Thermalhydraulics of pumped ice slurries in pipes and ducts

A semi-analytical model describing the thermalhydraulic behaviour of high ice fraction slurries in ducts is presented. The model is numerically solved and the resultant predictions are compared with experimental data generated in a laboratory environment for pipes of diameters 12 to 100mm and lengths no greater than 10m. This comparison has lead to the optimisation of a number of components of the model, reulting in an overall model system which is better able to represent the physics associated with phase change in a heat transfer regime dominated by convection and conduction processes. The ‘optimised’ model is then used to predict the performance of ice slurries pumped through large diameter pipes (typically 300mm diameter) over large very distances (in some cases greater than 5,000m). The agreement between the measured and the predicted longevity of the ice slurry is surprisingly good, suggesting that the model is probably representing the important/dominant physical mechanisms controlling the heat transfer rates between the cold ice slurry and the initially ambient temperature pipe and its environmental surroundings.
This work supports the development, application and expansion of the use thick ice slurries, ‘ice pigs’ as elegant artefacts which can be adopted to clean complex topology ducts where conventional solid pigs cannot be used, and where it is imperative that the ‘pig’ cannot, under any circumstance, get stuck in the duct.