scholarly journals Research of condensation induced water hammer under filling a horizontal pipe with subcooled water

2021 ◽  
Vol 2088 (1) ◽  
pp. 012028
Author(s):  
G J Volkov ◽  
V I Melikhov ◽  
O I Melikhov ◽  
S M Nikonov ◽  
S S Selkin
Keyword(s):  
Water Hammer ◽  
Test Facility ◽  
Transfer Model ◽  
Noticeable Effect ◽  
Horizontal Pipe ◽  
Interphase Heat Transfer ◽  
Small Water ◽  
Subcooled Water ◽  
System Pressure ◽  
Pipe Water

Abstract Experiments at the KGU test facility, devoted to condensation induced water hammers (CIWH) were analysed with the WAHA code. Test section of the KGU test facility is slightly inclined horizontal pipe of 3 m length and of 64 mm inner diameter. Subcooled water was supplied to the pipe inlet, pipe outlet was connected to separator vessel. Upper part of separator vessel was connected to steam source. Experiments were performed for different system pressure, different water subcooling and different mass flow rate of water supply. The performed experimental study of CIWH showed that in the investigated range of parameters, the development of CIWH occurs in different ways. At the stage of water propagation along the filled with steam horizontal pipe, water hammer was not observed. At the stage of free drainage of water from the outlet end of the pipe, water hammer was realized only when the water was sufficiently subcooled. At the stage of the water level rise in the horizontal pipe, water hammer occurred in all tests. At the last stage of filling the upper part in the separation vessel, there were small water hammers due to the collapses of the remaining steam bubbles. Numerical modelling of these experiments with the WAHA code revealed the shortcomings of the interphase heat transfer model developed for this code, which have a noticeable effect on the numerical solution.

On Modeling of Condensation-Induced Water Hammer in Horizontal Pipe

2009 ◽  
Author(s):  
Iztok Tiselj ◽  
Luka Sˇtrubelj
Keyword(s):  
Slug Flow ◽  
Fluid Model ◽  
Three Dimensional ◽  
Water Hammer ◽  
Stratified Flows ◽  
Transfer Model ◽  
Horizontal Pipe ◽  
Surface Renewal ◽  
Pressure Peak ◽  
Cold Liquid

Condensation-induced water hammer, which appears when horizontal pipe filled with hot vapor is being slowly flooded with cold liquid, is known to be very stochastic phenomena. Time and position of the slug that is followed by the rapid condensation of the bubble behind the slug, is very sensitive to the minor changes in the experimental setup and consequently: results of the simulations are also very sensitive to the minor changes of the physical and numerical parameters in the model. Selected condensation-induced water hammer experiments performed on PMK-2 (AEKI, Hungary) device were numerically modeled with three-dimensional two-fluid model of computer codes NEPTUNE CFD. In most of the experimental cases, slow flooding of the pipe was abruptly interrupted by a strong slugging and water hammer, while in the experimental runs selected in the present work, the transition from the stratified into the slug flow was not accompanied by the water hammer pressure peak. That makes these cases more suitable tests for evaluation of the various condensation models in the horizontally stratified flows and puts them in the range of the available CFD (Computational Fluid Dynamics) codes. The key models for successful simulation appear to be the condensation model of the hot vapor on the cold liquid and the interfacial momentum transfer model. The surface renewal types of condensation correlations, developed for condensation in the stratified flows, were used in the simulations and were applied also in the regions of the slug flow. The CFD simulations quantitatively capture the main phenomena of the experiments, while the stochastic nature of the particular condensation-induced water hammer experiments does not allow detailed prediction of the time and position of the slug formation in the pipe. It is shown that even the selected experiments without water hammer present a tough test for the applied CFD codes.

Water Hammer in Horizontal Water-Steam Counter-Current Flow

2006 ◽  
Author(s):  
Janez Gale
Keyword(s):  
Flow Regime ◽  
Current Flow ◽  
Fluid Model ◽  
Water Hammer ◽  
Test Facility ◽  
Two Phase ◽  
Horizontal Pipe ◽  
Water Steam ◽  
Counter Current Flow ◽  
Counter Current

A six-equation, one-dimensional, two-fluid model of the two-phase flow, incorporated into the recently developed computer code WAHA, was used to model water hammer transient initiated with liquid-vapor counter-current flow in the horizontal pipe. The applied flow regimes and closure relations of the WAHA code for the inter-phase exchange of mass, momentum and energy are described and discussed. Although the WAHA code flow regime maps turned out to be sufficient and accurate for simulations of the column separation type of the fast transients, the current analysis pointed out the need to introduce some limiting values for dispersed flow regime correlations in order to successfully simulate water hammer initiated by condensation-induced counter-current flow. The WAHA code with modified relaxation source terms was then successfully utilized for simulations of the experiments performed at the Hungarian PMK-2 test facility.

TRACE5 Simulation of Condensation-Induced Water Hammer Phenomena

2010 ◽  
Author(s):  
S. Gallardo ◽  
V. Abella ◽  
G. Verdu´
Keyword(s):  
Analytical Model ◽  
Water Injection ◽  
Interfacial Shear Stress ◽  
Branch Pipe ◽  
Water Hammer ◽  
Interfacial Instability ◽  
Test Facility ◽  
Time Step ◽  
Horizontal Pipe ◽  
Flow Rates

The purpose of this work is to test the capability of TRACE5 code in the simulation of thermal-hydraulic transients concerning Condensation-Induced Water Hammer (CIWH) phenomena in a horizontal branch pipe connected to the vessel downcomer. The CIWH is produced by the condensation of the steam by subcooled water counterflow in the horizontal pipe, which causes two-phase flow interfacial instability, and is capable of initiating a severe water hammer, possibly leading to significant plant damage. The work is developed in the frame of OECD/NEA ROSA Project Test 2, performed in the Large Scale Test Facility (LSTF) of the Japan Atomic Energy Agency (JAEA) [1]. The purpose is to provide an analytical model for the LSTF installation, in order to evaluate the critical inlet water flow rates and system pressures of CIWH in a long horizontal pipe without using interfacial friction factor or heat transfer coefficients and using the default TRACE criterion of transition from stratified to a slug flow. The analytical model is designed with the thermal-hydraulic code TRACE5 via 1D-components, reproducing the actual branch where the CIWH is produced. A TEE component is connected to a FILL component, which simulates the water injection, and to a BREAK component set to the boundary conditions that simulate the downcomer. Our model uses one-dimensional flow equations and default correlations of interfacial shear stress and heat and mass transfer available by TRACE. Several comparisons are performed, varying pressure system and water injection mass flow rates. Simulated pressure pulses are characterized, studying parameters such as geometry nodalization, time-step effect, Courant number, numerical diffusion, etc. Results show that 1D model slightly underestimates the maximum pressure pulse intensity in all cases considered.

Experiments to Investigate Flow Regime Transition for Steam and Subcooled Water From Stratified Flow to Slug Flow in Horizontal Pipe

2008 ◽  
Author(s):  
Hiral J. Kadakia ◽  
Brian G. Williams ◽  
Richard R. Schultz
Keyword(s):  
Flow Regime ◽  
Cross Section ◽  
Slug Flow ◽  
Good Description ◽  
Circular Cross Section ◽  
Water Hammer ◽  
Horizontal Pipe ◽  
Representative Data ◽  
Subcooled Water ◽  
Flow Regime Transition

Steam flowing over horizontally-stratified subcooled water in a circular-cross-section pipe may result in condensation-induced water hammer (CIWH). This subject has been studied by a number of researchers and representative data are given by Bjorge and Griffith 1986 who studied the conditions that lead to CIWH. Bjorge & Griffith give a good description of the phenomena including its precursors and characteristics.

scholarly journals Performance characteristics of a small water-hammer head pump

2019 ◽  
Vol 12 (2) ◽  
pp. 59-64
Author(s):  
Krishpersad Manohar ◽  
Anthony Ademola Adeyanju ◽  
Kureem Vialva
Keyword(s):  
Water Hammer ◽  
Maximum Height ◽  
Pump Efficiency ◽  
Inlet Section ◽  
Flowing Fluid ◽  
Test Configuration ◽  
Small Water ◽  
External Power Source ◽  
Hammer Head ◽  
Head Height

Abstract. Many rural farming areas are located far from a reliable electricity supply; hence, obtaining a reliable source of water for crops and livestock can prove to be an expensive venture. A water pump operating on the water-hammer effect requires no external power source and can serve as an effective means of pumping water to a higher altitude once a reliable supply is available. A low-cost small water-hammer head pump was designed to operate on the water-hammer head effect created by the sudden stoppage of a flowing fluid. This design consisted of an inlet section followed by the pump body, a pressure section and an outlet. The experimental set-up for testing the water-hammer head pump was designed with a variable head input and an adjustable head output. For each test configuration, a total of 10 samples of pump supply water and pump exhausted water were collected. The water samples were collected for 30 s in each case. The results showed a non-linear variation of water flow with respect to pump outlet height. The pump was capable of delivering water to a maximum height of 8 to 10 times the height of the input head. The pump operated at average efficiencies of 26 %, 16 % and 6 % when the delivery height was 2, 4 and 6 times the input head height, respectively. There was a 5 % incremental decrease in pump efficiency as the delivery height increased in increments of the corresponding input head height.

scholarly journals Study on a Multi-pipe Water Hammer Phenomenon by using CFD of Rapid Valve Closing

2013 ◽  
Vol 27 (4) ◽  
pp. 479-487 ◽  
Author(s):  
No-Suk Park ◽  
Seong-Su Kim ◽  
Moon-Sun Kang ◽  
Jong-Woong Choi
Keyword(s):  
Water Hammer ◽  
Pipe Water

Measurement and Simulation of Water Hammer in Piping Systems Including Junction Coupling

2013 ◽  
Author(s):  
Stefan Riedelmeier ◽  
Stefan Becker ◽  
Eberhard Schlücker
Keyword(s):  
Three Dimensional ◽  
Water Hammer ◽  
Test Facility ◽  
One Dimensional ◽  
Beam Elements ◽  
Coupled Codes ◽  
Piping Systems ◽  
Complex Test ◽  
System Configurations

For the analysis of the effects of fluid-structure interaction (FSI) during water hammer in piping systems, a complex test facility was constructed. Resonance experiments with movable bends in two system configurations were carried out. The pressure and the displacement of the bend were recorded. The aim was to reproduce the results with two coupled codes: a one-dimensional solver based on the method of characteristics (MOC) for the hydraulic system and a three-dimensional solver based on the finite element method (FEM) working with one-dimensional beam elements for the structural system. The calculation included junction and friction coupling. The models were fine-tuned separately. For this purpose, special measurements were carried out. These included the determination of the structural damping, the friction factor, the influence of the bending of the anchorage, etc. After the validation of the models, the results of the coupled calculations were compared against the measurements, the performance of the coupled codes was evaluated and the most important physical effects were analyzed and are discussed.

Evaluation of the Scaling Analysis Model of the EU-APR1400 Core Catcher Cooling System Test Facility

2014 ◽  
Author(s):  
Bo W. Rhee ◽  
K. S. Ha ◽  
R. J. Park ◽  
J. H. Song
Keyword(s):  
Performance Test ◽  
Cooling System ◽  
Reactor Core ◽  
Test Facility ◽  
Scaling Analysis ◽  
Analysis Model ◽  
System Pressure ◽  
Test Loop ◽  
Core Catcher ◽  
The Eu

This paper describes the basic design features of the EU-APR1400 reactor core catcher cooling system and its test facility, and the associated scaling analysis model. An assessment of the validity of the scaling analysis using the preliminary performance test result of the test facility is described. This includes comparison of the predicted mass flow rate of the test loop as a function of the heat load to the facility, inlet flow subcooling and system pressure to the experimental results.

Vapor Bubble Condensation Characteristics of Subcooled Flow Boiling in Vertical Rectangular Channel

2012 ◽  
Author(s):  
Zhi-wei Tan ◽  
Liang-ming Pan
Keyword(s):  
Bubble Size ◽  
Vapor Bubble ◽  
Large Scale ◽  
Flow Boiling ◽  
Rectangular Channel ◽  
Size Variation ◽  
Transfer Model ◽  
Bubble Deformation ◽  
Initial Diameter ◽  
System Pressure

In this study, the behavior of condensing single vapor bubble in subcooled boiling flow within two different vertical rectangular channels has been numerically investigated by using the VOF (Volume of Fluid) multiphase flow model. The mass and energy transfer model of bubble condensing process induced from the interfacial heat transfer was proposed to describe the interfacial transportation between the two phases. The results of VOF simulations showed good agreements with previous experimental data in the bubble size variation and lifetime. The bubble lifetime was almost proportional to bubble initial size and prolonged by system pressure. With the increase of subcooling, the bubble lifetime reduces significantly, and the effect of mass flux could be negligible. When bubble size increased, the bubble shape tends to be changed in a large-scale channel. The VOF simulation results of deformation have good agreement with those of Kamei’ experiment and the results of MPS (Moving Particle Semi-implicit) simulation in the large-scale channel. Furthermore, the initial bubble size, subcooling of liquid and system pressure play an important role to influence the bubble deformation behaviors significantly. The bubble could deform sharper with the increase of subcooling and initial diameter, or could breakup when the subcooling and the initial diameter reached a certain value at the last bubble stage. Whereas the trend of bubble deformation would be weaken with the increase of system pressure.

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