Response functions of HMX and RDX burning rates with allowance for melting

Abstract

Experimental values of the burning rate with variations in pressure and initial temperature are given, and identity of gasification laws in the wave for RDX and HMX is demonstrated. Differential parameters (sensitivities) of the burning rate and surface temperature are found. Based on these parameters, response functions of the burning rate to pressure oscillations are calculated. The calculations are performed with and without allowance for condensed phase melting. Allowance for melting is shown to reduce the amplitude of the real part of the response functions, while the thickness of the melted layer does not produce any significant effect on the response functions. Errors of calculating the response functions are presented. The calculated response functions are compared with experimental data.

Studying RDX and HMX combustion mechanisms by various experimental techniques

“…The parameters L R also have close values. A large difference in the melting points of the c-phase (204 • C for RDX and 282 • C for HMX) was found to induce no significant difference in the response functions of the burning rate to pressure fluctuations [22].…”

“…Both nitramines have a special combustion regime at p 1 MPa (negative thermal effect in the c-phase), which distinguishes them from almost all examined condensed explosives (where this regime is absent). It was shown [22] that the differential coefficients of RDX and HMX, i.e., the sensitivities of the burning rate to pressure and temperature…”

Nonlinear response functions of the burning rate of ballistite powders

“…Indeed, for instance, for m = 1 and 2 g/(cm 3 · sec), we have T s = 390 and 460 • C for HMX-containing ballistite powders (see Fig. 1), whereas T s = 480 and 520 • C for pure HMX [29] for the same values of m. Thus, the melted HMX acquires the value of the temperature T s of ballistite powders, which testifies to its interaction in the reactive layer of the condensed phase with constituents of the powder that "imposed" its kinetics onto HMX. We can only guess how this interaction occurs.…”