降膜过程中液膜厚度和温度同步测量系统研制

Development of a Synchronous Measurement System of Liquid Film Thickness and Temperature During the Film Falling Process

针对金属圆管外降膜过程中关键参数的高精度测量,研制了基于双波长激光吸收光谱技术的液膜厚度和温度同步测量系统,利用该系统对不同工况下竖直和水平金属圆管外降膜过程液膜厚度和温度进行同步测量,同时结合图像法和热电偶对该系统的测量精度进行验证。结果表明:不同方法测得的金属圆管外液膜厚度和温度的变化趋势吻合良好,二者最大平均偏差分别为4.3%和3.8%;该系统有望为深入研究液膜形成、流动及蒸发过程提供高精度、高灵敏度和无干扰的测试手段。

To obtain the high-precision measurement of key parameters during the falling film processes outside of the metal circular tube,a synchronous measurement system of liquid film thickness and temperature based on diode laser absorption spectroscopy(DLAS)was developed.Liquid film thickness and temperature outside of the vertical and horizontal tubes during the falling film processes under different conditions were measured through the system,whose measurement accuracy was also verified by photogrammetry and thermocouple.Results show that the variation trends of liquid film thickness and temperature fit in well in different measurement methods,and the maximum average errors are 4.3%and 3.8%respectively.The system can provide a high-precision,high sensitivity and interference-free measurement solutions for further research on the formation,flow and evaporation of liquid films.