附面层吸入式进气道内流动损失特性

Flow losses characteristics of BLI inlet

用数值仿真手段,对进气道内流总压损失采用逐段对比分析的方法,研究了附面层吸入式(BLI)进气道相对于常规S弯进气道的内流总压损失特性。结果表明:进气道出口马赫数不变,较低来流马赫数和较高来流马赫数工况下(方案对应马赫数0.3以下和马赫数0.6以上),BLI进气道产生的流动损失比常规S弯进气道的大,差量达2.4%;中等来流马赫数工况下(本文方案对应马赫数0.3与马赫数0.6之间),BLI进气道产生的流动损失比常规S弯进气道的略小,差量在0.3%以内;流动损失特性间的差异是由于BLI进气道进口前壁面与进口低能附面流改变了进口段流动特性、及在S弯管道内发展的综合作用结果。

In order to study the difference and mechanism of the internal flow total pressure loss between the boundary layer ingestion(BLI)inlet and the conventional S-shaped inlet,numerical simulation method was applied and step-by-step comparative analysis of the total pressure loss was carried out.The results showed that,when fan-face Mach number was kept unchanged,the flow loss of BLI inlet was larger than that of the conventional S-shaped inlet under the working conditions of relatively lower and higher Mach number of free-stream(corresponding to below 0.3 or above 0.6),and the maximum difference was 2.4 percent.Under the working condition of medium Mach number of free-stream(corresponding to between 0.3 and 0.6),the flow loss generated by the BLI inlet was slightly smaller than that of the conventional S-shaped inlet,and the maximum difference was 0.3 percent.The combined effect of the fore-wall of the BLI inlet and the low-energy boundary flow changed the flow characteristics in the inlet and developed rapidly in the diffuser of the S-shaped pipeline,leading to the difference in flow loss characteristics.