Time-Resolved Temperature Field Measurement of Direct Contact Condensation of Steam in Subcooled Water using Backlight Aided Planar Laser Induced Fluorescence with High-speed Camera

Instantaneous temperature field of vertical upward direct contact condensation of steam in subcooled water pool at the unstable bubbling condensation oscillation regime was measured using backlight aided planar laser induced fluorescence (PLIF) with high-speed camera. Rhodamine-B was used as fluorescence dye, and 532 nm wavelength laser sheet was applied to the test section to excite the fluorescent material. In-situ calibration was performed to obtain the spatially resolved correlation between the emission light intensity and temperature throughout the region of interest. Using the intensity-temperature correlation, temperature field around a site of the steam condensation was evaluated with the 2000 fps high-speed camera images. Results showed various instantaneous temperature field characteristics while phase change was occurring. Time-averaged temperature field showed the distinctive pattern of the average temperature gradient on both the single-phase and condensation regions. The detailed temperature field results obtained from this study can be extended to further investigation on the thermal-hydraulic bubble dynamics models for the specific condensation process.