Wall slip and viscous dissipation in ice cream pipe rheometry

This paper presents a study of wall slip in ice cream pipe rheometry. Measurement of ice cream temperature at the wall enabled energy balances in the near wall region. Experiments were carried out in pressure driven shear flow along insulated pipes of different diameters at different flow rates using ice cream produced with a continuous scraped surface heat exchanger. Pipe radius dependence was evident in the flow curves, indicative of wall slip effects. This apparent slip was amenable to analysis by the Mooney method and indicated the contribution of slip to flow ranged from 70% to 100%. Results indicated a moderately thick layer of slightly heated ice cream next to the wall. Whilst these flows may be interpreted as wall slip the origin of the phenomena is different from that in most suspension flows and significantly alters interpretation.