背负式进气道设计及其气动性能研究

Top-Mounted Inlet Design and Its Aerodynamic Performance

背部式进气道在无人机气动设计中得到了广泛的应用。针对背部进气的气动布局，进行了进气道的综合设计。并借助于风洞实验，研究了不同雷诺数下的机身背部附面层高度，测量了进气道不同隔道高度时的气动性能，最终选定了隔道高度与机身长度之比为H／L=O．19。通过进气道攻角特性、侧滑角特性的气动研究，设计进气道取得了良好的气动性能总压恢复系数达到0．98～O．99。最后对有、无前机身干扰影响时的进气道性能进行了对比实验，实验结果表明通过与前机身匹配设计的进气道性能要优于没有前机身的进气道性能。

In the full paper, we explain in detail the results of our UAV（Unmanned Air Vehicle） work. In this abstract,we just list the three topics of explaination and add some pertinent remarks. The first topic is. the design of the top mounted inlet. In this topic, we explain in general terms how to consider various factors in our design. The second topic is. experimental setup. The third topic is. experimental results and their analysis. Its five subtopics are. the measurement of the boundary layer of fuselage （subtopic 3.1）, the aerodynamic performance of inlet for different heights of diverter （subtopic 3. 2）, the flow characteristics of the inlet （subtopic 3.3）, the characteristics of the attack angle and the sideslip of the inlet （subtopic 3.4） and the comparison of the aerodynamic performance of the inlet with and without fuselage before it （subtopic 3. 5）. In all five subtopics, there are figures or tables in the full paper summarizing the experimental results. In subtopic 3.2, we point out that the ratio of the height of diverter to the length of the fuselage before the inlet should be selected as 0. 19. The experimental results in topic 3 show preliminarily that the total pressure recovery coefficient of our design reaches a value of between 98% and 99%, better than what was stipulated in design requirements. They also show preliminarily that the variation of inlet pressure distortion index under various conditions is within permissible limits.