Blast Parametric Study Using a 1:57 Scale Single Driver Model of a Large Blast Simulator

A 157 scale, single cold air driver model of a large blast simulator was constructed and operated in driver overpressure range of 300-1800 kPa. Recorded overpressures were in a 10-225 kPa range for the given driver pressures. Blast parameters of overpressure, positive impulse, cold gas arrival and drag enhancement, and recompression fan arrival were measured at stations 7- 28 diameters along the test section of the simulator model. The cold gas arrival at the test stations was found to enhance the dynamic drag pressure by a factor of two at the 220 kPa input level. Similar, although larger enhancement was predicted by the BRL-Q1D Code simulation. Effects of driver length, volume, and throat baffle ratio for the full-size simulator operating range are presented in tabular and graphical form. Because of the large cold gas dynamics drag enhancement at test section pressures above 100 kPa, it is recommended that a hot gas driver be used for the full-size simulator. Due to the side-on overpressure positive duration decrease caused by arrival of the throat nozzle recompression fan, a station at 20 test section diameters should be used for the full-scale simulator.