Accession Number : AD0474517


Title :   THE USE OF IONIZATION PROBES TO DETERMINE ROCKET MOTOR PARAMETERS.


Descriptive Note : Final rept. 9 Oct 64-9 Jul 65,


Corporate Author : AEROCHEM RESEARCH LABS INC PRINCETON NJ


Personal Author(s) : Gordon, Stuart A


Report Date : Sep 1965


Pagination or Media Count : 74


Abstract : Ultra-fast response and the ability to make local measurements of rocket plume velocity, turbulence level and electrical conductivity make electrostatic probes extremely promising diagnostic tools in future rocket motor development applications. While local time-of-flight velocity measurements can be made in the absence of a complete theoretical understanding of the probe response, quantitative turbulence measurements and, especially, local electrical conductivity measurements require a formulae based on a theory which accurately accounts for the important characteristics of aerodynamic electrostatic probes immersed in supersonic combustion gas plasma flows. A continuum theory meeting these requirements is now available, and the important first step of testing the accuracy with which local positive ion concentrations can be inferred from observed ion saturation currents has been taken. Using a stagnation-point probe in a seeded atmospheric-pressure burner, inferred ion concentrations were found to be of the order of magnitude of those predicted thermodynamically for sodium, cesium, and potassium seeding covering more than a three-decade range of alkali atom concentration. Although additional aspects of the probe theory remain to be verified, considerable design and operating experience with electrostatic probes in alkali seeded combustion plasmas has been obtained which will prove of value in developing practical diagnostic probes for rocket motor use. (Author)


Descriptors :   *ROCKET ENGINES , IONIZATION GAGES , ELECTROSTATICS , MEASURING INSTRUMENTS , IONS , DENSITY , ELECTRIC CURRENT , JET FLOW , VELOCITY , PHASE SHIFT CIRCUITS , TURBULENCE , SPECIFIC IMPULSE , THERMODYNAMICS , PLASMAS(PHYSICS) , LANGMUIR PROBES


Subject Categories : Rocket Engines


Distribution Statement : APPROVED FOR PUBLIC RELEASE