A Variational Approach to the Analysis of Fluid Distribution Networks in Steady State of Flow

1994 ◽  
Vol 15 (1) ◽  
pp. 19-32
Author(s):  
F. Russo Spena ◽  
A. Vacca
Keyword(s):  
Steady State ◽  
Variational Approach ◽  
Distribution Networks ◽  
Fluid Distribution

scholarly journals Hydraulic Transients in Viscoelastic Pipeline System with Sudden Cross-Section Changes

Energies ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 4071
Author(s):  
Michał Kubrak ◽  
Agnieszka Malesińska ◽  
Apoloniusz Kodura ◽  
Kamil Urbanowicz ◽  
Michał Stosiak
Keyword(s):  
Numerical Model ◽  
Cross Section ◽  
Laboratory Data ◽  
Experimental Studies ◽  
Distribution Networks ◽  
Water Hammer ◽  
Fluid Distribution ◽  
Pipeline System ◽  
Hydraulic Transients ◽  
Single Pipe

It is well known that the water hammer phenomenon can lead to pipeline system failures. For this reason, there is an increased need for simulation of hydraulic transients. High-density polyethylene (HDPE) pipes are commonly used in various pressurised pipeline systems. Most studies have only focused on water hammer events in a single pipe. However, typical fluid distribution networks are composed of serially connected pipes with various inner diameters. The present paper aims to investigate the influence of sudden cross-section changes in an HDPE pipeline system on pressure oscillations during the water hammer phenomenon. Numerical and experimental studies have been conducted. In order to include the viscoelastic behaviour of the HDPE pipe wall, the generalised Kelvin–Voigt model was introduced into the continuity equation. Transient equations were numerically solved using the explicit MacCormack method. A numerical model that involves assigning two values of flow velocity to the connection node was used. The aim of the conducted experiments was to record pressure changes downstream of the pipeline system during valve-induced water hammer. In order to validate the numerical model, the simulation results were compared with experimental data. A satisfactory compliance between the results of the numerical calculations and laboratory data was obtained.

Stability of disk-like galaxies – Part II: The Kuzmin disk

Analysis ◽  
2007 ◽  
Vol 27 (4) ◽  
Author(s):  
Roman Fiřt
Keyword(s):  
Steady State ◽  
Nonlinear Stability ◽  
Variational Approach ◽  
Poisson System ◽  
Finite Mass

SummaryWe prove the existence and nonlinear stability of the Kuzmin disk, a polytropic steady state of the Vlasov–Poisson system widely used in astrophysics, which has infinite support, but finite mass. As in Part I we use the variational approach by REIN and GUO.

Generalized Modeling of Three-phase Overhead Distribution Networks for Steady State Analysis

2011 ◽  
Vol 9 (3) ◽  
pp. 311-317 ◽  
Author(s):  
J. N. Souza ◽  
L. L. Diniz ◽  
O. R. Saavedra ◽  
J. E. Pessanha
Keyword(s):  
Steady State ◽  
Distribution Networks ◽  
Steady State Analysis ◽  
Three Phase ◽  
State Analysis

scholarly journals Investigation on Using Low Voltage Automatic Regulation to Minimize the Impacts of Charging Plug-in Electric Vehicles in Distribution Systems

2021 ◽  
Vol 19 ◽  
pp. 85-90
Author(s):  
Priscila Costa Nascimento ◽  
◽  
Michel Girotto de Oliveira ◽  
José Carlos M. Vieira
Keyword(s):  
Steady State ◽  
Electric Vehicles ◽  
Distribution System ◽  
Distribution Systems ◽  
Low Voltage ◽  
Electric Energy ◽  
Distribution Networks ◽  
Voltage Regulation ◽  
Automatic Regulation ◽  
Electric Energy Storage

The growth of micro and mini distributed generation and, more recently, the use of electric energy storage systems and the incentives for electric mobility are important examples of the transformations that distribution networks have been going through. In this context, this paper firstly presents the impacts of uncoordinated plug-in electric vehicles (PEVs) charging in a real Brazilian distribution system. Four scenarios were elaborated with different PEVs penetration levels and the results show increased voltage unbalance, system losses, and violations of the steady-state voltage limits, even in the presence of an automatic voltage regulator installed in the medium voltage network. Then, as the main contribution, the potential usage of automatic voltage regulation at the low voltage network was investigated to minimize the negative impacts of uncontrolled PEV charging on distribution system steady-state operation. It is important to highlight that this is not a common practice of utilities in Brazil. The obtained results showed that regulating the voltage at the low voltage side could be an effective solution to keep the voltages within statutory limits.

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