OH分子示踪法用于气态流场速度测量

Velocity Measurement of Gas Flow Field by Hydroxyl Tagging Velocimetry

研制了一套单线羟基(OH)分子标记示踪流场速度测量系统,OH分子标记线由193 nm波长脉冲氟化氩(ArF)准分子激光束解离流场中的水分子产生,利用脉冲染料激光倍频的约282 nm激光片显示OH分子荧光图像,由获得的两个时间关联的OH分子标记线位置图像计算流场的速度分布。研究了空气和火焰中193 nm波长激光解离水产生的OH分子寿命,实现了常温空气流场和高温超音速流场速度分布的测量,并对测量结果进行了分析讨论。

A single-line hydroxyl tagging velocimetric system for gas flow is constructed. Hydroxyl tagging line is generated through the photodissociation of H2O molecules in flow by a 193 nm pulsed ArF excimer laser beam. A laser sheet from a pulsed frequency-doubled dye laser operating at 282 nm is used to reveal the OH tagging line through fluorescence. Two time consecutive images are acquired to calculate the velocity distribution of flow field. The lifetime of OH photoproducts photo-dissociated by 193 nm laser in air and flame are studied. The velocity measurement for room-temperature air flow and high-temperature supersonic flow are carried out, and the basic analysis and discussion of experimental results are performed.