Iranian Journal of Chemical Engineering (IJChE)

Abstract Centrifugal pumps are extensively employed in mining, petrochemical, and wastewater treatment industries, where handling solid–liquid two-phase flows often results in the erosive wear of internal components. This study investigates slurry-induced erosion in a single-stage centrifugal pump through a three-dimensional CFD model developed in COMSOL Multiphysics. The model integrates Lagrangian particle tracking with an empirical erosion correlation and is validated with experimental data reported in the literature, showing good agreement with an average relative error of below 5%. Parametric simulations were conducted to examine the effects of two key operating parameters: flow rate and particle concentration. The results indicate that at sub-design flow rates, the prolonged particle residence time increases impact frequency, leading to severe localized erosion near the blade leading edges. Conversely, operating at rates close to the design flow rate and up to 1.4 Qd reduces erosion intensity and promotes a more uniform wear distribution. Increasing particle concentration produces a nearly linear rise in the maximum erosion rate—from approximately 3 mm/year at 0.5% to over 22 mm/year at 3%—while also expanding the affected blade area. Moreover, larger particles intensify erosion severity and shift erosion zones toward the downstream blade regions, altering the wear mechanism. Overall, the validated CFD framework provides a robust and predictive tool for evaluating both erosion intensity and spatial distribution in slurry-handling centrifugal pumps. The findings emphasize the importance of optimizing operational parameters and applying wear-resistant materials to enhance pump durability and reduce maintenance costs. 

Abstract > The motion and shape of a flattened drop and bubble through another continuous liquid phase (conveying phase) are investigated experimentally, using a narrow gap HeleShaw cell. Seven different liquid-liquid systems were tested. In all cases the continuous phase was the more viscous wetting phase. A number of observations on the shape and motion of the elongated flattened drops are noted and discussed. In the capillaritydominated (Ca<1.69×10-6) region, the irregular shape of the discontinuous phase drops changed with time and position, and the drop velocity was much lower than that of the conveying phase. Three different shapes of stabilized elongated drops were observed at higher Capillary numbers. The conditions that lead to the appearance of stabilized elongated drops are discussed. The velocities of these stabilized elongated flattened drops were 2 to 4.7 times higher than that of the conveying liquid. A correlation to predict the elongated flattened drop shape as a function of the dimensionless parameters governing the system is developed based on the experimental results.

Abstract n this work, computational fluid dynamics of the flow behavior in a cold flow of fluidized bed is studied. An improved finite volume based finite element method has been introduced to solve the two-phase gas/solid flow hydrodynamic equations. This method uses a collocated grid, where all variables are located at the nodal points. The fluid dynamic model for gas/solid two-phase flow is based on the two fluid model where both phases are continues and fully interpenetrating. For the gas and solid phases the Navier-Stokes equation based on the concept of local average is obtained. Results are verified against experimental data reported in the literature.