Solutions for Air Valve Breakage Caused by Hydraulic Transients in Pinellas County's Wastewater Force Main System

2009 ◽  
Vol 2009 (2) ◽  
pp. 143-163 ◽  
Author(s):  
Guohua Li ◽  
Christopher C. Baggett ◽  
John H. Horvath ◽  
Mike Engelmann ◽  
William H. Gill
Keyword(s):  
Hydraulic Transients ◽  
Main System ◽  
Air Valve

Experimental analysis of air valve behaviour during hydraulic transients

2015 ◽  
Vol 3 (1) ◽  
pp. 3-11 ◽  
Author(s):  
Gabriella Balacco ◽  
Ciro Apollonio ◽  
Alberto Ferruccio Piccinni
Keyword(s):  
Experimental Analysis ◽  
Hydraulic Transients ◽  
Air Valve

scholarly journals Experimental and Numerical Analysis of Hydraulic Transients in the Presence of Air Valve

2017 ◽  
Vol 62 (1) ◽  
pp. 1 ◽  
Author(s):  
Richárd Wéber ◽  
Csaba Hős
Keyword(s):  
Numerical Analysis ◽  
Ambient Pressure ◽  
The Other ◽  
Hydrodynamic Behavior ◽  
Hydraulic Transients ◽  
Air Content ◽  
Ansys Cfx ◽  
Visual Access ◽  
Air Valve ◽  
Entrained Air

This paper focuses on the hydrodynamic behavior of liquid pipelines in the presence of air valves. The aim of installing such valves on pipeline systems is twofold: on one hand, they release the accumulated air content and on the other hand, they allow the outer air to entrain the system when the internal pressure falls beneath ambient pressure (i.e. vacuum formation). We study the hydraulic transients in the presence of such air valve by means of experimental and numerical methods. The experiments were performed using a special test section where the pipeline close to the air valve was built from plexiglas allowing visual access. Furthermore, pressure signals were recorded at several locations of the pipeline. Numerical analysis was also performed using the commercially available CFD software (ANSYS CFX). It was revealed that the entrained air separates well from the primary liquid and the mixture behaves as two distinct phases.

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.

scholarly journals Experimental and Numerical Study on Water Filling and Air Expelling Process in a Pipe with Multiple Air Valves under Water Slow Filling Condition

Water ◽  
2019 ◽  
Vol 11 (12) ◽  
pp. 2511
Author(s):  
Jintao Liu ◽  
Di Xu ◽  
Shaohui Zhang ◽  
Meijian Bai
Keyword(s):  
Numerical Model ◽  
Stokes Equations ◽  
Numerical Study ◽  
Practical Method ◽  
Navier Stokes ◽  
Physical Processes ◽  
Two Phase ◽  
Saint Venant Equations ◽  
Water Filling ◽  
Air Valve

This paper investigates the physical processes involved in the water filling and air expelling process of a pipe with multiple air valves under water slow filling condition, and develops a fully coupledwater–air two-phase stratified numerical model for simulating the process. In this model, the Saint-Venant equations and the Vertical Average Navier–Stokes equations (VANS) are respectively applied to describe the water and air in pipe, and the air valve model is introduced into the VANS equations of air as the source term. The finite-volume method and implicit dual time-stepping method (IDTS) with two-order accuracy are simultaneously used to solve this numerical model to realize the full coupling between water and air movement. Then, the model is validated by using the experimental data of the pressure evolution in pipe and the air velocity evolution of air valves, which respectively characterize the water filling and air expelling process. The results show that the model performs well in capturing the physical processes, and a reasonable agreement is obtained between numerical and experimental results. This agreement demonstrates that the proposed model in this paper offers a practical method for simulating water filling and air expelling process in a pipe with multiple air valves under water slow filling condition.

Uncertain Gain and Time-Delay Control of 300-kW SOFC-GT

2021 ◽  
Author(s):  
Tooran Emami ◽  
David Tucker ◽  
John Watkins
Keyword(s):  
Fuel Cell ◽  
Time Delay ◽  
Pid Controller ◽  
Transfer Functions ◽  
Cell Mass ◽  
Electric Load ◽  
Cold Air ◽  
Internal Gain ◽  
Air Valve ◽  
Turbine Speed

Abstract This paper presents a Proportional Integral Derivative (PID) controller design with the presence of an uncertain internal gain and additional time delay in the forward path of a 300 kW Solid Oxide Fuel Cell-Gas Turbine (SOFC-GT). The outputs of the system are turbine speed and the fuel cell mass flow rate. A fixed set of proportional controller coefficients are determined to graphically develop an area of selection for the integral and derivative coefficients of the PID controller. The inputs to the power plant are the electric load and cold air valve. The decentralized controllers are applied to four sub-systems as a Single Input Single Output (SISO). The PID controller coefficients are selected from a singular matrix solution that stabilizes the system and satisfies the internal gain and time delay uncertainties. Two sub-systems are the transfer functions of the turbine speed over the electric load and the cold air valve. The other two sub-systems are the transfer functions of the fuel cell mass flow rate over the electric load and the cold air bypass valve. Multiple options for selecting PID controller coefficients are beneficial to the SOFC-GT plant due to the wide range of operations and internal uncertainty interactions. The specific internal time delay and gain margins increase the reliability and robustness of the SOFC-GT with multiple uncertain parameters.

Hydraulic Transients

2020 ◽  
pp. 279-318
Author(s):  
Sandro Longo ◽  
Maria Giovanna Tanda ◽  
Luca Chiapponi
Keyword(s):  
Hydraulic Transients
Sign in / Sign up

Export Citation Format

Share Document