In this paper the mass transfer behaviors of Fe(Ⅲ), Co(Ⅱ) and Ni(Ⅱ) with Cyanex302(bis(2,4,4- trimethylpentyl)monothiophosphinic acid) from sulfate medium by using hollow fiber membrane in counter-currently circula...In this paper the mass transfer behaviors of Fe(Ⅲ), Co(Ⅱ) and Ni(Ⅱ) with Cyanex302(bis(2,4,4- trimethylpentyl)monothiophosphinic acid) from sulfate medium by using hollow fiber membrane in counter-currently circulating operation were studied. The effect of acidity in aqueous solution and the extractant concentration on the mass transfer coefficient (Kw) was discussed. The reaction mechanism of membrane extraction was considered as a false one series reaCtion and the rate controlling step was membrane resistance. When the value of Kw arrived at 1.0 × 10-6 m/s, △pH:CoFe equaled tO 6.225, and △pH:NiFe was bigger than △p HCoFe.展开更多
运行数据显示全光纤电流互感器(fiber optic current transformer,FOCT)在极端环境下(温度为–45~85℃、振动加速度>15 m/s^(2))故障概率明显偏高,因此研究极端环境对FOCT性能的影响十分必要。在分析FOCT工作原理基础上,重点讨论了F...运行数据显示全光纤电流互感器(fiber optic current transformer,FOCT)在极端环境下(温度为–45~85℃、振动加速度>15 m/s^(2))故障概率明显偏高,因此研究极端环境对FOCT性能的影响十分必要。在分析FOCT工作原理基础上,重点讨论了FOCT核心模块的结构特征及极端环境的影响,并建立FOCT传变模型。根据FOCT真实工作环境,分析了极端环境对其测量准确性的影响。结果表明:温度的升高、光纤长度的增加、振动加速度的变大,都会使FOCT比差增大,测量精度下降。特别是在极端环境下,测量误差较大,无法满足0.2S级测量准确度的要求。为验证模型的可靠性,开展了温度和振动影响试验。针对现有试验缺乏对极端环境的考核,提出增加测点的温度试验方法和增加振动响应试验及振动耐久试验的振动试验方法。试验结果与仿真结果对比表明:两者结果具有一致性,偏差电流波形变化趋势比较一致。该研究为FOCT可靠性问题提供有益参考。展开更多
The high-temperature acoustic absorption performance of porous titanium fiber material was investigated in terms of sample thickness, porosity, temperature, air-cavity thickness and double-layer structure arrangement....The high-temperature acoustic absorption performance of porous titanium fiber material was investigated in terms of sample thickness, porosity, temperature, air-cavity thickness and double-layer structure arrangement. The effects on absorption coefficient were systematically assessed. The results show that the sound absorption performance is improved by increasing the sample porosity and/or thickness, and/or increasing the air-cavity thickness. Meanwhile, increasing the temperature gives better acoustic absorption performance in the low frequency range but also lowers the performance in the high frequency range, while double-layer structure enables better acoustic absorption performance.展开更多
变压器热点温度作为运行经济性、安全性的关键指标,是设备在线监测及状态评估中的重点。该文对变压器内部散热进行研究,着眼于饼式绕组及其油道结构,基于能量流向建立绕组温度变化的物理模型。基于这一模型,在一台内置分布式传感光纤的1...变压器热点温度作为运行经济性、安全性的关键指标,是设备在线监测及状态评估中的重点。该文对变压器内部散热进行研究,着眼于饼式绕组及其油道结构,基于能量流向建立绕组温度变化的物理模型。基于这一模型,在一台内置分布式传感光纤的110kV三相ONAN变压器上开展试验研究,使用分布式光纤测温(distributed temperature sensing,DTS)技术对运行状况下的绕组整体温度分布进行实时监测,分析绕组在ONAN冷却方式下的散热状况。在变压器启动初期,绕组各处散热量较低,温升速率较快。约2 h后,各饼散热量基本与损耗相一致,散热率可达98%以上,因此将这一阶段称为准稳态。准稳态阶段,绕组整体散热率基本一致。负载变化前期不同位置散热量的差异是温度梯度形成的主要原因。基于DTS手段及散热器进出口处油温,提出绕组每饼平均对流换热系数的计算方法,基于无量纲数建立绕组内外表面局部对流换热系数的计算方法,对不同位置、负载率下两种对流换热系数的变化规律进行分析获得了绕组运行过程中对流换热系数分布规律及变化趋势。展开更多
基金Supported by the National Natural Science Foundahon of China(No. 29771028, No. 29801004) and State Key Project of Fundamental
文摘In this paper the mass transfer behaviors of Fe(Ⅲ), Co(Ⅱ) and Ni(Ⅱ) with Cyanex302(bis(2,4,4- trimethylpentyl)monothiophosphinic acid) from sulfate medium by using hollow fiber membrane in counter-currently circulating operation were studied. The effect of acidity in aqueous solution and the extractant concentration on the mass transfer coefficient (Kw) was discussed. The reaction mechanism of membrane extraction was considered as a false one series reaCtion and the rate controlling step was membrane resistance. When the value of Kw arrived at 1.0 × 10-6 m/s, △pH:CoFe equaled tO 6.225, and △pH:NiFe was bigger than △p HCoFe.
文摘运行数据显示全光纤电流互感器(fiber optic current transformer,FOCT)在极端环境下(温度为–45~85℃、振动加速度>15 m/s^(2))故障概率明显偏高,因此研究极端环境对FOCT性能的影响十分必要。在分析FOCT工作原理基础上,重点讨论了FOCT核心模块的结构特征及极端环境的影响,并建立FOCT传变模型。根据FOCT真实工作环境,分析了极端环境对其测量准确性的影响。结果表明:温度的升高、光纤长度的增加、振动加速度的变大,都会使FOCT比差增大,测量精度下降。特别是在极端环境下,测量误差较大,无法满足0.2S级测量准确度的要求。为验证模型的可靠性,开展了温度和振动影响试验。针对现有试验缺乏对极端环境的考核,提出增加测点的温度试验方法和增加振动响应试验及振动耐久试验的振动试验方法。试验结果与仿真结果对比表明:两者结果具有一致性,偏差电流波形变化趋势比较一致。该研究为FOCT可靠性问题提供有益参考。
基金Projects(51671152,51304153)supported by the National Natural Science Foundation of China
文摘The high-temperature acoustic absorption performance of porous titanium fiber material was investigated in terms of sample thickness, porosity, temperature, air-cavity thickness and double-layer structure arrangement. The effects on absorption coefficient were systematically assessed. The results show that the sound absorption performance is improved by increasing the sample porosity and/or thickness, and/or increasing the air-cavity thickness. Meanwhile, increasing the temperature gives better acoustic absorption performance in the low frequency range but also lowers the performance in the high frequency range, while double-layer structure enables better acoustic absorption performance.
文摘变压器热点温度作为运行经济性、安全性的关键指标,是设备在线监测及状态评估中的重点。该文对变压器内部散热进行研究,着眼于饼式绕组及其油道结构,基于能量流向建立绕组温度变化的物理模型。基于这一模型,在一台内置分布式传感光纤的110kV三相ONAN变压器上开展试验研究,使用分布式光纤测温(distributed temperature sensing,DTS)技术对运行状况下的绕组整体温度分布进行实时监测,分析绕组在ONAN冷却方式下的散热状况。在变压器启动初期,绕组各处散热量较低,温升速率较快。约2 h后,各饼散热量基本与损耗相一致,散热率可达98%以上,因此将这一阶段称为准稳态。准稳态阶段,绕组整体散热率基本一致。负载变化前期不同位置散热量的差异是温度梯度形成的主要原因。基于DTS手段及散热器进出口处油温,提出绕组每饼平均对流换热系数的计算方法,基于无量纲数建立绕组内外表面局部对流换热系数的计算方法,对不同位置、负载率下两种对流换热系数的变化规律进行分析获得了绕组运行过程中对流换热系数分布规律及变化趋势。
