Volume 4: Fluid-Structure Interaction最新文献

{"title":"The Effect Mechanism of Hydrodynamic Factors on Naphthenic Acid Flow-Induced Corrosion","authors":"Yunrong Lyu","doi":"10.1115/pvp2019-93426","DOIUrl":"https://doi.org/10.1115/pvp2019-93426","url":null,"abstract":"\u0000 Hydrodynamic factors are the important factors affecting the flow-induced corrosion of naphthenic acid. The effect mechanisms of hydrodynamic factors such as flow velocity, flow pattern, erosion angle and multiphase flow, etc. on the flow-induced corrosion of naphthenic acid are analyzed comprehensively, and the effect mechanisms of critical hydrodynamic parameters such as surface shear stress and near-wall turbulence intensity, etc. on naphthenic acid corrosion are explained. It is pointed out that in the flow-induced corrosion system of naphthenic acid, hydrodynamic factors such as flow velocity, flow pattern, erosion angle and multiphase flow, etc. influence the erosion intensity and mass transfer process generally by changing the magnitude of surface shear stress and near-wall turbulence intensity, thus affecting the severity of corrosion.","PeriodicalId":185894,"journal":{"name":"Volume 4: Fluid-Structure Interaction","volume":"81 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"120994757","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Numerical Investigation of Pressure Fluctuations and Vibrations for Upward Two-Phase Flow in a Pipe","authors":"Alexander Meire, L. Moerloose, J. Degroote","doi":"10.1115/pvp2019-93994","DOIUrl":"https://doi.org/10.1115/pvp2019-93994","url":null,"abstract":"\u0000 Two-phase flows are encountered in a wide range of technological and natural situations. In the last decade, advances in the available computing power have enabled to solve the underlying equations with computational fluid dynamics (CFD) using multi-phase models for the interaction between the different phases. In this study, a volume of fluid (VOF) solver in OpenFOAM is used to investigate the pressure profile in a co-current upward pipe flow of air and water. It is hypothesized that pressure drop events are caused by local buildup of the slower liquid, whereas conservation of volume flow rate forces the dense liquid to accelerate. The calculated pressure gradients are larger than the corresponding experimental data. It is shown that this mismatch might be caused by the evaluation of the momentum balance based on mixture properties; the mixture density increases the effective liquid obstruction and the corresponding pressure drop. Finally, the effect of these pressure fluctuations on the pipe’s vibration is studied using a one-dimensional independent rings structural model.","PeriodicalId":185894,"journal":{"name":"Volume 4: Fluid-Structure Interaction","volume":"32 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122034999","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effect of Phase Velocities Prediction on Fluidelastic Instability of a Cantilever Pipe Subjected to Gas-Liquid Flow","authors":"L. E. Ortiz-Vidal","doi":"10.1115/pvp2019-94063","DOIUrl":"https://doi.org/10.1115/pvp2019-94063","url":null,"abstract":"\u0000 The effect of the phase velocity models on the prediction of fluidelastic instability of a cantilever pipe subjected to gas-liquid internal flow is studied. According to the accepted fluidelastic formulation, a two-phase flow correlation is needed to relate phase velocities in order to solve the system equation. In this study, seven reported correlations, including the homogeneous no-slip model, are used to study the effect of phase velocities prediction on fluidelastic instability parameters, specifically, critical mixture-velocity and critical frequency. Comparisons between simulations and previously reported experiments are performed. Results show that the correlation selection plays an important role in critical mixture-velocity predictions. On the other hand, the critical frequency is less sensitive to the correlation.","PeriodicalId":185894,"journal":{"name":"Volume 4: Fluid-Structure Interaction","volume":"9 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130343199","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Computation of Boiling Water Reactor Annulus Flow Loads Using 2D Potential Flow Methodology and 3D Finite Element Analysis: A Comparative Study","authors":"S. Day, M. Fong, M. Walter","doi":"10.1115/pvp2019-93753","DOIUrl":"https://doi.org/10.1115/pvp2019-93753","url":null,"abstract":"\u0000 During a Loss of Coolant Accident (LOCA) in a Boiling Water Reactor (BWR), subcooled water flows past jet pump assemblies located in the annular region between the Reactor Pressure Vessel (RPV) and the shroud as it moves toward the break location and is subsequently discharged from the RPV. Flow loads caused by such an event are required design basis loads that must be considered for BWR internal components. A comparison is presented between BWR annulus flow loads calculated by the 2D potential flow methodology using complex variables and the 3D finite element method using the heat transfer analogy described in PVP2016-63091 [1]. The comparison demonstrates that greater solution fidelity is available using the FEA method. The results also demonstrate the importance of applying the appropriate velocity correction factor when flow loads are computed using complex variable techniques.","PeriodicalId":185894,"journal":{"name":"Volume 4: Fluid-Structure Interaction","volume":"266 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133206179","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Random Excitation PSD Model Acting on Heat Exchanger Tube Bundle Under Two Phase Flow Condition","authors":"S. Nishida, Ryoichi Kawakami, K. Hirota, H. Morita, Seinosuke Azuma, Y. Kondo, Yoshiteru Komuro","doi":"10.1115/pvp2019-93458","DOIUrl":"https://doi.org/10.1115/pvp2019-93458","url":null,"abstract":"\u0000 A considerable amount of time and dedication have been devoted into the development of an unified non-dimensional random excitation forces (Power Spectrum Density) PSD model of tube bundles into two phase flow conditions. However, any model cannot be used for wide-range two phase flow conditions as random excitation forces depends strongly on a two phase flow regime. Therefore, we have developed a new scaling method for a two phase random excitation force PSD to be applicable for a wide-range of flow conditions. This method has been developed by focusing on the correlation between a two phase pressure loss and two phase turbulence energy. Comparisons of non-dimensional random excitation force PSDs in various conditions scaled by using the developed method, showed a good concordance between the two.","PeriodicalId":185894,"journal":{"name":"Volume 4: Fluid-Structure Interaction","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130066167","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Experimental Investigation of the Flow-Induced Vibrations of a Rod Cluster Control Assembly Inside Guides With Enlarged Gaps","authors":"P. Moussou, V. Fichet, L. Pastur, C. Duhamel, Yannick Tampango","doi":"10.1115/pvp2019-93143","DOIUrl":"https://doi.org/10.1115/pvp2019-93143","url":null,"abstract":"\u0000 In order to better understand the mechanisms of fretting wear damage of guide cards in some Pressurized Water Reactor (PWR) Nuclear Power Plant (NPP), an experimental investigation is undertaken at the Magaly facility in Le Creusot. The test rig consists of a complete Rod Cluster with eleven Guide Cards, submitted to axial flow inside a water tunnel. In order to mimic the effect of fretting wear, the four lower guide cards have enlarged gaps, so that the Control Rods are free to oscillate. The test rig is operated at ambient temperature and pressure, and Plexiglas walls can be arranged along its upper part, and a series of camera records the vibrations of the control rods above and below the guide cards. The vertical flow velocity is in the range of a few m/s. Beam-like pinned-pinned modes at about 5 Hz are observed, and oscillations of several mm of the central rods are measured, which come along with impacts at the higher flow velocities. A simple non-linear calculation reveals that the main effect of the impacts between Control Rods and Guide Cards is an increase of the natural frequency of the rods by about 10%. Furthermore, as the vibration spectra collapse remarkably well with the flow velocity, the experiments prove that turbulent forcing is responsible for the large oscillations of the control rods, no other mechanism being involved.","PeriodicalId":185894,"journal":{"name":"Volume 4: Fluid-Structure Interaction","volume":"3 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132291426","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Towards Understanding Two-Phase Flow Induced Vibration of Piping Structure With a U-Bend","authors":"O. Bamidele, W. Ahmed, Marwan Hassan","doi":"10.1115/pvp2019-93686","DOIUrl":"https://doi.org/10.1115/pvp2019-93686","url":null,"abstract":"\u0000 The current work investigates two-phase flow induced vibrations in 90° U-bend. The two-phase induced vibration of the structure was investigated in the vertical, horizontal and axial directions for various flow patterns from bubbly flow to wavy and annular-dispersed flow. The void fractions at various locations along the piping including the fully developed void fraction and the void fraction at the entrance of the U-bend were fully investigated and correlated with the vibration amplitude. The results show that the excitation forces of the two-phase flow in a piping structure are highly dependent on the flow pattern and the flow conditions upstream of the bend. The fully developed void fraction and slip between phases are important in modelling of forces in U-bends and elbows.","PeriodicalId":185894,"journal":{"name":"Volume 4: Fluid-Structure Interaction","volume":"21 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116664869","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Phase-Locked PIV Measurements of Vortex Shedding Characteristics Downstream of Straight Circular Finned Cylinders During Acoustic Resonance","authors":"Rashidul Islam, Mahmoud Shaaban, A. Mohany","doi":"10.1115/pvp2019-93745","DOIUrl":"https://doi.org/10.1115/pvp2019-93745","url":null,"abstract":"\u0000 Excitation of acoustic resonance by flow perturbation downstream of cylinders can result in hazardous levels of acoustic pressure. Previous studies have shown that straight finned cylinders are susceptible to flow-excited acoustic resonance. In this work, the excitation of acoustic resonance by flow around finned cylinders of different fin parameters including the spacing between the fins, the thickness of the fin, and the height of the fin is investigated. All the investigated finned cylinders have the same equivalent diameter. Phase-locked particle image velocimetry (PIV) measurements are carried out during acoustic resonance to characterize the flow field downstream of the cylinders and identify the influence of the fins on the flow structures at the peak of resonance excitation. Results show that straight circular fins excite acoustic resonance at lower velocities and result in higher sound pressure level compared with a single bare cylinder of the same effective diameter. This behaviour is due to the effect of fin parameters on the strength and the formation length of vortices shed during the acoustic cycle. A brief summary of the results is presented in this paper.","PeriodicalId":185894,"journal":{"name":"Volume 4: Fluid-Structure Interaction","volume":"58 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128448952","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Equivalent Theodorsen Function for Fluidelastic Excitation in a Normal Triangular Array","authors":"L. Alyaldin, N. Mureithi","doi":"10.1115/pvp2019-94010","DOIUrl":"https://doi.org/10.1115/pvp2019-94010","url":null,"abstract":"\u0000 Fluidelastic instability (FEI) remains an important concern to designers of heat exchangers subjected to high flow velocities of gases, liquids or a combination of the two phases. In the present work, experimental tests are conducted to measure the quasi-steady fluid forces acting on a normal triangular tube array of P/D = 1.5 subjected to single-phase cross-flow. The quasi-steady forces together with previously measured unsteady fluid forces are used to estimate the time delay between the central tube motion and fluid forces on itself. The time delay effect for the quasi-steady fluidelastic instability model is derived in the frequency domain in the form of an equivalent Theodorsen function. The results are compared with the Theodorsen function previously obtained for the rotated triangular array. Using the time delay formulation, a stability analysis is carried out to predict the critical velocity for fluidelastic instability in a normal triangular array subjected to single-phase flow.","PeriodicalId":185894,"journal":{"name":"Volume 4: Fluid-Structure Interaction","volume":"8 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-07-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114876828","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Fluid-Elastic Coefficients in Single Phase Cross Flow: Dimensional Analysis, Direct and Indirect Experimental Methods","authors":"R. Lagrange, P. Piteau, X. Delaune, J. Antunes","doi":"10.1115/PVP2019-93984","DOIUrl":"https://doi.org/10.1115/PVP2019-93984","url":null,"abstract":"\u0000 The importance of fluid-elastic forces in tube bundle vibrations can hardly be over-emphasized, in view of their damaging potential. In the last decades, advanced models for representing fluid-elastic coupling have therefore been developed by the community of the domain. Those models are nowadays embedded in the methodologies that are used on a regular basis by both steam generators providers and operators, in order to prevent the risk of a tube failure with adequate safety margins. From an R&D point of view however, the need still remains for more advanced models of fluid-elastic coupling, in order to fully decipher the physics underlying the observed phenomena. As a consequence, new experimental flow-coupling coefficients are also required to specifically feed and validate those more sophisticated models. Recent experiments performed at CEA-Saclay suggest that the fluid stiffness and damping coefficients depend on further dimensionless parameters beyond the reduced velocity.\u0000 In this work, the problem of data reduction is first revisited, in the light of dimensional analysis. For single-phase flows, it is underlined that the flow-coupling coefficients depend at least on two dimensionless parameters, namely the Reynolds number Re and the Stokes number Sk. Therefore, reducing the experimental data in terms of the compound dimensionless quantity Vr = Re/Sk necessarily leads to impoverish results, hence the data dispersion. In a second step, experimental data are presented using the dimensionless numbers Re and Sk. We report experiments, for a 3 × 5 square tube bundle subjected to water transverse flow. The bundle is rigid, except for the central tube which is mounted on a flexible suspension allowing for translation motions in the lift direction.\u0000 The evolutions of the flow-coupling coefficients with the flow velocity are determined using two different experimental procedures: (1) In the direct method, an harmonic motion of increasing frequency is imposed to the tube. (2) In the indirect method, the coefficients are obtained from the modal response of the tube (frequency, damping). The coefficient identification was performed well beyond the system instability boundary, by using active control, allowing an exploration of a significant range of flow velocity.\u0000 For a given Sk, the results show that: (a) at low Re, the flow-coupling coefficients are close to zero; (b) at intermediate Re, the flow stabilizes the tube; (c) at high Re, the flow destabilizes the tube, leading to a damping-controlled instability at a critical Re. Reducing the data in terms of Re and Sk clarifies the various experimental “branches”, which are mixed when using Vr. The two identification techniques lead to reasonably compatible fluid-elastic coefficients.","PeriodicalId":185894,"journal":{"name":"Volume 4: Fluid-Structure Interaction","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-07-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130458179","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}