INTERNATIONAL JOURNAL OF MULTIPHASE FLOW
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2024
·
IF 3.6
Jia-Jia Yu,Li Huang,Gu-Yuan Li,Maitiniyazi Bake,Chun-Mei Wu,You-Rong Li
The impact of hydrodynamic cavitation is one of the key factors in the fabrication and application of metal materials. The hydrodynamic cavitation in anisotropic fluids can be much different from common fluids due to the unique fluid dynamics characteristics related to the director field. In this paper, the hydrodynamic cavitation of nematic liquid crystal 5CB flowing around a cylindrical pillar in a microchannel in the Stokes flow regime is studied at various Reynolds numbers and blockage ratios by experiments. Once the Reynolds number rises over a threshold value, the hydrodynamic cavitation of nematic liquid crystal is generated in the stokes flow in the microchannel, which is the unique phenomenon for anisotropic fluids. The critical Reynolds number of cavitation inception decreases with the increase of the blockage ratio. The Strouhal number is induced to describe this unsteady oscillating cavitation flow, while the Strouhal number increases and decreases with the increase of the blockage ratio and Reynolds number, respectively. Dynamics characteristics of the cavitation including cavity volume, oscillation frequency, and pressure difference are analyzed at different Reynolds numbers and blockage ratios by image binarization treatment and Fast Fourier Transformation analysis. The results of this study are useful for the application of microfluidic chips based on nematic liquid crystals and protection of devices in the environment of similar anisotropic fluids.
研究领域:
流体力学
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材料科学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF FOOD ENGINEERING
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2024
·
IF 5.3
Guangyuan Jin,Qingyu Zheng,Zhengshan Zhu,Chunfang Song,Zhenfeng Li,Feihu Song,Jing Li,Boru Chen
To address the need for enhanced biochemical reactions and overcome the shortcomings associated with passive and active mixer fabrication, reactor designs must utilize the coupled mixing concept to address the lack of insufficient heat and mass transfer through notable alterations of the physical properties. This study introduces a tubular microwave reactor based on chaotic flow dynamics, attempting to combine the concept of active and passive mixing to stimulate the development of eddy and secondary flows through electromagnetic fields and geometric disturbance enhance heat and mass transfer. Experiments and simulation analysis validate the validity of the prediction model, and reveal the fluid flow, mixing, electromagnetic and thermal characteristics and their synergistic mechanism, and shows the potential to enhance the mass and heat transfer performance at low Reynolds number, which provides a new idea for the design of chemical reactors and biological analysis.
研究领域:
化学工程
·
生物分析
✓ 已验证
产品关联
DOI
高影响因子
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
·
2023
·
IF 5.2
Shuai Yuan,Mingyong Zhou,Xijiang Liu,Bingyan Jiang
The coupling of pressure-driven flow (PDF) and electroosmotic flow (EOF) has been widely applied in the field of microfluidics. However, the adverse effects of pressure induced by PDF on EOF in a confined space cannot be ignored. Herein, the interactions of these two streams when the Reynolds number ( Re ) varies from 0.1 to 10 are systematically explored through numerical simulations to gain an in-depth understanding of the mechanism of the pressure effect on mass species transport and to generate optimal separation of samples. The simulation results show that the length of the sample increases linearly and the molecular diffusion is accelerated due to the pressure effect caused by the EOF channel structure and PDF extrusion, which reduces the separation quality and even leads to the failure of electrophoresis . However, the deformation of the sample cannot be effectively resisted by increasing the applied voltage . A better separation effect can be obtained only when Re =0.1. To surmount the above disadvantages, a novel porous polymer plug with pores smaller than 5 μm that provides a region that has high flow resistance but allows the electromigration of charged analytes is established in the EOF channel. The experimental results show that this plug can effectively neutralize the EOF outlet pressure when Re ≤5. The shape of the sample is not distorted and the maximum gray values decreased by 26%, 30% and 49% respectively in 7 s when Re =0.1, 1 and 5, which are much better than the results without the plug.
研究领域:
微流控技术
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分析化学
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生物工程
✓ 已验证
产品关联
DOI
高影响因子
CHINESE JOURNAL OF CHEMICAL ENGINEERING
·
2022
·
IF 3.898
Xiaoping Li,Jiaxin Pan,Jinwen Shi,Yanlin Chai,Songwei Hu,Qiaorong Han,Yanming Zhang,Xianwen Li,Dengwei Jing
Although having been increasingly studied, there is still controversy as to when the addition of nanoparticles could improve the drag reduction performance of polymer drag reducer and particularly what is the underlying mechanism from the fluid dynamics viewpoint. The drag reduction effects of adding SiO 2 nanoparticles to various polymer polyacrylamide (PAM) solutions were examined in this work. The optimal combination of SiO 2 nanoparticles with cationic polyacrylamide was confirmed. Interestingly, the addition of SiO 2 nanoparticles to cationic polyacrylamide solution was shown to be quite efficient for reducing drag, but only at higher flow rates with Reynolds numbers more than 6000, below which the nanoparticle addition is even negative. The addition of SiO 2 nanoparticles to the PAM solution is supposed to play a dual role. The first is an increase in flow resistance caused by the Brownian motion of nanoparticles, while the second is a decrease in flow resistance caused by acting as nodes to protect the polymer chain from shear-induced breaking under high shear action. At optimal nanoparticle concentration and under higher Reynolds numbers, the later effect is dominant, which could improve the drag reduction performance of polymer drag reducers. Our work should serve as a guide for the application of natural gas fracturing, where the flow rate is frequently very high.
研究领域:
流体力学
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材料科学
✓ 已验证
产品关联
DOI
高影响因子
KOREA-AUSTRALIA RHEOLOGY JOURNAL
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2024
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IF 2.2
Yang Ding,Chen Jiaqi,Shen Ao,Wang Junfeng,Liu Hailong
The spreading behavior of droplets impacting solid surfaces is of significant importance in numerous industrial and medical applications. This study specifically focuses on the droplet impact behaviors of shear-thinning fluids. Extensive impact experiments were conducted using high-speed visualization techniques. Image sequences in the DI water and xanthan gum solution droplets impact process are captured at a We range of around 3.2–388 and Re n of 18–8145. The morphologies of spreading droplets on hydrophilic, moderate, and hydrophobic surfaces was observed with temporal evolution. The experimental results showed that the spreading behavior of shear-thinning droplets varies with the impact velocity, surface wettability, and fluid concentration. The droplets spread more widely and rapidly at larger We with the time evolution of the spreading factor. In addition, the spreading of the droplets becomes suppressed on a hydrophobic surface or with a higher xanthan concentration. With the increase of We , the effect of fluid viscosity gradually surpasses the surface wettability. The fluid viscosity with the shear-thinning properties has more influence on the spreading behavior at high We . Furthermore, the experimental data of the maximum spreading factor could be scaled with the We and Re n at low and high We , respectively. Finally, the maximum spreading of shear-thinning droplets was correlated with a universal rescaling model. The correlation shows good accordance with the experimental results of droplet impact from this study and the literature in a wide range of impact conditions and shear-thinning properties. Graphical abstract
研究领域:
流体力学
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材料科学
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工程学
✓ 已验证
产品关联
DOI
高影响因子
PHYSICS OF FLUIDS
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2024
·Vol. 36
·期 1
·
IF 4.1
Yu Jia-Jia,Jiang Lu-Yang,Huang Li,Li Gu-Yuan,Bake Maitiniyazi,Li You-Rong
Hydrodynamic cavitation, which occurs when the local pressure is below the saturated vapor pressure in hydrodynamic flow, is ubiquitous in fluid dynamics and implicated in a myriad of industrial and biomedical applications. Although extensively studied in isotropic liquids, corresponding investigations in anisotropic liquids are largely lacking. In this paper, the hydrodynamic cavitation in the bluff body bypass flow of nematic liquid crystal 5CB in the microchannel is experimentally investigated. By 5CB, we mean the thermotropic liquid crystal 4′-pentyl-4-biphenylcarbonitrile. When the Reynolds number is in the range of 3 × 10 −4 < Re < 1.2 × 10 −3 , a special flow phenomenon behind the bluff body is observed, namely, the disclination loop. The critical Reynolds number of cavitation inception varies with the shape of the bluff body, while the lowest value corresponds to the triangular bluff body. The hydrodynamic cavitation occurs in the Stokes flow regime with the Reynolds number significantly lower than 0.1 for all bluff bodies. There is a close relation between the oscillation behavior of cavitation domains and the structure of the bluff body. In addition, the pressure difference between the inlet and outlet of the microchannel shows linear relation with the Reynolds number rather than the quadratic relation for isotropic fluids, which proves the presence of shear thinning in the flow of nematic liquid crystals. The study in this paper on the hydrodynamic cavitation of nematic liquid crystal can broaden the research on providing new approaches for the enhancement of fluid mixing and heat transfer in microfluidic chips.
研究领域:
流体力学
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材料科学
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微流控技术
✓ 已验证
产品关联
DOI
高影响因子
PHYSICS OF FLUIDS
·
2022
·Vol. 34
·期 3
·
IF 4.98
Yuan Shuai,Zhou Mingyong,Peng Tao,Li Qiang,Jiang Fengze
Achieving rapid mixing of different liquids in a short distance is important in various biochemical applications. Herein, a novel planar mixer with staggered Z-shaped baffles is proposed. Numerical investigations are carried out to evaluate its mixing ability based on mixing quality and pressure drop when the Reynolds number (Re) varies from 0.1 to 50. The Lyapunov exponent, the Poincaré map, and the vortex visualization are conducted to comprehensively analyze the chaotic state and the mixing mechanism. Results show that the proposed mixer exceeds 0.9 mixing efficiency when 0.1 ≤ Re and Re ≥ 8. As Re ≥ 8, different vortex patterns appear by changing the inlet configuration. The disturbance for fluids induced by a vortex on the mass transfer surface is not only dependent on its intensity but also related to the position of the vortex/vortex leg. The proposed planar mixer, inducing a single vortex or vortex pair with different directions, presents different mixing performance when the Re varies from 8 to 50, from which the approach of the rotating vortex that can mainly improve the mixing quality is found. This well explains the chaotic mixing behavior observed in the planar mixer with Z-shaped baffles, which to date has not been studied before. Furthermore, the micromixer is fabricated, tested, and applied for luminol–peroxide chemiluminescence detection to characterize its performance.
研究领域:
流体力学
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生物化学工程
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微流控技术
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF MEMBRANE SCIENCE
·
2021
·
IF 8.742
Caijin Zhou,Bingqi Xie,Junxin Chen,Yiwei Fan,Jisong Zhang
The generation of Dean vortices in the membrane contactor is regarded as one of the critical technologies for gas-liquid mass transfer enhancement at low liquid Reynolds number. In this work, the gas-liquid mass transfer enhancement by Dean vortices in the curved hollow fiber membrane contactors is rapidly characterized based on the flux balance of gas across the membrane and dissolved in liquid. The effects of Reynolds number, curved diameter, liquid viscosity and rheology on the gas-liquid mass transfer enhancement with different curved shapes are systematically determined. The gas-liquid mass transfer correlations are proposed to describe the enhancement effect of Dean vortices on gas-liquid system with different viscosities. At the helical diameter of 6 mm and Reynolds number of 308, the enhancement factor is up to around 2.5. Furthermore, the trade-off relation between gas-liquid mass transfer intensification and energy consumption across the curved membrane contactors is investigated. The liquid velocity profile is also obtained by the finite element numerical simulation with COMSOL Multiphysics software to evaluate the Dean vortices intensity generated in different curved shapes, which agrees well with the experimental results.
研究领域:
化学工程
·
流体力学
✓ 已验证
产品关联
DOI
高影响因子
EXPERIMENTAL THERMAL AND FLUID SCIENCE
·
2022
·
IF 3.37
Shaobai Li,Jingbo Ji,Zhuang Liu
The motion of a single bubble rising in stagnant shear-thinning viscoelastic liquids was investigated using a high-speed camera. The recorded images were analyzed using MATLAB with a self-written code in order to obtain the bubble volume and velocity. Using the experimental observations, a simple shape map was proposed based on the Reynolds number and the Deborah number. The bubble velocity was also investigated, and the phenomenon of velocity jump was observed in the Polyacrylamide (PAA) solutions. Furthermore, an empirical correlation was proposed to predict the drag coefficient of bubbles rising in stagnant shear-thinning viscoelastic liquids. The predicted results of the correlation showed good conformity with the experimental values corresponding to the PAA solutions of different concentrations and 95 wt% glycerin solution.
研究领域:
流体力学
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化学工程
·
非牛顿流体
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多相流
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传质过程
✓ 已验证
DOI
高影响因子
ACS Omega
·
2021
·
IF 3.512
Shi-jun Lian,Zhong-xin Hu,Zhong Lan,Rong-fu Wen,Xue-hu Ma
In the process of industrial crystallization, it is always difficult to balance the secondary nucleation rate and metastable zone width (MSZW). Herein, we report an experimental and numerical study for the cooling crystallization of paracetamol in an oscillatory flow crystallizer (OFC), finding the optimal operating conditions for balancing the secondary nucleation rate and MSZW. The results show that the MSZW decreases with the increase of oscillation Reynolds number (Reo). Compared to the traditional stirring system, the OFC has an MSZW three times larger than that of the stirring system under a similar power density of consumption. With the numerical simulation, the OFC can produce a stable space environment and instantaneous strong disturbance, which is conducive to the crystallization process. Above all, a high Reo is favorable to produce a sufficient nucleation rate, which may inevitably constrict the MSZW to a certain degree. Then, the optimization strategy of the operating parameter (Reo) in the OFC is proposed.
研究领域:
化学工程
·
结晶工艺优化
✓ 已验证
DOI
高影响因子
Frontiers in Bioengineering and Biotechnology
·
2023
·
IF 5.7
Xiong Junfeng,Zhang Junkai,Zhong Yukun,Song Xiaoxia,Wang Haoying,Cheang U Kei
Ultraviolet lithography is a very promising technology used for the batch fabrication of biomedical microswimmers. However, creating microswimmers that can swim at low Reynolds number using biocompatible materials while retaining strong magnetic properties and excellent biomedical functionality is a great challenge. Most of the previously reported biomedical microswimmers possess either strong magnetic properties by using non-biocompatible nickel coating or good biocompatibility by using iron oxide particle-embedded hydrogel with weak magnetism, but not both. Alternatively, iron oxide nanoparticles can be coated on the surface of microswimmers to improve magnetic properties; however, this method limited the usability of the microswimmers’ surfaces. To address these shortcomings, this work utilized an in situ synthesis technique to generate high magnetic content inside hydrogel-based achiral planar microswimmers while leaving their surfaces free to be functionalized for SERS detection. The hydrogel matrices of the magnetically actuated hydrogel-based microswimmers were first prepared by ultraviolet lithography. Then, the high concentration of iron oxide was achieved through multiple continuous in situ coprecipitation cycles. Finally, the SERS detection capability of magnetically actuated hydrogel-based microswimmers was enabled by uniformly growing silver nanoparticles on the surface of the microswimmers. In the motion control tests, the microswimmers showed a high swimming efficiency, high step-out frequency, and consistent synchronized motion. Furthermore, the magnetically actuated hydrogel-based microswimmers were able to improve the detection efficiency of analytes under magnetic guidance.
研究领域:
生物医学工程
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材料科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Microfluidics and Nanofluidics
·
2022
·Vol. 26
·期 10
·1-11
·
IF 3.09
Yan Huilong,Qian Fang,Jiao Kai,Zhang Wenyao,Tan Zhoutuo,Zhao Lingru,Wang Qiuwang,Zhao Cunlu
The lubricant-infused surface (LIS) has emerged as a promising drag reduction surface for flow enhancement. At present, there are some applications of LISs in polymer-based microchannels for drag reduction. However, the use of the LIS in metal capillaries or microchannels for drag reduction or flow enhancement is lacking. The present work proposes a method for the fabrication of a LIS on the inner surface of copper (Cu) capillaries to grant them sustainable drag reduction properties. Cu capillaries with an inner superhydrophobic surface (SHS) (contact angle > 160°) are also prepared as a reference for comparison. To test the hydrodynamic performance under different working conditions, we fabricated LIS Cu capillaries with lubricants of varying viscosities, and their frictional factors were experimentally measured with a Reynolds number (Re) ranging from 0 to 1500. The drag reduction of the LIS Cu capillary (32%) is slightly lower than that of the SHS Cu capillary (36%), but the LIS Cu capillary has much better sustainability. The threshold Re for initiating the failure of LIS Cu capillaries is almost three times that of the SHS Cu capillary, and the durability of the LIS Cu capillary under high shear force conditions is also much higher. The superior sustainability of the LIS Cu capillaries is due to the enhanced capillary and Van der Waals (vdW) forces caused by the composite morphology and functional groups applied to the LIS. The present study will provide useful insights for designing robust and sustainable LISs for drag reduction or flow enhancement in Cu capillaries.
研究领域:
材料科学
·
流体力学
·
表面工程
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）