Ivan Sboev^1,*, Tatyana Lyubimova^2,3, Konstantin Rybkin³, Michael Kuchinskiy^2,3

FDMP-Fluid Dynamics & Materials Processing, Vol.20, No.6, pp. 1425-1439, 2024, DOI:10.32604/fdmp.2024.051341

Abstract The intensification of physicochemical processes in the sonochemical reactor chamber is widely used in problems of synthesis, extraction and separation. One of the most important mechanisms at play in such processes is the acoustic cavitation due to the non-uniform distribution of acoustic pressure in the chamber. Cavitation has a strong impact on the surface degradation mechanisms. In this work, a numerical calculation of the acoustic pressure distribution inside the reactor chamber was performed using COMSOL Multiphysics. The numerical results have revealed the dependence of the structure of the acoustic pressure field on the boundary conditions More > Graphic Abstract

Mengdong An¹, Weiyuan Zhong¹, Wei Xu², Xiuli Wang^1,*

FDMP-Fluid Dynamics & Materials Processing, Vol.20, No.6, pp. 1331-1349, 2024, DOI:10.32604/fdmp.2023.046604

Abstract The reactor coolant pump (RCP) rotor seizure accident is defined as a short-time seizure of the RCP rotor. This event typically leads to an abrupt flow decrease in the corresponding loop and an ensuing reactor and turbine trip. The significant reduction of core coolant flow while the reactor is being operated at full load can have very negative consequences. This potentially dangerous event is typically characterized by a complex transient behavior in terms of flow conditions and energy transformation, which need to be analyzed and understood. This study constructed transient flow and rotational speed mathematical More > Graphic Abstract

Michael Kuchinskiy^1,2,*, Tatyana Lyubimova^1,2, Konstantin Rybkin², Anastasiia Sadovnikova², Vasiliy Galishevskiy²

FDMP-Fluid Dynamics & Materials Processing, Vol.20, No.5, pp. 1093-1102, 2024, DOI:10.32604/fdmp.2024.050059

Abstract Ultrasonic baths and sonochemical reactors are widely used in industrial applications dealing with surface cleaning and chemical synthesis. The processes of erosion, cleaning and structuring of the surface can be typically controlled by changing relevant influential parameters. In particular, in this work, we experimentally investigate the effect of NaCl concentration (0–5.5 mol/L) on the erosion of an aluminum foil under ultrasonic exposure at a frequency of 28 kHz. Special attention is paid to the determination of cavitation zones and their visualization using heat maps. It is found that at low NaCl concentration (0.3 mol/L), the More > Graphic Abstract

Xukai Ren^1,2,*, Huanwei Yu², Xianfeng Chen², Yantong Tang², Guobiao Wang^1,*, Xiyong Du²

CMES-Computer Modeling in Engineering & Sciences, Vol.140, No.1, pp. 647-663, 2024, DOI:10.32604/cmes.2024.048782

Abstract Stirred reactors are key equipment in production, and unpredictable failures will result in significant economic losses and safety issues. Therefore, it is necessary to monitor its health state. To achieve this goal, in this study, five states of the stirred reactor were firstly preset: normal, shaft bending, blade eccentricity, bearing wear, and bolt looseness. Vibration signals along x, y and z axes were collected and analyzed in both the time domain and frequency domain. Secondly, 93 statistical features were extracted and evaluated by ReliefF, Maximal Information Coefficient (MIC) and XGBoost. The above evaluation results were More >

Muhd Hadi Iskandar Abd Razak^*, Motoki Tsuda, Yukio Hayakawa, Shinji Kambara

Energy Engineering, Vol.121, No.2, pp. 259-272, 2024, DOI:10.32604/ee.2023.043615

Abstract Hydrogen is an alternative energy source that has the potential to replace fossil fuels. One of the hydrogen applications is as a material for Polymer Electrolyte Membrane Fuel Cells (PEMFC) in fuel cell vehicles. High-purity hydrogen can be obtained using a hydrogen separation membrane to prevent unwanted contaminants from potentially harming the PEMFC components. In this study, we fabricated a plasma membrane reactor and investigated the permeation performance of a hydrogen separation membrane in a plasma membrane reactor utilizing atmospheric pressure plasma. The result showed the hydrogen permeation rate increasing with time as reactor temperature More >

Yonggang Zheng^1,*, Hanbo Zhang¹, Jingyan Li¹, Hui Li², Hongfei Ye¹, Hongwu Zhang¹

The International Conference on Computational & Experimental Engineering and Sciences, Vol.25, No.1, pp. 1-2, 2023, DOI:10.32604/icces.2023.010050

Abstract The reactor pressure vessels (RPV), a typical kind of axisymmetric structures, usually serve under high temperature and pressure conditions. The numerical analysis of the mechanical behaviors of these structures plays a dominant role for their structural design, advanced manufacture and safety assessment in practical engineering applications[1-2]. However, the extremely conditions bring great challenges for the numerical analysis of structures undergo ablation, plastic, damage and even fracture during an accident[3]. Based on the superior performance of peridynamics model in predicting fracture behaviors [4-7], a coupled axisymmetric non-ordinary state-based peridynamics (CA-NOSB-PD) model is proposed in this work… More >

Danyang Shao¹, Xiaojia Wang^1,*, Delu Chen¹, Fengxia An^1,2

Journal of Renewable Materials, Vol.11, No.10, pp. 3659-3680, 2023, DOI:10.32604/jrm.2023.029220

Abstract Methanation is an effective way to efficiently utilize product gas generated from the pyrolysis and gasification of organic solid wastes. To deeply study the heat transfer and mass transfer mechanisms in the reactor, a successful three-dimensional comprehensive model has been established. Multiphase flow behavior and heat transfer mechanisms were investigated under reference working conditions. Temperature is determined by the heat release of the reaction and the heat transfer of the gas-solid flow. The maximum temperature can reach 951 K where the catalyst gathers. In the simulation, changes in the gas inlet velocity and catalyst flow… More >

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 More >

Xiaojia Wang^1,*, Danyang Shao¹, Delu Chen¹, Yutong Gong¹, Fengxia An^1,2

Journal of Renewable Materials, Vol.11, No.7, pp. 3155-3175, 2023, DOI:10.32604/jrm.2023.027535

Abstract Organic solid waste (OSW) contains many renewable materials. The pyrolysis and gasification of OSW can realize resource utilization, and its products can be used for methanation reaction to produce synthetic natural gas in the specific reactor. In order to understand the dynamic characteristics of the reactor, a three-dimensional numerical model has been established by the method of Computational Fluid Dynamics (CFD). Along the height of the reactor, the particle distribution in the bed becomes thinner and the mean solid volume fraction decreases from 4.18% to 0.37%. Meanwhile, the pressure fluctuation range decreased from 398.76 Pa… More > Graphic Abstract

Xun Liu, Li Chen^* , Wen-Quan Tao

Frontiers in Heat and Mass Transfer, Vol.14, pp. 1-9, 2020, DOI:10.5098/hmt.14.16

Abstract Fluid flow, mass transport and catalytic reaction in micro-reactors with catalyst are studied. Optimized structures of the catalyst generating the maximum reaction rate are explored by numerically solving the reactive transport processes combined with topology optimization schemes in COMSOL 5.3a. Effects of several physicochemical parameters including pressure drop, reaction rate constant, permeability of the porous catalyst and radius of the reactor are investigated. Distributions of the optimized structures, velocity, pressure and concentration are discussed in detail. Results show that the four physicochemical parameters have significant effects on the optimized structures of the catalyst obtained, indicating More >