Energy losses of non-Newtonian fluids in sudden pipe contractions

There are very few experimental results available for flow of viscous fluids in sudden contractions. Furthermore, there are discrepancies between the few sets of experimental data published so far. The objective of this work is to provide a set of reliable experimental results that confirms and extends existing datasets for experimental and numerical validation and design purposes.The Flow Process Research Centre of the Cape Peninsula University of Technology has built and commissioned a test rig to study flows of both Newtonian and non-Newtonian fluids through sudden contractions of three diameter ratios β = 0.22, 0.5 and 0.85. This work extends the range of contraction ratios tested in literature from β = 0.66 to 0.85. The test fluids were water, glycerol solutions, lubrication oil, kaolin suspensions and carboxymethylcellulose (CMC) solutions at various concentrations. The Reynolds numbers ranged from approximately 0.01 to 100 000.The experimental data agrees with a mechanistic analytical model, based on another set of experimental data in the literature, thereby demonstrating the credibility of our experimental results. A database of the results is available for these contraction ratios for experimental and numerical validation.