Detonation pressure, estimation

Detonation pressures estimated by the simpler method are compared in Table VI with the corresponding ruby values for twenty-eight materials. Since we are at this point concerned only with reproducing ruby results, it is unimportant to the present discussion whether input heats of formation in the ruby computations are accurate although the AH/ for picric acid in Ref,... 

To a chemist concerned Tyith the synthesis of new high-explosive compounds the ability to compute detonation properties (detonation pressure, energy, and velocity as well as product composition) from a given molecular structure and the known or estimated crystal density is a problem of the utmost importance. The calculated properties could be meaningful in the decision as to whether it is worth the effort to attempt a new and complex synthesis. One reason behind the recent development of detonation-properties programs for use on high-speed computers has been to supply this desired information. One such program, the ruby code,1 has recently been made available to a number of laboratories, the authors included. 

In an effort to understand the formidable-appearing output of many computations for a wide variety of C-H-N-O explosives at various initial loading densities, we have investigated interrelationships between such properties as pressure, velocity, density, heat of reaction, etc. These studies have led to a number of interesting observations, important among which were the facts that much simpler semiempirical formulas could be written for desk calculation of detonation velocities and detonation pressures, with about the same reliance on their answers as one could attach to the more complex computer output. These equations require as input information only the explosive s composition and loading density and an estimate of its heat of formation, and, in their comparative simplicity,... 

Equations (8) and (13) -(15) provide the basis for a simple method of estimating detonation pressures, which requires as input information only the elemental composition, loading density, and an estimate of the heat of formation of the explosive. With the aid of a desk calculator, a typical calculation requires less than... 

In Paper I of this series1 it was suggested that detonation pressures of C-H-N-0 high explosives might be estimated by means of the simple empirical equation... 

It follows that the H20-C02 arbitrary must be considered similarly suspect as regards estimates of actual N, M, and Q. In consequence of the buffered equilibria, however, this arbitrary may nevertheless be completely adequate for the estimation of actual , and hence actual detonation pressures and velocities. 

The loss factor is claimed to correlate with a rather crude estimate of detonation pressure (usually an underestimate) as shown in Fig 31... 

The determination of the maximum detonation pressure pi, in equation (2d) has been studied by X ray measurements. While the detonation velocity can be measured directly by electronic recorders or by the - Dautriche Method, there is no direct measurement possibility for the fume velocity W, but it can be estimated by the flow off angle of the fumes behind the wave front this angle can be taken from X ray flash photographs. The relation between Dand M/is... 

According to Kamlet and Jacobs the detonation velocity (D) and the detonation pressure (pc.j) can be estimated. Give the relevant equations. 

In Section I, Chemistry of Explosives, methods were described that enable one to estimate detonation properties (detonation velocity D and detonation pressure Pcj) from the molecular structure of an explosive. This section gives an alternate method that utilizes the thermochemical properties of an explosive in order to estimate the values of these two output properties. This method was developed by M. J. Kamlet and S. J. Jacobs of the Naval Ordnance Laboratory in White Oak, MD (Ref 9) and is referred to in this text as the KJ method. 

We learned that we can easily estimate the density of the detonation product gases at the detonation front, and using this can then estimate the detonation pressure. 

At low loading densities, values of N, M, and Q calculated from the HjO-COj arbitrary show poor individual agreement with estimates of these quantities from the RUBY computer code. Nevertheless, when substituted into the equation P = 15.58 they lead to detonation pressures which correspond... 

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