Senchun Miao^1,2,*, 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 >

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

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 >

Yapu Zhang^1,2, Zhengming Yang^1,2, Dajian Li³, Xuewei Liu¹, Xinli Zhao^1,2,*

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 >

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 >

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 >

Li Lei¹, Jun An¹, Fushun Liang¹, Cheng Cheng¹, Naixiang Zhou², Yanhong Ning³, Jingzhi Zhang^1,4,*

FDMP-Fluid Dynamics & Materials Processing, Vol.17, No.6, pp. 1037-1048, 2021, DOI:10.32604/fdmp.2021.016081

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 >

Yongheng Ku¹, Jinguang Zhang^2,3, Zhenyu Wang^3,4, Youxin Li^3,5, Haowei Yao^3,5,*

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 >

Xiaoxia Li^1,2, Manyu Qian², Dan Tian³, Jihuan He^2,3,*

FDMP-Fluid Dynamics & Materials Processing, Vol.17, No.6, pp. 1015-1019, 2021, DOI:10.32604/fdmp.2021.015430

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 >

Jianghao Niu^*

FDMP-Fluid Dynamics & Materials Processing, Vol.17, No.6, pp. 1003-1013, 2021, DOI:10.32604/fdmp.2021.015225

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 >

Zhiyuan Tu¹, Fusheng Peng^1,*, 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 >