Comparison of laser ignition and torch ignition in a subscale rocket combustor

The controlled ignition of combustion chambers of rocket engines is a essential process during the operation of an engine and is in particular challenging if multiple ignitions are necessary during a space mission. During the last decade, laser-based ignition methods have been studied in detail, triggered by the availability of miniaturized diode-pumped solid-state lasers. This paper gives an overview of recent test results and achievements for laser-based ignition technologies obtained in the Rocket Propulsion Department at the German Aerospace Center (DLR), Lampoldshausen. Those tests proved the compatibility, reliability and re-usability for a variation of injector geometries for both LOX/hydrogen and LOX/methane and for sub-atmospheric to ambient pre-injection pressure levels. In particular, the spatial and time resolved pressure dynamics within a subscale combustion chamber for the ignition by a laser igniter and a torch igniter are compared. Based on recently obtained test results, development options like fiber-based systems are shortly discussed in the context of clustered engine architectures of future launcher systems.