A Shock Tube Study of the Kinetics of Nitric Oxide at High Temperatures PDF Download
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Author: Kurt L. Wray Publisher: ISBN: Category : Chemical kinetics Languages : en Pages : 41
Book Description
A shock tube program was carried out in which the NO concentration was followed as a function of time behind the shock front by absorption of 1270A radiation, where ground vibrational state O2 and N2 are essentially transparent. The absorption coefficients of the species NO, O2 and N2 as functions of the respective vibrational temperatures were determined by measuring theABSORPTION BY THE SHOCK-HEATED GAS AT A POINT IN THE TIME HISTORY CORRESPONDING TO COMPLETE VIBRATIONAL RELAXATION BUT BEFORE THE ONSET OF DISSOCIATION. Time history analyses were made on a total of 42 shock tube runs covering a temperature range of 3000-8000 K on the following six mixtures: 1/2% NO, 1/2% NO + 1/4% O2, 10% NO, 50% NO, 20% air and 100% air. The diluent in all cases was argon. An IBM 704 computer was programmed to integrate the vibrational and chemical rate equations as a function of time behind the shock front, subject to the constraints of the conservation equations. The pertinent rate constants were varied in a systematic trial and error manner in order to get the best fit to all the data. (Author).
Author: Kurt L. Wray Publisher: ISBN: Category : Chemical kinetics Languages : en Pages : 41
Book Description
A shock tube program was carried out in which the NO concentration was followed as a function of time behind the shock front by absorption of 1270A radiation, where ground vibrational state O2 and N2 are essentially transparent. The absorption coefficients of the species NO, O2 and N2 as functions of the respective vibrational temperatures were determined by measuring theABSORPTION BY THE SHOCK-HEATED GAS AT A POINT IN THE TIME HISTORY CORRESPONDING TO COMPLETE VIBRATIONAL RELAXATION BUT BEFORE THE ONSET OF DISSOCIATION. Time history analyses were made on a total of 42 shock tube runs covering a temperature range of 3000-8000 K on the following six mixtures: 1/2% NO, 1/2% NO + 1/4% O2, 10% NO, 50% NO, 20% air and 100% air. The diluent in all cases was argon. An IBM 704 computer was programmed to integrate the vibrational and chemical rate equations as a function of time behind the shock front, subject to the constraints of the conservation equations. The pertinent rate constants were varied in a systematic trial and error manner in order to get the best fit to all the data. (Author).
Author: David Gutman Publisher: ISBN: Category : Gases, Kinetic theory of Languages : en Pages : 158
Book Description
A quadrupole mass-filter was built and coupled to a shock tube in order to study high temperature gas kinetics. The chemical kinetics of the decomposition of nitrous oxide was studied with this apparatus in order to establish the mechanism of the reaction at temperatures above 1000K. Several instrumentation problems unique to shock tube mass-spectrometry were solved. The most serious problem, that of a rapid-pumping ion source, was overcome by the design and construction of an unusually thin ion source. The thermal decomposition of nitrous oxide was studied by shock-heating a mixture of 4% N2O in argon and monitoring the ion currents corresponding to all of the principal species involved in the reaction: N2O, N2, O2, NO, and O. In each run with the shock tube, the mass-filter was tuned to follow the concentration of a single species. Because enough runs were made with all of the species, a run for each species at the same temperature was made for several temperatures.
Author: Charles E. Treanor Publisher: ISBN: Category : Languages : en Pages : 52
Book Description
A previously published group of 02/N2 shock-tube experiments, wherein the time history of the NO 5 micrometers radiation was measured, has been studied to elicit information about the relevant chemical reactions which produce the radiation. It was found that the calculated radiation was sensitive to the rates used in the Zeldovich mechanism for NO formation, and that the rate measured by Monat et al. for N2 + 0 -- greater than NO + N produced important features of the observed radiation. Vibration-dissociation coupling in this reaction modifies the radiation history in an important way, and is an essential element in obtaining agreement with the experiment. To improve agreement over a range of 02/N2 mixtures, it was necessary to take into account the faster vibrational relaxation of N2 by 02 and 0 collisions and the subsequent effect on vibration-dissociation coupling ... Reaction rates, Vibration-dissociation coupling, Air chemistry, Nitric oxide radiation, Nitric oxide formation.
Author: William L. Flower Publisher: ISBN: Category : Chemical kinetics Languages : en Pages : 221
Book Description
The results of an investigation of the decomposition kinetics of nitric oxide at high temperatures are presented. Mixtures of nitric oxide, molecular hydrogen, and inert gas (either argon or krypton) were heated by incident shock waves in a shock tube. The subsequent chemical reaction was monitored by using two high-speed infrared detectors to measure infrared emission from the 5.3-micron fundamental vibration-rotation band of NO and the 6.3-micron v2-band of water vapor. Each detection system was calibrated to determine the response to NO and to H2O, which permits the calculation of NO and H2O concentrations from the measured emission records. Post-shock temperatures ranged from 2400 K to 4200 K. The pressure behind the incident shock was between 0.25 and 0.62 atm in all tests. The nominal initial NO:H2 ratios of the test gases were 1:2, 1:1, and 2:1 with the inert diluent making up approximately 90% of the test gas for all experiments. A seventeen-reaction kinetic model of the reacting flow was used to calculate theoretical NO and H2O concentration histories. Kinetic calculations indicate the rate-limiting reaction for NO decomposition for the experimental conditions of this study is the reaciton of NO with atomic hydrogen, (1) NO + H [right arrow] N + OH. The chemical rate constant for reaction (1), k1, was determined for each experiment by optimizing the agreement between calculated and measured emission records for NO and H2O. A thorough sensitivity analysis confirmed that calculated NO and H2O records are more sensitive to small changes in K1 than to variations in the rate constants of the other sixteen reactions within the uncertainty limits of each. The rate constant for the reaction NO + N [right arrow] N + OH which best fits the data from 21 shock-tube experiments was found to be k1 = 2.22 x 1014 − 0.08 exp( -50.5/RT) cm3/mole-sec in the temperature range 2400 - 4200 K. These data provide useful information for modelling the decomposition of NO at high temperatures.
Author: E. L Resler (Jr) Publisher: ISBN: Category : Languages : en Pages : 25
Book Description
The advantages of coupling gas dynamic principles and procedures to chemical kinetics investigations were demonstrated again by studies made during the report period. Two shock-tube techniques and various chemical diagnostics were used to develop a kinetic mechanism for the drastic reduction of nitric oxide pollutants by control of the levels of hydrocarbons and oxygen over a suitable temperature range. Also, a general procedure was formulated for writing computer codes for very complex kinetic systems. Parallel to these studies of reacting mixtures at high temperatures, research was continued on a novel method for measuring vibration - vibration - vibration and vibration - translation energy transfer rates at room temperature. These experiments are unique in that molecular states which cannot be directly pumped by infrared radiation can be populated by coherent raman excitation, so that direct measurement of transfer efficiencies from totally symmetric to dipolar states were made. Positive results were obtained for vibration - vibration rates from deuterium to carbon monoxide and to hydrogen chloride. (Author).
Author: Kurt L. Wray
Author: Kurt L. Wray
Author: David Gutman
Author: Jamie Peter Monat
Author: אכבה בר-נון
Author: Charles E. Treanor
Author: Casimir J. Jachimowski
Author: William L. Flower
Author: E. L Resler (Jr)
Author: Peter Craggs
Author: Lewis Phillip Leibowitz