Composition of detonation product

The methods for the determination of the composition of detonation products are mainly based on the determination of the composition after the products are cooled to room temperature at constant volume conditions. There were many attempts to freeze the state of the chemical equilibrium and to obtain the composition that would correspond as closely as possible to the composition at the end of the chemical reactions, i.e., at the CJ state. The composition of the detonation products changes with cooling. Therefore, the results obtained correspond only roughly to the real composition at the CJ state. 

Equation of State of Detonation Products Behind Overdriven Detonation Waves in Composition B , 4thONRSympDeton(1965), pp 47-51... 

The heat of detonation therefore is, like the heat of explosion, a function of the chemical energy of the explosive. In fact, the two heats differ only by the thermal effect, at standard temperature, of the shift in composition of the product mixture between (Tj) and (Tv). This depends on the... 

Ideal deton velocities correspond to a composition of the products of deton which depend only on the contents C - H - N - O and the temp pressure of deton all the parameters of the ideal deton wave of a mixed HE can be calcd exactly the same way as is done for individual HE s. It should only account for the peculiarity of the progress of the reaction in a deton wave of mixed HE s, associated with.the fact that at the start the expl components are decompd in a specific volume and then a prereaction takes place in the deton products. In the case when the decomposition of the deton products in the first stage is energetically more favorable than after the subreaction, the first stage of the reaction is responsible for the ideal velocity. This applies to mixtures of the type such as Pentolite... 

Given an explosive compound of composition C HiNA, in which there is at least enough oxygen to convert hydrogen to HaO but no more than is also required to convert carbon to CO2, the H2O-CO2 arbitrary calls for the formation of detonation products according to the following decomposition equation ... 

It was then demonstrated that A7uri), b, and Qnrb, as easily calculated from the H2O-CO2 arbitrary assumption of detonation product compositions, corresponded reasonably closely (i.e., to wi,thin 5%) to Vruby, Mruby, and Qruby at initial densities above 1.40 g/cc, but that differences became, significantly larger at lower loading densities (Table V of Ref. 1). The H2O-CO arbitrary represents N2, HjO, and CO2 as being the only important gaseous products in the detonation of most C-H-N-0 explosives, with H2O having priority in formation over CO2. 

In the same sense that the H2O-CO2 arbitrary assumption of detonation-product compositions represents Equilibria (2) and (3) as both lying far to the right, an H2O-CO-CO2 arbitrary concisely describes the condition where Equilibrium (2) is predominantly to the left and Equilibrium (3) predominantly to the right. In contrast with the former arbitrary, which has until now been used relatively infrequently,4 the latter method of estimating product compositions has... 

The nomenclature in the field of explosives and war chemicals is perplexing. Most of the chief explosives are known under many different names and designations, including the correct chemical name, chemical synonyms, American and foreign trade names, and warfare symbols. In literature on the subject sometimes one term is used, and sometimes another. Unless one knows the meaning of all of the terms, it is often necessary to make a search for information and this, in the literature on explosives, is a time-consuming procedure. For instance, in a technical article on detonators, a chemist may find a reference to Dinol. He knows this is a trade name and if he does not know the chemical composition of the product and wishes to find it out, he has to know its correct chemical name. He may spend quite a bit of time before he establishes the fact that Dinol is the commercial term for dinitrodiazophenol. 

Fugacity Determinations of the Products of Detonation were determined by M.A. Cook for PETN, RDX, LNG, Tetryl and 60% Straight Dynamite, by employing the equation of state derived from die hydrodynamic theory and observed velocities of detonation. The so-called reiteration method was developed for solving simultaneously as many equilibria as is necessary to define completely the composition of the products of detonation. Detailed description, together with 14 references is given-in the original article ... 

Mflrb, and Qarb, the values of which estimated from the H2O-CO2 arbitrary assumption of detonation product compositions, when substituted into Eq. (1), allowed relatively simple and straightforward hand calculations of detonation pressures. Results of such calculations corresponded quite closely (average absolute difference 1,77%) to values of this property obtained from the ruby or stretch ekw computer codes at loading densities from 1.00 to 1,96 g/cc. 

The measuring system used for the determination of detonation product composition is shown in Figure 4.75. 

The assumption of stable, one-dimensional detonations is not valid when one considers small-scale details, as Chapter 1 shows. However, although steady-state theory is invalid on a microscale, it does provide an excellent first approximation and a very useful aid in detonation performance calculations. Assumptions of chemical equilibrium in the steady-state model are incorrect. One of the interesting problems in modeling the equation of state of detonation products is finding reasonable changes in the detonation product composition which will reproduce the experimentally observed explosive and propellant performance. 

The Becker-Kistiakowsky-Wilson (BKW) equation of state described in Appendix E is the most used and best calibrated of those used to calculate detonation properties assuming steady-state and chemical equilibrium. Comparison of the calculated and experimental detonation properties permits evaluation of the errors to be expected from steady-state modeling of detonation products. Table 2.1 lists the calculated and experimental C-J properties of various explosives and mixtures. The calculated detonation product compositions of some of the explosives are given in Table 2.2. 

The Chapman-Jongnet (CJ) theory is a one-dimensional model that treats the detonation shock wave as a discontinnity with infinite reaction rate. The conservation equations for mass, momentum, and energy across the one-dimensional wave gives a unique solution for the detonation velocity (CJ velocity) and the state of combustion products immediately behind the detonation wave. Based on the CJ theory it is possible to calculate detonation velocity, detonation pressure, etc. if the gas mixtnre composition is known. The CJ theory does not require any information about the chemical reaction rate (i.e., chemical kinetics). 

PETN density favors Mader s detonation product computations since, as shown above, Mader calculates that the amount of free carbon decreases with a decrease in PETN packing density The product compns measured by Ornellas (Table 8) and the Mader CJ compositions differ appreciably. The Q s are, however, very similar. The agreement between calorimeter and computed Q s is certainly unexpected in view of the different product compns. Nevertheless, as stated in Vol 7, H38—39, there is rather good agreement between calorimeter Q s for confined samples and the CJ Q s computed by Mader (Ref 40) for expls that are not too deficient in oxygen. The following tabulation illustrates this ... 

Composition of Products of Detonation (and Explosion). See Detonation (and Explosion), Products of... 

Heat of Detonation is defined by Dunkle (Ref 40, p 248) as the "heat liberated at calorimeter temperature when an explosive detonates at constant volume and with no change in the product composition from that which was obtained at C-J point. Heat of detonation can be calculated from heat of explosion, or a closer experimental approach can be attempted by detonating the sample at high density and under strong confinement"... 

In addition to this definition, Dunkle stated in Ref 40, p 245 that the heat of detonation is the difference given by subtracting the heat of formation of the explosive, from the collective heat of formation of the mixture of products as it exists at the C-J point, where they ate at about 5000° K and still at about 10 atm. Both heats of formation are referred to the same standard temperature, but the product composition is taken as Corresponding to equilibrium at the C-J Point ... 

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