Henry Wise

Steady‐State Burning of a Liquid Droplet. I. Monopropellant Flame

The flame equations corresponding to the steady‐state combustion of a liquid droplet are presented and adapted to the case of a monopropellant system with chemical reaction diffused throughout the gas phase. The theoretical analysis is applied to the case of a liquid hydrazine monopropellant flame.

Acid Catalysis in the Thermal Decomposition of Ammonium Nitrate

Experimental measurements of the kinetics of thermal decomposition of ammonium nitrate have been made in the temperature range from 443 to 553°K. The results indicate that the degradation of ammonium nitrate is an autocatalytic liquid‐phase reaction, the rate of which is proportional to the product of the mass of salt and the concentration of acid. The activation energy for this process is found to be 31.4 kcal. Adjustment of the concentration of acid present offers an effective means for the control of the rate of thermal degradation of ammonium nitrate.

Kinetics of Decomposition of Nitric Oxide at Elevated Temperatures. I. Rate Measurements in a Quartz Vessel

The rate of thermal decomposition of nitric oxide has been measured in a quartz vessel from 872 to 1275°K. The reaction follows a second‐order rate law over the range of temperatures studied. Variations in the surface‐to‐volume ratio of the reaction vessel indicate the predominance of a heterogeneous mechanism at temperatures below 1000°K, whereas at higher temperatures a homogeneous mechanism prevails. The experimental data are interpreted on the basis of the relative contribution of the heterogeneous and homogeneous mechanisms to the over‐all kinetics. Such an analysis explains the variation in effective activation energy with temperature from a value of 21.4 kcal below 1000°K to 82 kcal above 1600°K. An intermediate temperature region exists in which both mechanisms contribute an important part to the over‐all rate.

Kinetics of Decomposition of Nitric Oxide at Elevated Temperatures. II. The Effect of Reaction Products and the Mechanism of Decomposition

The effects of nitrogen and oxygen on the kinetics of decomposition of nitric oxide have been investigated. In the temperature region in which the heterogeneous mechanism prevails (at T<1000°K) the presence of nitrogen has a marked retarding influence on the reaction rate of nitric oxide due to poisoning of the surface. On the other hand, the addition of oxygen results in a marked increase in the rate of decomposition of nitric oxide over the entire temperature range studied. At high concentrations of oxygen the following empirical rate expression obtains, −d[NO]dt=ka[NO]2+kb[NO][O2]12, with an activation energy of 78.2 kcal for the rate‐determining step. It is apparent therefore that the decomposition of nitric oxide is autocatalytic. On the basis of these experimental observations a mechanism is proposed involving a chain propagated by the atomic species formed in the reaction.

Kinetics of Reaction between Hydrogen and Nitrogen Dioxide

The gas‐phase reaction between hydrogen and nitrogen dioxide has been studied in the temperature range from 600 to 700°K. The stoichiometry of the reaction corresponds closely to H2+NO2=NO+H2O. The rate of disappearance of NO2 is given by −d(NO2)dt=1014(NO2)(H2)1.4e−46u2009000R/T(NO2)+(NO). The experimental observations are interpreted in terms of a chain mechanism involving hydrogen atoms and hydroxyl radicals as chain carriers.