Performance characteristics of a medium power hydrogen arcjet

A spatiotemporal study of neutral gas temperature during the first 100 s of operation for a radio-frequency electrothermal plasma micro-thruster operating on nitrogen at 60 W and 1.5 Torr is performed to identify the heating mechanisms involved. Neutral gas temperature is estimated from rovibrational band fitting of the nitrogen second positive system. A set of baffles are used to restrict the optical image and separate the heating mechanisms occurring in the central bulk discharge region and near the thruster walls. For each spatial region there are three distinct gas heating mechanisms being fast heating from ion-neutral collisions with timescales of tens of milliseconds, intermediate heating with timescales of 10 s from ion bombardment on the inner thruster tube surface creating wall heating, and slow heating with timescales of 100 s from gradual warming of the entire thruster housing. The results are discussed in relation to optimizing the thermal properties of future thruster designs.

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“…Radiative losses are assumed to be small and are therefore neglected. This is represented mathematically by Equation (5).…”

Section: Discussionmentioning

confidence: 99%

“…The resistojet heats the propellant gas through resistively heated walls, or by flowing the gas around a heater element within the thruster [2,4]. An arcjet operates on similar principles, but instead of heating the propellant through contact with hot surfaces, the propellant volume is heated through contact with a high current arc [1,5].…”

Section: Introductionmentioning

confidence: 99%