A design of a new class of plasma-based micro-thrusters is being proposed for in-space propulsion. This device, called Free Molecular Electro Jet (FMEJ), utilizes micro-actuators to accelerate the flow in a micro-channel with rarified gas. Numerical modeling of this device is being performed in order to predict the nature of the flow inside a micro-channel and the effectiveness of actuators for the given application. The numerical model is used to assess the improvements over existing micro-thruster designs such as free molecular micro resistojets and anode layer Hall thrusters. A finite element based multiscale ionized gas (MIG) flow code utilizing the Galerkin weak statement algorithm combined with an artificial diffusion method called Sub Grid eMbedding (SGM), is used to model the thruster using continuum approach. The results show that the thrust, specific impulse and efficiency seem to be similar to other electrical propulsion devices with similar input power despite the simplicity of the micro-thruster design.

This article numerically investigates a micro-thruster for small satellites which utilizes plasma actuators to heat and accelerate the flow in a micro-channel with rarefied gas in the slip flow regime. The inlet plenum condition is considered at 1 Torr with flow discharging to near vacuum conditions (<0.05 Torr). The Knudsen numbers at the inlet and exit planes are ~0.01 and ~0.1, respectively. Although several studies have been performed in micro-hallow cathode discharges at constant pressure, to our knowledge, an integrated study of the glow discharge physics and resulting fluid flow of a plasma thruster under these low pressure and low Knudsen number conditions is yet to be reported. Numerical simulations of the charge distribution due to gas ionization processes and the resulting rarefied gas flow are performed using an in-house code. The mass flow rate, thrust, specific impulse, power consumption and the thrust effectiveness of the thruster are predicted based on these results. The ionized gas is modelled using local mean energy approximation. An electrically induced body force and a thermal heating source are calculated based on the space separated charge distribution and the ion Joule heating, respectively. The rarefied gas flow with these electric force and heating source is modelled using density-based compressible flow equations with slip flow boundary conditions. The results show that a significant improvement of specific impulse can be achieved over highly optimized cold gas thrusters using the same propellant.

No abstract

No abstract