槽壁试验段低超声速流场特性数值模拟

 在跨声速风洞中通过开槽和抽气可以建立低超声速流场，由于槽壁试验段设计参数多，流场结构复杂，为提高设计准确性，通过数值模拟对槽壁试验段低超声速流场特性进行了研究。首先根据槽壁试验段的一般设计准则进行了气动设计，给出了槽壁尺寸和不同马赫数所对应的抽气量。基于设计结果，通过数值模拟对流场特性进行了研究，计算表明：通过抽气可以建立均匀的低超声速流场，抽气量对试验段马赫数均匀区长度有较大影响；随后对不同气动外形进行了比对，结果表明:抽气口位置、壁板厚度、驻室容积、开闭比及槽壁外形等对试验段的气流质量有影响，开闭比和槽型的影响尤为显著；最后对槽壁的通流特性进行了分析，探讨了槽型对试验段流场影响的成因。

Numerical Simulation on Characteristics of Slotted Test Section of Low Supersonic Field

Low supersonic field in a wind tunnel can be realized by using its slotted test section and the air mass exhausted from the chamber. This article presents the results of a numerical simulation of the flow field about the transonic wind tunnel slotted test sections in order to achieve more accurate design which takes into consi-deration the numerous design parameters and complex flow mechanism of the slotted test sections. First, slotted test sections are designed according to general design rules. Four wall configurations and the air mass exhausted corresponding to different Mach numbers are presented. With the designed configurations, the characteristics of a low supersonic field are studied by numerical simulation when part of the gas in the plenum chamber is discharged. It is shown that a low supersonic field can be formed but it is affected clearly by the exhaust mass. Then, different models are investigated based on the numerical results. Such parameters as the position of the vent, wall thickness, the volume of the plenum chamber, and especially the slot open area ratios and slot cross section geometry all have an impact on airflow quality. Finally, the flow mechanism across the slotted sections is analyzed to show how the slot cross section geometry affects the uniformity of the test section flow field.