Experimental investigation on the particle size distribution characteristics of ice slurry in double-tube heat exchanger

The heat transfer characteristics and particle size distribution (PSD) characteristics of ice slurry in double-tube heat exchanger (DTHE) are experimentally investigated. An experimental microscopic observation device is used to characterize the PSD of ice slurry. Experimental ice slurry PSDs are compared to classical normal, log-normal, Weibull and Gamma distributions, and the results match basically to log-normal distribution. The effects of flow rate, ice mass fraction and water temperature on the PSD and heat transfer coefficient of ice slurry are analyzed. The results showed that the heat transfer coefficient of ice slurry h c increases linearly with the increase of flow rate. The higher the water temperature and ice mass fraction, the larger h c , especially in the high flow rate region. After heat exchange, the peaks of PSD curves shift to the left and the range of PSD is significantly narrowed. The water temperature rises from 25℃ to 40℃, the differences in Sauter diameter (∆ d 32 ) can be increased by approximately 2 times. In addition, increasing the ice mass fraction can cause the increase of the Sauter diameter ( d 32 ) and decrease of ∆ d 32 . The increase of flow rate leads to the decrease of ∆ d 32 , which is caused by the insufficient heat exchange of ice slurry. These studies can give some help to further improve the heat transfer mechanism of ice slurry.