Atomic Recombination in Nozzles : Methods of Analysis for Flows with Complicated Chemistry
The object of this review is to study the feasibility of performing accurate calculations on the non-equilibzWm flow of a complicated gas mixture through nozzles, with partioular reference to the propulsive nozzle of the hypersonic ramjet. Equations are given for the steady, quasi-one-dimensional, adiabatic flow of a general reacting gas mixture, consisting of rl species related through N chemical reactions. A number of alternative methods of obtaining numerical solutions to these equations are described and evaluated. The formulation of the system of chemical reactions is also discussed, together with the availability of the large amount of thermodynamic and chemical kinetic data which is required before a numerical solution can be attempted. It is found that by far the most serious difficulti to be overcome, before accurate non-equilibrium nozzle calculations can be performed, is obtaining reliable data on the rates of the many chemical reactions which may be involved.
Reaction of Oxygen Atoms with Hydrogen
THE reaction between ground-state oxygen atoms and hydrogen : is known to be an elementary process in the branching chain reaction between hydrogen and oxygen, and it is therefore of interest to determine its kinetics. Harteck and Kopsch1 measured the amounts of water formed in the reaction between hydrogen and electrically discharged oxygen containing about 25 per cent of oxygen atoms at three temperatures between 300° K. and 462° K. From these data an activation energy of 6 ± 1 kcal./mole for reaction (1) was computed. However, the formation of water under these conditions may arise not only from reaction (1) followed by reaction (2) : but also from a chain reaction involving molecular oxygen. In the absence of undissociated oxygen, the only secondary reactions to be considered are reactions (2) and (3) : The velocity constant of reaction (2) has been determined as 1.2 × 1014 exp(− 10,000/RT) cm.3 mole−1 sec.−1 by Avramenko and Lorentso2, and a value of k = 2 × 1012 exp(− 2,000/RT) cm.3 mole−1 sec−1 can be obtained from Semenov's value3 for the rate constant of the reverse reaction and from the calculated equilibrium constant.
Vacuum Ultraviolet Photochemistry, Part I. Nitrous Oxide at 1470 A
The photolysis of nitrous oxide at 1470 A has been studied and the quantum yields measured for N2O disappearance and NO, O2, and N2 appearance. The average of 38 measurements gives φN2O=1.70, φO2=0.50, and φN2=1.44 with φNO being pressure dependent. The data obtained here can be explained by a mechanism involving initial dissociation of nitrous oxide into nitrogen molecules and oxygen atoms. The source of NO can be in the reaction O+N2O→2NO. These results are discussed in the light of previous work.