Experimental evaluation of ability of Relap5, Drako®, Flowmaster2™ and program using unsteady wall friction model to calculate water hammer loadings on pipelines

2008 ◽  
Vol 238 (8) ◽  
pp. 2084-2093 ◽  
Author(s):  
Jerzy Marcinkiewicz ◽  
Adam Adamowski ◽  
Mariusz Lewandowski
Keyword(s):  
Experimental Evaluation ◽  
Water Hammer ◽  
Friction Model ◽  
Wall Friction

Experimental Evaluation of Ability of Relap5, Drako®, Flowmaster2™ and Program Using Unsteady Wall Friction Model to Calculate Water Hammer Loadings on Pipelines

2006 ◽  
Author(s):  
Jerzy Marcinkiewicz ◽  
Adam Adamkowski ◽  
Mariusz Lewandowski
Keyword(s):  
Nuclear Power ◽  
Power Plants ◽  
Transient Flow ◽  
Water Hammer ◽  
Friction Model ◽  
Third Party ◽  
Wall Friction ◽  
Courant Number ◽  
Common Procedure ◽  
Friction Models

Mechanical loadings on pipe systems caused by water hammer (hydraulic transients) belong to the most important and most difficult to calculate design loadings in nuclear power plants. The most common procedure in Sweden is to calculate the water hammer loadings on pipe segments, according to the classical 1D theory of liquid transient flow in a pipeline, and then transfer the results to strength analyses of pipeline structure. This procedure assumes that there is quasi-steady respond of the pipeline structure to pressure surges — no dynamic interaction between the fluid and the pipeline construction. The hydraulic loadings are calculated with 1-D so-called “network” programs. Commonly used in Sweden are Relap5, Drako and Flowmaster2 — all using quasi-steady wall friction model. As a third party accredited inspection body INSPECTA NUCLEAR AB reviews calculations of water hammer loadings. The presented work shall be seen as an attempt to illustrate ability of Relap5, Flowmaster2 and Drako programs to calculate the water hammer loadings. A special attention was paid to using of Relap5 for calculation of water hammer pressure surges and forces (including some aspects of influence of Courant number on the calculation results) and also the importance of considering the dynamic (or unsteady) friction models. The calculations are compared with experimental results. The experiments have been conducted at a test rig designed and constructed at the Szewalski Institute of Fluid–Flow Machinery of the Polish Academy of Sciences (IMP PAN) in Gdansk, Poland. The analyses show quite small differences between pressures and forces calculated with Relap5, Flowmaster2 and Drako (the differences regard mainly damping of pressure waves). The comparison of calculated and measured pressures and also a force acting on a pre-defined pipe segment show significant differences. It is shown that the differences can be reduced by using unsteady friction models in calculations. Recently, such models have been subjects of works of several researches in the world.

Fast Meshless Solution With Lumped Friction for Water Hammer

2020 ◽  
Author(s):  
Yuanzhi Xu ◽  
Zongxia Jiao ◽  
Longfei Zhao
Keyword(s):  
Computational Grid ◽  
Water Hammer ◽  
Friction Model ◽  
Time Cost ◽  
Improved Method ◽  
Fluid Friction ◽  
Time Line ◽  
Practical Applications ◽  
Distributed Friction ◽  
Mesh Grid

Abstract The water hammer in pipelines, with the absence of fluid friction, could be solved by a time-domain exact solution, using a simple recursive process. No computational grid was needed, but the calculation time cost was extremely high. Its improved method, named as the fast meshless solution (FMS), was developed to speed the computation by introducing the time-line interpolation. For the purpose of practical applications, the attempt to consider fluid friction in the FMS is presented here. As there is no mesh grid in the distance-time plane, the distributed friction model can not be employed upon the presented method directly. The fluid friction lumped at the pipe end is proposed, and both steady and unsteady friction are studied. A benchmark problem of the water hammer in a reservoir-pipe-valve (RPV) system is employed for the validation and comparison. The water hammer considering lumped friction can be calculated fast by the FMS, and the accuracy is acceptable. The method discussed here may be of interest in a quick assessment of the piping water hammer.

Charts for water hammer in pipelines with air chambers

1977 ◽  
Vol 4 (3) ◽  
pp. 293-313 ◽  
Author(s):  
Eugen Ruus
Keyword(s):  
Water Column ◽  
Pipe Wall ◽  
Water Hammer ◽  
Wall Friction ◽  
Low Resistance ◽  
Discharge Line ◽  
Air Chamber ◽  
Basic Parameters ◽  
Computer Studies

Upsurges and downsurges are calculated and plotted for a simple pump discharge line provided with an air chamber. Basic parameters such as pipeline constant, air chamber parameter, pipe wall friction, and orifice resistance are used. The results of this paper can be used to determine the necessary volume of the air chamber. Computer studies indicate that the assumption of the rigid water column and the concentration of pipe friction at the pump end of the pipeline yields reasonably good results at the pump end; however, because of these assumptions, large errors in estimation of both upsurges and downsurges occur at the midpoint and particularly at the quarter point of the pipeline. Pipe friction has a substantially different effect on surges than that of the orifice resistance; these two effects should therefore be considered separately. A differential orifice is recommended and considered; this orifice should have a low resistance to flow out of the chamber.

Charts for water hammer in pipelines resulting from valve closure

1980 ◽  
Vol 7 (2) ◽  
pp. 243-255 ◽  
Author(s):  
Eugen Ruus ◽  
Farouk A. El-Fitiany
Keyword(s):  
Pipe Wall ◽  
Pressure Head ◽  
Water Hammer ◽  
Wall Friction ◽  
Maximum Pressure ◽  
Valve Closure ◽  
Closure Time ◽  
Basic Parameters

Maximum pressure head rises, which result from valve closure according to (a) uniform, (b) equal-percentage, and (c) optimum valve closure arrangements, are calculated and plotted for the valve end and for the midpoint of a simple pipeline. Basic parameters such as the pipeline constant, relative closure time, and pipe wall friction are considered for closures both from partial as well as from full valve openings. The results of this paper can be used to draw the maximum hydraulic grade line along the pipe for these closure arrangements. It is found that the equal-percentage closure arrangement yields consistently less pressure head rise than does the uniform closure arrangement. Further, the optimum closure arrangement yields consistently less head rise than the equal-percentage one. Closures from partial valve openings increase the pressure head rise considerably and must always be considered.

Effect of wall friction model on predicting emergency core coolant behavior in upper downcomer with direct vessel safety injection using MARS-KS

2018 ◽  
Vol 116 ◽  
pp. 395-406
Author(s):  
Chi-Jin Choi ◽  
Jin-Hwa Yang ◽  
Dong-Jin Euh ◽  
Goon-Cherl Park ◽  
Hyoung-Kyu Cho
Keyword(s):  
Friction Model ◽  
Wall Friction

scholarly journals Approximate approach for improving pressure attenuation accuracy during hydraulic transients

2021 ◽  
Author(s):  
Chao Yu ◽  
Xiaodong Yu ◽  
Lei Zhang ◽  
Bhusan Neupane ◽  
Jian Zhang
Keyword(s):  
Reynolds Number ◽  
Water Hammer ◽  
Friction Model ◽  
Pipe Network ◽  
Network Systems ◽  
Initial Flow ◽  
Friction Term ◽  
Smooth Pipe ◽  
The Relationship ◽  
Good Agreement

Abstract The quasi-steady friction model is generally adopted in water hammer simulation in pipe network systems, which cannot accurately reflect the attenuation of pressure, while the existing unsteady friction model is challenging to use in complex pipe network systems. In this study, a convenient method for treating the friction term is proposed based on the Moody diagram. The attenuation process of water hammer pressure can be accurately reflected by reading the relationship curve between Reynolds number and the Darcy friction factor in the pipeline transient process. Combined with the classical water hammer experiment and the long pipe valve closing experiment in our laboratory, the accuracy of this model is verified, and the influence of absolute roughness (e) and Reynolds number (Re) on the model was analyzed as well. The results show that the pressure attenuation using the Method of Characteristics (MOC) and the proposed friction model has a good agreement with the experimental data. The absolute roughness has little influence on the results in hydraulically smooth pipe, while the minimum Reynolds number has a significant influence. When selecting the minimum Reynolds number, 2% ∼ 5% of the initial flow rate is recommended for calculation.

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