대표
청구항
▼
We claim: 1. A system for providing electrical power for an airborne vehicle operating at an altitude of at least 50,000 feet, the system comprising: an engine operating with a working fluid in a closed cycle, the working fluid being recirculated within the closed cycle for alternately receiving heat and releasing heat, wherein the closed cycle has no communication with ambient air; a burner burning a fuel in the presence of ambient air present at an altitude of at least 50,000 feet to produce heated combustion by-products, the ambient air being unheate...
We claim: 1. A system for providing electrical power for an airborne vehicle operating at an altitude of at least 50,000 feet, the system comprising: an engine operating with a working fluid in a closed cycle, the working fluid being recirculated within the closed cycle for alternately receiving heat and releasing heat, wherein the closed cycle has no communication with ambient air; a burner burning a fuel in the presence of ambient air present at an altitude of at least 50,000 feet to produce heated combustion by-products, the ambient air being unheated and uncompressed by the system; and a heat exchanger transferring the heat contained in the heated combustion by-products to the working fluid, thereby converting the heated combustion by-products into cooled combustion by-products that are vented to the ambient air. 2. The system described in claim 1, wherein the airborne vehicle is a lighter-than-air airborne vehicle. 3. The system described in claim 1, wherein the burner is a catalytic burner. 4. The system described in claim 1, wherein the fuel is hydrogen gas. 5. The system described in claim 1, wherein the closed cycle is a Brayton cycle. 6. The system described in claim 1, wherein the closed cycle is a Rankine cycle, the heat exchanger is a boiler, and the working fluid is water that changes phases during the cycle. 7. The system described in claim 1, wherein the fuel is provided in a fuel stream having a pressure higher than that of the ambient air, wherein ambient air is entrained into the fuel stream. 8. The system described in claim 1, wherein the ambient air is provided by means of a fan. 9. A power generation system supplying electrical power in a lighter-than-air airborne vehicle operating at an altitude greater than 50,000 feet, the system comprising: a turbine engine operating in a closed Brayton cycle, the closed cycle with a working fluid for alternately receiving heat and releasing heat, wherein the working fluid within the closed Brayton cycle does not communicate with ambient air and has constant mass; a burner providing combustion of a fuel in the presence of ambient air found at altitudes greater than 50,000 feet at ambient pressure to produce heated combustion by-products, the ambient air being uncompressed and unheated by the system, wherein a fuel pressure is higher than the ambient air pressure; a heat exchanger transferring the heat contained in the heated combustion by-products to the working fluid, thereby converting the heated combustion by-products into cooled combustion by-products that are vented to the ambient air. 10. The system described in claim 9, wherein the fuel is hydrogen. 11. A power generation system for supplying electrical power in an airborne vehicle operating in-flight for a period of at least two continuous days, the system comprising a turbine engine adapted to operate in a closed cycle at an altitude of at least 50,000 feet with a working fluid for alternately receiving heat and releasing heat, wherein the working fluid within the closed cycle does not communicate with ambient air and has constant mass; a burner for providing combustion of a fuel in the presence of ambient air at said altitude, the ambient air being unheated and uncompressed by the system, the burner producing heated combustion by-products, wherein the fuel is injected into the burner at a pressure that is higher than ambient air pressure so as to entrain ambient air in the fuel and thereby improve combustion of the fuel at said altitude; and a heat exchanger for transferring the heat contained in the heated combustion by-products to the working fluid, thereby converting the heated combustion by-products into cooled combustion by-products that are vented to the ambient air. 12. The system described in claim 11, wherein the closed cycle is a closed Brayton cycle. 13. The system described in claim 11, wherein the airborne vehicle is a lighter-than-air airborne vehicle. 14. The system described in claim 11, wherein the fuel is hydrogen. 15. A method for heating a working fluid in a closed cycle turbine engine, the closed cycle having no communication with ambient air and containing a working fluid, the working fluid having constant mass, the method comprising the steps of burning a fuel in the presence of unheated ambient air that has not been compressed in a catalytic burner at altitudes greater than 50,000 feet to provide heated combustion by-products; transferring heat from the heated combustion by-products to the working fluid, thereby converting the heated combustion by-products into cooled combustion by-products; and venting the cooled combustion by-products to the ambient air. 16. The method described in claim 15, wherein transferring heat from the heated combustion by-products to the working fluid is accomplished by a heat exchanger. 17. The method described in claim 15, wherein the closed cycle turbine engine operates according to a Brayton cycle. 18. The method described in claim 15, wherein the closed cycle turbine engine operates according to a Rankine cycle. 19. A method for providing power using a closed Brayton cycle engine at altitudes greater than 50,000 feet, the method comprising directing a heated working fluid to a turbine to cause the turbine to rotate a shaft; directing the heated working fluid released by the turbine to a recuperator, wherein heat from the heated working fluid is removed to provide a cooled working fluid; directing the cooled working fluid to a radiator, whereby residual heat contained in the cooled working fluid is vented to the ambient air; directing the cooled working fluid from the radiator to a compressor; directing the cooled working fluid from the compressor to the recuperator, wherein the cooled working fluid receives the heat removed from the heated working fluid from the turbine to provide heated working fluid to a heat exchanger; and providing a heat source to the heat exchanger, wherein the heated working fluid receives additional heat from the heat source and wherein the heat source is the combustion by-products of a burner burning a fuel in the presence of ambient air found at altitudes greater than 50,000 feet, the ambient air being unheated and uncompressed. 20. A method described in claim 19, wherein the fuel is hydrogen. 21. A method for providing power using a closed Rankine cycle engine at altitudes greater than 50,000 feet, the closed Rankine cycle operating with a working fluid that has constant mass and no communication with ambient air, the method comprising the steps of: heating the working fluid in a boiler to provide a heated working fluid; directing the heated working fluid to a turbine to cause the turbine to rotate a shaft; directing the heated working fluid released by the turbine to a recuperator, wherein heat from the heated working fluid is removed to provide a cooled working fluid; directing the cooled working fluid to a condenser, whereby residual heat contained in the cooled working fluid is vented to ambient air; directing the cooled working fluid from the condenser to a pump; directing the cooled working fluid from the pump to the recuperator, wherein the cooled working fluid receives heat removed from the heated working fluid from the turbine to provide heated working fluid to the boiler; and providing the heated working fluid in the boiler with additional heat from combustion by-products of a burner to the boiler, the burner burning a fuel in the presence of ambient air found at altitudes greater than 50,000 feet, the ambient air being uncompressed and unheated. 22. The method described in claim 21, wherein the fuel is hydrogen. 23. A method for providing power using a closed Brayton cycle engine in an airborne vehicle operating in-flight for a period of at least two continuous days at altitudes greater than 50,000 feet, the method comprising directing a heated working fluid to a turbine to cause the turbine to rotate a shaft; directing the heated working fluid released by the turbine to a recuperator, wherein heat from the heated working fluid is removed to provide a cooled working fluid; directing the cooled working fluid to a radiator, whereby residual heat contained in the cooled working fluid is vented to the ambient air; directing the cooled working fluid from the radiator to a compressor; directing the cooled working fluid from the compressor to the recuperator, wherein the cooled working fluid receives the heat removed from the heated working fluid from the turbine to provide heated working fluid to a heat exchanger; providing heat to the heat exchanger by burning a fuel in the presence of ambient air that is uncompressed and unheated. 24. The method described in claim 23, wherein the fuel is hydrogen. 25. The method described in claim 23, wherein the airborne vehicle is a lighter-than-air airborne vehicle. 26. A method for providing power using a closed Rankine cycle engine in an airborne vehicle operating in-flight for a period of at least two continuous days at altitudes greater than 50,000 feet, the closed Rankine cycle engine operating with a working fluid having constant mass and no communication with ambient air, the method comprising heating the working fluid in a boiler to provide a heated working fluid; directing the heated working fluid to a turbine to cause the turbine to rotate a shaft; directing the heated working fluid released by the turbine to a recuperator, wherein heat from the heated working fluid is removed to provide a cooled working fluid; directing the cooled working fluid to a condenser, whereby residual heat contained in the cooled working fluid is vented to ambient air; directing the cooled working fluid from the condenser to a pump; and directing the cooled working fluid from the pump to the recuperator, wherein the cooled working fluid receives heat removed from the heated working fluid from the turbine to provide the heated working fluid to a boiler, the boiler adding heat provided by a burner to the working fluid, the burner burning a fuel in the presence of ambient air that is uncompressed and unheated, the ambient air being present at altitudes greater than 50,000 feet. 27. The method described in claim 26, wherein the fuel is hydrogen.
