Hybrid rocket fuel research being done by a University of Alabama in Huntsville (UAH) mechanical engineering doctoral student could hasten the day when a simpler, safer, more economical rocket engine propels space missions.
At UAH’s Johnson Propulsion Center, Matthew Hitt has experimented with varying solid fuel grain sizes to see how they burn at different combustion chamber pressures and oxidizer flow rates in an effort to improve the performance of hybrid engines.
“This is another step in making hybrids – which are a safer alternative to either solid or liquid engines – more practical for actual application,” he says
Improving the efficiency has to do with improving the fuel regression rate – a scientific way of saying you get the solid fuel to burn faster so it recedes back from the flame front at a faster rate.
“By increasing the fuel regression rate – which can lead to simpler designs – you are leaving less unburned fuel, so you are not carrying all this dead weight,” Hitt says.
Not having to carry fuel that won’t end up getting burned could reduce the weight of the rocket, allow for use of a smaller engine for the same flight result, or allow for a larger payload due to the weight savings.