Considerations for Hydrodynamic Slug Analysis in Pipelines

2014 ◽  
Author(s):  
Daniela Galatro ◽  
Daniel Fürtbauer ◽  
Xiangyu Hu ◽  
David-Emilio Nerucci ◽  
Flavio Marín
Keyword(s):  
Steady State ◽  
Slip Velocity ◽  
Mechanistic Model ◽  
Simulation Software ◽  
Transient Simulation ◽  
First Approximation ◽  
Elevation Changes ◽  
Relative Errors ◽  
Superficial Gas Velocity ◽  
Made In

Hydrodynamic slugs in pipelines are usually analyzed by using a steady-state flow assurance simulator as a first approximation. The pipelines are then modeled in transient simulation software to get more accurate values. Comparisons between an empirical and a mechanistic method are made in this work by running simulations in steady-state simulators in order to explain the differences in the calculated slug properties. It has been demonstrated that both methods cannot accurately estimate the maximum slug length in pipelines since the relative errors are significant; nevertheless the mechanistic model is more accurate than the empirical one with lower relative errors. Additionally, slug sizes for operational slugging have been analyzed by using a new alternative pseudo transient approach to the Lagrangian slug tracking scheme. The model expresses an unsteady state mass balance in a pipeline, formulated utilizing the slip velocity written in terms of the void fraction and superficial gas velocity. Our model includes a constitutive equation for slip velocity, elevation changes to represent the hydraulic profile of the pipeline, a method for the calculation of the maximum slug length, a modified correlation for the slug length calculation and the variation of the fluid density along the pipeline profile. The results yielded by this model have been compared with field data and results performed by using a transient simulation software, showing fairly accurate values.

A Practical Approach to Operational Hydrodynamic Slug Analysis in Pipelines

2015 ◽  
Vol 13 (4) ◽  
pp. 503-510
Author(s):  
Daniela Galatro ◽  
Dario Ercolani ◽  
Daniel Fuertbauer
Keyword(s):  
Steady State ◽  
Flow Simulation ◽  
Simulation Software ◽  
Transient Simulation ◽  
Practical Approach ◽  
Accurate Estimation ◽  
Steady State Flow ◽  
Hydrodynamic Analysis ◽  
First Approximation ◽  
Transient Simulations

Abstract Hydrodynamic slugs in pipelines are usually analysed by using steady-state flow simulation software as a first approximation and then modelled in transient simulation software in order to get more accurate values. In this work, the ILF approach for hydrodynamic analysis is presented by using an empirical and a mechanistic method for steady-state simulations and by using a transient approach. For both, steady-state and transient simulations commercial software is applied. Furthermore, a new pseudo-transient approach as an alternative to the Lagrangian slug tracking scheme that is currently tested is presented. A set of operational hydrodynamic slug examples illustrates the use and accuracy of both commercial simulation programs and the newly developed pseudo-transient approach. Finally, a set of considerations for the hydrodynamic slug analysis in pipelines is proposed as a guide for accurate estimation of the slug properties.

Validation of On-line Respiration Meter and its Applications by Computer Simulation

1992 ◽  
Vol 26 (5-6) ◽  
pp. 1355-1363 ◽  
Author(s):  
C-W. Kim ◽  
H. Spanjers ◽  
A. Klapwijk
Keyword(s):  
Steady State ◽  
Activated Sludge ◽  
Respiration Rate ◽  
Oxygen Demand ◽  
Operating Conditions ◽  
Mass Balances ◽  
Short Term ◽  
Respiration Rates ◽  
On Line ◽  
Made In

An on-line respiration meter is presented to monitor three types of respiration rates of activated sludge and to calculate effluent and influent short term biochemical oxygen demand (BODst) in the continuous activated sludge process. This work is to verify if the calculated BODst is reliable and the assumptions made in the course of developing the proposed procedure were acceptable. A mathematical model and a dynamic simulation program are written for an activated sludge model plant along with the respiration meter based on mass balances of BODst and DO. The simulation results show that the three types of respiration rate reach steady state within 15 minutes under reasonable operating conditions. As long as the respiration rate reaches steady state the proposed procedure calculates the respiration rate that is equal to the simulated. Under constant and dynamic BODst loading, the proposed procedure is capable of calculating the effluent and influent BODst with reasonable accuracy.

An Assessment of the Value of Theory in Predicting Gas-Bearing Performance

1961 ◽  
Vol 83 (2) ◽  
pp. 195-200 ◽  
Author(s):  
S. Cooper
Keyword(s):  
Steady State ◽  
Slip Velocity ◽  
Reynolds Equation ◽  
Energy Equation ◽  
Experimental Methods ◽  
Experimental Results ◽  
Theoretical Investigations ◽  
Gas Bearing ◽  
Theoretical Results

The object of the paper is to indicate the value of theoretical investigations of hydrodynamic finite bearings under steady-state conditions. Methods of solution of Reynolds equation by both desk and digital computing, and methods of stabilizing the processes of solution, are described. The nondimensional data available from the solutions are stated. The outcome of an attempted solution of the energy equation is discussed. A comparison between some theoretical and experimental results is shown. Experimental methods employed and some difficulties encountered are discussed. Some theoretical results are given to indicate the effects of the inclusion of slip velocity, stabilizing slots, and a simple case of whirl.

scholarly journals Diagnostic and prognostic simulations with a full Stokes model accounting for superimposed ice of Midtre Lovénbreen, Svalbard

2009 ◽  
Vol 3 (2) ◽  
pp. 217-229 ◽  
Author(s):  
T. Zwinger ◽  
J. C. Moore
Keyword(s):  
Free Surface ◽  
Steady State ◽  
Thermal State ◽  
Steady State Solution ◽  
Radar Data ◽  
Data Set ◽  
Surface Evolution ◽  
Steady State Model ◽  
Elevation Changes ◽  
Ground Penetrating

Abstract. We present steady state (diagnostic) and transient (prognostic) simulations of Midtre Lovénbreen, Svalbard performed with the thermo-mechanically coupled full-Stokes code Elmer. This glacier has an extensive data set of geophysical measurements available spanning several decades, that allow for constraints on model descriptions. Consistent with this data set, we included a simple model accounting for the formation of superimposed ice. Diagnostic results indicated that a dynamic adaptation of the free surface is necessary, to prevent non-physically high velocities in a region of under determined bedrock depths. Observations from ground penetrating radar of the basal thermal state agree very well with model predictions, while the dip angles of isochrones in radar data also match reasonably well with modelled isochrones, despite the numerical deficiencies of estimating ages with a steady state model. Prognostic runs for 53 years, using a constant accumulation/ablation pattern starting from the steady state solution obtained from the configuration of the 1977 DEM show that: 1 the unrealistic velocities in the under determined parts of the DEM quickly damp out; 2 the free surface evolution matches well measured elevation changes; 3 the retreat of the glacier under this scenario continues with the glacier tongue in a projection to 2030 being situated ≈500 m behind the position in 1977.

scholarly journals Density Variations during Solidification of Grey Cast Iron

2018 ◽  
Vol 925 ◽  
pp. 155-162 ◽  
Author(s):  
Kristina Hellström ◽  
Péter Svidró ◽  
Lucian Vasile Diaconu ◽  
Attila Diószegi
Keyword(s):  
Complex Geometry ◽  
Control Volume ◽  
Solidification Process ◽  
Simulation Software ◽  
Volume Changes ◽  
Silicon Alloys ◽  
Know How ◽  
Grey Cast ◽  
Using Data ◽  
Made In

As part of moving towards a sustainable production of diesel engines for heavy vehicle applications, the ability to predict casting defects has become ever so important. In order to model the solidification process for cast components correctly, it is of essence to know how the material will actually behave. To produce sound castings, often of complex geometry, the industry relies on various simulation software for the prediction and avoidance of defects. Thermophysical properties, such as density, play an important part in these simulations.Previous measurements of how the volume of liquid grey iron changes with temperature has been made with a conventional dilatometer. Measurements have also been made in the austenitic range, then on iron-carbon-silicon alloys with a carbon content lower than 1.5 wt%. Based on these measurements the density variations during solidification were calculated. The scope for this paper is to model the volume changes during solidification with the control volume finite difference method, using data from the density measurements.

Optimization of Preform for Stub Axle Forging Using Simulation Software

2021 ◽  
Vol 1016 ◽  
pp. 1337-1343
Author(s):  
T. Lachana Dora ◽  
Niranjan Kumar Singh ◽  
Rajkumar Ohdar
Keyword(s):  
Computer Aided Design ◽  
Simulation Software ◽  
Die Design ◽  
Design And Manufacturing ◽  
Cad Cam ◽  
Increase Productivity ◽  
Aided Design ◽  
Preform Shape ◽  
Deform 3D ◽  
Made In

There is a growing demand for more efficient and economic manufacturing process to improve product quality, reduce production cost, reduce lead time and increase productivity. The application of computer aided design and manufacturing (CAD/CAM) techniques to forging is becoming increasingly popular as the resulting improvements in yield and productivity. Modeling and simulation have become a major concern in recent and advanced research. In this paper die design for forging of an automobile component “Stub Axle” is presented. In die forging process, complex shape component cannot be made in one stage and therefore, the use of preform die becomes essential. The initial preform design was carried out by conventional method. The simulation has been carried out using software DEFORM-3D. The main goal of this study is to design an optimal preform shape resulting an optimal initial billet selection. Keywords:CAD/CAM, Preform, DEFORM-3D, Simulation, Forging

scholarly journals Simulation, Design, and Test of a Dual-Differential D-Dot Overvoltage Sensor Based on the Field-Circuit Coupling Method

Sensors ◽  
2019 ◽  
Vol 19 (15) ◽  
pp. 3413 ◽  
Author(s):  
Pengcheng Zhao ◽  
Jingang Wang ◽  
Qian Wang ◽  
Qianbo Xiao ◽  
Ruiqiang Zhang ◽  
...  
Keyword(s):  
Steady State ◽  
Power Transmission ◽  
Circuit Simulation ◽  
Structural Parameters ◽  
Equivalent Circuit Model ◽  
Simulation Software ◽  
Power Grids ◽  
Coupling Method ◽  
Transient Performance ◽  
Simulation Design

Accurate measurement of overvoltage in power grids is of great significance to study the characteristics of overvoltage and design of insulation coordination. Based on the research of D-dot voltage sensor, we designed a Dual-Differential D-dot overvoltage sensor. In order to quantify the structural parameters of the sensor, improve the performance and measurement accuracy of the sensor. The Field-Circuit Coupling method was proposed to be used in the parameter design of D-dot overvoltage sensor. The joint simulation of space electromagnetic field model and equivalent circuit model of the Dual-Differential D-dot overvoltage sensor was established with the finite element simulation software Ansoft Maxwell and circuit simulation software Simplorer. Finally, the actual sensor was manufactured. A test platform was built to verify the steady-state and transient performance of the sensor. The results show that the Dual-Differential D-dot sensor has excellent steady-state and transient performance, the error of phase and amplitude are small, and the sensor can achieve the non-contact measurement of power transmission line. Simultaneously, the rationality of the Field-Circuit Coupling method was further verified.

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