The Effects of Chamber Geometry, Surface Characteristics, and Temperature Boundary Conditions on the Hydrogen-Oxygen Reaction

Author: Marks, Craig

Year: 1955

Degree: Dissertation (Ph.D.)

Advisor: Kyropoulos, Peter R.

Committee Member: Unknown, Unknown

Option: Mechanical Engineering; Chemistry

DOI: 10.7907/76DZ-EH40

Abstract

The established mechanism of the hydrogen-oxygen reaction is reviewed and calculated results presented concerning the rates of reaction and the explosion temperatures expected with various concentrations of water vapor. A simplified theory is developed to predict the overall rate of reaction in the case where a strong temperature gradient exists. Experiments are described in which stoichiometric mixtures of hydrogen and oxygen are introduced to a closed, shallow, nickel plated, cylindrical combustion chamber and measurements made of the pressure change with time. The top surface of the chamber is heated while the bottom surface is either heated or cooled to provide isothermal or gradient conditions, respectively. A large catalytic reaction due to the nickel surfaces is observed. The measured reaction rates and the conditions for explosion with isothermal heating are consistent with predictions based on the established reaction scheme. With gradient heating the rates measured are larger than those predicted. by the simplified theory with temperatures of the top surface above 1300[degrees]R. This fact is believed to be caused by the diffusion of active intermediate reaction products from hot regions into the cooler reactants. These intermediate products are neglected in the simplified analysis. No explosion was observed with gradient heating even when the hot plate was above the temperature which caused isothermal explosion. This fact is explained on the basis of the strong inhibiting effect which water vapor exhibits toward the hydrogen-oxygen reaction.

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