Hydrogen is the fuel of choice for long-range hypersonic flight vehicles from the standpoint of enthalpy of reaction. However, the extremely low density of hydrogen results in excessive tank volume requirements which result in adverse effects on vehicle size and weight. Hydrocarbon fuels do not have the enthalpy of reaction of hydrogen, but their higher density drastically reduces fuel tank volume. A novel solution to this problem of size, weight and fuel enthalpy is to employ thermal reformation of a hydrocarbon fuel such as methane into pure carbon and hydrogen, and then use these as the primary fuel.

An experimental investigation of the feasibility of performing fuel reformation of methane into carbon and hydrogen gas is reported. Methane is used because it has the highest hydrogen-to-carbon ratio. The experiments make use of a 1.6 MW electric arc tunnel facility. A high voltage, moderate pressure DC electric arc heater (Thermal Dynamics F-5000) powers the arc tunnel. Plenum chamber pressures range from 3 to about 20 atm, depending on nozzle throat size. A schematic of the arc tunnel facility is shown in below.