Additives to Improve Methane Combustion

Liquefied methane is a promising fuel for space launch vehicles because it has a high specific impulse, excellent cooling capacity, and is very resistant to coking and soot formation. Unfortunately, it is also a very stable molecule and therefore ignition delay times can exceed combustor residence times. In the Phase I portion of the project, TDA Research Inc. (TDA) developed catalysts that improved methane combustion when added to the fuel mixture. Specifically, we identified a catalyst that reduced the temperature required for combustion by about 400°C compared to the temperature required for methane alone. The overall goal of the Phase II project is to determine how the improvements we measured in our laboratory scale experiments can be translated into improved performance in a scramjet engine cycle. Our test plan includes preparing a catalyst that is soluble in liquid methane, measuring the important catalyst physical parameters, scaling up the catalyst synthesis to support larger-scale tests, conducting combustion tests to identify the optimum catalyst composition and concentration, measuring the effect the catalyst under scramjet conditions, extending the modeling studies to better characterize the individual reaction steps, and finally constructing a liquid methane fuel handling system.