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Modeling ex-situ thermal impulse sensor responses to non-isothermal heating profiles

NCJ Number
301013
Author(s)
B. R. Anderson; H. Eilers
Date Published
2019
Annotation

To better understand how real-world temperature profiles influence the sensor’s thermal impulse determinations, the current project performed phenomenological modeling of a thermal impulse sensor’s response to non-isothermal heating with four-key profile characteristics: finite heating rate, non-zero cooling time constant, temperature spikes, and non-isothermal heating due to the finite size of sensors.

Abstract

Ex-situ thermal impulse sensing based on irreversible phase transitions has been a developing field over the past two decades. Typically, these techniques determine thermal impulses assuming a perfect isothermal heating profile, which is not the case for real-life temperature profiles in extreme environments (e.g., structural fires, explosions, gas turbines). The current study found that in all cases, these effects resulted in the corresponding equivalent isothermal temperature being lower than the peak temperature, while the equivalent isothermal duration was found to be either lengthened or shortened, depending on the effect of interest. These results have important implications for the interpretation of thermal impulse calculations from a wide range of ex-situ thermal impulse sensors. (publisher abstract modified)

Date Published: January 1, 2019