The paper deals with an experimental activity carried out at Alta on a multichannel hollow cathode. The cathode has been operated at currents from 20 to 160 A, with argon mass flow rates ranging between 1 and 5 mg/s. During operation, the cathode external wall temperature has been measured using a bi-color video pyrometer, mounted on a 1-axis slide to record the temperature profile along the cathode axis. A 100-hr endurance test has been performed at discharge current of 150 A and mass flow rate of 4.5 mg/s. To assess the effect of cathode degradation cumulated during the endurance test, electrical characteristics at various mass flow rates have been measured before and after the 100-hr test. The maximum temperature measured at the cathode tip was 2500°C. The cathode mass difference between the beginning of life and the end of test was 2.32 g, from which an average erosion rate of about 33 ng/C is valuated. Moreover, the results of the numerical model developed by the RIAME-MAI are compared with the data collected during the test activities in terms of electrical characteristic and erosion rate.
100-hr Endurance Test on a Tungsten Multi-rod Hollow Cathode for MPD Thrusters
PAGANUCCI, FABRIZIO;ANDRENUCCI, MARIANO;
2011-01-01
Abstract
The paper deals with an experimental activity carried out at Alta on a multichannel hollow cathode. The cathode has been operated at currents from 20 to 160 A, with argon mass flow rates ranging between 1 and 5 mg/s. During operation, the cathode external wall temperature has been measured using a bi-color video pyrometer, mounted on a 1-axis slide to record the temperature profile along the cathode axis. A 100-hr endurance test has been performed at discharge current of 150 A and mass flow rate of 4.5 mg/s. To assess the effect of cathode degradation cumulated during the endurance test, electrical characteristics at various mass flow rates have been measured before and after the 100-hr test. The maximum temperature measured at the cathode tip was 2500°C. The cathode mass difference between the beginning of life and the end of test was 2.32 g, from which an average erosion rate of about 33 ng/C is valuated. Moreover, the results of the numerical model developed by the RIAME-MAI are compared with the data collected during the test activities in terms of electrical characteristic and erosion rate.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
