微型电容层析成像传感器的设计及应用

Design and application of electrical capacitance tomography micro-sensors

本文提出一种电容层析成像微型传感器,实现脉动热管内两相流的可视化监测及液膜厚度的测量。该传感器也作为流动管道,具有和测量管道基本相同的传热和流动特性。同时,建立基于图像灰度的液膜厚度测量方法,并采用最大类间方差法对重建图像进行处理。实验结果表明:可视化监测图像与实际相符,液膜厚度测量结果与Nusselt理论计算结果吻合较好。相比普通电容层析成像传感器,其测量精度和空间分辨率都有一定提高,从而拓宽了电容层析成像技术的应用范围。

An electrical capacitance tomography micro-sensor was developed and applied to the visualized measurement of two-phase flow as well as the measurement of the liquid film thickness in a pulsating heat pipe. The microsensor was also applied as a part of the flow channel, and has the characteristics of heat transfer and h · rodynamics similar to the measurement tube. Moreover, the liquid film thickness measurement method based on image grey-level was developed, and Ostu method was applied to the image processing. Experimental results indicate that the visualized test image is consistent with the reality and the liquid film thickness test result is well consistent with that from Nusselt equation. Compared with conventional capacitance tomography sensors, the measurement accuracy and image resolution of the ECT micro-sensor are improved, which widens the application area of the ECT technology.