BLI进气道流动特性的地面模拟方法和初步实验研究

发布时间：2018-05-08 05:59

本文选题：BLI进气道 + 流动特性　；参考：《南京航空航天大学》2016年硕士论文

【摘要】：BLI进气道是一类不采用边界层隔道、与机体结构融合的进气道,特别适用于翼身融合体飞行器。本文设计了一种BLI进气道,并对其展开了模拟外流条件下的仿真研究,获得了其流动特性。在此基础上,设计并搭建了BLI进气道双流路地面抽吸实验台,通过仿真验证了实验台流动与待模拟流动的一致性。另外,本文还对BLI进气道进行了初步的实验研究,所获结果和仿真结果基本一致。仿真和实验研究表明,由于吸入了大量的来流边界层,BLI进气道内形成了不同于无边界层吸入的常规S弯进气道的特殊流动结构:BLI进气道的进口段流场主要受钝体绕流与边界层相互干扰作用,流场中鞍点和分离线的数目、位置均随出口马赫数的变化而变化;在内通道中,吸入的边界层在下壁面附近堆积,在第二弯段后半段,边界层内的二次流逐渐发展成对涡,并将低能流卷向截面中间,最终在出口截面的中下半部形成了低总压区;并且,出口马赫数越低、来流马赫数越高、吸入的来流边界层越厚,出口截面上的低能流堆积就越严重,对涡影响范围越大,总压恢复系数ζ也越低。在不同工况下,BLI进气道的性能参数随出口马赫数的变化规律基本一致:随着出口马赫数的升高,BLI进气道总压恢复系数ζ先升高后降低,而常规S弯进气道的ζ则随之单调下降。另外,实验台的仿真校验和初步实验均表明,其可较为真实地模拟带外流条件下BLI进气道的流动特性,并可获得不同的来流马赫数、出口马赫数、来流边界层厚度等流动条件,因此该实验台的设计是成功的。
[Abstract]:The BLI inlet is a kind of inlet which does not use the boundary layer septum and is fused with the airframe structure. It is especially suitable for the wing body fusion vehicle. In this paper, a BLI inlet is designed, and its flow characteristics are obtained. On this basis, a two-way ground suction test bench for BLI inlet is designed and built, and the consistency between the experimental bed and the simulated flow is verified by simulation. In addition, a preliminary experimental study of the BLI inlet is carried out, and the results obtained are in good agreement with the simulation results. Simulation and experimental studies show that, The inlet flow field of the inlet is mainly affected by the interaction between the blunt body and the boundary layer due to the formation of a special flow structure in the inlet of the BLI inlet which is different from the conventional S-bend inlet without boundary layer inhalation. The flow field in the inlet section of the inlet is mainly affected by the interaction between the blunt body and the boundary layer. The number and position of saddle points and separation lines in the flow field vary with the Mach number at the exit. In the inner channel, the inhaled boundary layer accumulates near the lower wall, and in the second half of the second bend, the secondary flow in the boundary layer gradually develops into a pair of vortices. The lower the Mach number is, the higher the Mach number is, and the thicker the boundary layer of incoming flow is. The more serious the accumulation of low energy flow on the exit section is, the greater the range of influence on the vortex is, and the lower the recovery coefficient 味 of the total pressure is. Under different operating conditions, the performance parameters of the BLI inlet vary with the outlet Mach number. With the increase of the outlet Mach number, the total pressure recovery coefficient 味 of the BLI inlet increases first and then decreases, while that of the conventional S-curved inlet decreases monotonously. In addition, the simulation and preliminary experiments of the test bench show that the flow characteristics of the BLI inlet can be simulated more truthfully under the condition of the outflow, and the flow conditions such as the Mach number of the incoming flow, the Mach number of the outlet, the thickness of the boundary layer of the incoming flow can be obtained. Therefore, the design of the experimental platform is successful.
【学位授予单位】：南京航空航天大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：V211.48

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