Experimental study on the coupling of shock wave and temperature field from a thermobaric explosive in a confined space

In order to investigate the coupled enhancement effects of shock wave and temperature generated by thermobaric explosives in confined spaces, internal explosion experiments were conducted with 100−400 g charges in a confined building space. Pressure sensors and thermocouples were employed to obtain the explosion pressure and temperature data at different locations within the confined space. The experiments revealed the evolution characteristics and propagation patterns of the shock wave and temperature field produced by the thermobaric explosive. The results show that the temperature generated by the internal explosion of the thermobaric explosive exhibits significant secondary heating and prolonged duration characteristics. A decay model for the initial peak temperature based on the scaled distance was established. The TNT equivalence coefficient of the shock wave from the internal explosion of the thermobaric explosive exhibits a concave hyperbolic trend with increasing scaled distance. At a scaled distance of 1.7 m/kg^1/3, the TNT equivalence coefficient of the shock wave overpressure reaches a minimum value of 1.43, indicating that this position is the turning point where the energy from aerobic afterburn combustion exerts a significant effect on the peak overpressure. A two-stage prediction model for the peak overpressure was established, describing the contributions of non-ideal detonation and the aerobic afterburn effect of aluminum powder to the shock wave in different regions. Based on the pressure rise caused by the expansion of detonation products and the temperature rise due to afterburn combustion, a quasi-static pressure prediction model for the internal explosion of thermobaric explosives was established. Taking the quasi-static pressure of the 100 g charge as the reference, the quasi-static pressures for the 200, 300, and 400 g charges increased to 2.27, 3.21, and 4.18 times the reference value, respectively, showing a nonlinear growth under the coupled effect of detonation product expansion and afterburn temperature rise.