Doctoral Dissertations

Abstract

"The explosive properties of ammonium nitrate-fuel blasting agents were investigated by measuring their detonation velocity and sensitivity. Detonation velocity was measured by a pin oscillograph method with a modified pin technique. Five types of tests were used to evaluate the explosive sensitivity of AN-fuel mixtures under varied environmental conditions. These tests measured the confined and unconfined critical diameter, minimum primer for a three inch diameter iron pipe confined charge, for an unconfined charge at the critical diameter, and minimum primacord primer under special conditions.

Properties of ammonium nitrate-fuel blasting agents were evaluated by considering the effects which each component of a mixture has upon its explosive behavior. These test results showed that the detonation properties of AN-fuel mixtures are dependent upon the type of fuel and ammonium nitrate used in the mixture.

Explosive properties of regular prilled ammonium nitrate-fuel oil mixtures were found to be dependent upon: (1) preparation method and formulation, (2) charge shape and external charge environment, and (3) the physical condition of the prilled AN. The particle size, shape, and structure of AN particles used in a 94/6 AN-fuel oil mixture have a pronounced influence on the explosive properties. The porous structure of regular prilled AN was shown to be the primary reason for its higher mass reaction rate compared to other types of commercially manufactured AN. The mass reaction rate varied within limits in agreement with the theory of Eyring's grain surface burning model.

Investigation of the explosive properties of 33 dense microprilled AN products in a 94/6 AN-fuel oil mixture indicate that particle size distribution exerts a measurable amount of influence on detonation velocity and sensitivity. Advantages of dense microprilled AN over regular prilled AN for use in blasting agents are its pouring density of 1.10 grams per cubic centimeter and greater detonation velocity of approximately 4000 feet per second for similar charge conditions. The significant difference between the two AN products was that the 94/6 dense AN mixture behaved as an ideal explosive in steel confined charges greater than eight inches in diameter.

The ideal explosive parameters of AN-fuel oil mixtures were calculated by the thermohydrodynamic theory using the general method developed by Cook which was adapted for an IBM 704 computer. The basic mathematical problem was reduced to the solution of six simultaneous non-linear equations which were solved by a modified Newton-Raphson method. The set of non-linear equations was transformed into a set of linear equations and solved by a modified Gauss reduction.

Four theories of non-ideal detonation: the nozzle, curved front, variable reaction zone length, and geometrical model were applied to the observed explosive properties of eight AN-fuel oil mixtures in which the particle size and structure of the AN was varied. The geometrical model was shown to be the most useful for the prediction of detonation velocities at varying charge diameters. The ideal reaction times given by the nozzle theory were three to five times those predicted by the curved front theory. The variable reaction zone length theory gave ideal reaction times 10 to 25 times greater than those of the curved front theory. The ideal reaction times given by the geometrical model were 50 to 100 times those given by the curved front theory. Specific reaction rate constants computed by the geometrical model agreed within an order of magnitude of ten with the reaction constants given by the absolute reaction rate theory"--Abstract, pages 1-3.

Advisor(s)

Clark, George Bromley, 1912-

Department(s)

Mining Engineering

Degree Name

Ph. D. in Mining Engineering

Sponsor(s)

Monsanto Chemical Company

Publisher

Missouri School of Mines and Metallurgy

Publication Date

1960

Pagination

xv, 278 pages

Note about bibliography

Includes bibliographical references (pages 204-210).

Rights

© 1960 Joseph J. Yancik, All rights reserved.

Document Type

Dissertation - Open Access

File Type

text

Language

English

Subject Headings

Ammonium nitrate fuel oil
Detonation waves -- Mathematical models
Explosives -- Analysis
Explosives -- Testing

Thesis Number

T 1277

Print OCLC #

5931422

Electronic OCLC #

913796080

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