发射药混同过程静电性能测试及风险评估

To prevent accidents and assess the risk of static disasters in propellant mixing process, we designed devices to test electrostatic parameters such as resistivity, dielectric constant and charge accumulation. 11/7 single-base propellant was chosen to be tested as a typical product. It shows that the volume resistivity, surface resistivity and dielectric constant of 11/7 single-base propellant are 1.87 × 10¹⁰ Ω• m, 1.06 × 10¹² Ω, and 1.88, respectively, and the saturated charge-to-mass ratio at friction state of chute is -1.85 μC•kg^-1. ANSOFT MAXWELL software was used to simulate the electrostatic field in mixing silo of 11/7 propellant, obtaining the change curve of the maximum field strength with powder 's height in 1000 mm diameter mixing silo. Results show that the electric field strength increases with the increase of powder 's height. When the powder's height is 40 mm, the air breakdown field strength is reached and there is a risk of electrostatic discharge. In addition, the critical discharge powder 's heights at different diameters of mixing silos were simulated, and the corresponding change curve was also obtained. It shows that the critical discharge powder 's heights are 81, 46, 42, 41 mm and 40 mm when the diameters of material silo are 100, 200, 300, 400 mm and 500 mm, respectively. However, when the diameter is greater than 500 mm, the critical discharge powder's height reasonably maintains at 40 mm.