Detonation product

Both RDX and HMX are stable, crystalline soHds, somewhat less sensitive to impact than PETN. Both may be handled with no physiological effect if appropriate precautions are taken to assure cleanliness of operations. Both RDX and HMX detonate to form mostiy gaseous, low molecular weight products and some intermediate formation of soHd carbons. The calculated molar detonation products of RDX are 3.00 H2O, 3.00 N2, 1.49 CO2, and 0.02 CO. RDX has been stored for as long as 10 months at 85°C without perceptible deterioration. 

Figure 4.9. Shock pressure versus particle velocity for engineering materials, geological material, and explosive detonation products. Intersection of detonation product curves with nonreactive media predicts shock pressure and particle velocity at an explosive sample interface. (After Jones (1972).)...

Davis, W.C., Equation of State for Detonation Products, in Eighth Symposium (International) on Detonation, NSWC MP 86-194 (edited by Short, J.M.), Naval Surface Weapons Center, White Oak, Silver Spring, MD, 1986, pp. 785-795. 

Cook (Ref 21) presents a thermo-hydrodynamic calcn of the detonation parameters and detonation products of two NS expls containing 25/1.5/73.5 NS/A1/AN-SN dope and 27-5/3/ 69.5 NS/A1/AN-SN dope... 

However, upon expansion of the detonation products, substantial amounts of CO are formed if the expl OB is negative. This is illustrated in Table 2 by using data from Ref 11... 

A novel use of PETN or rather PETN detonation products in high stagnation temp lasers is claimed by Robinson (Ref 95). These N2—C02 and N2— CO gas lasers are based on expln products obtained from detonation of mixts of PETN and acrylonitrile, or detonation of PETN in 02 or 02/He mixts... 

The PETN Detonation Pressure, P (also called the CJ Pressure), is shown as a function of packing density in Table 7 and in Fig 4. Note that the measured P values in Fig 4 lie quite close to the theoretical curve developed by Lee Homig (Ref 72), which is based on a Wilkin s type equation of state (see Vol 4, D294-L) with a Grueneisen ratio, r, for the detonation products, that is solely a function of specific volume. Shea et al obtained an effective T = 8.077 p-12.288 (Ref 74)... 

Zubarev Telegin (Ref 40a) developed an equation of state for detonation products based on the dynamic compressibility data for these substances and the requirement that product... 

Note that these values are fairly close to those shown in Table 7 and Figs 4 and 5, as well as the exptl and computed D — p data for Fig 6 (Hornig et al, Ref 74) and Fig 7 (Mader, Ref 74). Thus it is abundantly dear that comparison of exptl and computed D and/or P data provides no real test of the validity of an equation of state of detonation products, since P and D data com- puted on the basis of widely different equations "g of state can be made to agree with measured P j and D values ... 

A much more rigorous test of the validity of J a detonation product s equation of state is pro- > vided by the comparison of observed and com-, 2 puted detonation temps (CJ temps), TCJ and/or detonation product compns which depend on TCj and to a lesser extent on P. Unfortunately, there are no exptl detonation product compns, and exptl Tq s are open to serious uncertainties, particularly so in the case of solid expls,... 

We will not list Up or V, the steady detonation particle velocity and detonation product specific volume, as they are completely determined by the conservation equations, namely p /Ro0 md... 

Compn of PETN detonation products and the heat of detonation will be discussed in the next subsection... 

CsH8N4012 PETN detonation product conductance on initial ... 

Measurements of the electrical conductance of PETN detonation products, obtained by Hayes (Ref 45, p 599) show that conductance increases with PETN packing density. Since the peak conductivities of PETN, NM, Comp B and liq TNT... 

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 ... 

Detonation Products CJ Parameters. Mader (Ref 33a) computed the following detonation... 

As will be shown below, a more exact dependence is that power is proportional to Q—q (rather than just Q), but q, the residual heat of the detonation products, is usually quite small compared to Q... 

Detonation pressure may be computed theoretically or measured exptly. Both approaches are beset with formidable obstacles. Theoretical computations depend strongly on the choice of the equation of state (EOS) for the detonation products. Many forms of the EOS have been proposed (see Vol 4, D269—98). So.far none has proved to be unequivocally acceptable. Probably the EOS most commonly, used for pressure calcns are the polytropic EOS (Vol 4, D290-91) and the BKW EOS (Vol 4, D272-74 Ref 1). A modern variant of the Lennard Jones-Devonshire EOS, called JCZ-3, is now gaining some popularity (Refs -11. 14). Since there is uncertainty about the correct form of the detonation product EOS there is obviously uncertainty in the pressures computed via the various types of EOS ... 

Detonation Equilibria. Most of the commonly used expls are compds or mixts whose elemental compn consists of C, H, N, O. If the expl is reasonably oxygen-balanced (see Oxygen Balance in this Vol) then the detonation product... 

Except for 02 (a product in oxygen-rich expls), equilibria (1) thru (6) account for all, major detonation products of condensed CHNO expls. In gas detonations (ie, at low detonation pressures) such species as OH, H etc may also exist. In experimental measurements of detonation products (to be discussed later) HCN frequently appears as a minor product... 

For expls containing halogens (X), there is some controversy about the form in which these appear in detonation products. Some theoretical ealens (Ref 2) indicate that halogenated expls produce CX4. Exptl measurement (Ref 4),... 

The effect of temp on chemical equilibria is conventially determined via the free energy function AG°/RT and the ideal equilibrium constant K. Table 1 gives the free, energy function G°/RT for the important detonation products of CHNO expls. From these data A G°/(RT) can be obtained for different temps for the reactions of interest, and ideal equilibrium constants computed according to ... 

Ideal Gas Free Energy Functions [G°/(RT)] for Detonation Products... 

For nearly oxygen-balanced expls equilibrium (1) will dominate and control the compn of the detonation products. As already stated this equilibrium is expected to be independent of pressure if the gases behave ideally. But even for ideal gas behavior and an oxygen-balanced expl, no direct comparison can be made between theoretical detonation product calcns and observed products. This is so because measurements are made at temps much lower than detonation temps, and the products reequilibrate as the temp drops. Further complications arise because the reequilibration freezes at some rather high temp. This is a consequence of re-, action rates. At temps below some frozen equb... 

Except for oxygen-balanced expls, the computation of detonation products depends strongly on the choice of the equation of state (EOS) for these products. In the US the BKW EOS (see Vol 4, D272-R) has been favored and most of the computed product compns below will be based on it. Some of these will be compared with the relatively few calcns based on a Lennard-Jones-Devonsnire (UD) EOS (see Voi 4, D287-L)... 

Actual measurements of detonation products at CJ conditions do not exist for pure expls, but may be available for expl mixts with inerts. 

The major difficulty in applying this hydrodynamic theory of detonation to practical cases lies in the calculation of E2, the specific internal energy of the explosion products immediately behind the detonation front, without which the Rankine-Hugoniot curve cannot be drawn. The calculations require a knowledge of the equation of state of the detonation products and also a full knowledge of the chemical equilibria involved, both at very high temperatures and pressures. The first equation of state used was the Abel equation... 

Extension of the hydrodynamic theory to explain the variation of detonation velocity with cartridge diameter takes place in two stages. First, the structure of the reaction zone is studied to allow for the fact that the chemical reaction takes place in a finite time secondly, the effect of lateral losses on these reactions is studied. A simplified case neglecting the effects of heat conduction or diffusion and of viscosity is shown in Fig. 2.5. The Rankine-Hugoniot curves for the unreacted explosive and for the detonation products are shown, together with the Raleigh line. In the reaction zone the explosive is suddenly compressed from its initial state at... 

Hornberg, H. The State of the Detonation Products of Solid Explosives, Propellants Explos. 3, 97-106 (1978)... 

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