The effect of solid particles on the heat transfer in a slurry pipe flow

von Karman Institute for fluid dynamics, Waterloosesteenweg 72, 1640 Sint-Genesius-Rode, Belgium

^* e-mail: scelzo@vki.ac.be

Published online: 4 July 2024

Abstract

This work discusses the results of the temperature measurements performed on a water-based slurry, seeded with polystyrene spherical particles and flowing in a heated horizontal pipe. The flow is fully turbulent, characterized by a Reynolds number between 4500 and 14000. Two particle size distributions are tested (with mean diameter of 0.35 mm and 0.85 mm respectively), which lead to homogeneous and heterogeneous flow regimes. A solid volume fraction up to 7% is reached. The results show that particles increase the liquid bulk temperature by lessening the mixture heat capacity. Moreover, the particles increase the liquid heat transfer co-efficient. Additionally, in the bottom part of the pipe, the heat transfer coefficient behaves similarly to fluidised bed. Based on these results, a new semi-empirical correlation for the slurry Nusselt number in function of the relevant dimensionless groups of the problem (Reynolds and Prandtl numbers, density ratio, particles size to pipe diameter ratio and solid volume fraction) is proposed.