激波风洞内超燃冲压发动机三面压缩进气道流场实验观测

主要进行了超燃冲压发动机三面压缩进气道的实验观测。利用来流马赫数4.5的直通式激波风洞,考察了三组具有不同压缩角度的进气道模型内部的流场情况。实验观测手段为油流法、丝线法和高速纹影,同时,辅以数值模拟以有助于流场细节分析。纹影照片展示了进气道内部以激波边界层相互作用为主要影响因素的流场复杂结构,数值模拟也显示了相近的结果。油流技术与丝线法显示了近壁面处的流动图像,照片中可见激波、分离线、再附线等分界线位置。根据实验结果,可以推测唇口激波与进气道内边界层的相互作用及其引起的壁面分离是影响进气道内流动的主要因素。同时,尝试了利用抽吸方法减弱激波与边界层相互作用诱发的壁面流动分离,并取得一定结果。

An Experimental Observation of 3-D Scramjet Inlet Flow in a Shock Tunnel

An experimental observation was carried out for three-dimensional scramjet inlet flow. Six 3-D inlet models with different swept and wedge angles were examined in a M4.5 straight shock tunnel to review the inner flow field of inlet model by means of high speed schlieren photography, oil dot visualization technology and surface tuft method,respectively. As a valuable supplement, 2-D numerical simulation was also conducted. Schlieren photos clearly show the very complex flow structure in the inlet, which is mainly caused by the shock wave-boundary interaction. The shock wave interaction consists of shock waves and viscous separation regions. These phenomena are also confirmed by numerical simulation. Oil dot photos capture the flow patterns near the walls of the inlet. The fin shock, separation line and reattachment line can be identified. According to the experimental results, it is presumed that the interaction of shock wave caused by cowl with the boundary layer over the inlet top and the boundary layer over the sidewall are main flow structures, which deteriorate the flow field in the inlet. Pumping was used to control the separation, and presented some positive results.