考虑进口非均匀的喷管设计及冷流条件下的性能研究

超燃冲压发动机尾喷管与燃烧室直接相连，由于没有几何喉道和收缩段的整流作用，实际工作过程中尾喷管的进口气流是非均匀的，因而有必要研究非均匀进口条件下的尾喷管设计方法。以超燃冲压发动机尾喷管非均匀进口马赫数分布为条件，采用有旋特征线设计了超燃冲压发动机非对称尾喷管的等熵膨胀型线。利用数值模拟和试验相结合的方法研究了冷流条件下喷管的气动性能。结果表明，在相同的进口条件下，相对于假定进口马赫数均匀分布设计得到的喷管，考虑进口马赫数非均匀分布设计的喷管推力增加0.6%~2.0%，负升力降低可达82.0%，俯仰力矩增加8.6%~13.0%，这说明在喷管的设计过程中考虑进口参数分布的非均匀性是有必要的。

Design and Cold Flow Experiment of a Scramjet Nozzle Considering Nonuniform Entrance Flow Effects

A scramjet nozzle is directly connected to the combustor and there is no contraction section or throat, which makes the nozzle entrance flow nonuniform, it is therefore necessary to obtain the design method for a scramjet nozzle with nonuniform entrance flow. In this paper, a scramjet nozzle is designed using the rotational method of characteristics which takes into consideration the nonuniform entrance flow effects. Experimental and numerical studies are performed to investigate the aerodynamic performance of this scramjet nozzle in conditions of cold flow, and the comparison is made with the nozzle which is designed with a uniform entrance flow in the same condition. Results obtained from the comparison conclude that the performance improvement obtained from the nonuniform nozzle design is about 0.6%-2.0% for thrust, 82.0% for negative lift, and 8.6%-13.0% for pitch moment, which demonstrates it is highly necessary to take into consideration the nonuniform distribution of entrance flow parameters when designing a scramjet nozzle.