高速风洞运转特性数值模拟

Numerical investigations about running characteristics of hypersonic wind tunnel

关键词:  高超声速风洞  模型  试验舱  收集器  扩压器  激波  数值模拟

Key words:  Hypersonic wind tunnel  Model  test cabin  Pickup collector  Diffuser  Shock  Numerical simulation

摘要:

下吹-抽吸式高超声速风洞的起动和运转对试验进程有重要影响。为获得试验模型和扩压器对风洞起动和运转特性的影响，采用数值模拟方法，使用二维轴对称模型对Φ0.5米高超声速风洞的流场进行了研究，控制方程为粘性可压缩Navier-Stokes方程。对马赫数5和10两种状态下的流场行了对比，结果表明，试验段基本流态受试验舱静压控制，收集器对流动状态有很大影响。当带模型运转时，试验段内激波结构更为复杂，出现明显溢流，总压损失更大，所需起动压比越大；扩压器平直段直径决定了其静压恢复效率。扩压器平直段直径增加或安装模型时，临界运转压比都会明显增加；且马赫数越大，受到的影响越大。

Abstract:

Starting and running characteristics plays an important role in the course of design and model tested in blowing-down and suction hypersonic wind tunnel. To analyze the effect about what model tested and diffuser is on the starting and running of Φ0.5m hypersonic wind tunnel, field structure and evolvement was simulated numerically. In the simulation, the flow field calculation simplified two-dimensional axisymmetric model was performed. The control equations were the conservational Navier-Stokes equations, which described two-dimensional viscous, compressible flows. The numerical simulation results of Mach number 5 and 10 showed that basic state of test section was under the control of static pressure in test cabin. Pickup collector had some effect on the field structure. Running with model than without model, shock system was more complex. There was evidently ovefall around pickup collector wall. There was more total pressure loss, which leaded to higher pressure-ratio when starting wind tunnel. The diameter of straight-pipe section in diffuser influenced the efficiency of static pressure recovery evidently. When enhancement of straight-pipe section diameter or in conjunction with model, critical running pressure-ratio became higher obviously. Bigger was Mach number, more distinctly was critical running pressure-ratio affected.