Article
Engineering, Chemical
Hong Yao, Jinjing Tang, Zuohua Liu, Changyuan Tao, Yundong Wang
Summary: This study proposes a dual-shaft eccentric impeller to improve the flow field structure in a stirred reactor and enhance fluid transfer efficiency and mixing degree. The results show that changing the impeller types and height difference between shafts can improve mixing efficiency, as the reasonable combination of these variables can utilize the advantages of different impellers and disrupt the symmetrical flow field structure, enhancing energy dissipation and improving mixing efficiency.
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
(2022)
Article
Mechanics
Xin Zhang, Yong Wang
Summary: Dielectric barrier discharge plasma actuators are effective in flow control and can generate steady wall jets. Pressure field distributions are obtained through experiments, and the formation mechanism of the pressure field is discussed based on different discharge stages.
Article
Chemistry, Multidisciplinary
Alessio Panunzi, Monica Moroni, Alessio Mazzelli, Marco Bravi
Summary: This study investigates the feasibility of using tools like computational fluid dynamics (CFD) to address bioreactor improvement problems, and demonstrates successful predictions of model results based on experimental data.
Article
Engineering, Multidisciplinary
Federico Zabaleta, Santiago Marquez Damian, Fabian A. Bombardelli
Summary: This study presents a novel theoretical/numerical model for simulating self-aerated flows using a Reynolds-Averaged Navier-Stokes (RANS) framework. The model incorporates a three-phase mixture approach and a mass transfer mechanism to account for the presence of air in the flow. It also modifies the Volume-of-Fluid algorithm to capture the increase in water depth due to bubbles. The proposed model shows satisfactory results in simulating self-aerated flows.
COMPUTER METHODS IN APPLIED MECHANICS AND ENGINEERING
(2023)
Article
Mechanics
Zhizhou Zhao, Wenwu Song, Yongxin Jin, Lei He
Summary: Stall is a common phenomenon in centrifugal pumps under low-flow conditions and has significant implications for fatigue and mechanical damages. High-precision numerical calculations using computational fluid dynamics were conducted to describe multiple operating conditions. The accuracy of the simulations was validated by comparing with experimental data. Based on this, the spatiotemporal evolution of stall vortex and the kinetic energy conversion relationship were determined. The results showed relative motion between the stall vortex and the impeller under rotating stall condition, with a propagation frequency of 0.71 Hz. Additionally, the critical stall condition exhibited greater kinetic energy dissipation compared to the deep stall condition, with energy differences more than three times larger at the blade leading edge where the stall vortex is formed.
Article
Engineering, Chemical
Helvio Mollinedo, Victor X. Mendoza-Escamilla, Gabriela Rivadeneyra-Romero, Israel Gonzalez-Neria, J. Antonio Yanez-Varela, Alejandro Alonzo-Garcia, Jesus Lugo-Hinojosa, Sergio A. . Martinez-Delgadillo
Summary: The effects of axially symmetric control rods on the hydrodynamic performance of a four-blade pitched blade turbine (PBT) were evaluated. The modified PBT with control rods showed improved efficiency and reduced power consumption, as well as a decrease in energy dissipation rate.
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
(2022)
Article
Engineering, Chemical
A. Zak, F. Alberini, F. Maluta, T. Moucha, G. Montante, A. Paglianti
Summary: This study investigates a gas-liquid stirred tank of high aspect ratio that replicates the geometry of typical industrial aerated fermenters. The liquid phase homogenization dynamics and gas phase spatial distribution are determined using Electrical Resistance Tomography. The reliability of the collected data is quantitatively evaluated by comparing results obtained from vertical and horizontal arrangements of electrodes.
CHEMICAL ENGINEERING RESEARCH & DESIGN
(2022)
Article
Mechanics
Giorgia Tagliavini, Majid H. Khan, Mark McCorquodale, Chris Westbrook, Markus Holzner
Summary: Experimental and numerical approaches have advantages and limitations in studying complex phenomena such as the falling of snow particles. This study compares the time- and space-averaged flow quantities in the wake of falling snowflakes using both experimental and numerical methods. The results show that a fixed-particle model can accurately represent the wake flow for steadily falling snowflakes, but significant differences are present at moderate/high Reynolds numbers (unsteady falling motion). The findings suggest that an unsteady fall significantly alters the average wake structure compared to a fixed particle model.
Article
Energy & Fuels
Daniel Fuzesi, Siqi Wang, Viktor Jozsa, Cheng Tung Chong
Summary: This study investigated three ammonia/methane flames through numerical and experimental methods, with a focus on robust modeling approaches for the combustion of ammonia in the industry. The comparison between steady-state and unsteady results showed that steady calculations were accurate for chemical conversion but fell behind in flow field modeling. The CO emission matched the experiments, but the concentration was low, while the CFD underpredicted the NOx emission by a factor of two.
Article
Engineering, Aerospace
Alessandro Apollonio, Alessandro Anderlini, Dario Valentini, Giovanni Pace, Angelo Pasini, Maria Vittoria Salvetti, Luca d'Agostino
Summary: This article expands on the assessment of a reduced-order model proposed for the evaluation of mixed-flow centrifugal turbopumps. The model's predictions are compared with simulations and validated against experimental results, demonstrating its capability for preliminary design and optimization of turbopumps.
AEROSPACE SCIENCE AND TECHNOLOGY
(2022)
Article
Energy & Fuels
Jingyu Zhu, Conghui Shan, Keiya Nishida, Wuqiang Long, Dongsheng Dong
Summary: This study examines the two-phase flow characteristics of transient Diesel spray using optical diagnosis techniques and numerical simulation methods, providing insights into the spray structure and turbulent mixing features. Additionally, an improved velocity predicting model accounting for spatial variation is developed for enhanced understanding of the flow dynamics.
Article
Engineering, Chemical
Xia Xiong, Songsong Wang, Peiqiao Liu, Changyuan Tao, Yundong Wang, Zuohua Liu
Summary: The process intensification mechanism of fluid mixing was investigated by studying the evolution of sub-steady flow pattern. The modified dual impeller system eliminated the isolation zone and symmetry of the flow pattern observed in the traditional dual impeller system. The mixing time and dynamic equilibrium time were significantly shorter in the modified system, attributed to enhanced fluid flow fluctuations caused by the loss of stability of sub-steady flow field.
CHEMICAL ENGINEERING SCIENCE
(2023)
Article
Engineering, Aerospace
Ali Zamiri, Minsuk Choi, Jin Taek Chung
Summary: This paper numerically investigates the rotating stall mechanism in a NASA CC3 transonic centrifugal compressor with a wedge-type vaned diffuser. The study validates the numerical model through experiments and analyzes stall characteristics, showing good agreement between numerical results and experimental data. The research demonstrates that the current numerical approach is beneficial for accurate prediction of rotating stall and resolving unsteady turbulence structures.
JOURNAL OF PROPULSION AND POWER
(2021)
Article
Thermodynamics
Hao Fu, Chuangxin He
Summary: This study investigates the dynamics of coherent vortex rings in a successively generated turbulent pulsed jet. The results demonstrate a close relationship between turbulence enhancement and the generation and structure of vortex rings. Furthermore, it is found that the compactness of the vortex rings is positively correlated with the pulsing frequency.
EXPERIMENTAL THERMAL AND FLUID SCIENCE
(2022)
Article
Mathematics, Interdisciplinary Applications
Minggao Tan, Chen Shao, Xianfang Wu, Houlin Liu, Bo Pan
Summary: The current research on slurry pump particles mainly focuses on spherical particles, neglecting the non-spherical particles commonly found in practical engineering. This study applies a multi-sphere model to construct a cylindrical particle model and analyzes the movement characteristics of cylindrical particles within a slurry pump using the RANS-DEM approach. The research findings show that the average velocity of cylindrical particles decreases with increasing particle density and concentration, and cylindrical particles tend to accumulate in the middle of the guide vane.
COMPUTATIONAL PARTICLE MECHANICS
(2023)
