Void Fraction Measurement of Transparent Resin Evaporation via Image Processing

Bubble Flow Motion in Low Void Fraction Range

Abstract

In low-grade thermal energy conversion system, plate heat exchangers that are compact and high-performance are used as evaporators and condensers for applying small available heat source temperature difference. In particular, the understanding of two-phase flow pattern with evaporation in the narrow channel of plate heat exchangers will contribute to the improvement of performance. In this research, the transparent resin made plates are used to visualize and observe the two-phase flow on the herringbone plates in evaporators. In the experiment, the flow patterns of three chevron angle plates are compared with image processing manipulated by the original Python and OpenCV codes. As the results, this process clarified the void fraction variations in the flow, and the flow patterns were estimated by the void fractions in the low void fraction range.