Volume 3B: Fluid Applications and Systems最新文献_第8页

Unsteady Flow in the Vaned Diffuser of a Low Specific Speed Centrifugal Pump With an Unshrouded Impeller 低比转速无冠叶轮离心泵叶片扩压器内的非定常流动

Volume 3B: Fluid Applications and Systems Pub Date : 2019-07-28 DOI: 10.1115/ajkfluids2019-5599

Asuma Ichinose, Tomoki Takeda, K. Miyagawa, Y. Ogawa, H. Negishi, Kazuki Niiyama

{"title":"Unsteady Flow in the Vaned Diffuser of a Low Specific Speed Centrifugal Pump With an Unshrouded Impeller","authors":"Asuma Ichinose, Tomoki Takeda, K. Miyagawa, Y. Ogawa, H. Negishi, Kazuki Niiyama","doi":"10.1115/ajkfluids2019-5599","DOIUrl":"https://doi.org/10.1115/ajkfluids2019-5599","url":null,"abstract":"\u0000 The unsteady internal flow in a low specific speed centrifugal pump was experimentally and numerically investigated. Unshrouded impellers enable high head designs but on the other hand, they exhibit complicated internal flow and an efficiency decline compared to shrouded impellers. Furthermore, the complicated impeller outlet flow induces unsteady internal flow in the vaned diffuser. Therefore, a detailed investigation of the internal flow is required in order to increase the efficiency of these low specific speed centrifugal pumps. The aims of this paper are to clarify the loss mechanisms in the impeller and to investigate the effect of impeller outlet flow to the diffuser internal flow at the design point. The detailed pump internal flow is investigated using unsteady computation, which enables the computation of the 3D flow pattern. The reversed flow and the secondary flow are induced by the tip leakage flow, and this creates a high loss region in the blade-to-blade region. On the other hand, the mixing effect is remarkable at the impeller outlet, and this affects the creation of the wake. This flow behavior makes the internal flow of the diffuser unsteady and the diffuser performance fluctuates due to the impeller wake at the design point.","PeriodicalId":270000,"journal":{"name":"Volume 3B: Fluid Applications and Systems","volume":"237 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-07-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134543614","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: 1

Numerical Investigation of Tip Leakage Vortex Cavitation in Axial Waterjet Pump With Different Tip Gap Sizes 不同叶尖间隙尺寸轴向喷水泵叶尖泄漏涡空化的数值研究

Volume 3B: Fluid Applications and Systems Pub Date : 2019-07-28 DOI: 10.1115/ajkfluids2019-4990

Shun Xu, B. Ji, X. Long, Z. Qian, Gui-bin Li, Jia-jian Zhou

{"title":"Numerical Investigation of Tip Leakage Vortex Cavitation in Axial Waterjet Pump With Different Tip Gap Sizes","authors":"Shun Xu, B. Ji, X. Long, Z. Qian, Gui-bin Li, Jia-jian Zhou","doi":"10.1115/ajkfluids2019-4990","DOIUrl":"https://doi.org/10.1115/ajkfluids2019-4990","url":null,"abstract":"\u0000 The flow field in the tip region of the axial-flow waterjet pump is very complex. Although it has been studied for many years, many relevant phenomena have still been a puzzle. In present paper, many detailed data on instantaneous inner structures of the tip leakage flow and evolution of the tip leakage vortex cavitation with different tip gap sizes are offered. The numerical simulation has been conducted by using SAS turbulence model and ZGB cavitation model to understand the cavitation-vortex interaction mechanism. The predicted cavitation performance exhibits a reasonable agreement with the experimental results. Based on the illustration, with the impeller tip gap size decreasing, the cavitation area in rotating region gradually decreases. The cavitation development enhances vorticity production in an axial-flow waterjet pump. Vortices are mainly located at the impeller tip leakage region. The analysis of the relative vorticity transport equation indicates that the baroclinic torque term and the vortex dilation term have significant effects on cavitation, the main contributor to vortex generation is the vortex dilation term. In addition, in the impeller tip region, the effect of viscous diffusion term cannot be ignored, and the cavitation area has a larger amplitude of pressure pulsation.","PeriodicalId":270000,"journal":{"name":"Volume 3B: Fluid Applications and Systems","volume":"135 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-07-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122427063","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

Flow Visualization Study of Jet and Bucket Interactions in Traditional and Hooped Pelton Runner 传统和圈式滚轮射流与斗流相互作用的流动可视化研究

Volume 3B: Fluid Applications and Systems Pub Date : 2019-07-28 DOI: 10.1115/ajkfluids2019-4974

G. Chaudhari, S. Channiwala, Samip P. Shah, D. Kulshreshtha

引用次数: 1

CFD-Based Hydraulic Design and Manufacturing of a Multistage Low Specific-Speed Diffuser Pump 基于cfd的多级低比速扩散泵液压设计与制造

Volume 3B: Fluid Applications and Systems Pub Date : 2019-07-28 DOI: 10.1115/ajkfluids2019-5661

M. V. D. Schoot, K. Bruurs, Eric van der Zijden

{"title":"CFD-Based Hydraulic Design and Manufacturing of a Multistage Low Specific-Speed Diffuser Pump","authors":"M. V. D. Schoot, K. Bruurs, Eric van der Zijden","doi":"10.1115/ajkfluids2019-5661","DOIUrl":"https://doi.org/10.1115/ajkfluids2019-5661","url":null,"abstract":"\u0000 A multistage low specific-speed diffuser pump was designed to achieve very good hydraulic performance with a newly designed integrated diffuser, crossover and return guide vane. The diffuser was designed using a continuous crossover design. The design space of this diffuser was limited because of the usage of a mechanical pump design from a similar existing pump. This paper presents the simulation-based design of this new pump and the role that simulation can play in the manufacturing process.\u0000 A new diffuser has been designed to obtain optimum efficiency and to ensure that the pump will operate most of its time very close its best efficiency point. The new diffuser was designed using an approach where the diffuser vane was stretched to completely cover the area starting just behind the impeller trailing edge towards the eye of the next stage impeller. This means that the diffuser vanes should now convert velocity into pressure, guide the fluid to the next stage impeller eye while reducing the swirl and uniformizing the flow. The shape of the diffuser has been optimized using response surfaces that were created using Computation Fluid Dynamics (CFD). This way, a diffuser with a minimum amount of losses was obtained, due to smooth and gradual area changes of the waterway.\u0000 The final design incorporating this diffuser was analyzed using steady-state CFD to create the full performance curve. The design was transferred into a real physical product by manufacturing it. The resulting casting of the diffuser component was scanned using a 3D scanner. The 3D model of the scan was used to make a comparison using CFD between the performance of the designed and the manufactured diffuser. This provided understanding in how deviations due to the manufacturing process influence the performance. Finally, the complete pump underwent a performance test and its results closely matched the performance as calculated using CFD.","PeriodicalId":270000,"journal":{"name":"Volume 3B: Fluid Applications and Systems","volume":"43 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-07-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121503224","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 on Cavitation Performance of Torque Converter Using Transparent Model 基于透明模型的液力变矩器空化特性实验研究

Volume 3B: Fluid Applications and Systems Pub Date : 1900-01-01 DOI: 10.1115/ajkfluids2019-4906

Y. Katayama, Y. Hosoi, Y. Fukuda, S. Watanabe, S. Tsuda, Yoshihide Mori, Kazuyoshi Ito

引用次数: 0