Boiling Visualization of Two Adjacent Impinging Jets on Hot Steel Plate

Abstract

The simultaneous measurement between the boiling visualization and the boiling heat transfer characteristics by two adjacent impinging jets on hot steel plate was made by the experimental technique that has a function of high-temperature flat-plate heat flux gauge. The 22 K-type thermocouples were installed at 1 mm below the surface of flat-plate heat flux gauge. The 2-D inverse heat conduction was formulated to solve the surface temperature and heat flux. The boiling visualization was synchronized with a 4K video camera which was meaningful to understand complex boiling heat transfer phenomena. The heat flux gauge was uniformly heated up to 900°C by induction heating. The successive boiling images show where the nucleate boiling starts to occur on hot surface and the film boiling turns to be collapsed. The measured surface temperature and heat flux distribution agrees well with the corresponding boiling visualization: While heat transfer at the stagnation point shows a maximum heat flux, the interaction between two adjacent impinging jets exhibits a relative high heat flux and a steep temperature gradient until the end of boiling heat transfer at which single-phase convection occurs near 200°C.