Thermal Decomposition Characteristics and Thermal Safety Performance Evaluation of Han-Based Propellant Under Different External Stimulations

Abstract

In the event of upset conditions, such as exposure to high storage temperatures and pressures or adiabatic conditions, Hydroxylamine nitrate (HAN)-based liquid propellant is at risk of exploding unexpectedly, with potentially devastating consequences including property damage and fatalities. This research aims to investigate the thermal characteristics and assess the resulting thermal hazard using a combination of accelerating rate calorimeter and high-pressure differential scanning calorimetry. Adiabatic experiments revealed that HAN-based liquid propellant was particularly susceptible to a catastrophic explosion. As the time to maximum rate under adiabatic condition was 24 h, the initial temperature was predicted to 111.3 °C. To ensure the thermal hazards during storage and transportation are manageable, it is crucial to control the temperature below this threshold. We also obtained the activation energy using various isoconversional methods and identified the thermal explosion temperature and self-accelerating decomposition temperature (TSADT) at different storage temperatures. Additionally, the relationship between apparent activation energy and temperature was deduced theoretically. The reliability of the TSADT prediction was validated through slow cook-off test. Furthermore, the propellant exhibited more violent thermal decomposition under high pressure, resulting in a higher peak power. The thermokinetic parameters related to this phenomenon were identified, specifically at pressure of 4.0 MPa.

Keywords: Hydroxylamine nitrate, Thermal decomposition, Thermal hazard, Slow cook-off, High pressure stimulation