Article
Engineering, Chemical
Deyin Gu, Tao Yang, Longfei Xie
Summary: Fractal perforating impeller was introduced to improve the mixing performance of shear-thinning fluids with yield stress in a stirred reactor. Experimental analyses and numerical simulation showed that the fractal spaces in the impeller blades reduced power consumption and improved mixing efficiency. The fractal-3 perforating impeller achieved significant reductions in power consumption and mixing time compared with other impellers. The introduction of fractal spaces in the impeller blades also reduced the size of trailing vortices and promoted fluid mixing.
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
(2023)
Article
Nanoscience & Nanotechnology
Yoshiyuki Komoda, Tomoya Date
Summary: This study investigates the usefulness of an anchor-type impeller in enhancing two-dimensional fluid mixing under a laminar regime. Numerical simulations and experimental observations show that an appropriate central clearance size can prevent the segmentation of mixing regions and improve the uniformity of fluid mixing.
Article
Engineering, Chemical
Jacek Stelmach, Czeslaw Kuncewicz, Tomas Jirout, Frantisek Rieger
Summary: This study used a PIV laser system to analyze the distribution of velocities and mixing power in a mixing tank with narrow and wide propeller impellers. The results showed that propeller impellers with wide blades were the most efficient in terms of energy consumption for achieving the desired mixing time. Additionally, the share of pumping capacity in the total secondary circulation was found to be almost double that of induced circulation.
CHEMICAL ENGINEERING RESEARCH & DESIGN
(2023)
Article
Engineering, Chemical
Angus Shiue, Likuan Zhu, Chao-Li Wang, Jyh-Cheng Jeng, Graham Leggett
Summary: This study evaluated the power demand and mixing performance of three different coaxial mixers in laminar, transition, and turbulent flows. The results showed that the combination of a 4-pitched blade turbine and an anchor impeller provided the shortest mixing time given the same power consumption, making it the optimized combination among the three mixers.
JOURNAL OF THE TAIWAN INSTITUTE OF CHEMICAL ENGINEERS
(2023)
Article
Engineering, Chemical
Jacek Stelmach, Czeslaw Kuncewicz, Szymon Szufa, Tomas Jirout, Frantisek Rieger
Summary: This study conducted an analysis of hydrodynamics in a tank with a 45 degrees and 60 degrees pitched blade turbine impeller operating while emptying the mixer, as well as the working scenarios of an axial agitator during axial pumping-down of water at different levels. Measurements with the PIV method confirmed the change in liquid pumping direction after the liquid level dropped below the critical value, with an increase in tangential velocity in the impeller area depending on the blade pitch angle and rotational frequency, leading to an increase in mixing power.
Article
Engineering, Chemical
Jacek Stelmach, Czeslaw Kuncewicz, Lukasz Adrian, TomaS Jirout, Frantisek Rieger
Summary: This paper investigates the increase in mixing power during tank emptying with two axial impellers in operation. A significant increase in mixing power was observed when the liquid's free surface was above one of the impellers, exceeding the design power for a fully filled vessel. The study also explored the potential damage from high motor overload and provided correlation relationships for calculating power increase factors.
Article
Engineering, Chemical
Riki Takahashi, Mai Iwata, Haruki Furukawa, Yoshihito Kato, Yoshikazu Kato, Takahiro Nemoto, Ken-ichi Ago, Seung-Tae Koh
Summary: A large two blade paddle impeller GD220 was developed for aeration agitation, and its performances were evaluated. The mixing performance was equivalent to that of similar large paddle MR203. The impeller design made it difficult to form cavities during aeration and reduced aeration power consumption.
KAGAKU KOGAKU RONBUNSHU
(2023)
Article
Engineering, Chemical
Liangchao Li, Bin Xu
Summary: This study investigated the influence of a forward-reverse rotating impeller in an unbaffled tank on flow field and power characteristics. The findings revealed that the fluid in the unbaffled tank flows periodically with the forward-reverse impeller agitation, resulting in zonal flow phenomenon. The effects of operating conditions on instantaneous fluid velocity vary with positions in the tank. The flow field characteristics in the forward-reverse agitated unbaffled tank are significantly different from those in constant agitated unbaffled and baffled tanks.
JOURNAL OF THE TAIWAN INSTITUTE OF CHEMICAL ENGINEERS
(2022)
Article
Engineering, Chemical
Deyin Gu, Jie Wang, Hao Yang, Yaoyao Deng
Summary: This study compared the mixing performance of a dislocated self-similarity impeller (DS impeller) and a dislocated pitched-blade impeller (DPB impeller) in the mixing process of solid particles and pseudoplastic fluid using experimental and computational fluid dynamics simulation. The results showed that the DS impeller could improve solid particle distribution and decrease power consumption by decomposing vortices and utilizing the self-similar structure design of impeller blades. The DS-2 impeller reduced about 40.56% and 13.50% of power consumption compared to the DPB impeller and DS-1 impeller, respectively. Therefore, the self-similar structure design significantly improves mixing effectiveness in the solid particles and pseudoplastic fluid mixing process.
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
(2023)
Article
Engineering, Chemical
Lele Xu, Zhuotai Jia, Mengke Guo, Zai-Sha Mao, Yiqun Fan, Qinghua Zhang, Chao Yang
Summary: A V-shaped punched baffle (VSPB) is developed to enhance fluid mixing in a stirred tank. Experimental results show that VSPB reduces mixing time by a maximum of 23% and 14.7% compared to standard baffles (SB) and standard punched baffles (SPB) at low speeds. Simulation results demonstrate that the punched baffle significantly increases fluid velocity and turbulence in the baffle region, forming tiny vortices.
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
(2023)
Article
Engineering, Chemical
Sumit S. Joshi, Vishwanath H. Dalvi, Vivek S. Vitankar, Aniruddha J. Joshi, Jyeshtharaj B. Joshi
Summary: Critical speed for solid suspension in stirred tanks is significant in chemical processes. A generalized correlation is needed for various literature data, while a comparative study of different ML models for the prediction of the critical speed is lacking in the literature. In this study, ML models including RF, CatB, and ANN were compared, and the CatB model achieved the highest effectiveness. Novel correlations for HE-3, PTD, and DT impellers were developed, outperforming previous correlations in the literature.
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
(2023)
Article
Biotechnology & Applied Microbiology
Francesco Maluta, Alessandro Paglianti, Giuseppina Montante
Summary: The study reveals challenges in industrial production with multiple impeller fermenters, such as gas accumulation and reduction of power transfer, which hinder mass transfer. Through simulation methods, fluid dynamics features can be accurately predicted, and mass transfer limitations can be effectively overcome.
BIOCHEMICAL ENGINEERING JOURNAL
(2021)
Article
Engineering, Environmental
S. S. Hoseini, G. Najafi, B. Ghobadian, A. H. Akbarzadeh
Summary: This study investigates the importance of mixing in the chemical industry and proposes a computational framework for optimizing power consumption and impeller stress in stirred-tank reactors. By using Computational Fluid Dynamic (CFD) analysis, the study examines three types of impellers and utilizes Multi-objective Genetic Algorithm (MOGA) to optimize the geometrical parameters of the blades. The results show a decrease in power consumption with V- and U-shape impellers compared to the 6-blade Rushton turbine, and indicate differences in turbulent kinetic energy and stress distribution among different impeller designs.
CHEMICAL ENGINEERING JOURNAL
(2021)
Article
Chemistry, Multidisciplinary
Ivan Pavlenko, Oleksandr Kulikov, Oleksandr Ratushnyi, Vitalii Ivanov, Jan Pitel, Vladyslav Kondus
Summary: The article presents a study on increasing the pressure and power characteristics of centrifugal pumps by using a counter-rotating pumping stage. The research uses CFD modeling and the Moore-Penrose pseudoinverse approach to analyze the performance of the pumps. The results show that pumps with a counter-rotating stage can significantly increase the pressure head, reaching 2.1 times higher than the standard design, while reducing weight and size indicators.
APPLIED SCIENCES-BASEL
(2023)
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
Ryuta X. Suzuki, Yuichiro Nagatsu, Manoranjan Mishra, Takahiko Ban
JOURNAL OF FLUID MECHANICS
(2020)
Article
Mechanics
Vandita Sharma, Hamirul Bin Othman, Yuichiro Nagatsu, Manoranjan Mishra
Summary: Through numerical computations and experimental studies, miscible viscous fingering (VF) in an annulus is examined, showing contrast to classical radial VF and instability of a straight displaced slice. The persistence of VF in a miscible annular ring is observed, with variance as a non-monotonic function indicating interaction of two fronts, pressure fingers growing faster than concentration fingers. The variation of finger length with flow rate depends on the amount of more viscous fluid in the annulus, with critical parameters for instability related to viscosity contrast and sample amount.
JOURNAL OF FLUID MECHANICS
(2021)
Article
Energy & Fuels
Mohammad Azis Mahardika, Yun She, Fujiura Shori, Anindityo Patmonoaji, Shintaro Matsushita, Tetsuya Suekane, Yuichiro Nagatsu
Summary: The study showed that calcium hydroxide flooding significantly improves oil recovery, especially in heterogeneous porous media. However, if water flooding is conducted afterwards, oil production will decline promptly.
Article
Energy & Fuels
Yun She, Mohammad Azis Mahardika, Yingxue Hu, Anindityo Patmonoaji, Shintaro Matsushita, Tetsuya Suekane, Yuichiro Nagatsu
Summary: Alkaline flooding is a promising method for enhanced oil recovery by forming oil-in-water emulsions in-situ. This study investigates the effects of total acid number (TAN) and injected flow rate on oil recovery performance through 3D oil displacement experiments, confirming that oil recovery increases with higher acid concentration and optimal flow rate. The study also observes nonlinear finger-finger interactions in 3D porous media and verifies oil displacement mechanisms through 2D pore-scale micromodel experiments, concluding that emulsification ability strengthens with higher acid concentration, leading to stable oil displacement mechanisms.
JOURNAL OF PETROLEUM SCIENCE AND ENGINEERING
(2021)
Article
Chemistry, Physical
Ryuta X. Suzuki, Shuntaro Kobayashi, Yuichiro Nagatsu, Takahiko Ban
Summary: In this study, hydrodynamic interfacial instability controlled by a thermodynamic parameter driving liquid-liquid phase separation is reported during fluid displacement. Adjusting salt concentration controls the miscibility of solutions, changing interface patterns from stable circular to fingering and droplet formation as salt concentration decreases. The patterns transition to a state with higher entropy production.
JOURNAL OF PHYSICAL CHEMISTRY B
(2021)
Article
Mechanics
Weicen Wang, Chunwei Zhang, Anindityo Patmonoaji, Yingxue Hu, Shintaro Matsushita, Tetsuya Suekane, Yuichiro Nagatsu
Summary: The study investigates the impact of gas-bubble generation by chemical reaction on viscous fingering using a Hele-Shaw cell in a miscible two-phase liquid. It discusses the effect of four characteristic times on displacement pattern with gas bubbles, highlighting the shorter characteristic time of the chemical reaction and the quick bubble coalescence. The research shows that the competition between displacement and nucleation times determines the flow pattern in the system.
Article
Chemistry, Physical
Takahiko Ban, Ryohei Tanaka, Ryuta X. Suzuki, Yuichiro Nagatsu
Summary: The displacement of one fluid by another fluid is a significant process in various fields. Understanding the fluctuations at the interface under different miscibility conditions is crucial. The roughness exponent and growth exponent of the partially miscible case are larger, indicating the impact of Korteweg convection during phase separation. Despite miscibility conditions, fluctuations in the systems can be accurately predicted using a single curve, allowing for predictions at any scale and time.
Article
Physics, Fluids & Plasmas
Sae Hirano, Yuichiro Nagatsu, Ryuta X. Suzuki
Summary: In this paper, the authors investigate the impact of chemical reaction-induced gel production on viscous fingering dynamics. They propose a model that explains the opposite effects observed and demonstrate that the rheological properties of the gel can lead to different flow patterns.
PHYSICAL REVIEW FLUIDS
(2022)
Article
Mechanics
Shoji Seya, Ryuta X. Suzuki, Yuichiro Nagatsu, Takahiko Ban, Manoranjan Mishra
Summary: We developed coupled evolution equations for viscous fingering and phase separation, and demonstrated the transition of VF pattern into droplet formation pattern by spinodal decomposition effect. The experimental results matched the theoretical predictions.
JOURNAL OF FLUID MECHANICS
(2022)
Article
Mechanics
Yuka F. Deki, Yuichiro Nagatsu, Manoranjan Mishra, Ryuta X. Suzuki
Summary: Viscous fingering or Saffman-Taylor instability occurs when a more mobile fluid displaces a less mobile one in porous media, creating finger-like patterns. The effective interfacial tension (EIT) acts like capillary force at the miscible interface. Numerical studies have shown that fingers are wider with EIT. However, a recent experiment on a miscible system with EIT observed finger widening with increasing flow rate, which is not observed in other systems. This study numerically investigates the effect of injection flow rates on miscible viscous fingering with and without EIT, and explains the mechanism using a one-dimensional analysis of concentration and EIT profiles.
JOURNAL OF FLUID MECHANICS
(2023)
Article
Mechanics
Harumi Yagi, Yuichiro Nagatsu, Masayoshi Takano, Ryuta X. Suzuki
Summary: This study experimentally investigates the interfacial flow dynamics and viscoelastic material production at the interface between two liquids through a chemical reaction. The flow dynamics show fingering patterns at low flow rates and fracturing patterns at high flow rates in Hele-Shaw cells. The transition from fingering to fracturing patterns is influenced by the concentration of Fe(NO3)(3). The study also highlights the importance of rheology under large deformation of the viscoelastic interface in interfacial flow and demonstrates the successful elucidation of physical phenomena using interfacial large amplitude oscillatory shear (LAOS).
JOURNAL OF RHEOLOGY
(2023)
Article
Chemistry, Physical
Kaori Iwasaki, Yuichiro Nagatsu, Takahiko Ban, Jun Iijima, Manoranjan Mishra, Ryuta X. Suzuki
Summary: Phase separation occurring at the interface has attracted more attention recently, especially when combined with hydrodynamics. This study investigates the dynamics of phase separation during fluid displacement experiments in a radially confined geometry. The results show that the fingering pattern caused by viscosity contrast can be suppressed by phase separation, and the direction of the Korteweg force determines whether the pattern changes to droplets or remains as fingering. These findings have direct implications for improving processes such as enhanced oil recovery and CO2 sequestration.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2023)
Article
Chemistry, Physical
Sae Hirano, Yuichiro Nagatsu, Ryuta X. X. Suzuki, Jun Iijima
Summary: A chemical reaction in a flow field can affect the physical properties of fluids, leading to changes in flow dynamics. However, it has been found that comparing the pre- and post-reaction fluid properties is insufficient to evaluate the effects of the reaction on flow dynamics in certain polymeric reacting flows. In this study, experiments were conducted using partially hydrolyzed polyacrylamide (HPAM) solution and Fe(NO3)(3) solution to investigate the appearance and disappearance of the Weissenberg effect under specific pH conditions. The mechanisms for the temporal increase in viscoelasticity were proposed, and the study also explored the disappearance of the Weissenberg effect in the case of Al(NO3)(3) solution.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2023)
Proceedings Paper
Materials Science, Multidisciplinary
Noor Azwani Mohd Rasidek, Mariam Firdhaus Mad Nordin, Hideaki Tokuyama, Yuichiro Nagatsu, Norlisa Mili, Ahmad Syahmi Zaini, Zuhaili Idham, Mohd Azizi Che Yunus
Summary: The study demonstrates that subcritical water extraction of pectin from banana peels can serve as a natural gelling agent with good gelation properties. The optimal extraction conditions are temperature at 140 degrees Celsius, time of 5 minutes, and particle size of 1.18 mm.
MATERIALS TODAY-PROCEEDINGS
(2021)
Article
Chemistry, Physical
Ryuta X. Suzuki, Hikari Tada, Sae Hirano, Takahiko Ban, Manoranjan Mishra, Risa Takeda, Yuichiro Nagatsu
Summary: Phase separation is divided into spinodal decomposition and nucleation and growth types, which can lead to different effects when coupled with hydrodynamic and thermodynamic conditions, affecting the formation of droplets.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2021)
