基于相态图像在线检测的RCP轴封内流场试验研究

Experimental study on inner flow field of RCP shaft seal based on phase image edge online detection

为了研究反应堆冷却剂主泵动压轴封异常工作状态、验证第三级副密封所处工况条件,开展了轴系温度分布仿真分析.采用微型内窥装置在线获取三级低压泄漏流相态图像,对所得图像进行数值化处理;采用Sobel边沿检测算法求取图像边沿化后的均方差,实现了基于内窥图像的主泵轴封低压泄漏流相态的在线监测.通过提高密封第三级泄漏背压,改善浮动密封的润滑状态,并开展了多水平背压试验.以流场图像Sobel边沿检测算法特征值δ_(s1s2)评价轴封泄漏流场的流态变化.结果表明,当背部压力等效水柱高度H为0.77,1.30,1.55,1.80 m时,δ_(s1s2)分别为0.005549,0.015100,0.020690,0.198400.基于以上结论,设计了一个具有最优高度的U形管,可提高密封低压泄漏背压、改善三级密封O形圈的润滑.

In order to study the abnormal working condition of the reactor coolant pump hydrodynamic pressure shaft seal and verify the working conditions of the third stage secondary seal,a simulation analysis of the shaft temperature distribution of the syatem was carried out.The three-stage low pressure leakage flow phase state images were obtained online by using a micro endoscopic device,and a digital images process method was applied.The mean square error value was obtained by using the Sobel edge detection algorithm.The online monitoring of the phase state of the low pressure leakage flow of the RCP shaft seal was realized based on the endoscopic image.The lubrication state of the dynamic seal was improved by increasing the third-stage leakage back pressure,and the multi-level back pressure validation tests were carried out.The characteristic value obtained by Sobel edge detection algorithm for flow field image was used to evaluate the flow status change of shaft seal leakage flow field.The results show that when the back pressure equivalent water column height are H=0.77,1.30,1.55,1.80 m,the Sobel mean square error value areδ_(s1s2)=0.005549,δ_(s1s2)=0.015100,δ_(s1s2)=0.020690 andδ_(s1s2)=0.198400,respectively.Based on that the above conclusions,a U-shaped pipe with the optimal height was designed,which can improve the low pressure leakage back pressure of the lubrication of the three-stage dynamic O-ring of the three stage seal.