MPD Thrust Chamber Flow Dynamics
Abstract
Flow within the thrust chamber of an MPD arcjet is examined experimentally and modeled with a two-dimensional MHD code. Two quasi-steady MPD thrusters are considered under the same input conditions of current (21 kA) and total mass flow rate (0.006 kg/s, argon + 1.5% hydrogen). The arcjets have the same basic design, consisting of a central cathode, 3.8 cm diameter and 5 cm long, separated from a coaxial anode of equal length by a uniform gap of 2.3 cm. Two different mass injection arrangements are used (100% at mid-radius, and 50% at the cathode base, with the remainder at mid-radius). A new spectroscopic analysis procedure is developed that allows distributions of radial speed, heavy-particle temperature and turbulent speed to be extracted from chordal measurements of light emission by the two species in the plasma flow. Good qualitative (and reasonable quantitative) agreement exists with distributions calculated by the MHD code, indicating that flow within the thrust chamber expands from an electromagnetically-pumped plasma base (vs a pumped jet off the cathode tip). The significant variation of internal flow dynamics with mass injector arrangement implies the need for extensive experimentally-validated code modeling in order to evaluate the potential performance of MPD thrusters.
Document Details
- Document Type
- Technical Report
- Publication Date
- Aug 23, 1990
- Accession Number
- ADA227305