Centrifugal pumps performance estimation with non-Newtonian fluids: review and critical analysis

Buratto, Carlo; Occari, Matteo; Aldi, Nicola; Casari, Nicola; Pinelli, Michele; Spina, Pier Ruggero; Suman, Alessio

doi:10.29008/etc2017-248

Cited by 10 publications

(8 citation statements)

References 7 publications

(17 reference statements)

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“…The average shear rate varies at each point of the pump volume and depends on the design and the speed of the impeller. 135 Nevertheless, the average shear rate in the impeller volume can be estimated as 1000−1500 s −1 . 136 Taking into account the density of the emulsions, their kinematic viscosity at a shear rate of 1000 s −1 can be evaluated to lie in the range of 20−550 cSt.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

“…The oil-in-water emulsions under study are non-Newtonian systems; therefore, their effective viscosity should not be too high under conditions of exposure by the pump blades. The average shear rate varies at each point of the pump volume and depends on the design and the speed of the impeller . Nevertheless, the average shear rate in the impeller volume can be estimated as 1000–1500 s –1 .…”

Section: Resultsmentioning

confidence: 99%

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Morphology and Rheology of Heavy Crude Oil/Water Emulsions Stabilized by Microfibrillated Cellulose

Gorbacheva

Ilyin

2021

Energy Fuels

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The application of microfibrillated cellulose and sodium dodecyl sulfate (SDS) to obtain heavy crude oil emulsions in water has been considered. First of all, the optimal concentration of cellulose in its aqueous dispersion was studied. A rheological study showed that cellulose dispersions exhibit viscoplasticity when the content of microfibrils is 0.3% or higher. At the same time, these dispersions are capable of flowing under high shear stresses only when the cellulose content does not exceed 1%. The use of 1% cellulose dispersion allows for obtaining stable direct emulsions with oil content up to 30 vol %, while a higher oil concentration leads to the phase inversion with a transition from viscoplasticity of oil-in-water emulsions to almost Newtonian behavior of water-inoil systems. In the case of using SDS, cellulose-free oil emulsions are not resistant to creaming even in a concentrated aqueous SDS solution. The combined application of cellulose microfibrils (1%) and SDS (5%) helps to obtain stable highly concentrated direct emulsions containing up to 80 vol % heavy crude oil. Calculations have shown that the use of 50 vol % emulsion is optimal and allows for reducing energy consumption for transportation of heavy crude oil by 13 times.

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Section: ■ Results and Discussionmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Morphology and Rheology of Heavy Crude Oil/Water Emulsions Stabilized by Microfibrillated Cellulose

Gorbacheva

Ilyin

2021

Energy Fuels

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“…The kinematic viscosity in the existing prediction models is a well-defined parameter for Newtonian fluids but not for the non-Newtonians; it is not constant but depends on the shear rate. Although some research has been carried out on non-Newtonian pump degradation [7]- [10], there is still very little scientific understanding of this problem [11]. Pinelli et al [12] showed that the shear rate field inside the pump varies widely with power-law fluid.…”

Section: Introductionmentioning

confidence: 99%

Prediction Of Head Degradation Of A Centrifugal Pump Handling Power-Law Fluid

Csizmadia¹,

Lukácsi²,

Till³

2021

Proceedings of the 2nd International Conference on Fluid Flow and Thermal Science (ICFFTS'21)

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Operation of centrifugal pumps with non-Newtonian fluids is usually estimated with the help of correction factors. The calculation of these factors is based on methods defined fundamentally for high viscosity Newtonian fluids. A prediction model for head degradation based on the dimensional groups of a centrifugal pump is known for viscous liquids. This model uses experimentally obtained parameters. In this paper, the model's parameters with glycerol solution were validated by comparing the performance curves estimated with the predicted and measured ones. In addition, a possible way of using the estimation model with power-law fluid was investigated. Based on our experimental results at nominal rotational speed, a form for calculating a virtual shear rate was determined, with the help of which the predicted correction factors and head degradation curves at other rotational speeds showed a good agreement with the measurements. The reported results can be considered as a first step in developing an estimation procedure for head degradation of centrifugal pump's operation with power-law fluids.

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“…Centrifugal pumps are often used to handle large amounts of solid-water slurries, with some decrease in performance due to differences in density and flow path with respect to water [1], similar to the effects of non-Newtonian fluids on the impeller [2][3][4]. Scientific literature on dredge pump design [5][6][7] provides many correlations and methods in order to predict and measure pump performance using different solid densities, particle sizes and concentrations, based on empirical studies.…”

Section: Introductionmentioning

confidence: 99%

Eulerian multi-phase CFD model for predicting the performance of a centrifugal dredge pump

Beccati¹,

Ferrari²,

Parma³

et al. 2019

Int. J. CMEM

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Dredge pumps are a complex engineering topic in comparison to water pumps. Mixtures of seawater with several types of soils do not behave as a homogenous fluid, and numerical simulations of these machines can be very challenging. Typical numerical approaches to simulations of dredge pumps are single-phase equivalent slurry and multi-phase liquid-solid, where the specification of the particle flow field can be Eulerian or lagrangian. The single-phase slurry approach is not sufficient to describe the effects of particle size and concentration of the solid phase on pump performance; for this reason, this paper examines a multi-phase CFD model applied to a dredge pump. The solid phase is modelled with an Eulerian approach, in order to reduce the computational effort required by a lagrangian method, mainly used for low solid-phase concentrations. The primary purpose of the presented model, developed using commercial software aNSYS CFX, is to predict head losses in a dredge pump working with several particle sizes, from 0.1 to 5 mm, and different volume concentrations of the solid phase, from 20% to 30%. For numerical solid-phase calibration, the effect of the particle size on pump performance is associated with non-Newtonian rheology of the simulated Eulerian phase. The numerical model is validated via experimental tests on the dredge pump using seawater. The calibration of the particle size effect is obtained from scientific literature data about dredge pump losses in different conditions. The model presented could be a useful tool for the analysis of existing dredge pumps or for the design of new machines.

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Centrifugal pumps performance estimation with non-Newtonian fluids: review and critical analysis

Cited by 10 publications

References 7 publications

Morphology and Rheology of Heavy Crude Oil/Water Emulsions Stabilized by Microfibrillated Cellulose

Morphology and Rheology of Heavy Crude Oil/Water Emulsions Stabilized by Microfibrillated Cellulose

Prediction Of Head Degradation Of A Centrifugal Pump Handling Power-Law Fluid

Eulerian multi-phase CFD model for predicting the performance of a centrifugal dredge pump

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