• Non ci sono risultati.

Finally, the choice of the electrical insulation is presented, as well as the


Academic year: 2021

Condividi "Finally, the choice of the electrical insulation is presented, as well as the "


Testo completo



Among the various components characterizing a cathode neutralizer, the heater has a fundamental role in the reliability and performance of such kind of electron source. The development of a heater is a significant technological challenge tied with the need of reaching high ignition temperatures (1500-2000 K) minimizing the power consumption and reducing the heat losses during nominal operation.

The present work describes the study of a heater for hollow cathode neutralizers, with the aim of providing guidelines for the design of the heating system composed by heater, electrical and thermal insulation.

After a brief introduction on space propulsion and hollow cathodes, in the first part of the thesis two different heating systems are studied, alternative to the classical ohmic resistance, namely conduction and induction heating. For each heating procedure, a physical model and a numerical simulation have been developed using the software Comsol Multiphysic® 3.4. Afterwards, the design of a coiled wire electrical resistance is performed, analyzing the possibility of radiation heating.

Finally, the choice of the electrical insulation is presented, as well as the



Documenti correlati

If the aforementioned temperature difference is treated as a decision variable of the problem, standing for the corresponding working fluid, it shows a maximum

(web, mobile, canali fisici) per il suo processo d’acquisto - passaggio dalla logica multichannel, in cui i differenti canali di vendita vengono pensati e

Powder XRD patterns of the samples (Figure S1); N 2 adsorption/desoprtion isotherms at 77 K of the samples (Figure S2); SEM images of the samples (Figure S3); comparison of

This paper reports an experimental study of transient natural convection heat and mass transfer between two large cylindrical reservoirs connected through a short

The form f lu-da-qé-e of CTMMA 148A would represent the inaccuracy of an unexperienced scribe (or of a scribe who was not much familiar with the Greek language); 14) while the

The different types of membranes are released at times depending on the TMAH solution formulation, etching temperature, and pattern dimensions (but not membrane dimensions).. A


A similar conclusion regards the vortex core radius, which values at different streamwise locations, for the data affected from wandering, are determined by the 3HFP