Change in liquid temperature behind the impeller blades with impeller speed in boiling stirred tanks

In our previous study (Fukuda, R., Tokumura, M., Znad, H.T. and Kawase, Y., 2009, Vapour generation from the impellers in boiling stirred tank reactors. Chem Eng Res Des, 87: 452–459), it was found that in boiling stirred tanks with multiple impeller systems vapour was generated from the heater at lower impeller speeds and with an increase in impeller speed most vapour was generated from the top impeller rather than the lower impellers and the heater. The change of nucleation sites with the impeller speed might be controlled by the local liquid temperature. Therefore we measured the liquid temperature behind the impellers blades and found the decrease in liquid temperature with increasing impeller speed. In this paper, a simple model was developed to predict the change in liquid temperature behind the impeller blades in which nucleation takes place. In the proposed model based on the results for pressure distribution on the impeller blade in the literature, the liquid temperature behind the impeller blades is estimated from the measured power consumption. The validation of the proposed model was conducted using the experimental results in our previous study and reasonable agreement was obtained.