Experimental and simulation investigations of combustion and explosion properties of isopropyl nitrate at different concentrations

To reveal the explosion hazard properties and combustion mechanism of isopropyl nitrate (IPN), a 20 L spherical explosion device was used to conduct macroscopic explosion property tests, and ReaxFF MD simulations were employed to analyze the microscopic reaction mechanisms. The findings demonstrated that the maximum explosion pressure (pmax) and the maximum rate of pressure rise ((dp/dt)max) of IPN initially increased and then decreased with increasing concentration under both closed and ducted venting conditions. The optimum explosion concentration under closed conditions was 750 g/m3, which corresponded to apmaxof 0.779 MPa and a pressure rise rate of 232.5 MPa/s. Ducted venting significantly reduced the peak pressure and achieved a maximum flame propagation distance of 0.529 m at 750 g/m3. ReaxFF MD simulations revealed that the initial decomposition of IPN followed the dominant pathway C3H7NO3→ C3H7O + NO2, subsequently generating radicals such as C3H6O and·CH3, and further reacting with O2, ·OH, and ·HO2 to form a complex chain reaction network. These results elucidated the concentration effect and venting behavior of IPN, providing a theoretical basis for its safe application and explosion hazard assessment.