Phosphor thermometry on a rotating flame holder for combustion applications

Abstract

This study presents a method to measure wall temperatures of a rotating flame holder, which could be used as a combustion control device. Laser induced phosphorescence (LIP) is found to be a reliable technique to gather such experimental data. The paper first investigates how the coating (thickness, emissivity and lifetime) influence the flame stabilization. While the low thermal conductivity of the coating is found to induce a temperature dif- ference of 3 − 5 K, the emissivity increases by 40%. Nevertheless, the transient and steady-state flame location are not affected. Second, because temperature measurements on the rotating cylinder are likely to fail due the long phosphor lifetimes, we modify the classical point-wise arrangement. We propose to illu- minate a larger area, and to correct the signal with a distortion function that accounts for the displacement of the target. An analytical distortion function is derived and compared to measured ones. It shows that the range of mea- surements is limited by the signal extinction and the rapid distortion function decay. A diagram summarizes the range of operating conditions where mea- surements are valid. Eventually, these experimental data are used to validate direct numerical simulations. A sensitivity analysis shows that the precision of the technique still gives a good agreement for the flame location.