【摘要】 <正> 连续波化学激光器中,两股超音速气流的扩散混合情况相当复杂,激光器性能在很大程度上受扩散混合过程的控制。因此,流场显示诊断以及流速测量等,对于这类器件来说是至关重要的。人们采用诸如阴影法、纹影法、干涉法、相干反斯托克斯喇曼光谱法、激光多普勒测速计以及全息干涉法等探测手段来显示和诊断流场,以期更好地了解超音速流混合的具体过程。然而,由于连续波化学激光器喷管尺寸小、腔压低(即气体密度低)以及气流速度高等缘故,上述方法都有各自的困难和局限。更多还原

【Abstract】 By using an improved laser fluorescence (LIF) technique, we have succeeded in displaying the whole flowfield of cw supersonic chemical lasers. A salient feature of this method is its high spatial resolution (<0.5mm) in the direction normal to the incident beam, which is hardly attainable by other methods. Owing to the fluorescence quenching at the shock front, distinct shock patterns become observable in the LIP photograph. These are subjected to quantitative data processing to obtain the local Mach numbers. The influence of the trip, i.e., a minute amount of He gas injected transversely into the main flow, on the spreading and mixing of two supersonic gas streams is investigated.更多还原