Engineering topics

Paulin, P. A.

Publications and source records attributed to Paulin, P. A..

4 records

NASA NTRS1987

Catalytic Oxidation of CO for Closed-Cycle CO2 Lasers

Stoichiometric mixture converted completely. High-energy pulsed CO2 lasers have potential for measuring many different features of atmosphere of Earth and particularly useful on airborne or space platforms. For this application, laser must be operated in closed cycle to conserve gas, especially if rare nonradioactive isotopes of carbon and oxygen used. However, laser discharge decomposes fraction of CO2 to CO and O2, causing rapid loss in power leading to erratic behavior. To maintain operation, CO and O2 must be recombined to form CO2.

Miller, I. M.↗

NASA NTRS1987

Characterization of Pt/SnO2 catalysts for CO oxidation

Results are presented of surface characterization of 2% and 1% (w/w) Pt on SnO2 catalysts which are being used in promoting the oxidation of CO in pulsed CO2 lasers. The N2 adsorption BET surface area for both catalysts is 6.9 sq m/g. The CO chemisorbed area at 313K is 0.17 sq m/g and 0.062 sq m/g for the 2% and 1% catalysts, respectively. Monitoring the reaction between CO and O2 by the same technique, at the same temperature yields a turn-over frequency (TOF) for the 2% catalyst of 2.7 x 100 molecules of CO2/site/s and for the 1% catalyst a value of 1.2 x 100. The ratio of the TOFs for the two catalysts is 2.2 which is approximately the ratio of the Pt loading.

Brown, K. G.↗

NASA NTRS1986

Mass spectrometric gas composition measurements associated with jet interaction tests in a high-enthalpy wind tunnel

Knowledge of test gas composition is important in wind-tunnel experiments measuring aerothermodynamic interactions. This paper describes measurements made by sampling the top of the test section during runs of the Langley 7-Inch High-Temperature Tunnel. The tests were conducted to determine the mixing of gas injected from a flat-plate model into a combustion-heated hypervelocity test stream and to monitor the CO2 produced in the combustion. The Mass Spectrometric (MS) measurements yield the mole fraction of N2 or He and CO2 reaching the sample inlets. The data obtained for several tunnel run conditions are related to the pressures measured in the tunnel test section and at the MS ionizer inlet. The apparent distributions of injected gas species and tunnel gas (CO2) are discussed relative to the sampling techniques. The measurements provided significant real-time data for the distribution of injected gases in the test section. The jet N2 diffused readily from the test stream, but the jet He was mostly entrained. The amounts of CO2 and Ar diffusing upward in the test section for several run conditions indicated the variability of the combustion-gas test-stream composition.

Lewis, B. W.↗

NASA NTRS1983

Developing mass spectrometric techniques for boundary layer measurement in hypersonic high enthalpy test facilities

Thermodynamic flow properties of gases in the boundary layer or the flowfield have been mainly deduced from pressures and temperatures measured on a model. However, further progress with respect to an understanding of these properties requires a more complete characterization of the layer including determination of the gas composition and chemistry. Most attempts to measure boundary layer chemistry involve the employment of a mass spectrometer and an associated gas sampling system. The three major limiting factors which must be addressed for species measurement in aerothermodynamic investigations on models at reentry stream velocities, are gas sampling effects, instrument limitations, and problems with data acquisition. The present investigation is concerned with a concentrated effort to quantitatively identify and correct for instrument and sampling system effects, and to develop a miniaturized high performance mass spectrometer for on-model real-time analysis of the boundary layer and its associated atmosphere.

Wood, G. M., Jr.↗