Preliminary performance characterization of a l n laboratory Resistojet (DUR-1)

At DUT a laboratory resistojet has been developed. It has a modular build-up in order to evaluate various heaters, heater configurations, insulation concepts and nozzles. The first configuration tested, Delft University Resistojet - 1 (DUR-1), uses the direct heating method. The heater/heat exchanger is a coiled tube, which reduces dimensions of the resistojet while maintaining high heater exhaust temperature. Research focuses on heat transfer within the resistojet to identify ways to efficiently heat propellants to high temperature. Performance is measured using DUT's low-thrust (< l N) rocket test facility. The thruster is operated under
ambient conditions with mass flow rate up to 0.8 g/s and current up to 30A. Preliminary test results for nitrogen show a significant increase in specific impulse up to 52s at a propellant temperature of 470K and heater temperature of 675K. Transient results indicate long settling times. These can be significantly reduced by pre-heating the thruster. The paper first gives a discussion on the test motor and test facility. Next, preliminary test results are presented and discussed and conclusions are drawn.