不同条件下平面叶栅风洞流场品质的实验研究

Experimental Study on Flow Field Quality of Linear Cascade Wind Tunnel under Different Conditions

关键词:  平面叶栅风洞  流场品质  准确性  均匀性  周期性  攻角

Key words:  Linear cascade wind tunnel  Flow quality  Accuracy  Uniformity  Periodicity  Incidence angle

摘要:

为了全面认识亚声速平面叶栅风洞的流场品质及其影响因素，以典型高亚声速平面叶栅风洞为研究对象，试验测量并分析了空风洞的来流品质以及安装叶栅试验件后来流马赫数、来流攻角、以及叶片数对叶栅进口准确性、均匀性以及出口周期性的影响。研究结果表明：空风洞内主流区域宽广且基本均匀，来流马赫数偏差不超过±0.005，来流气流角偏差不超过±1°；加装叶栅试验件后叶栅风洞周向流场分布表现出不对称，靠近可移动上侧壁的三个通道的来流均匀性和准确性普遍较差，叶栅中间和偏向可移动下侧壁的通道进口均匀性和准确性较好；来流攻角对叶栅进口流场品质的影响比马赫数更明显，在负攻角和较小的正攻角下，叶栅进口流场品质较好；在较大的正攻角下，叶栅进口均匀性和准确性明显下降；叶栅进口均匀性直接影响了通道内以及叶栅出口的周期性。

Abstract:

In order to fully understand the flow quality of the subsonic linear cascade wind tunnel and its influencing factors， based on a typical high subsonic cascade wind tunnel， the cascade wind tunnel flow quality were measured and analysed with and without cascade and the effects of the inlet Mach number. The incidence and the number of blades on the inflow accuracy， uniformity and outflow periodicity were studied. The results show that the main flow of empty wind tunnel is broad and basically uniform， the inlet Mach number deviation is no more than ±0.005， and the inlet flow angle deviation is no more than ±1°. After installing the test cascade， the pithwise distribution of cascade flow shows asymmetry， mainly due to the poor flow uniformity and accuracy upstream of the three blade passages near the upper movable sidewall， while the blade passages from middle to lower sidewall show good flow quality. The incidence shows larger influence on the flow quality than inlet Mach number，and the inflow of cascade shows good quality at a negative or smaller positive incidence， while the inflow of cascade is encountered with poor uniformity and accuracy at a large positive incidence. And the inflow uniformity and accuracy of cascade can directly affect the flow periodicity within the blade passages and downstream of the cascade.