Simultaneous measurement of temperature and flow field formed by a small heated sphere in water by near-infrared absorption imaging method and particle tracking velocimetry

Abstract

Prediction and measurement of temperature fields formed by a small heat source inside liquid are important for various thermal applications such as inductive heating of magnetic particles, crystal growth, laser heating, etc. However, as local temperature differences cause natural convection in many cases, the temperature field becomes complicated, which makes the prediction and measurement more difficult. We thus used the temperature imaging method based on the temperature dependence of the absorption band of water in the near-infrared region to investigate the temperature field around a 1-mm-diameter magnetic sphere under induction heating. Furthermore, to construct a quantitative model of natural convection around the heated sphere, the flow field was measured using particle tracking velocimetry with Kalman filter simultaneously with the temperature field.