An experimental study on head loss characteristics of pipe bends for flow of coal–water slurry at high solid concentration

2019 ◽  
Vol 233 (5) ◽  
pp. 1151-1161 ◽  
Author(s):  
Jatinder Pal Singh ◽  
Satish Kumar ◽  
SK Mohapatra
Keyword(s):  
Flow Velocity ◽  
Flow Characteristics ◽  
Head Loss ◽  
Solid Concentration ◽  
Pipe Bend ◽  
Water Suspension ◽  
Water Slurry ◽  
Test Loop ◽  
Coal Water Slurry ◽  
Pilot Plant Test

Bending of pipes is a major problem facing the engineers during the construction of a long pipeline for transporting coal–water slurry. However, the use of 90° bends in slurry transportation is restricted because it causes high head loss, and so very high pumping power is required to overcome this resistance. In this context, the present study is carried out to reduce the head loss for the flow of coal–water suspension across 90° pipe bends by varying bend geometry. Rheological experiments were performed to study flow characteristics of coal–water suspension with/without the additive. Coal–water slurry exhibits Newtonian behavior at a solid concentration of 30 wt% and pseudoplastic flow nature at concentration above 30%. Head loss experiments were carried out on a pilot plant test loop for a solid concentration of 30.27–61.56% with flow velocity ranging from 2 to 5 m/s. The r/ D ratio for the pipe bend varied within the range of 1.5–2.5. The present study reveals that the head loss across pipe bends increased as solid concentration and flow velocity was increased. The optimum r/ D ratio value for a minimum head loss was found to be 2.0. Also, significant decreases in apparent viscosity and head loss were perceived with the addition of a small amount of sulfonic acid. Power required to pump coal–water slurry was decreased by 15.93% with the use of an additive. A correlation for the head loss in terms of solid concentration, flow velocity, and r/ D ratio was also developed.

scholarly journals Experimental and Numerical analysis of Flow characteristics of sand water slurry in a horizontal pipe

2021 ◽  
Author(s):  
Varinder Singh ◽  
◽  
Satish Kumar ◽  
Dwarikanath Ratha ◽  
◽  
...  
Keyword(s):  
Numerical Analysis ◽  
Pressure Loss ◽  
Volume Fraction ◽  
Head Loss ◽  
Experimental Results ◽  
Solid Concentration ◽  
Horizontal Pipe ◽  
Slurry Concentration ◽  
Water Slurry ◽  
Test Loop

The transportation of the solid material using hydraulic transportation method is economically the best method. The head loss occurs during transportation of slurry through horizontal pipelines usually depends on the rheological behavior of slurry, slurry concentration, particle size, and influx velocity. An experimental investigation has been performed using sand-water slurry flowing through the horizontal pipe section of a pilot plant test loop. The head loss obtained from the experimental results was validated through CFD simulation using FLUENT. The solid concentration of sand-water slurry and influx velocity used during both experiments and numerical simulation were in the range of 10-40% (by weight) and 1 to 4 m/s respectively. The numerical simulations were performed using five different turbulence models and the results obtained using SST k-omega model was in close agreement with experimental results. It is observed from both the experiment and numerical analysis that the pressure loss, granular pressure, volume fraction and skin fraction coefficient during transportation of slurry through a horizontal pipe is a function of solid concentration and influx velocity. The present study observed that as the flow velocity increases four times, the pressure loss is increasing more than 10 times. Uniform volume fraction at middle zone of outlet of the pipe is observed as both the slurry concentration and velocity of flow increases.

3D CFD Modeling and Experimental Validation for Slurry Flow Through Pipe Bend

2008 ◽  
Author(s):  
Arvind Kumar ◽  
D. R. Kaushal ◽  
Umesh Kumar
Keyword(s):  
Experimental Data ◽  
Pressure Drop ◽  
Flow Velocity ◽  
Cfd Modeling ◽  
Pipeline System ◽  
Detailed Knowledge ◽  
Eulerian Model ◽  
Pipe Bend ◽  
Horizontal Pipe ◽  
Test Loop

Bends are integral part of any slurry pipeline system and are prone to excessive wear. Therefore, a detailed knowledge of the flow characteristics in the bends will enable us to identify the causes of excessive wear which in turn may help in developing remedial steps to control the excessive wear. In the present study, experimental data are collected in a 90 degree horizontal pipe bend having bend radius of 148 mm situated in a pilot plant test loop with pipe diameter of 53 mm. The experiments are performed at volumetric concentration of 16.28% of silica sand having mean particle diameter of 448.5 micron. The flow velocity was varied from 1.78 to 3.56 m/s. Separation chambers are provided at each pressure tap for interface separation of slurry and manometric fluid, water being the intermediate fluid. For better accuracy, pressure drop along the pipeline is measured by an inclined manometer. Electromagnetic flow meter is used for the measurement of slurry discharge. It is observed that pressure drop along the pipe bend increases with flow velocity. The experimental data collected in the present study have been compared with the three-dimensional computational fluid dynamics (CFD) modeling, using Eulerian two-phase model and commercial CFD package FLUENT 6.2. Eulerian model expands the definition of continuum assumption to the dispersed phase and treats both continuous and dispersed phases separately as two phases. Both phases are linked using the drag force in the momentum equation. The standard k-epsilon model is used to treat turbulence phenomena in both the phases. The granular theory for the liquid–solid flow of the Eulerian model is introduced. Gambit software is used for the development of mesh. It is observed that CFD modeling gives fairly accurate results for almost all the pressure drop data considered in the present study. CFD modeling results for concentration and velocity profiles for collected experimental data have also been presented.

scholarly journals Influence of different dispersants on rheological behaviors of coal water slurry prepared from a low quality coal

RSC Advances ◽  
2019 ◽  
Vol 9 (56) ◽  
pp. 32911-32921 ◽  
Author(s):  
Shunxuan Hu ◽  
Liming Liu ◽  
Xin Yang ◽  
Junguo Li ◽  
Baonan Zhou ◽  
...  
Keyword(s):  
Rheological Properties ◽  
Combustion Process ◽  
Solid Concentration ◽  
Rheological Behaviors ◽  
Water Slurry ◽  
Coal Water Slurry

To improve the efficiency of the gasification or combustion process of coal water slurry (CWS), it is significant to optimize the rheological properties and increase the solid concentration of CWS.

scholarly journals Progress on Opposed Multi-Burner (OMB) Coal-Water Slurry Gasification Technology and Its Industrial Applications

2017 ◽  
Vol 142 ◽  
pp. 1089-1094 ◽  
Author(s):  
Yan Gong ◽  
Guangsuo Yu ◽  
Qinghua Guo ◽  
Yifei Wang ◽  
Xueli Chen ◽  
...  
Keyword(s):  
Industrial Applications ◽  
Water Slurry ◽  
Coal Water Slurry ◽  
Gasification Technology
Sign in / Sign up

Export Citation Format

Share Document