Isothermal and Non-Isothermal Transient Gas Flow in Submarine Pipeline

2015 ◽  
Author(s):  
Augusto F. Nalin ◽  
Raphael I. Tsukada ◽  
Denis A. Shiguemoto ◽  
Jose R. P. Mendes ◽  
Adriane B. S. Serapiao
Keyword(s):  
Gas Flow ◽  
New Technologies ◽  
Transient Flow ◽  
Flow Analysis ◽  
Petroleum Industry ◽  
Compressibility Factor ◽  
Fluid Properties ◽  
The Difference ◽  
Subsea Pipelines ◽  
Flow Simulator

The discoveries of the Pre-salt oilfields have driven the development of new technologies to enable the production of the deepwater reservoirs. In this scenario, subsea pipelines play an important role. Analysis of the steady and transient flow inside the pipes should be addressed in the design, considering the variation of the fluid properties. In this context, a pipe flow simulator project has been developed to attend gas flow analysis for petroleum industry. In this project, the fluid compressibility factor (Z-factor) and the viscosity are considered function of the pressure, temperature and gas composition. The non-isothermal transient gas flow were calculated using the Method of Characteristics (MOC). The results shown the difference of the isothermal and non-isothermal steady state and transient flow.

Nonisothermal Transient Flow in Natural Gas Pipeline

2008 ◽  
Vol 75 (3) ◽  
Author(s):  
M. Abbaspour ◽  
K. S. Chapman
Keyword(s):  
Gas Flow ◽  
Transient Flow ◽  
Flow Analysis ◽  
Compressibility Factor ◽  
Momentum Equation ◽  
Gas Pipeline ◽  
Time Step ◽  
Inertia Term ◽  
Fully Implicit ◽  
Energy Equations

The fully implicit finite-difference method is used to solve the continuity, momentum, and energy equations for flow within a gas pipeline. This methodology (1) incorporates the convective inertia term in the conservation of momentum equation, (2) treats the compressibility factor as a function of temperature and pressure, and (3) considers the friction factor as a function of the Reynolds number and pipe roughness. The fully implicit method representation of the equations offers the advantage of guaranteed stability for a large time step, which is very useful for gas pipeline industry. The results show that the effect of treating the gas in a nonisothermal manner is extremely necessary for pipeline flow calculation accuracies, especially for rapid transient process. It also indicates that the convective inertia term plays an important role in the gas flow analysis and cannot be neglected from the calculation.

Micro Flow Sensor Based on Frequency Measurement of Micro Whistles

2012 ◽  
Vol 468-471 ◽  
pp. 2061-2064
Author(s):  
Yan Bin Di ◽  
Ying Miao
Keyword(s):  
Flow Rate ◽  
Gas Flow ◽  
Volume Flow Rate ◽  
Frequency Measurement ◽  
Flow Sensor ◽  
Fluid Properties ◽  
Micro Flow ◽  
The Difference ◽  
Rate Frequency ◽  
Geometrical Dimensions

In this work, several millimeter sized micro whistles have been tested as potential frequency analog gas flow sensors. The characteristic curves of the whistles were systematically investigated as a function of geometrical dimensions, the kind of gas applied, and temperature. Both a micro¬phone and a PVDF foil were employed to record the frequencies. The relation be¬tween oscillation frequency and volume flow rate only shows a weak function of fluid properties and temperature. At a given flow rate, the difference of argon and nitrogen is 120 Hz on average, which is corresponding to 1.4 %. For air flow at a given flow rate, frequency rises approximately 380 Hz (2.73 %) per 10 °C. This kind of micro whistle could be employed as gas flow sensor which is insensitive to fluid properties.

Transient Flow Study of a Novel Three-Cylinder Double-Acting Reciprocating Multiphase Pump

2017 ◽  
Vol 139 (10) ◽  
Author(s):  
Yi Ma ◽  
Huashuai Luo ◽  
Tao Gao ◽  
Zhihong Zhang
Keyword(s):  
Gas Flow ◽  
High Efficiency ◽  
Transient Flow ◽  
Volume Fraction ◽  
Petroleum Industry ◽  
Flow Characteristics ◽  
Multiphase Model ◽  
Pump System ◽  
Multiphase Pump ◽  
Working Cycle

In petroleum industry, the stability of multiphase pumping is highly disturbed by the gas' presence with high content and variable working conditions. This paper is focused on studying the whole working cycle of the novel three-cylinder double-acting reciprocating multiphase pump. Based on the theoretical analysis, the method of computational fluid dynamics (CFD) is adopted to simulate the oil–gas flow in reciprocating multiphase pump. The numerical methodology, involving multiphase model, dynamic grid technique and user defined functions (UDF), is used to deal with in the calculation. The transient flow characteristics in pump cavity are obtained, and the flow ripples of reciprocating multiphase pump are analyzed. Furthermore, the effects of different operating parameters, such as suction and discharge pressures, inlet gas volume fraction (GVFi) on the capacity, and stability of pump, are studied. The results could help to develop and optimize the high-efficiency multiphase pump system.

Gas flow analysis in a Kraft recovery boiler

2010 ◽  
Vol 91 (7) ◽  
pp. 789-798 ◽  
Author(s):  
D.J.O. Ferreira ◽  
M. Cardoso ◽  
S.W. Park
Keyword(s):  
Gas Flow ◽  
Flow Analysis ◽  
Recovery Boiler

Mixing Enhancement of Two Gases in a Microchannel Using DSMC

2013 ◽  
Vol 307 ◽  
pp. 166-169 ◽  
Author(s):  
Masoud Darbandi ◽  
Elyas Lakzian
Keyword(s):  
Gas Flow ◽  
Flow Analysis ◽  
Direct Simulation Monte Carlo ◽  
Equilibrium Composition ◽  
Mass Composition ◽  
Mixing Enhancement ◽  
Mixing Process ◽  
Result Section ◽  
Flow Through ◽  
Simulation Monte Carlo

Microgas flow analysis may not be performed accurately using the classical CFD methods because of encountering high Knudsen number regimes. Alternatively, the gas flow through micro-geometries can be investigated reliably using the direct simulation Monte Carlo (DSMC) method. Our concern in this paper is to use DSMC to study the mixing of two gases in a microchannel. The mixing process is assumed to be complete when the mass composition of each species deviates by no more than ±1% from its equilibrium composition. To enhance the mixing process, we focus on the effects of inlet-outlet pressure difference and the pressure ratios of the incoming CO and N2 streams on the mixing enhancement. The outcome of this study is suitably discussed in the result section.

Digital Transformation of the Service Sector

2021 ◽  
pp. 41-54
Author(s):  
D. Shevchenko ◽  
V. Mihaylov
Keyword(s):  
Business Model ◽  
Service Sector ◽  
New Technologies ◽  
Rapid Development ◽  
Digital Transformation ◽  
Services Sector ◽  
Remote Maintenance ◽  
New Business ◽  
The Difference ◽  
Cloud Technologies

The article is devoted to the problems of digital transformation of companies in the service sector. The article describes the concepts of "digitization", "digitalization", "digital transformation", "automation". The analysis of the main sectors of the public services sector, the processes of transformation into a new business model of their development is carried out. Specific examples show the role of digital technologies implemented by individual companies, the leaders of their industry: "Internet of Things" (IoT); virtual diagnostics of the service; mobile applications and portals; artificial intelligence and machine learning (AI / ML); remote maintenance; UX design; virtual reality; cloud technologies; online services and others. The authors proceed from understanding the difference between automation and digitalization, the strategic goal of which is to create a new digital business model that creates new value. The result of digital transformation is the reconfiguration of processes that change the business logic of the company and the process of creating value. The article concludes that the rapid development of new technologies leads to the fact that companies face not only a dilemma when choosing the most suitable technologies for investment, but also the problem of staffing and finding an adequate organizational structure to create and maintain a new business model of the company.

Influence of Surge Tank and Relief Valve on Transient Flow Behaviour in Hydropower Stations

2011 ◽  
Author(s):  
Alireza Riasi ◽  
Ahmad Nourbakhsh
Keyword(s):  
Power Plants ◽  
Transient Flow ◽  
Flow Analysis ◽  
Internal Boundary ◽  
Transient Condition ◽  
Maximum Pressure ◽  
Surge Tank ◽  
Small Hydropower ◽  
Relief Valve ◽  
Hydropower Stations

Unsteady flow analysis in water power stations is one of the most important issues in order to predict undesirable pressure variations in waterways and also probable changes in rotor speed for the power plants safe operation. Installation of surge tank and relief valve is the two main methods for controlling of hydraulic transient. The relief valve is used in several medium and small hydropower stations instead of the surge tank and mounted on the penstock near the powerhouse. The recent generation of relief valves are reliable and beneficial and consist of fully control system that directly conducted by governor. This paper presents a numerical method for transient flow in hydropower stations using surge tank and relief valve. For this purpose the governing equations of transient flow in closed conduit are solved using the method of characteristics (MOC) using unsteady friction. Hydraulic turbine, surge tank and relief valve are considered as internal boundary conditions. The influence of surge tank and also relief valve on the maximum pressure in spiral case and turbine over speed has been studied for a real case. The results show that the transient condition is considerably improved by using a relief valve and this device can be mounted in lieu of an expensive surge tank.

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