A new model for the viscosity of highly concentrated multi-sized particulate Bingham slurries

The key issue associated with the thermal power plant is the disposal of ash-water slurry and the process of its transportation is accomplished using long length pipelines. The designing of such pipelines is a vital endeavor of researchers and designers globally. In this perspective, numerical simulation of 42 mm diameter three-dimensional slurry flow pipeline carrying high concentration of mono-dispersed fine ash particles has been carried out. The study is enunciated by employing Eulerian-Eulerian two-phase model with RNG k-ɛ turbulence model with the aim of visualizing and understanding the characteristics of the slurry flow behavior. The coal ash slurry concentration varies between 50% to 70% (by weight) for velocity ranges, 1-3 ms -1 . The modeling is done using Fluent commercial software with the intention of predicting the characteristics of flow for 300 µm particle size. It is observed that pressure drop upsurges non-linearly with solid concentrations and slurry velocity across pipeline. The obtained results of predetermined pressure drop are analytically compared with the experimental results. Moreover, the results are also compared with that of Eulerian-Langrange model using SST K-ω turbulence model and it is found that RNG k-ɛ turbulence model yields more accurate and desirable results.

Section: Introductionmentioning

confidence: 99%

Flow Characterization of Multi-Phase Particulate Slurry in Thermal Power Plants Using Computational Fluid Dynamics

Parkash¹

2020

“…Melorie et al [28] found the addition of hydrated lime increases the rheological behavior and high yield stress for all volumetric concentration of slurry. Assefa et al [29] proposed new empirical viscosity model for the highly concentrated Bingham slurry ranging from 50 -70% by weight and found the proposed viscosity model in agreement with the experimental study for determining the viscosity of multi sized particulates Bingham slurry flowing at higher concentration. Singh et al [30] added an additive sodium bicarbonate in highly concentrated fly ash slurry, which modified the rheological characteristics of the fly ash slurry.…”

Section: Introductionmentioning

confidence: 65%

CFD Modeling of Slurry Pipeline at Different Prandtl Numbers

Parkash¹,

Kumar²,

Sikarwar³

2021

The present work shows the slurry flow characteristics of glass beads having density 2470 kg/m3 at different Prandtl number through a horizontal pipeline. The simulation is conducted by Eulerian two-phase model using RNG k-ε turbulence closure in available commercial software ANSYS FLUENT. The transportation of solid particulates has the settling behaviour in the slurry pipeline and that leads to the sedimentation and blockage of the pipeline resulting more power and pressure drop in the pipeline. Therefore, it is important to know the transport capability of the solid particulates at different Prandtl fluids to minimise the pressure loss. The fluid properties at four Prandtl numbers i.e. 1.34, 2.14, 3.42 and 5.83 is used to carry the solid concentration ranges from 30-50 % (by volume) at mean flow-velocity ranging from 3 to 5 ms-1 . The obtained computational results are validated with the published data in the literature. The results show that the pressure-drop rises with escalation in flow velocity and solid concentration at all Prandtl number. It is found that the suspension stability enhancement is considerable for lower range of Prandtl number and decreases for higher range of Prandtl number. Finally, glass beads concentration contours, velocity contours, concentration profile, velocity profiles and pressure drop are predicted to understand the slurry flow for chosen Prandtl numbers.

“…Mohanty et al [26][27] carried out the numerical simulation of counter flow heat exchanger and predicted the flow characteristics. Some of the recent work on slurry pipeline for obtaining the slurry flow characteristics is done by Parkash et al [28][29][30][31][32][33]. Arora et al [34][35] optimized the irreversible engine using ecological criteria.…”

Section: Introductionmentioning

confidence: 99%

Analytical and Comparative Investigation of Particulate Size Effect on Slurry Flow Characteristics Using Computational Fluid Dynamics

Parkash¹,

Kumar

Sikarwar³

2021

The key issue associated with the industries is the transportation and dumping of solids particulates in the form of slurry at the desired place using long length pipelines. In this perspective, numerical simulation of three-dimensional horizontal slurry pipeline of 0.0549 m diameter using Eulerian two-phase model with RNG kɛ turbulence closure is carried out. The glass -beads solid particulates having density (  = 2470 kg/m 3 ) and slurry concentration varies as 10% to 50% (by volume) for velocity ranges of 3-5 ms -1 . The computational modeling is done using available commercial software ANSYS Fluent for 125µm and 440 µm particulate size at different velocity and concentration range to know their effect on slurry flow characteristics. It is observed that for chosen particulate size pressure drop increases with increase in velocity at all solid concentration range. The pressure drop in slurry for 440 µm solid particulates is found higher as compared to the pressure drop of 125 µm solid particulates slurry. The percentage change in pressure drop is also reported in the paper due to particulate size effect at all velocity and solid concentration. The obtained results of predicted pressure drop are analytically compared with the available experimental results of literature and are in synchronism with that. A parametric study is carried out with the aim of visualizing and understanding the solid particulate size effect on slurry flow characteristics. Finally, the results of settling solid concentration contour, velocity contour, concentration profiles, velocity profiles and vector representation of concentration/velocity were also predicted for chosen particulates sized slurry.