Journal of Fluids Engineering-Transactions of the Asme最新文献_第10页

A Comparison of Different Approaches to Estimate the Efficiency of Wells Turbines 井式水轮机效率估算方法的比较

IF 2 3区工程技术

Journal of Fluids Engineering-Transactions of the Asme Pub Date : 2021-05-01 DOI: 10.1115/1.4049686

F. Licheri, F. Cambuli, P. Puddu, T. Ghisu

引用次数: 5

Simulation and Experimental Investigation of a New Type of Combined Seal Structure 一种新型组合密封结构的仿真与实验研究

IF 2 3区工程技术

Journal of Fluids Engineering-Transactions of the Asme Pub Date : 2021-05-01 DOI: 10.1115/1.4049678

Jin Li, Xiaoli Fu, Shenglin Yan

{"title":"Simulation and Experimental Investigation of a New Type of Combined Seal Structure","authors":"Jin Li, Xiaoli Fu, Shenglin Yan","doi":"10.1115/1.4049678","DOIUrl":"https://doi.org/10.1115/1.4049678","url":null,"abstract":"\u0000 Based on the study of leakage characteristics of labyrinth seal structure (LSS), a new type of combined seal structure (CSS) consisting of the labyrinth structure and the nozzle structure has been proposed. The sealing characteristics of CSS and LSS are compared by means of numerical simulation and experiments, and the effects of the internal resistance of the device, structural geometric parameters and other factors on the leakage characteristics of CSS are studied. The results illustrate the following conclusions: (a) When the inlet flow is 12 m3/h and the internal resistance of the device is 2000–4000 Pa, the leakage rate of CSS decreases by 30%–40% in comparison with that of LSS, which indicates that the performance of CSS is much better than that of LSS. (b) The leakage rate increases as the internal resistance of the device increases. When the internal resistance of the device increases from 2000 Pa to 8000 Pa, the leakage rate increases from 26% to 72%. (c) When the internal resistance of the device is constant, the larger the inlet flow, the smaller the leakage rate. (d) The choice of nozzle radius in structural geometric parameters is more important for the leakage rate than the tooth height and teeth numbers. When the nozzle radius decreases, ΔPAB (pressure difference between the labyrinth structure and the nozzle structure) and the leakage rate decrease accordingly.","PeriodicalId":54833,"journal":{"name":"Journal of Fluids Engineering-Transactions of the Asme","volume":"16 1","pages":""},"PeriodicalIF":2.0,"publicationDate":"2021-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82167404","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 2

Design and Evaluation of Generic Bump for Flow Control in a Supersonic Inlet Isolator 超声速进口隔振器流动控制通用凸点的设计与评价

IF 2 3区工程技术

Journal of Fluids Engineering-Transactions of the Asme Pub Date : 2021-05-01 DOI: 10.1115/1.4049677

Md. Raihan Ali Khan, A. Hasan

{"title":"Design and Evaluation of Generic Bump for Flow Control in a Supersonic Inlet Isolator","authors":"Md. Raihan Ali Khan, A. Hasan","doi":"10.1115/1.4049677","DOIUrl":"https://doi.org/10.1115/1.4049677","url":null,"abstract":"\u0000 In this paper, the geometry of a supersonic inlet isolator is modified by the introduction of a two-dimensional (2D) bump to control the complex lip shock wave/boundary layer interaction (SWBLI). The bump is of general shape whose profile is designed primarily based on the inviscid theory of oblique shock waves, which accommodates the effect of freestream conditions; particularly, the flow Mach number. Further, the geometric constraints of the inlet are taken into consideration to generate a contoured bump. This well-designed generic bump is tested in the range of flight Mach number of 2.5 to 3.8 through numerical computations. The adopted computational methods are validated with the available experimental data. Results showed that the modified inlet using the present generic bump changes the internal shock structure, weakens the intensity of SWBLI, and subsequently reduces shock reflection phenomena which are prevalent in baseline inlet. The wall characteristics such as separation bubble (SB), skin friction, and total pressure loss are found to be reduced in inlet with bump. The SB in baseline inlet typically corresponds with the geometric profile of the bump. As a result, ramp of baseline inlet is apparently replaced by this generic bump, which eliminates the low momentum fluid adjacent to the wall and the passage of modified inlet is found to be mostly occupied by high momentum supersonic flow. The flow control and associated performance improvement are linked with this modification of supersonic inlet isolator.","PeriodicalId":54833,"journal":{"name":"Journal of Fluids Engineering-Transactions of the Asme","volume":"24 1","pages":""},"PeriodicalIF":2.0,"publicationDate":"2021-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84365301","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 2

Numerical Study of Tip Leakage Vortex Around a NACA0009 Hydrofoil NACA0009型水翼叶尖泄漏涡的数值研究

IF 2 3区工程技术

Journal of Fluids Engineering-Transactions of the Asme Pub Date : 2021-05-01 DOI: 10.1115/1.4049671

Zhenqing Bi, Xueming Shao, Lingxin Zhang

{"title":"Numerical Study of Tip Leakage Vortex Around a NACA0009 Hydrofoil","authors":"Zhenqing Bi, Xueming Shao, Lingxin Zhang","doi":"10.1115/1.4049671","DOIUrl":"https://doi.org/10.1115/1.4049671","url":null,"abstract":"\u0000 In the tip clearance flow, the dominant vortex is the tip leakage vortex (TLV), which has a significant impact on the hydraulic and cavitation performance of axial flow machineries. In order to reveal the impact mechanism of the gap size on the TLV, gap flows with two gap sizes, i.e., τ=0.2 (2 mm) and τ=1.0 (10 mm), are numerically investigated. A NACA0009 hydrofoil is selected to create the gap flow, with an incoming velocity of 10 m/s and an attack angle of 10 deg. The results show that the two flow cases are significantly different in terms of vortex feature and the leakage flow distribution. In the small gap, a type of jet-pattern flow appears, whereas a type of rolling-pattern flow passes over the large gap. The vertical velocity gradient of the leakage flow has a decisive influence on the TLV trajectory. In addition, for the large gap, the axial velocity in the vortex center exceeds the incoming flow. This jet-like state of axial velocity can be maintained for a long distance, making the vortex more stable. However, the axial velocity in the case of τ=0.2 cannot stay at the jet-like state and rapidly switches to a wake-like state.","PeriodicalId":54833,"journal":{"name":"Journal of Fluids Engineering-Transactions of the Asme","volume":"1 1","pages":""},"PeriodicalIF":2.0,"publicationDate":"2021-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88631671","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 9

Forced Convective Flow of Bingham Plastic Fluids in a Branching Channel With the Effect of T-Channel Branching Angle 受t形通道分支角影响的Bingham塑性流体在分支通道中的强迫对流流动

IF 2 3区工程技术

Journal of Fluids Engineering-Transactions of the Asme Pub Date : 2021-05-01 DOI: 10.1115/1.4049673

Anamika Maurya, Naveen Tiwari, R. Chhabra

{"title":"Forced Convective Flow of Bingham Plastic Fluids in a Branching Channel With the Effect of T-Channel Branching Angle","authors":"Anamika Maurya, Naveen Tiwari, R. Chhabra","doi":"10.1115/1.4049673","DOIUrl":"https://doi.org/10.1115/1.4049673","url":null,"abstract":"\u0000 This work aims to explore the T-channel momentum and heat transfer characteristics with the combined effect of Bingham plastic fluids (0.01 ≤ Bn ≤ 20) behavior and geometrical variation in terms of branching angle (30 deg ≤ α ≤ 90 deg). The problem has been solved over a wide range of Reynolds number (50 ≤ Re ≤ 300) and Prandtl number (10 ≤ Pr ≤ 50). For the momentum flow, qualitative and quantitative features are analyzed in terms of streamlines, structure of yielded/unyielded regions, shear rate contours, plug width and length variation, and local pressure coefficient. These features have been represented in terms of isotherm patterns, temperature profile, Nusselt number, and its asymptotic value for heat transfer characteristics. The recirculating flows have been presented here in the vicinity of T-junction, which promote mixing and heat transfer. Broadly, the size of this zone bears a positive dependence on Re and α. However, fluid yield stress tends to suppress it. The critical Reynolds and Bingham numbers were found to be strong functions of the pertinent parameters like α. The inclination angle exerts only a weak effect on the yielded/unyielded regions and on the recirculation length of main branch. Results show a strong relationship of the plug width and length with key parameters and branches. The Nusselt number exhibits a positive relationship with α, Bn, and Re but for lower Pr in the T-junction vicinity for both branches. Such length indicates the required optimum channel length for thermal mixing.","PeriodicalId":54833,"journal":{"name":"Journal of Fluids Engineering-Transactions of the Asme","volume":"30 1","pages":""},"PeriodicalIF":2.0,"publicationDate":"2021-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89888301","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 2

Computational Simulation of Spontaneous Liquid Penetration and Depression Between Vertical Parallel Plates 垂直平行板间液体自发穿透和沉降的计算模拟

IF 2 3区工程技术

Journal of Fluids Engineering-Transactions of the Asme Pub Date : 2021-05-01 DOI: 10.1115/1.4049683

M. Naghashnejad, H. Shabgard, T. Bergman

{"title":"Computational Simulation of Spontaneous Liquid Penetration and Depression Between Vertical Parallel Plates","authors":"M. Naghashnejad, H. Shabgard, T. Bergman","doi":"10.1115/1.4049683","DOIUrl":"https://doi.org/10.1115/1.4049683","url":null,"abstract":"\u0000 A computational fluid dynamics model is developed to study the dynamics of meniscus formation and capillary flow between vertical parallel plates. An arbitrary Lagrangian–Eulerian approach is employed to predict and reconstruct the shape of the meniscus with no need to employ implicit interface tracking schemes. The developed model is validated by comparing the equilibrium capillary height and meniscus shape with those predicted by available theoretical models. The model was used to predict the capillary flow of water in hydrophilic (silver) and hydrophobic (Teflon) vertical channels with wall spacings ranging from 0.5 mm to 3 mm. It is shown that the computational model accurately predicts the capillary flow regardless of the channel width, whereas the theoretical models fail at relatively large wall spacings. The model captures several important hydrodynamic phenomena that cannot be accounted for in the theoretical models including the presence of developing flow in the entrance region, time-dependent formation of the meniscus, and the inertial effects of the liquid in the reservoir. The sharp interface tracking technique enables direct access to the flow variables and transport fluxes at the meniscus with no need to use averaging techniques.","PeriodicalId":54833,"journal":{"name":"Journal of Fluids Engineering-Transactions of the Asme","volume":"61 1","pages":""},"PeriodicalIF":2.0,"publicationDate":"2021-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91189761","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 4

Discordance of Tracer Transport and Particulate Matter Fate in a Baffled Clarification System 挡板澄清系统中示踪剂输运与颗粒物命运的不一致

IF 2 3区工程技术

Journal of Fluids Engineering-Transactions of the Asme Pub Date : 2021-05-01 DOI: 10.1115/1.4049690

Haochen Li, S. Balachandar, J. Sansalone

{"title":"Discordance of Tracer Transport and Particulate Matter Fate in a Baffled Clarification System","authors":"Haochen Li, S. Balachandar, J. Sansalone","doi":"10.1115/1.4049690","DOIUrl":"https://doi.org/10.1115/1.4049690","url":null,"abstract":"\u0000 Large eddy simulation (LES) and coupled physical laboratory-scale modeling are performed to elucidate tracer transport and particulate matter (PM) fate in a baffled clarification system. Such baffled systems are common for urban water unit operations and processes. Flow hydrodynamic indices of these systems such as short-circuiting are often examined with measurement of inert tracer transport as a surrogate for chemical or PM transport and fate. Results of this study illustrate complex interactions between turbulent flow, tracer, and various PM diameters at the system scale. PM preferential accumulation and the discordance of PM transport with respect to flow hydrodynamics are observed based on the modeling results; otherwise not practical with physical model testing. Results demonstrate that baffling can promote system tracer mixing and improve volumetric utilization by extending the mean flow path through flow separation and bifurcation. The baffle tested produced high turbulence kinetic energy near the sedimentation floor and reduced PM separation (clarification) as compared to the unbaffled system used as a control. The unbaffled system in this study yields the highest PM separation, even though significant short-circuiting occurs during the residence time distribution (RTD) of the tracer. Further analysis demonstrates the mechanistic difference between the tracer transport and the finer suspended PM as compared to larger settleable and sediment PM diameters. Results illustrate that the tracer RTD, residence time (RT) and hydraulic efficiency indices are not reliable surrogates for PM or PM-bound chemical/pathogen separation. In addition, simulations suggest a site, system or condition-specific design approach given the coupled dependence on flow and design geometry.","PeriodicalId":54833,"journal":{"name":"Journal of Fluids Engineering-Transactions of the Asme","volume":"23 1","pages":""},"PeriodicalIF":2.0,"publicationDate":"2021-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83969498","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 7

A Preliminary Study on the Simulation of Vortex Flow in Pump Intake Based on LBM-VOF-LES Combined Model 基于LBM-VOF-LES组合模型的泵进气口涡流模拟初探

IF 2 3区工程技术

Journal of Fluids Engineering-Transactions of the Asme Pub Date : 2021-05-01 DOI: 10.1115/1.4049684

Guo Miao, Xuelin Tang, Xiaoqin Li, Fujun Wang, Xiao-yan Shi

{"title":"A Preliminary Study on the Simulation of Vortex Flow in Pump Intake Based on LBM-VOF-LES Combined Model","authors":"Guo Miao, Xuelin Tang, Xiaoqin Li, Fujun Wang, Xiao-yan Shi","doi":"10.1115/1.4049684","DOIUrl":"https://doi.org/10.1115/1.4049684","url":null,"abstract":"\u0000 In this paper, the lattice Boltzmann method-large eddy simulation (LBM-LES) model was combined with the volume of fluid (VOF) method and used to simulate vortex flow in a typical pump intake. The strain rate tensor in the LES model is locally calculated utilizing nonequilibrium moments based on Chapman–Enskog expansion, and the bounce-back scheme is used for nonslip condition on the solid wall and VOF method for the free surface. The evolution of all kinds of cells on the free surface is based on the mass exchange in the VOF method, i.e., lattice Boltzmann-single phase (LB-SP) free surface model. The introduction of the external force terms is established through adding corresponding expressions on the right of the lattice Boltzmann equation (LBE), and by modifying the velocity. The predicted vortex flow patterns (core location and strength of the vortex) and velocity correlate with the experiments undertaken with the physical model. A comparison of the results demonstrates the feasibility and stability of the model and the numerical method in predicting vortex flows inside pump intakes. The model developed and presented in this paper provides a new analysis method of vortex flow patterns in pump intake from a mesoscopic perspective, enriches the relevant technologies, and makes corresponding contributions to further engineering applications.","PeriodicalId":54833,"journal":{"name":"Journal of Fluids Engineering-Transactions of the Asme","volume":"9 1","pages":""},"PeriodicalIF":2.0,"publicationDate":"2021-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80213398","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 3

Wake and Performance Predictions of Two- and Three-Bladed Wind Turbines Based on the Actuator Line Model1 基于作动器线模型的二、三叶风力机尾迹及性能预测

IF 2 3区工程技术

Journal of Fluids Engineering-Transactions of the Asme Pub Date : 2021-05-01 DOI: 10.1115/1.4049682

Sebastian Henao Garcia, A. Benavides-Moran, O. L. Mejía

{"title":"Wake and Performance Predictions of Two- and Three-Bladed Wind Turbines Based on the Actuator Line Model1","authors":"Sebastian Henao Garcia, A. Benavides-Moran, O. L. Mejía","doi":"10.1115/1.4049682","DOIUrl":"https://doi.org/10.1115/1.4049682","url":null,"abstract":"\u0000 This paper challenges the standard wind turbine design numerically assessing the wake and aerodynamic performance of two- and three-bladed wind turbine models implementing downwind and upwind rotor configurations, respectively. The simulations are conducted using the actuator line model (ALM) coupled with a three-dimensional Navier Stokes solver implementing the k−ω shear stress transport turbulence model. The sensitivity of the ALM to multiple simulation parameters is analyzed in detail and numerical results are compared against experimental data. These analyses highlight the most suitable Gaussian radius at the rotor to be equal to twice the chord length at 95% of the blade for a tip-speed ratio (TSR) of ten, while the Gaussian radius at the tower and the number of actuator points have a low incidence on the flow field computations overall. The numerical axial velocity profiles show better agreement upstream than downstream the rotor, while the discrepancies are not consistent through all the assessed operating conditions, thus highlighting that the ALM parameters are also dependent on the wind turbine's operating conditions rather than being merely geometric parameters. Particularly, for the upwind three-bladed wind turbine model, the accuracy of the total thrust computations improves as the TSR increases, while the least accurate wake predictions are found for its design TSR. Finally, when comparing both turbine models, an accurate representation of the downwind configuration is observed as well as realistic power extraction estimates. Indeed, the results confirm that rotors with fewer blades are more suitable to operate at high TSRs.","PeriodicalId":54833,"journal":{"name":"Journal of Fluids Engineering-Transactions of the Asme","volume":"46 1","pages":""},"PeriodicalIF":2.0,"publicationDate":"2021-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82247806","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 1

Excitation of Shear Layer Due to Surface Roughness Near the Leading Edge: An Experiment 前缘表面粗糙度对剪切层激发的实验研究

IF 2 3区工程技术

Journal of Fluids Engineering-Transactions of the Asme Pub Date : 2021-05-01 DOI: 10.1115/1.4049685

P. Singh, S. Sarkar

{"title":"Excitation of Shear Layer Due to Surface Roughness Near the Leading Edge: An Experiment","authors":"P. Singh, S. Sarkar","doi":"10.1115/1.4049685","DOIUrl":"https://doi.org/10.1115/1.4049685","url":null,"abstract":"\u0000 In this paper, a comprehensive study has been performed to address the excitation of a separated boundary layer near the leading edge due to surface roughness. Experiments are performed on a model airfoil with the semicircular leading edge at a Reynolds number (Rec) of 1.6×105, where the freestream turbulence (fst) is 1.2%. The flow features are investigated over the three rough surfaces with the roughness characteristic in the wall unit of 17, 10.5, and 8.4, which are estimated from the velocity profile at a location far downstream of reattachment. The wall roughness results in an early transition and reattachment, leading to a reduction of the laminar shear layer length apart from the bubble length. It is worthwhile to note that although the large-amplitude pretransitional perturbations are apparent from the beginning for the rough surface, the shear layer reflects the amplification of selected frequencies, where the fundamental frequency when normalized is almost the same as that of the smooth wall. The universal intermittency curve can be used to describe the transition of the shear layer, which exhibits some resemblance to the excitation of the boundary layer under fst, signifying the viscous effect.","PeriodicalId":54833,"journal":{"name":"Journal of Fluids Engineering-Transactions of the Asme","volume":"303 1","pages":""},"PeriodicalIF":2.0,"publicationDate":"2021-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83802486","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 3