Investigation into the transportation and melting of thick ice slurries in pipes

This paper presents the results of experiments and modelling carried out on ice slurries flowing in uninsulated steel pipes with a nominal diameter of 50 mm. The slurries used were formed from 4.75% NaCl aqueous solution and had ice mass fractions in the range 18–42%, with a view to the use of thick ice slurry ‘pigs’ as a pipeline clearing technique. Of particular interest was the distance over which such slurries can survive as plug-like entities, before melting reduces them to ineffective thin two-phase suspensions. The experiments showed that for small volumes of slurry, survivability is directly proportional to the quantity of slurry used, but that increasing the ice fraction has a more marked effect. A simple one-dimensional numerical model that accounts for transportation, heat transfer and melting was developed that produces reasonable predictions.