On the streaming video of all typical flow pattern filmings on the experiment system by the high-speed video camera,the information of a single-frame was extracted and made into time-series.The series was analyzed wit...On the streaming video of all typical flow pattern filmings on the experiment system by the high-speed video camera,the information of a single-frame was extracted and made into time-series.The series was analyzed with the non-linear chaotic recurrence plot(RP),less used in the last years.It was combined with the average diagonal length and Shannon entropy of recursive features changed after the increase of gas superficial velocity.The results showed that the information entropy of flow image combined with RP could well characterize the evaluated tract of gas-liquid two-phase flow patterns.At the same time,the information well characterized the volume fraction of all kinds of gas-liquid two-phase flow patterns.The average diagonal length and recursive Shannon entropy of recursive features all increased first and then decreased with the increase of gas superficial velocity,and it reflected the transition of the mechanisms of five typical flow patterns from the recursive characteristics.展开更多
为进一步提高有载分接开关(on-load tap changer,OLTC)机械状态监测的准确性,文中基于递归定量分析(recurrence quantification analysis,RQA)法对OLTC切换过程中的振动信号进行了分析。首先应用相空间重构和递归图理论获取了OLTC切换...为进一步提高有载分接开关(on-load tap changer,OLTC)机械状态监测的准确性,文中基于递归定量分析(recurrence quantification analysis,RQA)法对OLTC切换过程中的振动信号进行了分析。首先应用相空间重构和递归图理论获取了OLTC切换过程中振动信号的递归图,然后引入递归率、层流性和确定性等递归定量指标及其统计分布结果对OLTC振动信号的动力学特征进行了描述。对某CM型组合式OLTC正常与典型故障下振动信号的分析结果表明:OLTC从正常到典型机械故障的演变过程中,振动信号伴随有周期性减弱、预测性增强、平稳性提高的变化特性,所定义的振动信号的RQA指标的分布范围可较为准确地判断OLTC的运行状态。研究结果可为基于振动分析法的OLTC机械状态监测技术提供参考。展开更多
文摘On the streaming video of all typical flow pattern filmings on the experiment system by the high-speed video camera,the information of a single-frame was extracted and made into time-series.The series was analyzed with the non-linear chaotic recurrence plot(RP),less used in the last years.It was combined with the average diagonal length and Shannon entropy of recursive features changed after the increase of gas superficial velocity.The results showed that the information entropy of flow image combined with RP could well characterize the evaluated tract of gas-liquid two-phase flow patterns.At the same time,the information well characterized the volume fraction of all kinds of gas-liquid two-phase flow patterns.The average diagonal length and recursive Shannon entropy of recursive features all increased first and then decreased with the increase of gas superficial velocity,and it reflected the transition of the mechanisms of five typical flow patterns from the recursive characteristics.
文摘为进一步提高有载分接开关(on-load tap changer,OLTC)机械状态监测的准确性,文中基于递归定量分析(recurrence quantification analysis,RQA)法对OLTC切换过程中的振动信号进行了分析。首先应用相空间重构和递归图理论获取了OLTC切换过程中振动信号的递归图,然后引入递归率、层流性和确定性等递归定量指标及其统计分布结果对OLTC振动信号的动力学特征进行了描述。对某CM型组合式OLTC正常与典型故障下振动信号的分析结果表明:OLTC从正常到典型机械故障的演变过程中,振动信号伴随有周期性减弱、预测性增强、平稳性提高的变化特性,所定义的振动信号的RQA指标的分布范围可较为准确地判断OLTC的运行状态。研究结果可为基于振动分析法的OLTC机械状态监测技术提供参考。
