Protection Design and Effectiveness Verification of High-temperature Fire for Civil Aviation Emergency Locator Transmitter

Considering the coupling between the heat of emergency locator transmitter and the external high-temperature fire environment, a thermal protection system for external insulation and internal heat absorption is proposed. The external insulation layer consists of flexible nanofiber heat insulation film and quartz ceramics to withstand the thermal impact of the external environment. The internal heat absorption layer is composed of microcapsulated paraffin, which is used to absorb the heat transmitted through the insulation layer and the heat generated by emergency locator transmitter. Using the enthalpy method to establish a transient heat transfer mathematical model of thermal protection system, and the protection performance of the system in high-temperature fire is analyzed. The calculation results show that the system can withstand a high-temperature fire for at least 15 minutes, during which the temperature of emergency locator transmitter is controlled below 60℃. After the fire is over, under the coupling of the waste heat of the incoming system and the heat of emergency locator transmitter, the temperature of emergency locator transmitter continues to rise to a maximum of 107℃. Then, as the influence of the waste heat of the incoming system weakens, the temperature of emergency locator transmitter gradually decreases. Finally, the accuracy of the simulation model and the effectiveness of the thermal protection system are verified through destructive experiments.