Home / Journals / FDMP / Vol.17, No.6, 2021
Table of Content
  • Open Access

    ARTICLE

    CFD Analysis of the Influence of Ionic Liquids on the Performances of a Refrigeration System

    Jianghao Niu*
    FDMP-Fluid Dynamics & Materials Processing, Vol.17, No.6, pp. 1003-1013, 2021, DOI:10.32604/fdmp.2021.015225
    (This article belongs to this Special Issue: EFD and Heat Transfer III)
    Abstract The falling film of an ionic liquid ([EMIM] [DMP] + H2O) and its effect on a refrigeration system are numerically simulated in the framework of a Volume of Fluid (VOF) method (as available in the ANSYS Fluent computational platform). The properties of the liquid film and the wall shear stress (WSS) are compared with those obtained for a potassium bromide solution. Different working conditions are considered. It is noted that the ionic liquid demonstrates a better absorption capability, with a coefficient of performance (COP) of 0.55. It is proved that the [EMIM] [DMP] + H2O ionic liquid working substance is… More >

  • Open Access

    ARTICLE

    Needleless Electrospinning: Reciprocation vs. Rotation

    Xiaoxia Li1,2, Manyu Qian2, Dan Tian3, Jihuan He2,3,*
    FDMP-Fluid Dynamics & Materials Processing, Vol.17, No.6, pp. 1015-1019, 2021, DOI:10.32604/fdmp.2021.015430
    (This article belongs to this Special Issue: Nanoscale Flow and Nanomaterial Fabrication)
    Abstract Needleless electrospinning is a versatile method to produce nanofibers. In particular, the rotary version of this technique has enjoyed widespread use because there is no need to clean the spinneret. The rotation speed is limited by the potential deviation of the jet due to the centrifugal force. Other limitations are due to the fast volatilization of the solvent from the opened spinning system. In order to overcome these drawbacks, here a novel reciprocating system based on a moving spinning-plate is proposed. The spinning process is implemented in a half-closed system with the spinning-plate immersed in the solution tank. When the… More >

  • Open Access

    ARTICLE

    A Study on the Unsteady Flow Characteristics and Energy Conversion in the Volute of a Pump-as-Turbine Device

    Senchun Miao1,2,*, Hongbiao Zhang1, Wanglong Tian1, Yinqiang Li2
    FDMP-Fluid Dynamics & Materials Processing, Vol.17, No.6, pp. 1021-1036, 2021, DOI:10.32604/fdmp.2021.016925
    Abstract To study the unsteady flow and related energy conversion process in the volute of a pump-as-turbine (PAT) device, six different working conditions have been considered. Through numerical calculation, the spatio-temporal variation of static pressure, dynamic pressure, total pressure and turbulent energy dissipation have been determined in each section of the volute. It is concluded that the reduction of the total power of two adjacent sections of the PAT volute is equal to the sum of the power lost by the fluid while moving from one section to the other and the power output from the two adjacent sections. For a… More >

  • Open Access

    ARTICLE

    An Experimental Study on the Void Fraction for Gas-Liquid Two-Phase Flows in a Horizontal Pipe

    Li Lei1, Jun An1, Fushun Liang1, Cheng Cheng1, Naixiang Zhou2, Yanhong Ning3, Jingzhi Zhang1,4,*
    FDMP-Fluid Dynamics & Materials Processing, Vol.17, No.6, pp. 1037-1048, 2021, DOI:10.32604/fdmp.2021.016081
    (This article belongs to this Special Issue: Recent Advances in Fluid Mechanics and Thermal Sciences)
    Abstract The flow patterns and the void fraction related to a gas-liquid two-phase flow in a small channel are experimentally studied. The test channel is a transparent quartz glass circular channel with an inner diameter of 6.68 mm. The working fluids are air and water and their superficial velocities range from 0.014 to 8.127 m/s and from 0.0238 to 0.556 m/s, respectively. The void fraction is determined using the flow pattern images captured by a high-speed camera, while quick closing valves are used for verification. Four flow patterns are analyzed in experiments: slug flow, bubbly flow, annular flow and stratified flow.… More >

  • Open Access

    ARTICLE

    Assessment of the Application of Subcooled Fluid Boiling to Diesel Engines for Heat Transfer Enhancement

    Xiaoyu Hu, Yi Wang, Siyuan Li, Qiang Sun, Shuzhan Bai, Guoxiang Li*, Ke Sun*
    FDMP-Fluid Dynamics & Materials Processing, Vol.17, No.6, pp. 1049-1066, 2021, DOI:10.32604/fdmp.2021.016763
    (This article belongs to this Special Issue: Recent Advances in Fluid Mechanics and Thermal Sciences)
    Abstract The increasing demand of cooling in internal combustion engines (ICE) due to engine downsizing may require a shift in the heat removal method from the traditional single phase liquid convection to the application of new technologies based on subcooled fluid boiling. Accordingly, in the present study, experiments based on subcooled flow boiling of 50/50 by volume mixture of ethylene glycol and water coolant (EG/W) in a rectangular channel heated by a cast iron block are presented. Different degrees of subcooling, velocity and pressure conditions are examined. Comparison of three empirical reference models shows that noticeable deviations occur especially when low… More >

  • Open Access

    ARTICLE

    On the Development of an Effective Pressure Driving System for Ultra-Low Permeability Reservoirs

    Yapu Zhang1,2, Zhengming Yang1,2, Dajian Li3, Xuewei Liu1, Xinli Zhao1,2,*
    FDMP-Fluid Dynamics & Materials Processing, Vol.17, No.6, pp. 1067-1075, 2021, DOI:10.32604/fdmp.2021.016725
    Abstract Given its relevance to the exploitation of ultra-low permeability reservoirs, which account for a substantial proportion of the world’s exploited and still unexploited reserves, in the present study the development of an adequate water injection system is considered. Due to the poor properties and weak seepage capacity of these reservoirs, the water injection pressure typically increases continuously during water flooding. In this research, the impact on such a process of factors as permeability, row spacing, and pressure gradient is evaluated experimentally using a high-pressure large-scale outcrop model. On this basis, a comprehensive evaluation coefficient is introduced able to account for… More >

  • Open Access

    ARTICLE

    A Numerical Study on the Extinguishing Performances of High-Pressure Water Mist on Power-Transformer Fires for Different Flow Rates and Particle Velocities

    Yongheng Ku1, Jinguang Zhang2,3, Zhenyu Wang3,4, Youxin Li3,5, Haowei Yao3,5,*
    FDMP-Fluid Dynamics & Materials Processing, Vol.17, No.6, pp. 1077-1090, 2021, DOI:10.32604/fdmp.2021.015779
    Abstract In order to study the extinguishing performance of high-pressure-water-mist-based systems on the fires originating from power transformers the PyroSim software is used. Different particle velocities and flow rates are considered. The evolution laws of temperature around transformer, flue gas concentration and upper layer temperature of flue gas are analyzed under different boundary conditions. It is shown that the higher the particle velocity is, the lower the smoke concentration is, the better the cooling effect on the upper layer temperature of flue gas layer is, the larger the flow rate is and the better the cooling effect is. More >

  • Open Access

    ARTICLE

    Numerical Study on the Blade Channel Vorticity in a Francis Turbine

    Zhiqi Zhou*
    FDMP-Fluid Dynamics & Materials Processing, Vol.17, No.6, pp. 1091-1100, 2021, DOI:10.32604/fdmp.2021.016618
    Abstract A relevant way to promote the sustainable development of energy is to use hydropower. Related systems heavily rely on the use of turbines, which require careful analysis and optimization. In the present study a mixed experimental-numerical approach is implemented to investigate the related mixed water flow. In particular, particle image velocimetry (PIV) is initially used to verify the effectiveness of the numerical model. Then numerical results are produced for various conditions. It is shown that an increase in the guide vane opening can reduce the extension of the region where the fluid velocity is 0 at the inlet of the… More >

  • Open Access

    ARTICLE

    A Study on the Pyrolytic Characteristics of Xanthoceras Sorbifolia Husk and Its Crude Cellulose Extract

    Hongmei Zhang1,*, Quancheng Zhou2
    FDMP-Fluid Dynamics & Materials Processing, Vol.17, No.6, pp. 1101-1111, 2021, DOI:10.32604/fdmp.2021.017202
    Abstract Huge amounts of Xanthoceras sorbifolia husks (XSH) are typically discarded after oil extraction. Since pyrolysis represents a promising solution to harness the bio-energy of XSH, in the present work the pyrolytic and kinetic characteristics of XSH and related crude cellulose extract (CCE) were studied considering different rates of heating (10, 30 and 50°C min−1). The pyrolysis activation energy, pre-exponential factors and mechanism function were computed using different models namely Popescu, FWO (Flynn-Wall-Ozawa) and KAS (Kissinger-Akahira-Sunose). The pyrolysis process was articulated into three stages: dehydration (Stage I), primary devolatilization (Stage II), residual decomposition (Stage III). Marked variations in the average activation… More >

  • Open Access

    ARTICLE

    Numerical and Experimental Study of a Tornado Mixer

    Yibao Wang, Dongsheng Wang, Yudan Xue, Dailong Shi*, Xiaoli Zhang, Yang Chai, Bang An
    FDMP-Fluid Dynamics & Materials Processing, Vol.17, No.6, pp. 1113-1127, 2021, DOI:10.32604/fdmp.2021.017591
    (This article belongs to this Special Issue: Advances in Fluid Flow, Heat and Thermal Sciences)
    Abstract A new design of a selective catalytic reduction (SCR) mixer called tornado was developed for a heavy-duty diesel engine to solve the urea deposition problem. A combination of CFD simulation and experimental studies was used to comprehensively evaluate the performance of the tornado mixer. According to the numerical simulations, this mixer can improve the front surface flow uniformity of the SCR carrier by 6.67% and the NH3 distribution uniformity by 3.19% compared to a traditional mixer. Similarly, steady state SCR conversion efficiency test results have shown that the tornado mixer can increase the average SCR conversion efficiency by 1.73% compared… More >

  • Open Access

    ARTICLE

    Experimental Study on the Axial Compression Behavior of Short Columns of Steel-Fiber-Reinforced Recycled Aggregate Concrete

    Chunyang Liu1,2,*, Jia Xu1, Yifan Gu1, Ruofan Shi1
    FDMP-Fluid Dynamics & Materials Processing, Vol.17, No.6, pp. 1129-1142, 2021, DOI:10.32604/fdmp.2021.017376
    Abstract In order to study the axial compression performances of short columns made of recycled aggregate concrete, four samples were designed with different recycled aggregate replacement rates and carbon fibre reinforced plastics (CFRP) sheets. Then, monotonic loading was implemented to assess the variation trends of their axial compression properties. The ABAQUS finite element software was also used to determined the compression performances. Good agreement between experimental and numerical results has been found for the different parameters being considered. As shown by the results, recycled coarse aggregates result in improved ductility and better deformation performance of the specimens. The failure of specimens… More >

  • Open Access

    ARTICLE

    Experimental and Numerical Analysis of the Relationship between Pressure and Drip Rate in a Vertical Polypropylene Infusion Bag

    Weiwei Duan*, Lingfeng Tang
    FDMP-Fluid Dynamics & Materials Processing, Vol.17, No.6, pp. 1143-1164, 2021, DOI:10.32604/fdmp.2021.016692
    Abstract Vertical infusion (self-emptying) bags used for Intravenous infusion are typically obtained by moulding a soft envelope of polypropylene. In normal conditions a continuous flow of liquid can be obtained with no need to use a pump. In the present study, the relationship between air pressure effects and the drug drip rate have been investigated experimentally and numerically. After determining relevant experimental data about the descending height of liquid level, the dropping speed and pressure, the ordinary least square method and MATLAB have been used to reconstruct the related variation and interrelation laws. Numerical simulations have been performed to determine the… More >

  • Open Access

    ARTICLE

    On the Stability of Carbon Shale Slope under Rainfall Infiltration

    Haifeng Huang1, Zhao Li2,*, Junhui Luo1, Zhenchao Chang1
    FDMP-Fluid Dynamics & Materials Processing, Vol.17, No.6, pp. 1165-1178, 2021, DOI:10.32604/fdmp.2021.017256
    (This article belongs to this Special Issue: EFD and Heat Transfer III)
    Abstract Carbonaceous shale is a sedimentary rock containing a large amount of dispersed carbonaceous organic material. It is easy to crack and soften when exposed to water. In the present work, the stability of such a rock and its sensitivity to the formation of infiltrations due to rainfall are analyzed numerically using the GeoStudio software. The slope stability coefficient is calculated and verified using the landslide thrust calculation method. The results show that under the action of heavy rainfall, water infiltrates into the slope layer by layer, and, accordingly, the soil volume water content is different with respect to that typical… More >

  • Open Access

    ARTICLE

    Development and Application of a Heating Remote Monitoring System Based on KingSCADA

    Chunlei Liu, Tian Gao, Chen Wang, Peiqi Wang, Limin Wang, Yi Wang, Yong Sun*
    FDMP-Fluid Dynamics & Materials Processing, Vol.17, No.6, pp. 1179-1193, 2021, DOI:10.32604/fdmp.2021.017543
    Abstract A remote monitoring system for a secondary heating pipe network is designed on the basis of the KingSCADA software. Remote data communication is implemented through the IP mapping technology. Remote data are sorted through IOServer, and the remote monitoring of the pipe network unit port return is implemented accordingly. Using data such as water temperature and pressure of the water supply and return pipes, valve opening can be remotely adjusted to optimize the performances of the network to meet user needs in real time. The research results show that this remote monitoring system displays a reasonable degree of stability and… More >

  • Open Access

    ARTICLE

    Simplified Calculation of Flow Resistance of Suspension Bridge Main Cable Dehumidification System

    Zhiyuan Tu1, Fusheng Peng1,*, Zijie Wei1, Guo Qian2, Jie Wang1, Chunjie Huang1
    FDMP-Fluid Dynamics & Materials Processing, Vol.17, No.6, pp. 1195-1211, 2021, DOI:10.32604/fdmp.2021.011753
    Abstract To calculate the flow resistance of a main cable dehumidification system, this study considers the air flow in the main cable as the flow in a porous medium, and adopts the Hagen–Poiseuille equation by using average hydraulic radius and capillary bundle models. A mathematical derivation is combined with an experimental study to obtain a semi-empirical flow resistance formula. Additionally, Fluent software is used to simulate the flow resistance across the main cable relative to the experimental values. Based on the actual measured results for a Yangtze River bridge, this study verifies the semi-empirical formula, and indicates that it can be… More >

  • Open Access

    ARTICLE

    Using Image Processing Technology and General Fluid Mechanics Principles to Model Smoke Diffusion in Forest Fires

    Liying Zhu*, Ang Wang, Fang Jin
    FDMP-Fluid Dynamics & Materials Processing, Vol.17, No.6, pp. 1213-1222, 2021, DOI:10.32604/fdmp.2021.017572
    (This article belongs to this Special Issue: EFD and Heat Transfer III)
    Abstract In the present study, the laws of smoke diffusion during forest fires are determined using the general principles of fluid mechanics and dedicated data obtained experimentally using an “ad hoc” imaging technology. Experimental images mimicking smoke in a real scenario are used to extract some “statistics”. These in turn are used to obtain the “divergence” of the flow (this fluid-dynamic parameter describing the amount of air that converges to a certain place from the surroundings or vice versa). The results show that the divergence of the smoke depends on the outside airflow and finally tends to zero as time passes.… More >

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