The minds behind the refitting of the Sea Bird (previously the USNS New Bedford T-AKL-17) are working hard to produce some of the most innovative and promising concepts possible. Each focuses on creating a vessel that runs efficiently, burns fuel cleanly, and operates with maximum conservation of resources. Pulse combustion has been one of the most exciting new technologies considered for the Sea Bird. It is important that each system and design be put to the test to ensure it is truly as effective as we want it to be. These tests not only tell us what, if any, changes need to be made, but reassure us that we are on the right path to refitting the Sea Bird.
Pulse Combustion in a Working Environment
After the hot rotor section was fully assembled, we attached it to the turbine nozzle of the pulse combustor to test operation. The combustor performed properly, however, the rotor was slow to self start and could not achieve more than about 25rpm's. Problems were created by the small size of the 1.5" x 3" rectangular tube, which lowered the amount of gas between plates in the Tesla turbine. A majority of the gas wound up around the discs, leaving through the hot rotor case without supplying any power to the turbine.
This test has shown us that Tesla turbines are very different from conventional designs. While a traditional bladed turbine would need large volumes of low velocity fluid, the Tesla turbines require high velocity fluid accurately guided in lower volumes. In the past, the Tesla turbine has proven useful when working with air, steam or a hot gas fed into a slotted nozzle. So in our second set of tests we designed and built an internal directional nozzle that focused the high heat, high velocity gasses directly into the turbine plates. This provided a significant improvement over the first test and as can be seen we achieved around 200rpm's.
New Approaches to the Pulse Combustion Engine
We now know that in order to make the Tesla turbine design functional, air and fuel must be fed into the chamber at pressures that will create well over 8000 to 16000 PSI of hot gas to the rotor nozzle. This has helped us plan future tests to work towards a system that will be functional when implemented in the Sea Bird project. These changes include experimentation with 950 degree steam power as well as an improved combustion system that will power up the hot rotor.
Through testing, we can learn the best approach to developing a pulse combustion engine that will power the Sea Bird and could possibly inspire changes in the way future ships are constructed. We will keep you updated on the progress of our work as it is made available. Stay current with our blog and forum!