Fengxia Shi^1,2, Yucai Tang^1,*, Dedong Ma¹, Xiangyun Shi¹, Guangbiao Zhao¹

FDMP-Fluid Dynamics & Materials Processing, Vol.19, No.10, pp. 2481-2497, 2023, DOI:10.32604/fdmp.2023.028416

Abstract In order to analyze the response of a hydraulic turbine to a variation in the operating conditions, different laws of variation in time of the mass flow rate have been considered. After validating the overall numerical framework through comparison with relevant experiments, the performances of the considered turbine have been analyzed from a fluid-dynamic point of view. The results show that different time profiles of the mass flow rate (in this work, for simplicity, referred to as “transition functions”) have a varying influence on the transient behavior of the turbine. When a quadratic function is considered for the case of… More > Graphic Abstract

Jiuxuan Liu, Yong Zeng^*, Xueya Zhao, Hongbo Chen, Bin Yan, Qian Lu

FDMP-Fluid Dynamics & Materials Processing, Vol.19, No.10, pp. 2499-2518, 2023, DOI:10.32604/fdmp.2023.028413

Abstract

A method combining computational fluid dynamics (CFD) and an analytical approach is proposed to develop a prediction model for the variable thickness of the spray-induced liquid film along the surface of a cylindrical workpiece. The numerical method relies on an Eulerian-Eulerian technique. Different cylinder diameters and positions and inclinations of the spray gun are considered and useful correlations for the thickness of the liquid film and its distribution are determined using various data fitting algorithms. Finally, the reliability of the proposed method is verified by means of experimental tests where the robot posture is changed. The provided correlation are intended… More > Graphic Abstract

Yue Yu^*

FDMP-Fluid Dynamics & Materials Processing, Vol.19, No.10, pp. 2681-2694, 2023, DOI:10.32604/fdmp.2023.028250

Abstract A triethylenetetramine epoxy mixture was synthesized through the reaction of a low-molecular-weight liquid epoxy resin with triethylenetetramine (TETA). Then triethyltetramine (TETA) was injected dropwise into a propylene glycol methyl ether (PM) solution for chain extension reaction. A hydrophilic and flexible polyether segment was introduced into the hardener molecule. The effects of TETA/DGEPG, reaction temperature and reaction time on the epoxy conversion of polyethylene glycol diglycidyl ether (DGEPG) were studied. In addition, several alternate strategies to add epoxy resin to the high-speed dispersion machine and synthesize MEA DGEBA adduct (without catalyst and with bisphenol A diglycidyl ether epoxy resin) were compared.… More >

Jun Li¹, Guofeng Cheng², Hongwei Xiao³, Xiang Li⁴, Lizhi Wang⁴, Hui Xu^5,*, Yu Wang⁶, Nannan Liu⁵, Shangping Chen⁵, Xing Shi⁵

FDMP-Fluid Dynamics & Materials Processing, Vol.19, No.10, pp. 2695-2706, 2023, DOI:10.32604/fdmp.2023.028115

Abstract Assuming a reservoir with a typical salt-lake background in the Qaidam Basin as a testbed, in this study the variation law of the rock electrical parameters has been determined through water displacement experiments with different salinities. As made evident by the results, the saturation index increases with the degree of water injection. When the salinity of the injected water is lower than 80000 ppm, the resistivity of the rock sample first decreases, then it remains almost constant in an intermediate stage, and finally it grows, thereby giving rise to a ‘U’ profile behavior. As the salinity decreases, the water saturation… More > Graphic Abstract

Dalia S. Makki¹, Hasan Sh. Majdi², Amer A. Abdulrahman¹, Abbas J. Sultan^1,3,*, Zahraa W. Hasan¹, Laith S. Sabri^1,3, Bashar J. Kadhim¹, Muthanna H. Al-Dahhan³

FDMP-Fluid Dynamics & Materials Processing, Vol.19, No.10, pp. 2613-2637, 2023, DOI:10.32604/fdmp.2023.028081

Abstract Bubble and slurry bubble column reactors (BCRs/SBCRs) are used for various chemical, biochemical, and petrochemical applications. They have several operational and maintenance advantages, including excellent heat and mass transfer rates, simplicity, and low operating and maintenance cost. Typically, a catalyst is present in addition to biochemical processes where microorganisms are used to produce industrially valuable bio-products. Since most applications involve complicated gas-liquid, gas-liquid-solid, and exothermic processes, the BCR/SBCR must be equipped with heat-exchanging tubes to dissipate heat and control the reactor’s overall performance. In this review, past and very recent experimental and numerical investigations on such systems are critically discussed.… More >

Chunyan Zhang¹, Shuaishuai Wang^1,2, Yinhu Qiao^1,*, Zhiqiang Zhang^1,2

FDMP-Fluid Dynamics & Materials Processing, Vol.19, No.10, pp. 2661-2679, 2023, DOI:10.32604/fdmp.2023.028059

Abstract Numerical simulations are conducted to improve the energy acquisition efficiency of H-type vertical axis wind turbines through the optimization of the related blade airfoil aerodynamic performance. The Bézier curve is initially used to fit the curve profile of a NACA2412 airfoil, and the moving asymptote algorithm is then exploited to optimize the design of the considered H-type vertical-axis wind-turbine blade airfoil for a certain attack angle. The results show that the maximum lift coefficient of the optimized airfoil is 8.33% higher than that of the original airfoil. The maximum lift-to-drag ratio of the optimized airfoil exceeds the maximum lift-to-drag ratio… More > Graphic Abstract

Marwah Subhi Attallah, Reem Alaa Mohammed^*, Ruaa Haitham Abdel-Rahim

FDMP-Fluid Dynamics & Materials Processing, Vol.19, No.10, pp. 2449-2469, 2023, DOI:10.32604/fdmp.2023.027750

Abstract This study aims to evaluate the erosion behavior and the hardness of hybrid composites made of varying amounts of coconut shells, walnut shells, and carbon fibers dispersed in a polyester matrix. MINITAB (L16) Taguchi experiments were used to determine the optimal combination of parameters. In particular, an erosion device consisting of a motor with a constant flow rate of 45 L/min, a pump with a diameter of 40 mm, a nozzle with a diameter of 5 mm, and a tank made of “perspex glass” 55 cm long, 30 cm tall, and 25 cm wide was used. The tests were conducted by varying the sample-to-nozzle distance, the… More > Graphic Abstract

Yue Liang, Wenxuan Dai, Wei Chen^*

FDMP-Fluid Dynamics & Materials Processing, Vol.19, No.10, pp. 2639-2659, 2023, DOI:10.32604/fdmp.2023.027622

Abstract Glass powder of various particle sizes (2, 5, 10 and 15 μm) has been assessed as a possible cement substitute for mortars. Different replacement rates of cement (5%, 10%, 15%, and 20%) have been considered for all particle sizes. The accessible porosity, compressive strength, gas permeability and microstructure have been investigated accordingly. The results have shown that adding glass powder up to 20% has a significantly negative effect on the porosity and compressive strength of mortar. The compressive strength initially rises with a 5% replacement and then decreases. Similarly, the gas permeability of the mortar displays a non-monotonic behavior; first, it… More >

Weiting Jiang^1,*, Lei Zhao^1,*, Chongyang Wang², Tingni He¹, Weiguo Pan¹

FDMP-Fluid Dynamics & Materials Processing, Vol.19, No.10, pp. 2597-2611, 2023, DOI:10.32604/fdmp.2023.027504

Abstract When a brazed plate heat exchanger is used as an evaporator, the working mass in the channel may undergo solidification, thereby hindering the refrigeration cycle. In this study the liquid solidification process and its optimization in a brazed plate heat exchanger are investigated numerically for different inlet velocities; moreover, different levels of corrugation are considered. The results indicate that solidification first occurs around the contacts, followed by the area behind the contacts. It is also shown that dead flow zones exist in the sharp areas and such areas are prone to liquid solidification. After optimization, the solidification area attains its… More >

Amer A. Abdulrahman¹, Bashar J. Kadhim¹, Zainab Y. Shnain¹, Hassan Sh. Majidi², Asawer A. Alwaiti^1,*, Farooq Al-Sheikh¹, Adnan A. AbdulRazak¹, Mohammed Shorbaz¹, Mazin J. Shibeeb³

FDMP-Fluid Dynamics & Materials Processing, Vol.19, No.10, pp. 2579-2595, 2023, DOI:10.32604/fdmp.2023.027454

Abstract The well-known frictional effect related to liquid-liquid two-phase flow in pipelines can be reduced using drag-reducing additives. In this study, such an effect has been investigated experimentally using a mixture of oil and water. Moreover, numerical simulations have been carried out using the COMSOL simulation software. The measurements were taken in a horizontal pipe with the length and diameter equal to 3 and 0.125 m, respectively. Moreover, Polyethylene oxide with 150 ppm was exploited to reduce the drag effect while considering different water-to-oil fractions (0.3, 0.4, 0.5, and 0.7) and a constant total flow velocity of 2.3 m/s. As made… More >