NASA SBIR 2003 Solicitation


PROPOSAL NUMBER: 03- II A2.03-8170
SUBTOPIC TITLE: Revolutionary Technologies and Components for Propulsion Systems
PROPOSAL TITLE: Methods to Remove Coke from Endothermic Heat Exchangers

PRINCIPAL INVESTIGATOR/PROJECT MANAGER (Name, E-mail, Mail Address, City/State/Zip, Phone)
David T. Wickham
12345 W. 52nd Ave.
Wheat Ridge, CO 80033-1916
U.S. Citizen or Legal Resident: Yes

In February 2004 NASA released "The Vision for Space Exploration", which describes a strategy for exploring our solar system that builds upon the policy announced by President Bush earlier in the year. The goals of this strategy include extending human presence in the solar system culminating in the exploration of Mars. To accomplish this goal, affordable, new propulsion technologies must be developed. A key component to this goal will be the development of reusable launch vehicles that use single stage to orbit (SSTO) or two stage to orbit (TSTO) propulsion systems. These vehicles generate high heat loads and require additional cooling capacity from the fuel, which can get very hot in the process.

Unfortunately when hydrocarbon fuels are heated, carbonaceous deposits (coke) can form in the heat exchanger, reducing heat transfer and potentially inhibiting fuel flow. If vehicles are reused, then coke accumulation eventually will become a serious problem. However, if the coke could be removed periodically between missions, then the dangers associated with coke accumulation could be avoided. In this Phase I project, TDA developed a process to remove these deposits. The process is safe, inexpensive, and is conducted at low temperature and at ambient pressure.

In addition to NASA applications, our process could have several important commercial uses. The process can be applied to any situation where oxidation at low temperatures is necessary. For example ozone can be used to clean hydrocarbons from semiconductors, magnetic disks, medical devices, flight hardware, etc. High temperature processes would damage these components, however at the moderate temperatures required with ozone, these components would not be harmed. Although ozone has been used, the goal of our project will be to optimize treatment conditions and If our project is successful, significant improvements in cleaning methods could be achieved.

The ability to clean carbon deposits effectively will be critical to the development of reusable, high speed aircraft that must utilize the heat sink capacity of fuel to meet high heat loads generated at high speed. We have shown that under these conditions coke deposition can be expected and under high heat flux conditions, very thin layers of carbon cause significant increases in the metal wall temperature, possibly reaching temperatures where the material may fail. Therefore, identifying an effective procedure to remove coke between missions represents enabling technology for the continued development of reusable high speed aircraft.