Research of non-contact measurement for high viscous fluid falling film thickness on spherical series surface

In the heat exchange system, the thickness of viscous liquid film on the surface of corrugated tube formed by fluid is an important parameter to control the performance of heat exchange. Because the surface of corrugated tube is a spherical series surface, it makes it difficult for measuring the thickness of liquid film. Based on the measuring object of liquid film formed by fluid on the surface of the corrugated tube, we specially designed a capacitive sensor for this kind of abnormity surface in the paper. We detailedly introduced the structure and operational principle of capacitive sensor, the circuit design and software system analysis, finally we displayed the waveform chart formed from the field data. Experimental results showed that the measuring system realized high precise and non-contact measurement for the liquid film thickness on the surface of the corrugated tube.