Journal of Applied Fluid Mechanics最新文献_第3页

Effect of the Return-channel Geometric Parameters on the Performance of a Centrifugal Compressor with a High-flow Coefficient 回流道几何参数对高流量系数离心式压缩机性能的影响

IF 1 4区工程技术

Journal of Applied Fluid Mechanics Pub Date : 2024-01-01 DOI: 10.47176/jafm.17.3.2211

K. Zhao, Y. Liu, Y. Zhang, Y. Sun, X. Liu, H. Shi

{"title":"Effect of the Return-channel Geometric Parameters on the Performance of a Centrifugal Compressor with a High-flow Coefficient","authors":"K. Zhao, Y. Liu, Y. Zhang, Y. Sun, X. Liu, H. Shi","doi":"10.47176/jafm.17.3.2211","DOIUrl":"https://doi.org/10.47176/jafm.17.3.2211","url":null,"abstract":"The return-channel of a preceding stage in a multi-stage centrifugal compressor has a significant effect on the aerodynamic performance of the current and subsequent stages. However, due to the relatively complex nature of the return-channel configuration with many geometric parameters, no general design guidance is available in the literature. In this study, numerical methods are used to study the effects of different geometric parameters of a return-channel on the performance of a high-flow-coefficient centrifugal compressor. A multi-objective genetic algorithm is applied to optimize the return-channel. The effects of different geometric parameters on the performance are then studied using a sensitivity analysis method. Calculation results show that the residual vortex intensity at the outlet of the return-channel is affected by the geometric angles of the inlet and outlet of the return-channel blades. The flow uniformity at the stage outlet is primarily affected by the geometric angle of the blade outlet and the number of blades. The overall performance of the compressor stage is primarily affected by the geometric angle of the blade inlet and the lateral inclination angle of the cover plate. Calculation results for a two-stage compressor consisting of the optimized first stage and its following stage show that the outlet flow field of the first stage is more uniform than the original first stage. Additionally, at the design operating condition, the polytropic efficiency and pressure ratio of the entire unit increase by 1.07% and 4.07%, respectively. The polytropic efficiency and pressure ratio for the second stage increase by 2.34% and 3.51%, respectively. The impeller head coefficient increases by 7.33%. The theoretical analysis shows that for high-flow-coefficient centrifugal compressors, reducing the residual vortex intensity of the outlet flow field of the return-channel in a stage can significantly improve the off-design performance of the following stage.","PeriodicalId":49041,"journal":{"name":"Journal of Applied Fluid Mechanics","volume":" 11","pages":""},"PeriodicalIF":1.0,"publicationDate":"2024-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139392318","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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: 0

Analysis of Cavitation-induced Vibration Characteristics of a Vortex Pump Based on Adaptive Optimal Kernel Time-frequency Representation 基于自适应最优核时频表示法的涡旋泵气蚀诱发振动特性分析

IF 1 4区工程技术

Journal of Applied Fluid Mechanics Pub Date : 2024-01-01 DOI: 10.47176/jafm.17.3.2172

Y. Wang, †. P.Zhou, C. Zhou, W. Zhou, J. Li

{"title":"Analysis of Cavitation-induced Vibration Characteristics of a Vortex Pump Based on Adaptive Optimal Kernel Time-frequency Representation","authors":"Y. Wang, †. P.Zhou, C. Zhou, W. Zhou, J. Li","doi":"10.47176/jafm.17.3.2172","DOIUrl":"https://doi.org/10.47176/jafm.17.3.2172","url":null,"abstract":"Cavitation-induced vibration presents a significant challenge in vortex pumps, leading to potential damage to hydraulic components and adverse effects on pump performance. This study aims to investigate the long-term implications of such phenomena. To capture the vibration signals caused by cavitation, we utilized vibration acceleration sensors on the vortex pump and collected data at five predetermined measuring points under three different operating conditions. The analysis used two prominent techniques, fast Fourier transform (FFT) and adaptive optimal kernel time-frequency representation (AOK-TFR), to explore the frequency-domain and time-frequency characteristics of the vibration signals. The findings reveal a notable increase in frequency amplitude at each monitoring point as the flow rate rises. Under cavitation conditions, pronounced vibration characteristics are observed along the y-axis and z-axis of the volute, with maximum vibration intensities of 1.83 m/s² and 1.80 m/s², respectively. The frequency amplitude exhibits non-constant behavior in the time series. Moreover, variations in the time-frequency characteristics are identified with changing flow rates. A distinct signal with a frequency of 750 Hz manifests in the x-axis and y-axis of the volute when the head experiences a 3% reduction from the cavitation level.","PeriodicalId":49041,"journal":{"name":"Journal of Applied Fluid Mechanics","volume":"1 4","pages":""},"PeriodicalIF":1.0,"publicationDate":"2024-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139395009","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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: 0

Investigation of An Inverted Bow on Frigate Hull Resistance 倒艏对护卫舰船体阻力的影响研究

IF 1 4区工程技术

Journal of Applied Fluid Mechanics Pub Date : 2024-01-01 DOI: 10.47176/jafm.17.1.2122

S. Samuel, A. Wicaksono, W. A. Kurniawan, E. S. Hadi, T. Tuswan, A. Trimulyono, M. Muryadin

引用次数: 0

On an Efficient Solution of the Boltzmann Equation Using the Modified Time Relaxed Monte Carlo (MTRMC) Scheme 论使用修正时间松弛蒙特卡洛（MTRMC）方案高效求解玻尔兹曼方程

IF 1 4区工程技术

Journal of Applied Fluid Mechanics Pub Date : 2024-01-01 DOI: 10.47176/jafm.17.1.1922

M. Eskandari, †. S.S.Nourazar

引用次数: 0

A Data-Driven Machine Learning Approach for Turbulent Flow Field Prediction Based on Direct Computational Fluid Dynamics Database 基于直接计算流体力学数据库的数据驱动型湍流场预测机器学习方法

IF 1 4区工程技术

Journal of Applied Fluid Mechanics Pub Date : 2024-01-01 DOI: 10.47176/jafm.17.1.2109

M. Nemati, †. A.Jahangirian

{"title":"A Data-Driven Machine Learning Approach for Turbulent Flow Field Prediction Based on Direct Computational Fluid Dynamics Database","authors":"M. Nemati, †. A.Jahangirian","doi":"10.47176/jafm.17.1.2109","DOIUrl":"https://doi.org/10.47176/jafm.17.1.2109","url":null,"abstract":"A novel approach is presented for predicting compressible turbulent flow fields using a neural network-based data-driven method. Accurate prediction in turbulent regions heavily relies on the resolution of available data. Traditional methods, employing image-based techniques by mapping scattered computational fluid dynamics (CFD) data onto Cartesian grids, encounter data scarcity in critical areas such as the boundary layer and wake. Recently, convolutional neural networks (CNN) have gained prominence as the most widely referenced technique in fluid dynamics, utilizing flow field images as datasets for flow field prediction. However, CNN requires datasets with a high pixel density to enhance training accuracy in crucial regions, thereby increasing the input data volume and machine training time. To address this challenge, our proposed method deviates from using flow field images and instead generates datasets directly from the flow field properties of CFD grid points. By employing this approach, several advantages are realized. Firstly, the network benefits from the favorable characteristics of unstructured grids, such as varying point spacing near the object surface and in the far field, which effectively reduces the amount of input data and consequently the machine training cost. Secondly, the construction of the training dataset eliminates the need for interpolation or extrapolation, thereby preserving the accuracy of CFD data. In this case, a simple multilayer perceptron can be trained using the proposed dataset. Various flow field properties, including static pressure, turbulent kinetic energy, and velocity components, can be predicted with high accuracy within a few seconds.","PeriodicalId":49041,"journal":{"name":"Journal of Applied Fluid Mechanics","volume":"43 11","pages":""},"PeriodicalIF":1.0,"publicationDate":"2024-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139127960","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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: 0

Dynamic Modeling and Combination Analysis of Plunger Valve Considering Both Flow and Actuator 同时考虑流量和执行器的柱塞阀动态建模和组合分析

IF 1 4区工程技术

Journal of Applied Fluid Mechanics Pub Date : 2024-01-01 DOI: 10.47176/jafm.17.1.1998

Y. Ren, C. Bai, H. Zhang

{"title":"Dynamic Modeling and Combination Analysis of Plunger Valve Considering Both Flow and Actuator","authors":"Y. Ren, C. Bai, H. Zhang","doi":"10.47176/jafm.17.1.1998","DOIUrl":"https://doi.org/10.47176/jafm.17.1.1998","url":null,"abstract":"The plunger valve has an important role in a large compressor system as its operating characteristics directly affect the aerodynamic boundary condition of the compressor equipment. In this study, dynamic modeling and analysis method of the plunger valve are proposed for an accurate control of the system. By considering the interaction between the dynamic flow in the valve and actuator action, a lumped parameter model for the fluid–structure interaction force and multibody dynamic model of the actuator are developed based on intrinsic correlation parameters. A combination analysis to simultaneously predict valve flow and actuator dynamic characteristics is proposed. The predicted results are in a good agreement with experimental data, which validates the proposed model and analysis method. The analysis results show that the coupling effect between the valve flow and actuator is significant and has an important role in valve control, particularly when the valve opening is smaller. Compared to the experimental data and computational fluid dynamics results, the presented methods are accurate for valve control and effective for prediction of flow rate.","PeriodicalId":49041,"journal":{"name":"Journal of Applied Fluid Mechanics","volume":"18 12","pages":""},"PeriodicalIF":1.0,"publicationDate":"2024-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139128957","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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: 0

3D Numerical Modelling of Turbulent Flow in a Channel Partially Filled with Different Blockage Ratios of Metal Foam 部分填充不同阻塞比金属泡沫的通道中湍流的三维数值建模

IF 1 4区工程技术

Journal of Applied Fluid Mechanics Pub Date : 2024-01-01 DOI: 10.47176/jafm.17.3.2189

A. Narkhede, †. N.Gnanasekaran

{"title":"3D Numerical Modelling of Turbulent Flow in a Channel Partially Filled with Different Blockage Ratios of Metal Foam","authors":"A. Narkhede, †. N.Gnanasekaran","doi":"10.47176/jafm.17.3.2189","DOIUrl":"https://doi.org/10.47176/jafm.17.3.2189","url":null,"abstract":"The aim of the present research work is to understand the intricacies of fluid flow through a rectangular channel that has been partially filled with a metal foam block of different blockage ratio (0.16-1), with a pore density (5–30 Pores Per Inch i.e. PPI), along with varying inlet velocity (6.5–12.5 m/s). For the porous region, numerical solutions are acquired using the Darcy Extended Forchheimer model. The Navier-Stokes equation is used in the non-porous zone. Different flow behaviours were seen as a function of PPI, height, and inlet velocity. The pressure drop increases with inlet velocity, PPI, and block height, with a maximum value of approximately 4.5 kPa for the case of 30 PPI, 12.5 m/s, and a blockage ratio of 1. Results show that the existence and location of the formation of eddies depends on the inlet velocity, PPI, and blockage ratio. Such studies have been reported less and will aid research on forced convection through a channel partially filled with metal foam and optimisation studies between increased heat transmission and the additional pressure drop for the same by providing a detailed fluid flow analysis.","PeriodicalId":49041,"journal":{"name":"Journal of Applied Fluid Mechanics","volume":"3 6","pages":""},"PeriodicalIF":1.0,"publicationDate":"2024-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139395511","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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: 0

Effect of the Guide Vane on the Hydraulic Stability of a Low-head, Large-discharge Industrial Hydraulic Turbine 导叶对低水头大排量工业水轮机水力稳定性的影响

IF 1 4区工程技术

Journal of Applied Fluid Mechanics Pub Date : 2024-01-01 DOI: 10.47176/jafm.17.3.2056

L. Xue, B. Cui, Z. Zhu, R. Wang, Z. Yang, J. Hu, X. Su

{"title":"Effect of the Guide Vane on the Hydraulic Stability of a Low-head, Large-discharge Industrial Hydraulic Turbine","authors":"L. Xue, B. Cui, Z. Zhu, R. Wang, Z. Yang, J. Hu, X. Su","doi":"10.47176/jafm.17.3.2056","DOIUrl":"https://doi.org/10.47176/jafm.17.3.2056","url":null,"abstract":"The hydraulic turbine has been used extensively in the field of energy conservation. For turbines that have low heads and large discharge, improving recovery efficiency and stability is crucial due to their significant hydraulic impact. This paper provides a detailed analysis of the correlation between the influence of radial guide vanes on the stability of low-head, large-discharge turbines focusing on hydraulic performance and energy dissipation before and after the implementation of guide vanes. Moreover, in this paper, two types of turbines, with and without guide vanes, were designed considering the desulfurization scenario. Hydraulic efficiency, radial force, and internal flow field mechanics were numerically studied, and validated through experiments. The results reveal that the working range of the hydraulic turbine could be widened and the energy recovery efficiency improved by a maximum of 3.11% in the small flow rate under the action of guide vanes. Furthermore, it results in a substantial reduction in the radial force of the impeller. Subsequently, the variation in entropy production of different components under full flow rate conditions was compared between the models with and without guide vanes. The total energy consumption decreases sharply under overall working conditions due to the flow control ability of guide vanes affecting the flow state. The entropy production rate of the impeller remains the largest regardless of the presence of a guide vane in the turbine. The vortices inside the guide vanes increase obviously with the flow rate increase.","PeriodicalId":49041,"journal":{"name":"Journal of Applied Fluid Mechanics","volume":"48 5","pages":""},"PeriodicalIF":1.0,"publicationDate":"2024-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139395884","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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: 0

Pressure Pulsation Analysis of Oscillating Water Column Rotor Eccentricity Based on the Pulsation Tracking Network Method 基于脉动跟踪网络法的振荡水柱转子偏心压力脉动分析

IF 1 4区工程技术

Journal of Applied Fluid Mechanics Pub Date : 2024-01-01 DOI: 10.47176/jafm.17.3.2070

J. Lu, Q. Liu, Z. Lu, R. Tao, F. Jin, D. Zhu, R. Xiao

{"title":"Pressure Pulsation Analysis of Oscillating Water Column Rotor Eccentricity Based on the Pulsation Tracking Network Method","authors":"J. Lu, Q. Liu, Z. Lu, R. Tao, F. Jin, D. Zhu, R. Xiao","doi":"10.47176/jafm.17.3.2070","DOIUrl":"https://doi.org/10.47176/jafm.17.3.2070","url":null,"abstract":"An oscillating water column (OWC) is typical of axial rotor turbines, which are used to convert ocean wave energy into electrical energy. This device impacts downstream pressure pulsations when its rotor becomes eccentric. This study compared the details of pressure pulsations downstream of eccentric and non-eccentric rotors under three operating conditions: low flow A, high-efficiency flow B, and high flow C. Computational fluid dynamics (CFD) simulations based on the pulsation tracking network (PTN) method were used for the OWC device to compare the experimental results. The results indicate downstream pressure pulsations were mostly dominated by the blade frequency in non-eccentric low-flow cases. In the other eccentric operating conditions, downstream pressure pulsations were mainly dominated by the 2-, 3.6-, 6-, and 7-times rotation frequencies and the 0.5-times blade frequency. The phase change of downstream pressure pulsations in eccentric and non-eccentric conditions is consistent with the flow direction. The phase change is relatively uniform and steady before eccentricity and becomes turbulent after eccentricity, which affects its steadiness. In this study, the OWC device did not significantly change with or without rotor eccentricity at a 1-time blade frequency intensity; however, at a 1-time rotation frequency, the OWC device showed a significant increase in the pressure pulsation amplitude after rotor eccentricity. The study of the dominant frequency, amplitude, and phase of pressure pulsations in OWC devices with eccentric rotors can help prevent excessive pressure pulsations that can lead to incidents.","PeriodicalId":49041,"journal":{"name":"Journal of Applied Fluid Mechanics","volume":"95 9","pages":""},"PeriodicalIF":1.0,"publicationDate":"2024-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139454288","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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: 0

Scale Effects Investigation in Physical Modeling of Recirculating Shallow Flow Using Large Eddy Simulation Technique 利用大涡模拟技术研究再循环浅层流物理建模中的尺度效应

IF 1 4区工程技术

Journal of Applied Fluid Mechanics Pub Date : 2024-01-01 DOI: 10.47176/jafm.17.1.1980

R. A. Tartandyo, B. M. Ginting, J. Zulfan

{"title":"Scale Effects Investigation in Physical Modeling of Recirculating Shallow Flow Using Large Eddy Simulation Technique","authors":"R. A. Tartandyo, B. M. Ginting, J. Zulfan","doi":"10.47176/jafm.17.1.1980","DOIUrl":"https://doi.org/10.47176/jafm.17.1.1980","url":null,"abstract":"In this study, the Large Eddy Simulation (LES) model in OpenFOAM was used to investigate the scale effects in the physical modeling of recirculating shallow flow at low Froude numbers. A laboratory test of turbulent flow through a submerged conical island with a Reynolds number of 6,210 was selected. The lab prototype was scaled with factors of 3 and 10 for both undistorted and distorted models. Our study employed the Froude similarity as the gravitational force is more dominant than the others (viscous, drag, and cohesion forces). Because the fluid (water) used for the prototype and model is the same, it is impossible to match the Reynolds, Weber, and Froude numbers simultaneously, resulting in the scale effects. For a scale of 1:1, the LES model could simulate the experimental data by appropriately capturing the vortices behind the conical island. For the undistorted models with scales of 3 and 10, the numerical model captured weaker magnitudes of vortices than the 1:1 scale, indicated by the discrepancies in velocity. In fact, the magnitudes of vortices became weaker with the distorted models. We also observed a significant increment in energy loss behind the conical island (where recirculating flows exist) as the scale increased. However, no significant discrepancies in velocity were observed between the results of the 1:1 scale and the scaled models in front of the conical island, where vortices were absent. These results indicate that the scale effects due to the Froude similarity are quite significant provided that recirculating turbulent flow occurs.","PeriodicalId":49041,"journal":{"name":"Journal of Applied Fluid Mechanics","volume":"96 7","pages":""},"PeriodicalIF":1.0,"publicationDate":"2024-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139126108","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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: 0