Measurement of water temperature and velocity fields by applying thermography on two-phase flow through horizontal rectangular channel

The infrared thermography and optical-flow based method were proposed for the measurement of water temperature and velocity fields in stratified steam-water flow through horizontal channel. Generally, this method is applicable for any turbulent flow with temperature gradient. Spinel polycrystalline (MgAl2O4) material was chosen for infrared optical window, as, besides excellent optical properties, it has exceptional durability in harsh environment. Different mounting types and dimensions were tested in order to investigate Spinel application possibilities and limitations. A significant influence of window specific thermal radiation on measurement results (>20% inaccuracy) was observed during experiments. The best identified configuration ensures good temperature measurement accuracy (< = 2%). Graphical analysis was applied to infrared images, and good results of turbulence structure identification were achieved using combined local-global optical flow technique.