SBIR-STTR Award

Brayton Energy is a developer of turbomachinery systems, specializing in gas turbines, turbojets, turbochargers, and turbo-compounding equipment. In the proposed program, Brayton will design and bench-test the critical elements of novel single-shaft turbocharger with integral motor/alternator capability, including its air bearing system. The proposed variant on turbo-compounding enables motor-assisted"super-charging"for take-off and dash conditions, and electrical power extraction during cruise for auxiliary loads. The very light-weight high-speed alternator will off-set the need for the heavier low-speed alternator and power take-off (PTO) system on the piston engine. A single shaft turbomachine will operate on air bearings. Brayton and the University of Texas Arlington will collaborate on the air bearings, employing the principles of a design which our teams co-developed and tested between 2011 and 2013. In furthering the objectives towards longevity and light-weight, Brayton brings the experience of our silicon nitride radial turbine and volute to the project. This is partially relevant to the very high exhaust temperature of certain rotary engines.

Keywords:
turbomachinery,turbochargers,turbo-compounding, turbo-alternator, air bearings, super-charging, turbojet, silicon-nitride-radial-turbine

The benefits of greater power and efficiency are offered by using turbochargers and superchargers for small UAS propulsion systems which including rotary, piston, and other developing engines. Present day UASs suffer performance losses upon takeoff and at altitude. Therefore, the need for improved, light weight turbo and superchargers which eliminate the use of oil lubrication for the bearing system is needed. Furthermore, current UAS systems are experiencing durability issues with turbochargers due to oil coking. Light weight forced induction systems with improved bearing and lubrication circuits are sought for the 50 to 150 HP UAS class. The bearing systems in turbochargers and superchargers are normally oil-fed from the engine oiling system. The bearings in these systems run in an extremely harsh environment and are subjected to axial, radial and thermal loads that limit the life of the turbocharger system and can cause failures during important mission sorties. The elimination of the pressurized oil bearing system would greatly enhance reliability and durability and decreases losses of aircraft that are employing turbochargers and superchargers. There are a number of engines that could use turbocharger technology but some do not have pressurized oiling systems. Even systems that have pressurized oiling systems suffer from pumping losses due to the oiling system having to supply oil to the turbocharger and supercharger. Additionally, when operating at high angles of attack, the pressurized oil systems may not provide adequate lubrication for the bearing systems. Having a system that optimizes the ability to place the turbocharger or supercharger in airframe positions that are not possible with a pressurized oiling system is a must. Lastly, the forced induction system should be light weight and reliable. The weight should less than 5% of the overall engine system.