粗糙度对压气机叶栅损失特性影响的实验研究

Experimental Study for Effects of Surface Roughness on Compressor Cascade Loss Characteristics

关键词:  压气机叶栅  总压损失  粗糙度量级  粗糙度位置  雷诺数  攻角

Key words:  Compressor cascade  Total pressure loss  Roughness magnitude  Roughness location  Reynolds number  Incidence angle

摘要:

为了研究粗糙度对压气机叶栅损失特性的影响，采用实验方法研究了三种雷诺数条件下表面粗糙度量级和位置对压气机平面叶栅不同攻角下总压损失特性的影响。叶片表面粗糙度通过贴砂纸的方式改变。对每种雷诺数，定量考察了由叶片表面贴砂纸引起的叶片厚度变化对叶栅攻角-损失特性的影响；对整体粗糙叶片，分析了四种粗糙度量级的影响；讨论了叶片表面局部粗糙度位置的影响。研究表明，定量比较损失时需考虑贴砂纸引起的叶片厚度变化，以加厚光滑叶片作为比较基准。粗糙度量级和位置对叶栅损失特性的影响与雷诺数密切相关，其影响趋势和程度在不同攻角范围内表现出明显的差异。高Re数条件下，当无量纲粗糙度[k+≤14.6]时，叶栅性能尚可接受，当[k+≥20.1]时，可认为叶栅已基本失效。总体上，叶片前缘和吸力面粗糙度对损失变化的影响最大。Re=[1.0×105]，-0.6°攻角情况下整体和吸力面前部加粗糙度80μm时，总压损失值相比加厚光滑叶片分别降低了17.3%和23.1%。

Abstract:

In order to study the effects of surface roughness， the effects of surface roughness magnitudes and location on total pressure loss characteristics of a planar compressor cascade at three Reynolds numbers and different incidence angles were studied experimentally. Blade surface roughness was changed by sticking sandpapers. For each Reynolds number，firstly，the effects of blade thickness variation induced by sticking sandpaper on cascade total pressure loss - incidence angles characteristics were quantitatively investigated. Then，for the entire roughened blade，the impacts of four kinds of roughness magnitudes were analyzed. Furthermore，the influence of blade surface partial roughness location was discussed. The results show that the changes of blade thickness induced by sticking sandpapers should be included in the quantitative comparison of cascade loss，in this paper the comparisons are made on the base of the thickened smooth cascade. The impacts of roughness magnitudes and location on cascade total pressure loss characteristics are closely related with Reynolds numbers，the trend and magnitude within different incidence angles show obvious difference. Under conditions of high Re number，the cascade performance is acceptable if the value of nondimensional roughness[k+] is less than 14.6，and the cascade can be considered to be almost failed if the value of [k+] is more than 20.1. On a whole，roughness around the leading edge and on the suction surface contributes most to the change of blade total pressure loss. The values of total pressure loss are decreased by 17.3% and 23.1%，respectively，compared with the case of the thickened smooth cascade at Re number of [1.0×105] and incidence angle of -0.6°，when the roughness magnitude of 80μm is imposed on blade entire and suction front portion surface respectively.