氣体及び固体爆轟速度

Abstract

The propagation velocities of detonating gas and solid explosives have been derived theoretically from the molecular standpoint. 1. Gas explosives: The energy released at the flame front of the detonation wave in explosive gas mixtures may be the sum of the heat of reaction (Q) and the activation energy (ε). It is supossd that ε may be consumed for activation of the adjacent reactive zone of the flame front and Q may be reserved as the kinetic energy of the reactant molecles which have 3 kinds of freedom i. e. translational, vibrational and rotational. Assuming that the velocity of the detonation wave corresponds with the mean translational velocity (Ѷ) of the reactant molecules whose total mass is M, we have 1/2MѶ2=JQft/F+1/2ftRT･･･(1) where J is the mechanical equivalent of heat, ft the degrees of freedom of translation, F the total degrees of reedom, R the gas constant and T the temperature of the experiment (ca. 300°K). Accordingly, from (1) approximately we have Ѷ=(2JQγ/M)1/2 (1+ftRT/4Qγ)･･･(2) where γ=ft/F. Calculated values of V show good agreement with the observed ones for 15 kinds of detonating gas mixtures (Table 1.). 2. Solid explosives: According to the recent theory of liquids, the sound velocity in liquids (Uι) and in gases (Ug) are related by the equation Uι=Ug(ν/νJ)1/3･･･(3) where ν is the molecular volume of the liquids and νJ "the free volume". Using an analogy, the detonation velocity of solid explosives Vs may be given by a similar relation Vs=VG(ν/νJ)1/3･･･(4) where VG is the detonation velocity of gas explosives defined by the equation (2), and expressed by (2JQγ/M)1/2 approximately. Estimating that γ=0.24 from the Table 1, (ν/νJ)1/3 can be calculated by Vs (observed)/VG, which is expected to be nearly equal to 5 theoreticaly. The results are given en the Table 2, and it is found that solids explosives can be classified by 3 groups i.e. (i) (ν/νJ)1/3≒5, (ii) (ν/νt)1/3<5, and (iii) (ν/νJ)1/3>5. It is discussed that those differences may be ascribed to the crystalline siructures or compositions of the solid explosives. Taking (ν/νJ)1/3=4.9 from the Table 2 for the group (i), the detonation velocity Ѷs can be calculated by the relation (4) as shown on the last column of the Table 2.