Temperature and pressure propagation characteristics in multi-media interfaces of PVDF pressure sensor near underwater explosion source

Abstract

In this paper, based on the self-made PVDF pressure sensor, the underwater explosion test of the emulsion explosive was performed to verify the measurement accuracy of the self-made PVDF pressure sensor and the feasibility of the pressure measurement near the explosive source. Then the single column emulsion explosive and gram-grade Al/PTFE underwater explosion experiment and numerical simulation were carried out, and the error between the experimental and numerical simulation results is small (The difference between the pressure peaks obtained from the emulsion explosive experiment and numerical simulation is about 25.07 MPa and the pressure decay trend is close; the peak difference in lane 1 obtained by Al/PTFE experiment and simulation is about 23 MPa, the second peak difference is about 0.8 MPa, the pressure decay trend after the second peak is close, and the shock wave arrival moment in experiment lags the numerical simulation by about 30μs), which verifies the reliability of the simulation model. Meanwhile, the numerical simulation of explosion at a depth of 10m below sea level was performed, the evolutionary law of the sensor and water pressure at 1–10 times the charge diameter is expounded, the variable rule of temperature during sensor response period is analyzed. The numerical simulation results show that the time-history curve of pressure includes two stages: bubble microjet and shock wave propagation, which the bubble microjet pressure can reach 10 GPa, and the sensor structure and shock wave pressure test will not be affected within the response period. The time history curves of shock wave pressure in experiments are basically the same by comparing with the simulation results of underwater pressure at the same position, and impact temperature rise will affect the measurement accuracy of PVDF film, but the lasting time of heat conduction in the PVDF sensor is longer than the response period of impact pressure, therefore the influence of heat conduction on the test accuracy can be ignored.