Check Valve Behavior Under Transient Flow Conditions: A State-of-the-Art Review

1989 ◽  
Vol 111 (2) ◽  
pp. 178-183 ◽  
Author(s):  
A. R. D. Thorley
Keyword(s):  
Transient Flow ◽  
State Of The Art ◽  
Check Valve ◽  
Reliable Information ◽  
Flow Conditions ◽  
Design Engineers ◽  
Performance Curves ◽  
Valve Dynamics ◽  
Pipeline Design ◽  
Data Design

Recent advances in the understanding of check valve behavior are reviewed. It is evident that the basis now exists for providing reliable information on valve dynamics that is in a form that can be easily assimilated and used by pipeline design engineers. The use of nondimensional valve performance curves is discussed and recommended. Manufacturers are encouraged to provide these data. Design engineers are charged with the responsibility of using it and are provided with guidelines for so doing.

Discussion: “Unsteady RANS Simulations of Wells Turbine Under Transient Flow Conditions” (Hu and Li, ASME J. Offshore Mech. Arct. Eng., 140(1), p. 011901)

2019 ◽  
Vol 141 (4) ◽  
Author(s):  
Tiziano Ghisu ◽  
Francesco Cambuli ◽  
Pierpaolo Puddu ◽  
Irene Virdis ◽  
Mario Carta
Keyword(s):  
Transient Flow ◽  
Careful Consideration ◽  
Navier Stokes ◽  
Flow Conditions ◽  
Wells Turbine ◽  
Numerical Errors ◽  
Performance Curves ◽  
Unsteady Rans ◽  
Computational Fluid Dynamics Cfd ◽  
Rans Simulations

The work by Hu and Li (2018, “Unsteady RANS Simulations of Wells Turbine Under Transient Flow Conditions,” ASME J. Offshore Mech. Arct. Eng., 140(1), p. 011901) presents the numerical simulation of a high-solidity Wells turbine by means of a computational fluid dynamics (CFD) (Reynolds-averaged Navier–Stokes (RANS)) approach. A key aspect highlighted by the authors is the presence of a hysteretic loop in the machine's performance curves, due (according to their explanation) to the interaction of vortices shed by the blade with the blade circulation, which is responsible for the aerodynamic forces. It is our opinion that this work contains some serious errors that invalidate the results. In this brief discussion, we aim to demonstrate how the hysteresis found and discussed by the authors should not be present in the turbine analyzed in Hu and Li (2018, “Unsteady RANS Simulations of Wells Turbine Under Transient Flow Conditions,” ASME J. Offshore Mech. Arct. Eng., 140(1), p. 011901), and it is unlikely to be present in any Wells turbine. The fact that Hu and Li find hysteresis in their simulations is most likely caused by numerical errors due to an insufficient temporal discretization. This and other inaccuracies could have been avoided with a more careful consideration of the available literature.

Effect of Salinity on Reaeration Coefficient of Receiving Waters

1984 ◽  
Vol 16 (5-7) ◽  
pp. 139-154 ◽  
Author(s):  
Ching-Gung Wen ◽  
Jao-Fuan Kao ◽  
Lawrence K Wang ◽  
Chii Cherng Liaw
Keyword(s):  
Saline Water ◽  
Chloride Concentration ◽  
Practical Method ◽  
Tidal River ◽  
Quality Analysis ◽  
Flow Conditions ◽  
Water Quality Analysis ◽  
Design Engineers ◽  
Reaeration Coefficient ◽  
Receiving Waters

A practical method of determining reaeration coefficients would greatly aid design engineers in determining the degree of wastewater treatment required for a proposed effluent discharge. Many previous tidal river and estuary studies emphasized mainly the effects of flow conditions (such as velocity, water depth, turbulent intensity, hydraulic gradient, etc.) and temperature on stream aeration, and the effect of salts was not seriously considered. In this research a new mathematical model of reaeration coefficient considering the effect of salts has been developed for water quality analysis in tidal rivers and estuaries. The reaeration coefficient in saline water, k2s(day−1, base e) at any chloride concentration C(g/l) and at 20°C, can be expressed byin which k2f is the reaeration coefficient in fresh water at 20°C. The correlation coefficient of k2s/k2f and C is 0.88.

Modelling solid transport in building drainage systems

1996 ◽  
Vol 33 (9) ◽  
pp. 9-16 ◽  
Author(s):  
John A. Swaffield ◽  
John A. McDougall
Keyword(s):  
Decision Making ◽  
Boundary Conditions ◽  
Numerical Solution ◽  
Water Conservation ◽  
Transient Flow ◽  
Drainage System ◽  
System Model ◽  
Flow Depth ◽  
Flow Conditions ◽  
Solid Transport

The transient flow conditions within a building drainage system may be simulated by the numerical solution of the defining equations of momentum and continuity, coupled to a knowledge of the boundary conditions representing either appliances discharging to the network or particular network terminations. While the fundamental mathematics has long been available, it is the availability of fast, affordable and accessible computing that has allowed the development of the simulations presented in this paper. A drainage system model for unsteady partially filled pipeflow will be presented in this paper. The model is capable of predicting flow depth and rate, and solid velocity, throughout a complex network. The ability of such models to assist in the decision making and design processes will be shown, particularly in such areas as appliance design and water conservation.

Transient flow behaviors of the check valve with different spool-head angle in high-pressure hydrogen storage systems

2022 ◽  
Vol 46 ◽  
pp. 103761
Author(s):  
Jianjun Ye ◽  
Zhenhua Zhao ◽  
Junxu Cui ◽  
Zhengli Hua ◽  
Wenzhu Peng ◽  
...  
Keyword(s):  
High Pressure ◽  
Hydrogen Storage ◽  
Transient Flow ◽  
Storage Systems ◽  
Check Valve ◽  
Pressure Hydrogen

Local characteristic of horizontal air–water two-phase flow by wire-mesh sensor

2016 ◽  
Vol 40 (3) ◽  
pp. 746-761 ◽  
Author(s):  
Weiling Liu ◽  
Chao Tan ◽  
Feng Dong
Keyword(s):  
Void Fraction ◽  
Transient Flow ◽  
Two Phase Flow ◽  
Wire Mesh ◽  
Local Characteristic ◽  
Phase Flow ◽  
Flow Conditions ◽  
Two Phase ◽  
Horizontal Pipe ◽  
Local Flow

Two-phase flow widely exists in many industries. Understanding local characteristics of two-phase flow under different flow conditions in piping systems is important to design and optimize the industrial process for higher productivity and lower cost. Air–water two-phase flow experiments were conducted with a 16×16 conductivity wire-mesh sensor (WMS) in a horizontal pipe of a multiphase flow facility. The cross-sectional void fraction time series was analysed by the probability density function (PDF), which described the void fraction fluctuation at different flow conditions. The changes and causes of PDFs during a flow regime transition were analysed. The local structure and flow behaviour were characterized by the local flow spectrum energy analysis and the local void fraction distribution (horizontal, vertical and radial direction) analysis. Finally, three-dimensional transient flow fluctuation energy evolution and characteristic scale distribution based on wavelet analysis of air–water two-phase flow were presented, which revealed the structural features of each phase in two-phase flow.

EXPERIMENTAL INVESTIGATION OF DEBRIS DAMMING IN TRANSIENT FLOW CONDITIONS

2019 ◽  
Author(s):  
GABRIELLA MAUTI ◽  
JACOB STOLLE ◽  
IOAN NISTOR ◽  
MAJID MOHAMMADIAN
Keyword(s):  
Experimental Investigation ◽  
Transient Flow ◽  
Flow Conditions

scholarly journals Transient Flow Characteristic of High-Pressure Hydrogen Gas in Check Valve during the Opening Process

Energies ◽  
2020 ◽  
Vol 13 (16) ◽  
pp. 4222
Author(s):  
Jianjun Ye ◽  
Zhenhua Zhao ◽  
Jinyang Zheng ◽  
Shehab Salem ◽  
Jiangcun Yu ◽  
...  
Keyword(s):  
High Pressure ◽  
Gas Flow ◽  
Transient Flow ◽  
Check Valve ◽  
Hydrogen Gas ◽  
Strong Impact ◽  
Hydrogen Flow ◽  
Hydrogen Systems ◽  
Pressure Hydrogen ◽  
Opening Process

In high-pressure hydrogen systems, the check valve is one of the most easy-to-damage components. Generally, the high-pressure hydrogen flow can generate a strong impact on the check valve, which can cause damage and failure. Therefore, it is useful to study the transient flow characteristics of the high-pressure hydrogen flow in check valves. Using dynamic mesh generation and the National Institute of Standards and Technology (NIST) real hydrogen gas model, a transient-flow model of the high-pressure hydrogen for the check valve is established. First, the flow properties of high-pressure hydrogen during the opening process is investigated, and velocity changes and pressure distribution of hydrogen gas flow are studied. In addition, the fluid force, acceleration, and velocity of the valve spool are analyzed quantitatively. Subsequently, the effect of the hydrogen inlet-pressure on the movement characteristic of the valve spool is investigated. The results of this study can improve both the design and applications of check valves in high-pressure hydrogen systems.

scholarly journals Evaluation of the Aerodynamic and Aeroacoustic Response of a Vehicle to Transient Flow Conditions

2013 ◽  
Vol 6 (1) ◽  
pp. 389-402 ◽  
Author(s):  
Nicholas Oettle ◽  
Oliver Mankowski ◽  
David Sims-Williams ◽  
Robert Dominy ◽  
Claire Freeman
Keyword(s):  
Transient Flow ◽  
Flow Conditions
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