NASA 1996 SBIR Phase I


PROPOSAL NUMBER : 96-1 01.16-9014

PROJECT TITLE : UAV Droplet Heat Exchanger

TECHNICAL ABSTRACT (LIMIT 200 WORDS)

Unmanned aerial vehicles (UAVs) are now being used for atmospheric sampling, but significant advances in performance must be achieved for sustained flight at altitudes up to 30 km. It is proposed to replace the standard metal finned circulating glycol/water heat exchanger with a droplet heat exchanger developed in this program. A circulating liquid sprayed into a ducted airstream creates a dense droplet field that directly transfers heat from the liquid to the gas and is then captured at the end of the duct by inertial separation from a sharply turning flow. A droplet heat exchanger efficiently rejects engine heat under widely varying conditions while greatly reducing heat exchanger weight and lowering aircraft drag. Heat transfer can be increased for high altitude flight, lower weight increases altitude capability and together with decreased drag increases range. Heat transfer and droplet collection can be maintained during speed and attitude changes, and the system tolerates rain, snow, and dust. DHXs have already been demonstrated experimentally; a Phase 1 modeling and analysis program is proposed to demonstrate the feasibility of a droplet heat exchanger for a UAV.
POTENTIAL COMMERCIAL APPLICATIONS
A droplet heat exchanger successfully applied to a UAV will permit a significant reduction in both aerodynamic drag and vehicle weight. The resulting increase in aircraft efficiency will greatly enhance the capabilities of a redesigned UAV. Droplet heat exchangers can be used for rejecting heat from any commercial engine. Once developed, weight savings and simplicity may lead to aircraft and other applications.
NAME AND ADDRESS OF PRINCIPAL INVESTIGATOR
Stephen C. Bates
Thoughtventions Unlimited
P. O. Box 1310
Glastonbury, CT 06033
NAME AND ADDRESS OF OFFEROR
Thoughtventions Unlimited
P. O. Box 1310
Glastonbury, CT 06033