57mm Diameter Hail Artificial Rainfall Time Bomb Fuze Related Technology Research

The key factor of the effect of weather modification projectiles is the location of its burst point. And where the weather modification projectiles detonate is decided by time fuzes. The exterior ballistics calculation of weather modification projectiles is the premise of the fuze design. Fuze design also needs to take the temperature of its working environment into account. That factor of the fuze temperature mainly consists of aerodynamic heat during flight and the propellant gases. The intensity of the projectiles also need to be ensured in fuze design, and some irrational structure shoud be improved.By using Fluent software to calculate the coefficient of resistance of weather modification projectiles, and comparing the results with the law of resistance issued in1943, it is summarized that:57mm caliber weather modification projectiles with two different fuzes differs little in the coefficient of resistance. The coefficient of resistance is stable both in subsonic and supersonic, unstable in the transonic section. In supersonic section, the coefficient of resistance of57mm caliber weather modification projectiles is slightly larger than it of the57mm caliber high explosive projectiles with tracer. In subsonic section, compared with the.57mm caliber high explosive projectiles with tracer, the coefficient of resistance of57mm caliber weather modification projectiles changes with the shape of the base of them. The shape of the point fuze of57mm caliber weather modification projectiles has little influence on the coefficient of resistance; however, the coefficient of resistance increases with the length of the exposed parts of the base fuze reduces.By using Matlab software to calculate the exterior ballistics and analyzing the impact between the various exterior ballistics elements, it is summarized that:when the angle is large, the air burst time has large influence on the standoff, and has little influence on the burst distance. According to the results of exterior ballistics calculation, we calculated the relationship between the time measured at the emplacement with the air burst time, and used test data to demonstrate and proved that this method can be used to measure the air burst time.By playing the aerodynamic heat theoretical calculations and aerodynamic simulation calculations of57mm caliber weather modification projectiles, it is summarized that: temperature generated by aerodynamic heat is proportional to the square of Mach; aerodynamic heat has little impact on the fuze of weather modification projectiles; the influence on the projectiles generated by the propellant gases can also be ignored.By calculating the base thickness of various caliber standard projectiles, the results show the irrationality of simplified formula to calculate the base thickness of the projectiles. By using ANSYS software to calculate the strength of57mm caliber weather modification projectiles base fuze, the results shows that the stress of risk locations increases as the base thickness decreases. Fuze body exists stress concentration phenomenon at the base of the hole; the stress concentration phenomenon can be solved by increasing the size of the chamfer.