Flow behaviour of molten 2,4,6-trinitrotoluene (TNT) between concentric cylinders

Abstract

Abstract." The flow behaviour of pure and commercial molten TNT when subjected to very high rates of shear in a rotational viscometer over the temperature range 82.0 to 95.4 °C is presented. All data obtained suggest that the behaviour of molten TNT is Newtonian, contrary to the conclusions of some published work, and the temperature dependence of the viscosity of pure TNT is adequately described by an Arrhenius-type relationship of the form ~/= A e B/T where A = 0.000541, B = 3570 and T is the Kelvin temperature. A similar relationship is obtained for commercial TNT. Under some instrumental conditions discontinuities are seen in the shear stress-shear rate flow curves. An analysis of these discontinuities shows them to be caused by the transition from laminar to turbulent flow. Possible implications for processibility and initiation of explosives are discussed.

Rheological Behavior of DNAN/HMX Melt‐Cast Explosives

“…As shown in Figure 8, the apparent viscosity of the DNAN/HMX suspensions decreases with increasing temperature. The effect of temperature is fit to the Arrhenius relationship [6] h ¼ Ae E RT (2) where E is the activation energy for flow, T is the absolute temperature, A is a constant, and R is the universal gas constant. As shown in Table 3, the activation energy E for suspensions with high solid content is greater than for suspensions with lower solid contents.…”

“…The rheological behavior of melt-cast explosives has been explored to some extent in previous work, especially for trinitrotoluene-based (TNT-based) melt-cast explosives. The general qualitative law for the rheological behavior of TNT-based melt-cast explosives can be summarized as follows: (1) Molten TNT is similar to a Newtonian fluid [1][2][3], whereas TNT-based melt-cast explosive suspensions are generally shear-thinning (non-Newtonian) fluids [4][5][6]. (2) The viscosity of the suspensions increases with increasing solid content [4,[7][8].…”

“…The general qualitative law for the rheological behavior of TNT-based melt-cast explosives can be summarized as follows: (1) Molten TNT is similar to a Newtonian fluid [1][2][3], whereas TNT-based melt-cast explosive suspensions are generally shear-thinning (non-Newtonian) fluids [4][5][6]. (2) The viscosity of the suspensions increases with increasing solid content [4,[7][8]. (3) Given a particular amount of solid content, a reduction in particle size generally results in increased viscosity of the suspensions [4,7,9], whereas suspensions containing particles with a smoother morphology have reduced viscosity [9].…”

Numerical and Experimental Investigation of Solidification Shrinkage

“…The casting assembly considered in this work consists of a stainless steel mold (ASTM 1026) and an aluminum riser, as illustrated in The thermophysical properties for TNT are well documented [24][25][26], and the relevant values are listed in Table 1. The density of TNT is strongly influenced by temperature, and can be given as follows: …”

Simulation of the Air Bubble Temperature in the Firing Projectile

“…The bubble under the pressure wave becomes more compressed and its temperature rises, so it has the potential of creating hot spots and initializing the detonation [5]. In Parry and Billon's experiment, which is done without any bubble, the initiation occurred at random points which has the maximum shear flow and show the heat effects of flow transition from laminar to turbulence during dynamic loading of TNT [6]. When the viscosity is high, the yield stress is low and the time for temperature raise is short, so the viscous work becomes important.…”