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An accurate estimation of the total pressure drop of a pipeline is important to the reliable design of a pneumatic conveying system. The present paper presents results from an investigation into the modelling of the pressure drop at a bend in the pneumatic conveying of fly ash. Seven existing bend models were used (in conjunction with solids friction models for horizontal and vertical straight pipes, and initial acceleration losses) to predict the total pipeline pressure drop in conveying fly ash (median particle diameter: 30μm; particle density: 2300kg/m 3 ; loose-poured bulk density: 700kg/m 3 ) in three test rigs (pipelines with dimensions of 69mm inner diameter (I.D.)x168m length; 105mm I.D.x168m length; 69mm I.D.x554m length). A comparison of the pneumatic conveying characteristics (PCC) predicted using the seven bend models and experimental results shows that the predicted total pipeline PCC and trends depend on the choice of bend model. While some models predict trends that agree with the experimental results, other models predicted greater bend pressure drops for the dense phase of fly ash than for the dilute phase. AbstractAn accurate estimation of the total pipeline pressure drop is of significant importance for the reliable design of a pneumatic conveying system. The present paper presents results from an investigation into the modelling of bend pressure drop for pneumatic conveying of fly ash.Seven existing bend models were used (in conjunction with solids friction models for straight pipes, verticals and initial acceleration losses) to predict the total pipeline pressure drop for conveying of fly ash (median particle diameter: 30 m; particle density: 2300 kg/m 3 ; loose- Chambers and Marcus (1986) models are found to be suitable to reliably predict the bend losses for fly ash conveying systems over a large range of air flows.