Experimental and numerical investigation of heat loss in transition modes of buried hot fuel oil pipeline

2021 ◽  
pp. 095440622110007
Author(s):  
Mohsen Dehdarinejad ◽  
Morteza Behbahani-Nejad ◽  
Ebrahim Hajidavalloo
Keyword(s):  
Experimental Data ◽  
Friction Factor ◽  
Heat Loss ◽  
Large Scale ◽  
Computer Network ◽  
Strong Dependence ◽  
Fuel Oil ◽  
Optimal Size ◽  
The Real ◽  
Oil Pipeline

In this research, heat transfer of fuel oil flow through the buried pipeline in three regimes, turbulent, transition, and laminar conditions are investigated. A large-scale laboratory set-up is designed for this purpose and numerical modeling was also performed to study the effect of different parameters. The simulation is based on the fluid's thermophysical properties and the results are validated using experimental data. Due to the strong dependence of viscosity and density of fuel oil on the temperature, regime changes along the pipeline happens which complicate the calculation of friction factor. Using the experiment results and choosing different numerical methods, the acceptable model of friction factor in the transition zone for the experimental pipe and the real pipeline was achieved. Numerical simulation was performed on a 107 km pipeline using a powerful computer network to achieve the results. The approach which is used to simulate laminarization shows just a 3% discrepancy with experimental data. For the real pipeline, about 30 percent of the length is in transition mode from turbulent to laminar. The diameter of 26” is chosen as the most optimal size to transform 180000 barrels per day (BPD). According to the design thickness, diameter, and length of the pipeline, the maximum safe stop time (MSST) of the pipeline is 41 hours which is the most important data in the pipeline's maintenance period. Based on the present experimental data and simulation results, the optimal depth for the least heat loss from this pipeline is 0.9 to 2.7 meters.

scholarly journals Experimental and numerical simulation on buried hot fuel oil pipelines in three modes flow regime considering temperature loss during a shutdown

2020 ◽  
pp. 345-345
Author(s):  
Mohsen Dehdarinejad ◽  
Morteza Behbahani-Nejad ◽  
Ebrahim Hajidavalloo
Keyword(s):  
Experimental Data ◽  
Numerical Simulation ◽  
Pour Point ◽  
Large Scale ◽  
Fuel Oil ◽  
Fluid Density ◽  
Temperature Dependent ◽  
Buried Pipelines ◽  
Temperature Loss ◽  
Oil Pipelines

Aiming to study the temperature distribution along buried pipelines containing hot fuel oil, a new large-scale laboratory is constructed from the perspective of the corresponding fluid thermophysical properties. Also, a modeling of the pipeline, and the soil around it, was performed along the pipeline for observation of all three modes of turbulent, laminarization, and laminar flow, which is validated by experimental results. Furthermore, the appropriate data are also gathered from the actual pipeline, 107 km of the 26? pipeline between Abadan Refinery and Mahshahr Port, and the results of the experiment and modeling are reconfirmed. The experiment shows that the viscosity and fluid density of fuel oil is strongly temperature-dependent. Many experiments are performed on the parameters affected by temperature according to their importance. The method chosen to simulate three flow modes along the pipeline shows less than 2% error in turbulent and laminar zones and reveals just a 3% error to experimental data in the laminar region. The maximum safe time during the stopping period of the pipeline (MSST) and holding fuel oil in it is calculated based on the pour point of fuel oil. This time is critical for the real pipeline in sudden shutdown and is calculated 41 hours.

Comments on Compressor Efficiency Scaling With Reynolds Number and Relative Roughness

1989 ◽  
Author(s):  
Terry Wright
Keyword(s):  
Experimental Data ◽  
Reynolds Number ◽  
Friction Factor ◽  
Model Test ◽  
Large Scale ◽  
Recent Literature ◽  
Test Results ◽  
Relative Roughness ◽  
Scaling Algorithms ◽  
Compressor Efficiency

The background and literature on scaling of model test results to predict the performance of large scale turbomachines are presented and discussed in the context of both industry restrictions and recent improvements in analytical rigor and accuracy of scaling algorithms. The variety and disparity of methods developed before about 1970 is illustrated and plausible explanation is offered to account for the broad differences. The more recent literature is considered and the older exponential algorithms for scaling are reconciled with the current methods based on friction factor correlations. A simpler form is developed in terms of either exponential or friction factor formulations which includes the influence of Reynolds Number, relative roughness and fixed, friction-independent losses. This method is compared to the recently developed algorithms and to experimental data taken from the literature.

scholarly journals Modelling Reliability Characteristics of Technical Equipment of Local Area Computer Networks

Electronics ◽  
2021 ◽  
Vol 10 (8) ◽  
pp. 955
Author(s):  
Vasyl Teslyuk ◽  
Andriy Sydor ◽  
Vincent Karovič ◽  
Olena Pavliuk ◽  
Iryna Kazymyra
Keyword(s):  
Large Scale ◽  
Computer Network ◽  
Network Reliability ◽  
Local Area ◽  
Technical Equipment ◽  
Time To Failure ◽  
Reliability Parameters ◽  
Reliability Characteristics ◽  
Global World ◽  
Level 2

Technical systems in the modern global world are rapidly evolving and improving. In most cases, these are large-scale multi-level systems and one of the problems that arises in the design process of such systems is to determine their reliability. Accordingly, in the paper, a mathematical model based on the Weibull distribution has been developed for determining a computer network reliability. In order to simplify calculating the reliability characteristics, the system is considered to be a hierarchical one, ramified to level 2, with bypass through the level. The developed model allows us to define the following parameters: the probability distribution of the count of working output elements, the availability function of the system, the duration of the system’s stay in each of its working states, and the duration of the system’s stay in the prescribed availability condition. The accuracy of the developed model is high. It can be used to determine the reliability parameters of the large, hierarchical, ramified systems. The research results of modelling a local area computer network are presented. In particular, we obtained the following best option for connecting workstations: 4 of them are connected to the main hub, and the rest (16) are connected to the second level hub, with a time to failure of 4818 h.

scholarly journals A study of computational methods for wake structure and base pressure prediction of a generic SUV model with fixed and rotating wheels

2017 ◽  
Vol 231 (9) ◽  
pp. 1222-1238 ◽  
Author(s):  
David Forbes ◽  
Gary Page ◽  
Martin Passmore ◽  
Adrian Gaylard
Keyword(s):  
Experimental Data ◽  
Computational Methods ◽  
Large Scale ◽  
Ground Plane ◽  
Computational Cost ◽  
Rear Wheel ◽  
Base Pressure ◽  
Detached Eddy Simulation ◽  
Wake Structure ◽  
Wake Interactions

This study is an evaluation of the computational methods in reproducing experimental data for a generic sports utility vehicle (SUV) geometry and an assessment on the influence of fixed and rotating wheels for this geometry. Initially, comparisons are made in the wake structure and base pressures between several CFD codes and experimental data. It was shown that steady-state RANS methods are unsuitable for this geometry due to a large scale unsteadiness in the wake caused by separation at the sharp trailing edge and rear wheel wake interactions. unsteady RANS (URANS) offered no improvements in wake prediction despite a significant increase in computational cost. The detached-eddy simulation (DES) and Lattice–Boltzmann methods showed the best agreement with the experimental results in both the wake structure and base pressure, with LBM running in approximately a fifth of the time for DES. The study then continues by analysing the influence of rotating wheels and a moving ground plane over a fixed wheel and ground plane arrangement. The introduction of wheel rotation and a moving ground was shown to increase the base pressure and reduce the drag acting on the vehicle when compared to the fixed case. However, when compared to the experimental standoff case, variations in drag and lift coefficients were minimal but misleading, as significant variations to the surface pressures were present.

An Experimental and Analytical Study of Single-Phase Liquid Flow in a Horizontal Well

1997 ◽  
Vol 119 (1) ◽  
pp. 20-25 ◽  
Author(s):  
H. Yuan ◽  
C. Sarica ◽  
S. Miska ◽  
J. P. Brill
Keyword(s):  
Experimental Data ◽  
Friction Factor ◽  
Horizontal Well ◽  
Flow Behavior ◽  
Reynolds Numbers ◽  
Test Facility ◽  
Phase Liquid ◽  
Rate Ratios ◽  
Friction Factor Correlation ◽  
Better Than

A new test facility was designed and constructed to simulate flow in a horizontal well with a single perforation. A total of 635 tests were conducted with Reynolds numbers ranging from 5000 to 60,000 with influx to main rate ratios ranging from 1/5 to 1/100, and also for the no-influx case. The flow behavior in a single-perforation new friction expression for a single-perforation horizontal well was developed. A new simple correlation for the horizontal well friction factor was developed by applying experimental data to the general friction factor expression. The new friction factor correlation and experimental data were compared with the Asheim et al. (1992) data and model, and showed that the new correlation performed better than the Asheim et al. (1992) model.

A Novel Stable Algorithm of Getting User’s Account Based on Telnet Protocol

2013 ◽  
Vol 299 ◽  
pp. 130-134
Author(s):  
Li Wei ◽  
Da Zhi Deng
Keyword(s):  
Network Security ◽  
Network Management ◽  
Large Scale ◽  
Computer Network ◽  
User Behavior ◽  
Political Stability ◽  
Future Internet ◽  
Stable Algorithm ◽  
Internet User Behavior ◽  
Security Incidents

In recent years,china input in the construction of the network management is constantly increasing;information technology has improved continuously,but,making a variety of network security incidents occur frequently,due to the vulnerability of the computer network system inherent,a direct impact on national security and social and political stability. Because of the popularity of computers and large-scale development of the Internet, network security has been increasing as the theme. Reasonable safeguards against violations of resources; regular Internet user behavior and so on has been the public's expectations of future Internet. This paper described a stable method of getting telnet user’s account in development of network management based on telnet protocol.

Investigation on hydrodynamic forces leading to coarse particle entrainment using Large-Eddy Simulations

2021 ◽  
Author(s):  
Gaston Latessa ◽  
Angela Busse ◽  
Manousos Valyrakis
Keyword(s):  
Experimental Data ◽  
Flow Field ◽  
Large Scale ◽  
Large Eddy Simulations ◽  
Flow Conditions ◽  
Mean Flow ◽  
Protection Measures ◽  
Practical Applications ◽  
Particle Entrainment ◽  
Large Eddy

<p>The prediction of particle motion in a fluid flow environment presents several challenges from the quantification of the forces exerted by the fluid onto the solids -normally with fluctuating behaviour due to turbulence- and the definition of the potential particle entrainment from these actions. An accurate description of these phenomena has many practical applications in local scour definition and to the design of protection measures.</p><p>In the present work, the actions of different flow conditions on sediment particles is investigated with the aim to translate these effects into particle entrainment identification through analytical solid dynamic equations.</p><p>Large Eddy Simulations (LES) are an increasingly practical tool that provide an accurate representation of both the mean flow field and the large-scale turbulent fluctuations. For the present case, the forces exerted by the flow are integrated over the surface of a stationary particle in the streamwise (drag) and vertical (lift) directions, together with the torques around the particle’s centre of mass. These forces are validated against experimental data under the same bed and flow conditions.</p><p>The forces are then compared against threshold values, obtained through theoretical equations of simple motions such as rolling without sliding. Thus, the frequency of entrainment is related to the different flow conditions in good agreement with results from experimental sediment entrainment research.</p><p>A thorough monitoring of the velocity flow field on several locations is carried out to determine the relationships between velocity time series at several locations around the particle and the forces acting on its surface. These results a relevant to determine ideal locations for flow investigation both in numerical and physical experiments.</p><p>Through numerical experiments, a large number of flow conditions were simulated obtaining a full set of actions over a fixed particle sitting on a smooth bed. These actions were translated into potential particle entrainment events and validated against experimental data. Future work will present the coupling of these LES models with Discrete Element Method (DEM) models to verify the entrainment phenomena entirely from a numerical perspective.</p>

scholarly journals Elastic scattering and breakup reactions with light proton- and neutron-rich exotic nuclei

2018 ◽  
Vol 194 ◽  
pp. 07002
Author(s):  
M.K. Gaidarov ◽  
V.K. Lukyanov ◽  
D.N. Kadrev ◽  
E.V. Zemlyanaya ◽  
A.N. Antonov ◽  
...  
Keyword(s):  
Experimental Data ◽  
Elastic Scattering ◽  
Cross Sections ◽  
Cluster Model ◽  
Microscopic Analysis ◽  
High Energy ◽  
The Real ◽  
Optical Potentials ◽  
Generator Coordinate ◽  
Energy Approximation

A microscopic analysis of the optical potentials (OPs) and cross sections of elastic scattering of 8B on 12C, 58Ni, and 208Pb targets at energies 20 < E < 170 MeV and 12,14Be on 12C at 56 MeV/nucleon is carried out. The real part of the OP is calculated by a folding procedure and the imaginary part is obtained on the base of the high-energy approximation (HEA). The density distributions of 8B evaluated within the variational Monte Carlo (VMC) model and the three-cluster model (3CM) are used to construct the potentials. The 14Be densities obtained in the framework of the the generator coordinate method (GCM) are used to calculate the optical potentials, while for the same purpose both the VMC model and GCM densities of 12Be are used. In the hybrid model developed and explored in our previous works, the only free parameters are the depths of the real and imaginary parts of OP obtained by fitting the experimental data. The use of HEA to estimate the imaginary OP at energies just above the Coulomb barrier is discussed. In addition, cluster model, in which 8B consists of a p-halo and the 7Be core, is applied to calculate the breakup cross sections of 8B nucleus on 9Be, 12C, and 197Au targets, as well as momentum distributions of 7Be fragments. A good agreement of the theoretical results with the available experimental data is obtained. It is concluded that the reaction studies performed in this work may provide supplemental information on the internal spatial structure of the proton- and neutron-halo nuclei.

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