Measurements of flame temperature are reported in a laminar non-premixed ethylene sooting flame under high-flux irradiation that simulates high temperature solar receiver-combustors. Simulated concentrated solar irradiation was provided by a metal-halide lamp configured in a series of three optical concentrators, with a peak flux of 0.7 MW/m2. Flame temperature was measured using one-dimensional non-linear two-line atomic fluorescence (NTLAF) at various distances up to the flame height of 64 mm with and without the high-flux irradiation. The strong scattering background originated from the irradiation on the soot particles in the TLAF signal was accounted for by subtracting the scattering background. A set of narrow-band filters with full width at half maximum (FWHM) ∼ 1.2 nm and transmission rate of ∼ 95% were used to collect the TLAF signal, resulting in a temperature measurement precision of ±40 K. The present work shows that the presence of high-flux solar irradiation causes the temperature to increasegradually from just above the burner to reach a maximum of ∼ 100 K at heights above burner (HAB) between 35 mm and 41 mm. The temperature increase is around ∼ 50 K elsewhere on the centreline. The corresponding soot volume fraction(fv) is increased by about 200% along the flame centreline, as measured by laser-induced incandescence (LII) in a separate study.
|Original language||English (US)|
|Title of host publication||ASPACC 2015 - 10th Asia-Pacific Conference on Combustion|
|State||Published - Jan 1 2015|