PLIF平面激光诱导荧光火焰燃烧检测系统

气体自由喷射的单次体视3维层析激光诱导荧光成像研究

Single-shot, tomographic imaging of the three-dimensional concentration field is demonstrated in a turbulent gaseous free jet in co-flow using volumetrically illuminated laser-induced fluorescence. The fourthharmonic output of an Nd:YAG laser at 266 nm is formed into a collimated 15 × 20 mm2 beam to excite the ground singlet state of acetone seeded into the central jet. Subsequent fluorescence is collected along eight lines of sight for tomographic reconstruction using a combination of stereoscopes optically coupled to four two-stage intensified CMOS cameras. The performance of the imaging system is evaluated and shown to be sufficient for recording instantaneous three-dimensional features with high signal-tonoise (130:1) and nominal spatial resolution of 0.6–1.5 mm at x/D = 7–15.5.

落到倾斜箔片上的液体薄膜流动的时间空间分辨热传导过程的实验研究

This paper describes the development of an experimental technique that combines simultaneous planar laser-induced fluorescence (PLIF) and infrared (IR) thermography imaging, and its application to the measurement of unsteady and conjugate heat-transfer in harmonically forced, thin liquid-film flows falling under the action of gravity over an inclined electrically heated-foil substrate. Quantitative, spatiotemporally resolved and simultaneously conducted measurements are reported of the film thickness, film free-surface temperature, solid–liquid substrate interface temperature, and local/instantaneous heat flux exchanged with the heated substrate. Based on this information, local and instantaneous heat-transfer coefficients (HTCs) are recovered. Results concerning the local and instantaneous HTC and how this is correlated with the local and instantaneous film thickness suggest considerable heat-transfer enhancement relative to steady-flow predictions in the thinner film regions.

湍流预混钝体火焰引燃几率的模拟和实验研究

The ignition characteristics of a premixed bluff-body burner under lean conditions were investigated experimentally and numerically with a physical model focusing on ignition probability. Visualisation of the flame with a 5 kHz OH* chemiluminescence camera confirmed that successful ignitions were those associated with the movement of the kernel upstream, consistent with previous work on non-premixed systems. Performing many separate ignition trials at the same spark position and flow conditions resulted in a quantification of the ignition probability Pign, which was found to decrease with increasing distance downstream of the bluff body and a decrease in equivalence ratio. Flows corresponding to flames close to the blow-off limit could not be ignited, although such flames were stable if reached from a richer already ignited condition.

聚焦燃烧，光学测量解决方案

不断发展的工业和快速成长的全球化市场对初级能源供应的增加，可靠的本地化制造和灵 活的公共交通运输都提出了与日俱增的需求。 尽管可替代技术方兴未艾并日益获得关注，但传统的、通过燃烧获得动力的途径在未来数 十年内仍将在能源结构中占有重要份额（参考下面“世界能源展望”图表）。 伴随可再生能源日益强烈的冲击，产生动力和热量的燃料种类的多样性也得到了空前规模 的扩展。此外，对能源利用效率和燃烧生成污染物控制的立法在逐步强化。对燃烧相关的 复杂过程的深入而细致的理解将会促进相关测量技术的进步。而这将有助于应对当前能源 领域的挑战并为未来发展储备所需技术。