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.

CFD Prediction of Gas-Liquid Separation Efficiency of Geothermal Steam-Water Cyclone Separator Using a Verified Turbulence Model

2017 ◽  
Author(s):  
Xidong Hu ◽  
Shaoxiang Qian ◽  
Kaori Yamauchi ◽  
Haruo Okochi
Keyword(s):  
Experimental Data ◽  
Pressure Drop ◽  
Velocity Distribution ◽  
Flow Velocity ◽  
Separation Efficiency ◽  
Turbulence Models ◽  
Phase Flow ◽  
Cyclone Separator ◽  
Steam Quality ◽  
Rsm Model

The present paper aims to predict the separation efficiency and pressure drop of a vertical geothermal cyclone type separator using CFD (Computational Fluid Dynamics) simulations, for optimizing the design of such separator. A benchmark study was firstly performed for a single phase flow in a Stairmand design cyclone using four different turbulence models, in order to verify the prediction accuracy of flow velocity distribution by comparison with experimental data in literature. The investigated turbulence models include (1) Renormalization Group (RNG) k-ε, (2) Realizable k-ε, (3) Reynolds stress turbulence model (RSM) and (4) Large eddy simulation (LES). Results show that RNG k-ε and Realizable k-ε models are not capable of reproducing the experimental data while the RSM and LES models reproduce the flow velocity distribution very well. Then, CFD simulations of two-phase flow in a steam-water cyclone separator were carried out for different stream inlet velocities applying the RSM model. This is based on the consideration that steady state analysis can be done for the RSM model, and however, transient analysis is needed for the LES model, and hence, more expensive and time-consuming for engineering applications. The CFD results for outlet steam quality and pressure drop were obtained under different stream inlet velocities. The separation efficiency and outlet steam quality decreases a little when the inlet velocity increases from 34.5m/s to 72m/s. However, the outlet steam quality predicted in the present CFD analysis is close to that of Lazalde-Crabtree.

Comparison of Particle-Wall Interaction Boundary Conditions in the Prediction of Cyclone Collection Efficiency in Computational Fluid Dynamics (CFD) Modeling

2010 ◽  
Vol 660-661 ◽  
pp. 158-163
Author(s):  
M.Ramirez Valverde ◽  
José Renato Coury ◽  
José Antônio Silveira Gonçalves
Keyword(s):  
Fluid Dynamics ◽  
Experimental Data ◽  
Computational Fluid Dynamics ◽  
Pressure Drop ◽  
Boundary Conditions ◽  
Collection Efficiency ◽  
Cfd Modeling ◽  
Wall Boundary Conditions ◽  
Computational Fluid Dynamics Cfd ◽  
Wall Interaction

In recent years, many computational fluid dynamics (CFD) studies have appeared attempting to predict cyclone pressure drop and collection efficiency. While these studies have been able to predict pressure drop well, they have been only moderately successful in predicting collection efficiency. Part of the reason for this failure has been attributed to the relatively simple wall boundary conditions implemented in the commercially available CFD software, which are not capable of accurately describing the complex particle-wall interaction present in a cyclone. According, researches have proposed a number of different boundary conditions in order to improve the model performance. This work implemented the critical velocity boundary condition through a user defined function (UDF) in the Fluent software and compared its predictions both with experimental data and with the predictions obtained when using Fluent’s built-in boundary conditions. Experimental data was obtained from eight laboratory scale cyclones with varying geometric ratios. The CFD simulations were made using the software Fluent 6.3.26.

Computational Fluid Dynamics Studies of Gas-Solid Flows in a Horizontal Pipe, Subjected to an Adiabatic Wall, Using a Variable Gas Properties Eulerian Model

2019 ◽  
Vol 14 (3) ◽  
Author(s):  
Brundaban Patro ◽  
K. Kiran Kumar ◽  
D. Jaya Krishna
Keyword(s):  
Heat Transfer ◽  
Pressure Drop ◽  
Volume Fraction ◽  
Solid Volume Fraction ◽  
Solid Loading ◽  
Eulerian Model ◽  
Adiabatic Wall ◽  
Horizontal Pipe ◽  
Loading Ratio ◽  
Gas Properties

Abstract In the present paper, a variable gas properties Eulerian model is employed to model the gas-solid heat transfer in a three-dimensional horizontal pipe, subjected to an adiabatic wall. The numerical model has been validated with the benchmark experimental data and other theoretical results available in the literature, and found satisfactory agreements. Moreover, the numerical heat transfer results considering the variable gas properties (i. e. density, dynamic viscosity, thermal conductivity, and specific heat) and constant gas properties are compared. It is noticed that the variable gas properties significantly affect the heat transfer, when compared to the constant gas properties. Therefore, the consideration of constant gas properties for the prediction of heat transfer may not be suitable in gas-solid flows, subjected to an adiabatic wall. Moreover, the temperature profiles, solid volume fraction profiles, and gas-solid Nusselt number are discussed. Finally, the pressure drop prediction with respect to the solid loading ratio is studied, and found that the pressure drop slightly decreases with increasing the solid loading ratio.

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 Flow Characteristics of Multiphase Glass Beads-Water Slurry through Horizontal Pipeline using Computational Fluid Dynamics

2019 ◽  
Vol 16 (2) ◽  
pp. 6605-6623 ◽  
Author(s):  
Shofique Uddin Ahmed ◽  
Rajesh Arora ◽  
Om Parkash
Keyword(s):  
Fluid Dynamics ◽  
Experimental Data ◽  
Computational Fluid Dynamics ◽  
Pressure Drop ◽  
Control Volume ◽  
Particle Diameter ◽  
Solid Particles ◽  
Slurry Flow ◽  
Two Phase ◽  
Horizontal Pipe

Over the decades conveying solid particles through pipelines is a prevalent usage for many industries like food industries, pharmaceutical, oil and gas-solid handling, power generations etc. In the present study, slurry flow through 54.9 mm diameter and 4 m long horizontal pipe with solid particle diameter 0.125 mm and specific gravity 2.47 has been numerically analysed using a granular version of Eulerian two-phase model and RNG K-  model. The solid particles are considered as mono-dispersed in the Eulerian model. These models are available in computational fluid dynamics (CFD) fluent software package. Non-uniform structured three-dimensional mesh with a refinement near wall boundary region has been selected for discretising the flow domain, and governing equations are solved using control volume finite difference method. Simulations are conducted at velocity varying from 1 m/s to 5 m/s and efflux concentration varying from 0.1 to 0.5 by volume. Different slurry flow parameters such as solid concentration distribution, velocity distribution, pressure drop etc. have been analysed from the simulated results. The simulated results of pressure drop are correlated with the experimental data available in previous literature and are found to be in excellent compliance with the experimental data.

Capsule-Pipelining—An Improved Theoretical Analysis

1977 ◽  
Vol 99 (4) ◽  
pp. 763-771 ◽  
Author(s):  
V. K. Garg
Keyword(s):  
Experimental Data ◽  
Theoretical Analysis ◽  
Pipe Wall ◽  
Energy Requirements ◽  
Pipeline System ◽  
Horizontal Pipe ◽  
Optimum Operation ◽  
Theoretical Results

This paper provides an improvement over the earlier theoretical analysis for a rigid, frictionless, cylindrical capsule moving parallel to the horizontal pipe wall (Garg and Round [1]) by taking into account the effects of friction between the capsule and pipe surfaces and of nonuniform clearance over the capsule length. It is found that these effects markedly affect the energy requirements suggesting, thereby, an optimum operation of the capsule-pipeline system. The theoretical results are also compared with the available experimental data.

Thermal Optimal Design for Partially-Confined Compact Heat Sinks

2005 ◽  
Author(s):  
M. P. Wang ◽  
H. T. Chen ◽  
J. T. Horng ◽  
T. Y. Wu ◽  
P. L. Chen ◽  
...  
Keyword(s):  
Experimental Data ◽  
Pressure Drop ◽  
Thermal Resistance ◽  
Flow Velocity ◽  
Thermal Performance ◽  
Heat Sink ◽  
Heat Sinks ◽  
Optimal Designs ◽  
Inlet Flow ◽  
Design Factors

An effective method for predicting the optimal thermal performance of partially-confined compact heat sinks under multi-constraints of pressure drop and heat sink mass has been successfully developed. The design variables of PPF compact heat sinks include: heat sink fin and base material, thickness of heat sink base, heat flux, channel top bypass and inlet flow velocity. A total of 108 experimental cases for confined forced convection are designed by the Central Composite Design (CCD) method. According to the results in ANOVA, a sensitivity analysis for the design factors is performed. From the analysis, the effect of inlet flow velocity, which has the contribution percentage of 86.24%, dominates the thermal performance. The accuracies of the quadratic RSM models for both thermal resistance and pressure drop have been verified by comparing the predicted response values to the actual experimental data. The maximum deviations of thermal resistance and pressure drop are 9.41% and 7.20% respectively. The Response Surface Methodology is applied to establish analytical models of the thermal resistance and pressure drop constraints in terms of the key design factors with a CCD experimental design. By employing the Sequential Quadratic Programming technique, a series of constrained optimal designs can be efficiently performed. The numerical optimization results for four cases under different constraints are obtained, and the comparisons between these predicted optimal designs and those measured by the experimental data are made with a satisfactory agreement.

Pressure Drop for Oil-Gas Two-Phase Flow Through Straight Horizontal Pipe

2007 ◽  
Author(s):  
Wenhong Liu ◽  
Liejin Guo ◽  
Ximin Zhang ◽  
Kai Lin ◽  
Long Yang ◽  
...  
Keyword(s):  
Pressure Drop ◽  
Two Phase Flow ◽  
Phase Flow ◽  
Two Phase ◽  
Horizontal Pipe ◽  
Flow Through ◽  
Oil Gas
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