Combustion-relevant aerosol phosphor thermometry imaging using Ce,Pr:LuAG, Ce:GdPO4, and Ce:CSSO

Aerosol phosphor thermometry (APT) is a promising temperature-imaging diagnostic that is currently being developed for combustion applications. To date, gas-phase APT measurements have been limited to temperatures below 1000 K due to thermal quenching and poor sensitivity at high temperatures. In this work, three phosphor compositions are investigated for application at flame relevant temperatures: Ce,Pr:LuAG, Ce:GdPO4, and Ce:CSSO. The phosphors were characterized in a temperature-controlled furnace, and measurements of gas temperature were performed in a seeded air jet after mixing with the products of an atmospheric methane-air flame. Furnace and flame measurements demonstrate that two of the phosphors are capable of temperature imaging at over 1000 K, with an upper temperature limit of at least 1400 K. Temperature precision estimates indicate 20-K or better single-shot precision from 500 to 1300 K for a seeding density corresponding to an added heat capacity of less than 1% of that of air at 1200 K at a spatial resolution of 1.12 line pairs per millimeter. This work represents the highest reported temperature measurements made using any APT technique for gas temperature measurements, and represents the highest measured quenching temperature of any phosphor exhibiting fast allowed emission for APT. These results extend the capabilities of APT for single-shot gas-phase temperature imaging up to at least 1400 K. This new capability will allow APT to be applied in combustion environments to study problems such as low-temperature ignition in engines. (c) 2020 The Combustion Institute. Published by Elsevier Inc. All rights reserved.

Automated summary

Aerosol phosphor thermometry (APT) is a promising temperature-imaging diagnostic being developed for combustion applications. This study shows that certain phosphors in APT can perform temperature imaging above 1000 K, up to at least 1400 K, with a single-shot precision of 20-K. This advancement allows APT to be applied in combustion environments to study issues such as low-temperature ignition in engines.