Accession Number : AD0615903

Title :   PERFORMANCE CHARACTERISTICS OF A FULLY DEVELOPED CONSTRICTED TRANSPIRATION-COOLED ARC.

Descriptive Note : Interim technical rept. for 1 Oct 63-1 May 64,

Corporate Author : MINNESOTA UNIV MINNEAPOLIS HEAT TRANSFER LAB

Personal Author(s) : Eckert,E. R. G. ; Anderson,J. E.

Report Date : APR 1965

Pagination or Media Count : 61

Abstract : A possible way to increase the peak enthalpy in a gas stream heated by a constricted arc is to make the constrictor wall porous and to inject some of the gas through this wall for cooling. In this paper, the peak enthalpy of such an arc heater is compared with the peak enthalpy obtainable in a heater of identical geometry, but with a water-cooled constrictor wall. The comparison is made on the basis of a model which strongly simplifies the thermodynamic and transport properties of the gas. (Ratio of specific heat to thermal conductivity is constant, electrical conductivity is zero below a certain enthalpy and increases linearly with enthalpy above, radiative power emitted per unit volume is zero below the specific enthalpy and constant above). The model predicts that the peak enthalpy at the center line of the exit cross-section of the transpiration-cooled constrictor can attain values more than an order of magnitude higher than in a water-cooled constrictor. Stability problems, difficulties at the electrodes, transition to turbulence and deviations from the assumed property variations will determine the upper limit of the peak enthalpy obtainable with this arc. These can only be determined by experiments. It is felt, however, that the present analysis indicates strong potentialities of a transpiration-cooled constricted arc. (Author) Presented at the AGARD Specialist's Meeting on 'Arc Heaters and MHD Accelerators for Aerodynamic Purposes,' in Rhode-Saint-Genese, Belgium, 21-23 September, 1964.

Descriptors :   (*ELECTRIC ARCS, COOLING), (*PLASMA JETS, HEATING), (*GAS FLOW, HEATING), ENTHALPY, WATER, POROUS MATERIALS, THERMODYNAMICS, TRANSPORT PROPERTIES, SPECIFIC HEAT, THERMAL CONDUCTIVITY, ELECTRICAL CONDUCTIVITY, THERMAL PROPERTIES, THEORY, MATHEMATICAL ANALYSIS

Distribution Statement : APPROVED FOR PUBLIC RELEASE