高超声速风洞流场中的气流旋转影响及消除

Investigation on the flow rotation effect and elimination in hypersonic wind tunnel

风洞实验需要高品质的来流,但部分高超声速风洞由于加热器特性可能导致流场中存在气流旋转,为了消除或减小旋转,提出了在风洞稳定段前加入反向旋转气流来抵消气流旋转的思路。为验证该思路及了解高超声速流场中旋转程度总体效应,设计了一种带翼模型和高精度滚转力矩天平。在Φ0.3m高超声速低密度风洞中进行了M6、总压约2×10~5Pa、氮气常温时(电弧加热器不通电)多种进气条件下的滚转力矩测量实验,结果表明流场中存在旋转,滚转力矩系数Cl最大为1.657×10^(-3),采用约2%总流量的反向气流可达到滚转力矩系数降低2个数量级的效果,为提高风洞流场品质提供了较为有效的解决措施。

Wind tunnel experiments require high quality flow field,but in some hypersonic wind tunnel,the inlet flow may be rotated for preventing the local overheating of the heater.In order to eliminate the rotation,a reverse rotating flow is added into the main stream before the stability section of the wind tunnel.A wing model and a high precision roll balance were designed to study the total effect of the flow rotation in the hypersonic wind tunnel.The rolling moment measurements are carried out in theΦ0.3mhypersonic low density wind tunnel of CARDC under the test conditions of Mach 6,stagnation pressure of about 2×10~5Pa and room temperature nitrogen.The results show the rotation exits and the maximum rolling moment coefficient is 1.657×10^（-3）;Reverse flow of about 2%total flow flux can reduce the rolling moment coefficient by 2orders of magnitude.It is proved to be an effective solution for improving the quality of the wind tunnel flow field.