COBEM99

S8 Engenharia Aeroespacial

Title:

EXPERIMENTAL MHD RESULTS RELEVANT TO ADVANCED PROPULSION CONCEPTS

Summary :

ABSTRACT THE MHD POWER GENERATION RESULTS OBTAINED IN A HYPERSONIC SHOCK TUNNEL AT MACH 30 AND 10.200 K ARE RELEVANT TO THE DEVELOPMENT OF ADVANCED PROPULSION SYSTEMS. THE INTERACTION OF HIGH VELOCITY AIR PLASMA WITH TRANSVERSE MAGNETIC FIELD STRENGTHS OF 2300 AND 6500 GAUSS WERE INVESTIGATED IN THE SHOCK TUNNEL. THE INCIDENT SHOCK MACH NUMBER VARIED FROM 10 TO 32 WITH CORRESPONDING PLASMA TEMPERATURES FROM 3600 TO 11.000 K. AT MACH 30, THE OBSERVED OPEN CIRCUIT POTENTIALS ACROSS THE ELECTRODES AGREED WITH THE THEORETICAL VALUES. BY VARYING THE EXTERNAL LOAD FOR A SHOCK MACH NUMBER OF 30, THE CURRENT FROM THE PLASMA WITH 2300 GAUSS FIELD VARIED FROM ZERO TO 115 A. THE OBSERVED POTENTIAL DECREASED LINEARLY WITH INCREASING CURRENT INDICATING A NEARLY CONSTANT PLASMA RESISTANCE. THE MAXIMUM POWER EXTRACTED FROM THE PLASMA WAS 7.8 KW WITH AN EXTERNAL LOAD OF 1,85 OHM. BUT WITH THE 6500 GAUSS FIELD, THE VOLTAGE ACROSS THE ELECTRODES WITH DIFFERENT EXTERNAL RESISTANCE DECREASED NONLINEARLY WITH INCREASING CURRENT FLOW. ALSO, THE PLASMA RESISTANCE ACROSS THE ELECTRODES DECREASED DRASTICALLY WITH CORRESPONDING INCREASE IN THE ELECTRICAL CONDUCTIVITY AT HIGH CURRENT FLOWS. A POWER OF 151 KW WAS EXTRACTED FROM THE MACH 30 PLASMA WITH ROOM TEMPERATURE COPPER ELECTRODES, WHICH WAS MUCH GREATER THAN THE THEORETICAL PREDICTION. KEY WORDS: MAGNETOHYDRODYNAMICS, HYPERSONICS, SHOCK TUNNEL, LASER PROPULSION

Author :

Minucci, Marco Antonio Sala
Myrabo, Leik Normand
Nagamatsu, Henry T.
Sheer, Jr., Russell E.

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