1. Transmission Probabilities of Rarefied Flows in the Application of Atmosphere-Breathing Electric Propulsion.
- Author
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Binder, T., Boldini, P. C., Romano, F., Herdrich, G., and Fasoulas, S.
- Subjects
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RAREFIED gas dynamics flow , *ELECTRIC propulsion , *COLLOID thrusters , *GAS flow , *DIFFUSION - Abstract
Atmosphere-Breathing Electric Propulsion systems (ABEP) are currently investigated to utilize the residual atmosphere as propellant for drag-compensating thrusters on spacecraft in (very) low orbits. The key concept for an efficient intake of such a system is to feed a large fraction of the incoming flow to the thruster by a high transmission probability Θ for the inflow while Θ for the backflow should be as low as possible. This is the case for rarefied flows through tube-like structures of arbitrary cross section when assuming diffuse wall reflections inside and after these ducts, and entrance velocities u larger than thermal velocities vth ∝ √kBT/m. The theory of transmission for free molecular flow through cylinders is well known for u = 0, but less research results are available for u > 0. In this paper, the desired theoretical characteristics of intakes for ABEP are pointed out, a short review of transmission probabilities is given, and results of Monte Carlo simulations concerning T are presented. Based on simple algebraic relations, an intake can be optimized in terms of collection efficiency by choosing optimal ducts. It is shown that T depends only on non-dimensional values of the duct geometry combined with v th and u. The simulation results of a complete exemplary ABEP configuration illustrate the influence of modeling quality in terms of inflow conditions and inter-particle collisions. [ABSTRACT FROM AUTHOR]
- Published
- 2016
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