Volume 3B: Fluid Applications and Systems最新文献

On the Effect of Trailing Edge Under-Filing on the Apparent Slip Factor of Centrifugal Impellers 后缘下锉对离心式叶轮表观滑移系数的影响

Volume 3B: Fluid Applications and Systems Pub Date : 2019-11-20 DOI: 10.1115/ajkfluids2019-5610

O. Litfin, A. Delgado

{"title":"On the Effect of Trailing Edge Under-Filing on the Apparent Slip Factor of Centrifugal Impellers","authors":"O. Litfin, A. Delgado","doi":"10.1115/ajkfluids2019-5610","DOIUrl":"https://doi.org/10.1115/ajkfluids2019-5610","url":null,"abstract":"\u0000 The trailing edge flow in a centrifugal impeller is of great importance as it determines the exit flow velocity triangle and therefore the work transferred to the fluid. The present study deals with the impact of trailing edge under-filing on the impeller exit flow and the resulting slip factor. Different under-filed trailing edge shapes are investigated by means of numerical simulations. 2D-RANS simulations are performed for a wide range of blade angles. For the default cut-off trailing edge configuration an attached and a separated flow regime around the blade trailing edge can be distinguished, mainly depending on the blade exit angle. The occurrence of the separated flow regime is associated with a significant change in performance, mainly due to the reduced flow deflection at the impeller exit. Under-filing of the trailing edge leads to less apparent slip for blade angles up to 40 degrees. This can be attributed to the fact that under-filing prevents the attached flow regime occurring in case of the default trailing edge. Additional DES simulations provide deeper insight into the detailed flow structures involved in this phenomena and reveal the turbulent flow structures in the trailing edge and wake flow. The obtained results provide a deep insight into trailing edge flows in centrifugal pump impellers and help to get a better understanding of the phenomena involved. Moreover, the results can provide an explanation to the often observed deviation of the apparent impeller slip from the theoretical slip predicted by slip factor models.","PeriodicalId":270000,"journal":{"name":"Volume 3B: Fluid Applications and Systems","volume":"2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122208812","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

Secondary Flow Loss Reduction Method by Use of 3D-Fence in a Gas Turbine Cascade 利用三维栅减少燃气轮机叶栅二次流损失的方法

Volume 3B: Fluid Applications and Systems Pub Date : 2019-11-20 DOI: 10.1115/ajkfluids2019-5367

Ryota Uehara, S. Mizuguchi, Kakeru Kusano, Masahiro Miyabe, Y. Kawata

{"title":"Secondary Flow Loss Reduction Method by Use of 3D-Fence in a Gas Turbine Cascade","authors":"Ryota Uehara, S. Mizuguchi, Kakeru Kusano, Masahiro Miyabe, Y. Kawata","doi":"10.1115/ajkfluids2019-5367","DOIUrl":"https://doi.org/10.1115/ajkfluids2019-5367","url":null,"abstract":"\u0000 The aerodynamic loss accounted to the secondary flow, or secondary loss is one of the most prominent causes of the internal losses in turbine cascades. The secondary flow losses are mostly due to the interaction between horseshoe vortex and endwall crossflow. The authors have developed a so-called endwall fence experimentally to reduce the secondary loss in a gas turbine cascade. However, it is very difficult to handle many design parameters simultaneously in experiment.\u0000 The objective of this research work is to optimize the shape of the 3D-fence with considering many design parameters and clarify the flow mechanism of loss reduction. In addition, one of the most important objectives of this paper is to show this optimization method is effective for the designer of the turbine. In this study, the optimization framework and CFD were applied to the endwall fence (3D-fence) and the effect of it on the crossflow was investigated. As a result, the optimized shape, installation position, and the setting angle of the 3D-fence to mitigate the interaction between the horseshoe vortex and endwall crossflow was specified. In order to validate the effectiveness of the optimization method, total pressure was measured and loss analysis was implemented and flow visualization using oil-film and smoke were implemented. Then, the good agreement can be seen qualitatively between the experimental results and CFD results. It is clarified the 3D-fence delays the confluence between suction side leg and pressure side leg of the horseshoe vortex. Based on both calculation and experiment, it is revealed that the 3D-fence has good effect to reduce the secondary flow loss.","PeriodicalId":270000,"journal":{"name":"Volume 3B: Fluid Applications and Systems","volume":"1954 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129301508","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

Inducer Design Optimization to Improve its Suction Performance 提高吸力性能的诱导体优化设计

Volume 3B: Fluid Applications and Systems Pub Date : 2019-11-20 DOI: 10.1115/ajkfluids2019-5371

Yushi Nakamura, Marek Lubieniecki, K. Hayashi, Y. Kawata, Masahiro Miyabe, Claudio Lettieri

{"title":"Inducer Design Optimization to Improve its Suction Performance","authors":"Yushi Nakamura, Marek Lubieniecki, K. Hayashi, Y. Kawata, Masahiro Miyabe, Claudio Lettieri","doi":"10.1115/ajkfluids2019-5371","DOIUrl":"https://doi.org/10.1115/ajkfluids2019-5371","url":null,"abstract":"\u0000 The purpose of this paper is to present optimization method of an inducer blade shape to improve its suction performance and clarify the relationship between pump performance and design parameters. In order to conduct the optimization process a response surface based optimization framework was established. Baseline was designed in previous research [1]. The inducers were 3Dprinted in ABS plastic and their wetted and cavitating characteristics were measured. It was confirmed that the optimized inducer can maintain its wetted performance at lower cavitation numbers. A response surface is a mathematical model that approximates the relationship between the input parameters and the objective function from a finite number of learning points within the design space. The design space was defined by four parameters: sweep angle, sweep radius, incidence angle and blade solidity at the tip that controlled the blade shape. The performance of each design was evaluated with a CFD simulation established in a commercial solver. The optimization goal was to minimize the critical cavitation number that corresponds to a 5% drop of pressure increase through the pump due to cavitation.\u0000 A starting point of the optimization was the industrial pump designed by a Japanese company Teral [1]. The results of the numerical optimization show that the critical cavitation number was decreased by 17.6% with respect to the baseline design. In the experimental results, an average improvement of 15.4% was achieved.","PeriodicalId":270000,"journal":{"name":"Volume 3B: Fluid Applications and Systems","volume":"12 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132885292","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: 2

Pressure Fluctuation Reduction in Side Channel Pumps Using a Modified Impeller Blade 采用改进型叶轮叶片降低侧流道泵压力波动

Volume 3B: Fluid Applications and Systems Pub Date : 2019-11-20 DOI: 10.1115/ajkfluids2019-4932

Wei Xueyuan, Fan Zhang, Desmond Appiah, Chen Ke, S. Yuan, M. Böhle

{"title":"Pressure Fluctuation Reduction in Side Channel Pumps Using a Modified Impeller Blade","authors":"Wei Xueyuan, Fan Zhang, Desmond Appiah, Chen Ke, S. Yuan, M. Böhle","doi":"10.1115/ajkfluids2019-4932","DOIUrl":"https://doi.org/10.1115/ajkfluids2019-4932","url":null,"abstract":"\u0000 For the unique performance advantages of side channel pump delivering flows at high heads, it has been applied in many fields such as petrochemical, pharmaceutical, food processing, automobile fuel pumping etc. However, the operation of the pump is strongly affected by the intensity of the pressure fluctuation, thus the pressure fluctuation exiting within the pump cannot be neglected because of its direct influence on the noise and vibration performance. Therefore, reducing the pressure fluctuation intensity is a key point for research. The side channel pump studied in this paper is a prototype with an axial channel and a 24-blade impeller. The pressure fluctuation intensity of the pump is studied using numerical simulations at best efficiency point. The Reynolds-averaged Navier-Stokes equations (URANS) are solved with the Shear Stress Transport (SST) k-ω turbulence model using commercial CFX codes. The time and frequency plots of the pressure fluctuation coefficient, Cp of the original impeller scheme at different monitoring points revealed high pressure fluctuation intensities affecting the pump’s operating reliability. For the purpose of reducing the pressure fluctuation intensity in the pump, the impeller geometry is modified with a small blade at the outer radius. The study showed that the pressure fluctuation within the pump is reduced significantly at the monitoring points. Moreover, it is found out that the pressure fluctuation in both impeller schemes are mainly caused by the flow exchange between the impeller and side channel. The results of this paper can provide reference for pressure fluctuation reduction and Noise-Vibration-Harshness (NVH) study in turbomachinery.","PeriodicalId":270000,"journal":{"name":"Volume 3B: Fluid Applications and Systems","volume":"80 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115700401","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: 4

Effect of Diffuser Vane Solidity on Performance of a Multistage Bowl Pump 扩压叶片强度对多级碗泵性能的影响

Volume 3B: Fluid Applications and Systems Pub Date : 2019-11-20 DOI: 10.1115/ajkfluids2019-5633

P. Cooper, A. Hosangadi

引用次数: 0

Design of a New Type of Balance Drum to Reduce Axial Loading in Centrifugal Pumps 减轻离心泵轴向负荷的新型平衡鼓的设计

Volume 3B: Fluid Applications and Systems Pub Date : 2019-11-20 DOI: 10.1115/ajkfluids2019-5450

K. Bruurs, B. Esch, M. V. D. Schoot, E. V. D. Zijden

引用次数: 3

Inter-Blade Vortex Characteristics With the Blockage Effects of Runner Blade in a Francis Hydro Turbine Model 混流式水轮机转轮叶片阻塞作用下的叶片间涡特性

Volume 3B: Fluid Applications and Systems Pub Date : 2019-11-20 DOI: 10.1115/ajkfluids2019-4805

Seung-Jun Kim, Jin-Hyuk Kim, Young-Seok Choi, Yong Cho, Jongwoong Choi

{"title":"Inter-Blade Vortex Characteristics With the Blockage Effects of Runner Blade in a Francis Hydro Turbine Model","authors":"Seung-Jun Kim, Jin-Hyuk Kim, Young-Seok Choi, Yong Cho, Jongwoong Choi","doi":"10.1115/ajkfluids2019-4805","DOIUrl":"https://doi.org/10.1115/ajkfluids2019-4805","url":null,"abstract":"\u0000 This study presents the numerical analysis on the inter-blade vortex characteristics along with the blockage effects of runner blade in a Francis hydro turbine model with various flow rate conditions. The turbine model showed different flow characteristics in the runner blade passages according to operating conditions, and inter-blade vortex was observed at lower flow rate conditions. This inter-blade vortex can lead to performance reduction, vibration, and instability for smooth operation of turbine systems. The previous study on blockage effects on various runner blade thickness, showed its influence on hydraulic performance and internal flow characteristics at low flow rate conditions. Therefore, the inter-blade vortex characteristics can be altered with the blockage effects at low flow rate conditions in a Francis hydro-turbine. For investigating the internal flow and unsteady pressure characteristics, three-dimensional steady and unsteady Reynolds-averaged Navier-Stokes calculations are performed. These inter-blade vortices were captured at the leading and trailing edges close to the runner hub. These vortex regions showed flow separation and stagnation flow while blockage effects contributed for decreasing the inter-blade vortex at low flow rate conditions.","PeriodicalId":270000,"journal":{"name":"Volume 3B: Fluid Applications and Systems","volume":"43 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115616679","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

Effects of Curvature Radius of Volute Profile on Aerodynamic Performance of Squirrel Cage Fan 蜗壳外形曲率半径对鼠笼式风机气动性能的影响

Volume 3B: Fluid Applications and Systems Pub Date : 2019-11-20 DOI: 10.1115/ajkfluids2019-5078

Ke Wang, Y. Ju, Chuhua Zhang

{"title":"Effects of Curvature Radius of Volute Profile on Aerodynamic Performance of Squirrel Cage Fan","authors":"Ke Wang, Y. Ju, Chuhua Zhang","doi":"10.1115/ajkfluids2019-5078","DOIUrl":"https://doi.org/10.1115/ajkfluids2019-5078","url":null,"abstract":"\u0000 Volute profile exerts great influences on flow losses and aerodynamic performance of squirrel cage fan. In practical, equilateral- or inequilateral-element method is usually applied to design the volute profile for convenient manufacture. This kind of volute profile consists of several arc segments, however, is discontinuous for curvature radius at the junctions of adjacent arc segments. To overcome this issue, we propose a new volute profiling method to guarantee the continuity of curvature radius along the whole volute profile. By means of three-dimensional computation fluid dynamic simulations, the proposed method is validated through comprehensive comparisons of aerodynamic performances and flow fields of squirrel cage fans with and without continuous curvature radius of volute profile. The results show that the continuous curvature radius of volute profile is of benefit to the aerodynamic performance increase of squirrel cage fan. The velocity downstream the volute tongue is improved. The local sudden diffusion-expansion around the junctions of volute arc segments nearly disappears with continuous increase of static pressure along the volute wall.","PeriodicalId":270000,"journal":{"name":"Volume 3B: Fluid Applications and Systems","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131573530","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 and Experimental Investigation on the Influence of Blades Gap Flow on Axial Blood Pump Performance 叶片间隙流动对轴向血泵性能影响的数值与实验研究

Volume 3B: Fluid Applications and Systems Pub Date : 2019-11-20 DOI: 10.1115/ajkfluids2019-5665

Guangmao Liu, Donghai Jin, Mengyu Wang, X. Gui

引用次数: 0

The Effect of Suction Pressure and Flow Rate on the Dynamic Characteristics of a Cavitating Inducer 吸气压力和流量对空化诱导器动态特性的影响

Volume 3B: Fluid Applications and Systems Pub Date : 2019-11-20 DOI: 10.1115/ajkfluids2019-5274

Yuta Morimoto, T. Sugiura, H. Horiguchi, K. Sugiyama

引用次数: 0