高温熔体表面张力的轮廓拟合悬滴法测量系统研制

DEVELOPMENT OF PROFILE-FITTING PENDANT-DROP METHOD FOR MEASURING SURFACE TENSION OF HIGH-TEMPERATURE MELT

基于悬滴法原理,设计制造用于测量高温熔体表面张力的图像提取装置,其测量温度范围可达20~1000℃,并通过Matlab中的Canny算子及坐标轮换法对提取的图形进行处理和表面张力的拟合计算。通过对装置背景光、滤波、温度补偿校正、像素等方面的分析和调整来改善其高温工况下的测量精度,获得了理论误差为0.714%的表面张力测量系统。于高温工况下测量四元混合溴化熔盐表面张力随温度变化规律,与其他学者所测数据进行比较之差低于1.6%,测量系统可信度良好,适用于熔融态传蓄热介质表面张力的测量。

The image extraction device was designed and manufactured to measure the surface tension of high-temperature melt based on the principle of pendant-drop method.The measuring temperature range can reach 20℃to 1000℃.The extracted figures can be processed and the fitting calculation of surface tension can be conducted through canny arithmetic and Cyclic Coordinate Method in Matlab.The measurement accuracy is improved under the working condition of high temperature by analyzing and adjusting background light,filtering,temperature compensation and correction as well as pixel to obtain the measurement system of surface tension with a theoretical error of 0.714%.The variation of the surface tension for quaternary mixed bromide molten salt at high temperature is measured at different temperatures.The deviation ratio is lower than 1.6%when it is compared with the data measured by other scholars,which indicates that the measurement system has good credibility and is suitable for measuring the surface tension of heat transfer and storage medium in molten state.