristics in strong winds. This represents an aerodynamic design prob-lem that is not only challenging but also expensive to con-firm through relatively large flight prototypes with sufficient buoyant lift. To address the challenges and expense of build-ing small-scale lighter-than-air test vehicles, Altaeros has developed a design process utilizing a number of numerical
and empirical tools to thoroughly evaluate the performance of candidate designs before building flight prototypes. The Altaeros team has developed a 6 degree-of-freedom dynam-ic model that has been used to evaluate flight characteris-tics under a range of wind inputs and identify desirable aero-dynamic parameters, which represent a design target for the aerodynamicist. Aerodynamic parameters of candidate de-signs are evaluated using Reynolds-averaged Navier-Stokes (RANS), and CFD calculations and fed back into the dynam-ic model to verify flight characteristdynam-ics. A full CFD sweep of angle-of-attack and side-slip angle is performed on promis-ing designs and the resultpromis-ing aerodynamic force and moment curves are verified or modified based on wind tunnel meas-urements. Finally, dynamic characteristics are empirically evaluated using very small scale, buoyant tethered models in a 2ft x 2ft water channel. This unique water channel test en-vironment enables inexpensive validation of new designs in a dynamically-scaled environment, while also providing a tool for validating and refining the 6-dof dynamic model.
