Investigation of a New Formula for Gurney Velocity Estimation

The formula for the analytical calculations of the shaped charge jetting parameters exhibit an explicit dependence upon the Gurney velocity of an explosive material. Many attempts have been done to approximate the characteristic constant (2E)^1/2 and to make its use more efficient. It is shown herein that the characteristic Gurney velocity parameter depends on the ratio of the Chapman Jouguet-pressure to explosive impulse ratio by the formula:(2E)^1/2=0.2415((P_CJ)/(I_SPρ₀))-970.76, where P_CJ is the Chapman Jouguet pressure (Pa), I_SP is the specific impulse of the explosive used as a monopropellant (N•s/kg) and ρ_o is the explosive density(kg/m³). The proposed empirical formula was found to be reasonable and quite accurate approximation that can be implemented over a wide range of explosives, where the maximum deviation between the measured and the calculated Gurney velocities was nearly 6%. Besides, the proposed approach has been used analytically to calculate the jet tip velocity of a small caliber shaped charge, which is measured experimentally. The difference between the measured and the calculated jet tip velocity was only 1.6%.