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远场脉冲涡流探头特性研究
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作者 刘威 《机械》 2018年第A02期67-71,共5页
在脉冲涡流检测和远场脉冲涡流检测的基础上研究平板导体试块上的远场效应,利用远场脉冲信号作为激励来检测缺陷探究其远场特性。首先比较近场区与远场区在缺陷的波形变化,找到最佳远场区是激励线圈与检测线圈距离10 mm位置、过渡区是... 在脉冲涡流检测和远场脉冲涡流检测的基础上研究平板导体试块上的远场效应,利用远场脉冲信号作为激励来检测缺陷探究其远场特性。首先比较近场区与远场区在缺陷的波形变化,找到最佳远场区是激励线圈与检测线圈距离10 mm位置、过渡区是激励线圈与检测线圈距离7 mm位置;得出在近场区没有二次回波,在过渡区与远场区都有二次回波。并在远场区探头对铝合金试块的12个缺陷进行探伤,选择感应电压的波峰、二次波波峰及过零时间为特征参数,分析了检测信号与缺陷的关系。实验结果表明:在远场区,缺陷深度、半径与二次回波成一定的线性关系,半径越大峰值越小,深度越大,峰值越小。比较在缺陷的正面与反面检测时得出,在缺陷的正面检测时二次回波的峰值比反面检测的要大。 展开更多
关键词 无损检测 远场涡流 远场区 探头特性 缺陷波形
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Effects of Probe Support on the Stall Characteristics of a Low-Speed Axial Compressor 被引量:6
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作者 Hongwei Ma Shaohui Li Wei Wei 《Journal of Thermal Science》 SCIE EI CAS CSCD 2016年第1期43-49,共7页
In order to investigate the effects of probe support on the stall characteristics of micro compressors, an experiment was carried out on a large-scale low-speed research compressor according to the principle of geomet... In order to investigate the effects of probe support on the stall characteristics of micro compressors, an experiment was carried out on a large-scale low-speed research compressor according to the principle of geometric similarity. A cylindrical probe support intruding to 50% blade span was mounted at 50% chord upstream from the rotor blade leading edge. The static pressure rise characteristic of the compressor is measured, with and without the probe support respectively. The dynamic compressor behavior from pre-stall to full stall was also measured. The results indicate that the stability margin of the compressor is lowered after installing the probe support. The stall inception is aroused by modal wave disturbances. The disturbances developed into two stall cells smoothly before installing the probe support, while the disturbances first developed into a single stall cell then splitting into two stall cells after installing the probe support. The presence of probe support lowers the initial intensity of the rotating stall of the compressor, while it doesn't alter the intensity of the rotation stall after the compressor enters into full stall. 展开更多
关键词 Probe support Compressor Stability Margin Stall inception Intensity/frequency of rotating stall
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