Journal of Fluids Engineering最新文献_第8页

Experimental Investigation of Part Load Vortex Rope Mitigation with Rod Protrusion in an Axial Turbine 轴流式涡轮机中利用杆突起缓解部分载荷涡流的实验研究

Journal of Fluids Engineering Pub Date : 2024-02-01 DOI: 10.1115/1.4064610

S. Shiraghaee, J. Sundström, M. Raisee, Michel J. Cervantes

{"title":"Experimental Investigation of Part Load Vortex Rope Mitigation with Rod Protrusion in an Axial Turbine","authors":"S. Shiraghaee, J. Sundström, M. Raisee, Michel J. Cervantes","doi":"10.1115/1.4064610","DOIUrl":"https://doi.org/10.1115/1.4064610","url":null,"abstract":"\u0000 The present paper investigates the rotating vortex rope (RVR) mitigation on an axial turbine model by the radial protrusion of four cylindrical rods into the draft tube. RVR mitigation is of particular interest due to the unfavorable pressure pulsations it induces in the hydraulic circuit that can affect turbine life and performance. The protrusion lengths, which were the same among the four rods, were varied according to a pre-defined sequence. The experiments were performed under four part-load regimes ranging from upper part load to deep part load. Time-resolved pressure measurements were conducted at two sections on the draft tube wall along with high-speed videography and efficiency measurement to investigate the effect of the mitigation technique on the RVR characteristics and turbine performance. The recorded pressure data were decomposed and studied through spectral analyses, phase-averaging, and statistical analyses of the RVR frequency and peak-to-peak pressure amplitude distributions. The results showed different levels of pressure amplitude mitigation ranging from approximately 10% to 85% depending on the operating condition, protrusion length, and the method of analysis. The hydraulic efficiency of the turbine decreased by a maximum of 3.5% that of the best efficiency point (BEP) with the implementation of the mitigation technique. The variations in the obtained mitigation levels and efficiencies depending on protrusion length and operating condition indicate the need for the implementation of a feedback-loop controller. Thus, the protrusion length can be actively optimizes based on the desired mitigation target.","PeriodicalId":504378,"journal":{"name":"Journal of Fluids Engineering","volume":"24 19","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139686518","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}

引用次数: 0

Design Method for Impeller of Centrifugal Pump with Guide Vanes Based On Oseen Vortex 基于奥森涡流的带导叶离心泵叶轮设计方法

Journal of Fluids Engineering Pub Date : 2024-02-01 DOI: 10.1115/1.4064607

Yangping Lu, Ming Liu, Lei Tan, Demin Liu

引用次数: 0

Derivation of “double-loop” Theory and Mechanism of Cavitation-vortex Interaction in Turbulent Cavitation Boundary Layer 湍流空化边界层中空化-涡流相互作用的 "双环 "理论和机制推导

Journal of Fluids Engineering Pub Date : 2024-01-25 DOI: 10.1115/1.4064532

Weiwei Jin

{"title":"Derivation of “double-loop” Theory and Mechanism of Cavitation-vortex Interaction in Turbulent Cavitation Boundary Layer","authors":"Weiwei Jin","doi":"10.1115/1.4064532","DOIUrl":"https://doi.org/10.1115/1.4064532","url":null,"abstract":"\u0000 “Double-loop” theory was determined by deriving a correlation between turbulent fluctuating kinetic energy and water vapor volume fraction from the momentum equation, which further logically revealed the mystery of cavitation breaking around a three-dimensional symmetry hydrofoil based on the numerical results of large eddy simulation and Zwart-Gerber-Belamri cavitation model. When the second-order fluctuation moment V'xV'x and the streamwise velocity Vx are depleted, a vortex is generated, leading to alternating cavitation interface fluctuations. In one state, cavitation naturally breaks outward from the inner zone, triggering an up-and-down fluctuation in the normal velocity in the gap vortex and transferring external energy to the inner zone. In another state, it triggers a rise in an upward normal velocity in the attached vortex, creating an exchange of energy through the wake. Cavitation collapse caused by a reentrant jet stagnates the reverse Vx so that V'xV'x tends to zero. The pressure implosion resulting from the Shrinkage of the “Like-Rayleigh-Plesset” cavity at cavitation onset is stronger than the pressure implosion created by the vortex field during cavitation breaking.","PeriodicalId":504378,"journal":{"name":"Journal of Fluids Engineering","volume":"12 6","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-01-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139596086","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}

引用次数: 0

An Air-Bearing Floating-Element Force Balance for Friction Drag Measurement 用于摩擦阻力测量的气浮元件测力天平

Journal of Fluids Engineering Pub Date : 2024-01-24 DOI: 10.1115/1.4064294

Xiaohui Wei, Xin Zhang, Jiangang Chen, Yu Zhou

引用次数: 0

The Effect of Curved Geometry on Exiting Flow of Fluidic Oscillators 曲面几何对流体振荡器出口流的影响

Journal of Fluids Engineering Pub Date : 2024-01-24 DOI: 10.1115/1.4064293

Brian T. Bohan, M. Polanka, Il J. Kim, Jeffrey M. Layng

{"title":"The Effect of Curved Geometry on Exiting Flow of Fluidic Oscillators","authors":"Brian T. Bohan, M. Polanka, Il J. Kim, Jeffrey M. Layng","doi":"10.1115/1.4064293","DOIUrl":"https://doi.org/10.1115/1.4064293","url":null,"abstract":"\u0000 Traditionally fluidic oscillators are designed to be planar. However, there are applications that may desire the exiting fluid to move in the third dimension. This could allow these oscillators to be more effective in applications such as fuel sprays, cooling flow, or flow control devices with its increase in effective spray area. This investigation designed a series of oscillators that curved the whole body and/or the exit nozzle to understand how to maximize out of plane motion. These configurations were compared to a baseline planar oscillator with no curved characteristics. Velocities were measured downstream of these oscillators within a data collection grid using a hot wire probe to determine the 3D shape of the exiting jet. Results show that configurations with only one of the two curved physical characteristics (i.e., only a curved body or a curved nozzle) produced the most curvature. Having both of the curved physical characteristics caused the nozzle width to decrease causing the axial spacing to decrease. Additionally, these curved exiting flows were only seen at mass flow rates below 40 standard liters per minute (SLPM). Higher mass flow rates caused the exiting flow to flatten, returning the flow to the baseline result of in-plane oscillations. This led to a decrease in jet spread.","PeriodicalId":504378,"journal":{"name":"Journal of Fluids Engineering","volume":"60 12","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-01-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139600793","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}

引用次数: 0

Exascale CFD in Heterogeneous Systems 异构系统中的超大规模 CFD

Journal of Fluids Engineering Pub Date : 2024-01-23 DOI: 10.1115/1.4064534

David Trebotich

{"title":"Exascale CFD in Heterogeneous Systems","authors":"David Trebotich","doi":"10.1115/1.4064534","DOIUrl":"https://doi.org/10.1115/1.4064534","url":null,"abstract":"\u0000 Exascale computing has extended the reach of resolved flow simulations in complex, heterogeneous systems far beyond conventional CFD capabilities. As a result, unprecedented pore and micro scale resolution has been achieved in domains that have been traditionally modeled by, and limited to, continuum, effective medium approaches. By making use of computational resources on the new exascale supercomputer, Frontier, at the Oak Ridge Leadership Computing Facility we performed flow simulations that have pushed the limits of domain-to-resolution ratios by several orders of magnitude for heterogeneous media. Our approach is an incompressible, Navier-Stokes CFD solver based on an adaptive, embedded boundary method supported by the Chombo software framework for applied PDEs. The computational workhorse in the CFD application code is an elliptic solver framework in Chombo for pressure-Poisson and viscous, Helmholtz terms that leverages a PETSc-hypre software interface tuned for accelerator-based platforms. We demonstrate scalability of our approach by replicating a unit cylinder packed with microspheres to achieve over 400 billion degrees of freedom simulated. These simulations model domain lengths of over 20 meters with channel volumes of over 400 cm^3 containing millions of packed spheres with 20 micron grid resolution, challenging current understanding of what it means to be a representative elementary volume of the continuum scale in heterogeneous media. We also simulate a range of Reynolds numbers to demonstrate wide applicability and robustness of the approach.","PeriodicalId":504378,"journal":{"name":"Journal of Fluids Engineering","volume":"35 9","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-01-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139603853","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}

引用次数: 0

Experimental Investigation of the Performance of a Novel Adiabatic Swirl-Flow Separation Apparatus in Air-Water Two-Phase Flow 新型绝热漩涡流分离装置在气水两相流中的性能实验研究

Journal of Fluids Engineering Pub Date : 2024-01-23 DOI: 10.1115/1.4064531

A. Thyagarajan, Gangchen Ren, Debjyoti Banerjee, Vijay K. Dhir

引用次数: 0

Towards Polydisperse Flows with MFIX-Exa 利用 MFIX-Exa 实现多分散流动

Journal of Fluids Engineering Pub Date : 2024-01-23 DOI: 10.1115/1.4064533

Aaron Lattanzi, William Fullmer, Andrew Myers, Jordan Musser

引用次数: 0

Direct Numerical Simulation of Involute Channel Turbulence 渐开线通道湍流的直接数值模拟

Journal of Fluids Engineering Pub Date : 2024-01-16 DOI: 10.1115/1.4064496

Emilian Popov, Nicholas Mecham, I. Bolotnov

{"title":"Direct Numerical Simulation of Involute Channel Turbulence","authors":"Emilian Popov, Nicholas Mecham, I. Bolotnov","doi":"10.1115/1.4064496","DOIUrl":"https://doi.org/10.1115/1.4064496","url":null,"abstract":"\u0000 A direct numerical simulation (DNS) study was performed on turbulent flow in the involute channel geometry to develop a numerical database and determine the differences compared with a flat parallel channel. The varying channel curvature along the walls was studied for differences in mean profiles. Parameters of interest include streamwise velocity, turbulent kinetic energy (TKE), and turbulence dissipation rate, as well as Reynolds stresses and turbulence transport terms. Profile sampling was carried out at 10 locations along the span of the involute. Additional DNS studies were performed on smaller domains of comparable curvature to the involute domain: a high curvature channel (high circular), a low curvature channel (low circular), and a flat channel (flat). Each of these four cases were compared against each other and to other DNS studies performed on parallel flows. The results indicate that the bulk involute channel flow does not differ significantly from a flat parallel channel flow and that the curvature of the walls does not significantly alter the mean flow parameters. However, the regions of the involute channel near the side walls exhibit interesting flow patterns, which warrant further study.","PeriodicalId":504378,"journal":{"name":"Journal of Fluids Engineering","volume":"34 14","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-01-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139528470","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}

引用次数: 0

Comparison of Heat Transfer and Friction in Pipes with Various Internal Roughness 不同内部粗糙度管道中传热和摩擦的比较

Journal of Fluids Engineering Pub Date : 2024-01-16 DOI: 10.1115/1.4064495

Abdolreza Raoufi, Andrew Williams, Craig Metcalfe, Paul-Emile Trudeau, Joshua R. Brinkerhoff, L. Warwaruk, Sina Ghaemi

{"title":"Comparison of Heat Transfer and Friction in Pipes with Various Internal Roughness","authors":"Abdolreza Raoufi, Andrew Williams, Craig Metcalfe, Paul-Emile Trudeau, Joshua R. Brinkerhoff, L. Warwaruk, Sina Ghaemi","doi":"10.1115/1.4064495","DOIUrl":"https://doi.org/10.1115/1.4064495","url":null,"abstract":"\u0000 The heat transfer and friction factor of turbulent pipe flows with different internal roughness are experimentally investigated. Three types of roughness in forms of a mesh, hemispherical elements, and a coil are added to the interior of pipes with a nominal diameter of two inches. The working fluid is air, and the Reynolds numbers varies from 20,000 to 90,000 in increments of 10,000. For investigating the heat-transfer properties the pipe wall is heated to 375°C while the inlet air remains at the room temperature. The measurements show that the mesh-type roughness results in a maximum Nusselt number, Nu, increase of approximately 6%, the pipes with hemispherical roughness increased the Nu by a maximum amount of 30%, and the coil increased Nu by up to 60% compared with the smooth pipe. The maximum increase of friction factor is 40% for the pipes with mesh-type roughness, 30% for pipes with hemispherical roughness, and 67% for pipes with coil roughness. The experimental results indicate that adding hemispherical and coil roughness to the internal surface of the pipe can lead to a significant improvement in the rate of heat-transfer while adding a mesh-type roughness can have marginal improvements and comes with a large frictional loss penalty. The analysis shows that the highest thermohydraulic performance is achieved using the hemispherical roughness elements.","PeriodicalId":504378,"journal":{"name":"Journal of Fluids Engineering","volume":"32 20","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-01-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139528504","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}

引用次数: 0