High-precision 2D surface phosphor thermometry at kHz-rates during flame-wall interaction in narrow passages
High-precision 2D surface phosphor thermometry at kHz-rates during flame-wall interaction in narrow passages
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DOI：
10.1016/j.proci.2022.09.048
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发表时间：
2022-11
影响因子：
3.4
通讯作者：
A. O. Ojo;David Escofet-Martin;B. Peterson
中科院分区：
文献类型：
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作者：
A. O. Ojo;David Escofet-Martin;B. Peterson
这项工作演示了在窄通道内火焰-壁面相互作用（FWI）期间发生的高速二维壁面温度测量。这些测量对于了解微燃烧室和指定发动机缝隙内的瞬态壁面传热和火焰行为至关重要。壁温测量使用磷铋掺杂钒酸钪（ScVO4:Bi3+）。ScVO4:Bi3+具有较短的磷光寿命（室温下约2µs），可实现kHz测量速率。ScVO4:Bi3+还具有很高的温度灵敏度，在295 - 335 K的温度范围内，单次射击精度< 0.5 K。利用发射400 nm光的倍频Ti：蓝宝石激光器激发ScVO4:Bi3+，在空间分辨率为380µm的~ 22 × 22 mm2区域内测量了壁温。荧光粉测温和CH*成像结合在1 kHz测量火焰和壁面温度（墙）的时空动态在一个2毫米的缝隙通道在一个固定体积的腔室设计的传热研究。测量描述了瞬态FWI事件相关的壁面特征，包括与褶皱火焰前缘相关的独特壁面特征。对于我们的操作条件，与火焰尖峰相关的墙壁始终显示出比火焰尖峰区域低5 - 20 K的温度。最极端的差异是在大尖峰形成时看到的，在火焰尖峰的槽处，局部壁面冷却是明显的。这种冷却特性可能是由固有的火焰/流动不稳定性引起的，它局部和暂时地冷却了壁。
This work demonstrates high-speed 2D wall temperature measurements occurring during flame-wall interaction (FWI) within a narrow channel. Such measurements are essential to understand transient wall heat transfer and flame behavior occurring within micro-combustors and designated engine crevices. Wall temperature is measured using the phosphor Bismuth-doped Scandium vanadate (ScVO4:Bi3+). ScVO4:Bi3+exhibits a short phosphorescence lifetime (∼ 2 µs at room temperature), enabling kHz measurement rates. ScVO4:Bi3+also exhibits a high temperature sensitivity, which yields single-shot precision < 0.5 K within the temperature range of 295 – 335 K. A frequency-doubled Ti:Sapphire laser emitting light at 400 nm is used to excite ScVO4:Bi3+, and wall temperature is measured within a ∼ 22 × 22 mm2region with 380 µm spatial resolution. Phosphor thermometry and CH* imaging are combined at 1 kHz to measure the spatiotemporal dynamics of the flame and wall temperature (Twall) within a 2 mm crevice passage in a fixed volume chamber designed for heat transfer studies. Measurements describe Twallsignatures associated with transient FWI events, including unique Twallfeatures associated with wrinkled flame fronts. For our operating conditions, Twallassociated with flame cusps consistently exhibit temperatures 5 – 20 K lower than flame crest regions. The most extreme difference is seen for large cusp formation, where local wall cooling is noticeable at the trough of the flame cusp. This cooling feature may be caused by intrinsic flame/flow instabilities, which locally and temporally cool the wall.