Engineering Applications of Computational Fluid Mechanics
·
2023
·
IF 6.1
Mohamed Boujelbene,Sohail Rehman,Sultan Alqahtani,Sultan Alshehery,Sayed M. Eldin
This study enlightens the magnetohydrodynamic Jeffery-Hamel flow under an inclined Lorentz force through a non-uniform conduit having slip at walls, which is frequently applied in geothermal applications, electronic cooling devices, and modern energy systems, etc. Therefore, the performance of a two-dimensional purely radial flow inside a converging-diverging channel is explored from the perspective of second law of thermodynamics for Carreau nanofluids. The intersecting walls of conduit are inclined with horizontal plane to construct a converging flow for negative angle (α<0) and a diverging flow for positive angle (α>0). Additionally, second law thermodynamic evaluation offers an effective method for improving thermal performance by reducing entropy production. To accomplish the main objective, rigorous physical theories and assumptions are implemented based on the passive control approach of Buongiorno's model. By applying distinctive modifications, the governing equations are renovated into a system of ordinary differential equations, which are solved numerically by a collocated technique based on finite difference code. Simple shear near the wall influences the flow configurations allow compression in a local flow topology in regions of divergent channel. The temperature profiles increase with sophisticated heat source and Brinkman number. Entropy is minimum and uniform with optimum channel angle and velocity slip.
研究领域:
工程热物理
·
流体力学
·
纳米科技
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DOI
高影响因子
COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
·
2017
·
IF 2.714
Qindan Zhang,Huajun Li,Chunying Zhu,Taotao Fu,Youguang Ma,Huai Z. Li
The combination of microfluidics with magnetism has led to the emergence of a new scientific domain known as micro-magnetofluidics. The present study aims to investigate the interfacial dynamics of ferrofluid droplet formation under magnetic field in a microfluidic T-junction. A non-uniform magnetic field was constructed by placing a permanent magnet at one side of the T-junction. Three typical flow regimes including the slug, slug-dripping transition and dripping flow were observed. The external magnetic field promotes the transition from the slug-dripping transition flow to the slug flow, prolongs the generation cycle of ferrofluid droplets and hinders the ferrofluid droplet formation. As the magnetic flux density increases, both the increasing rate of the length for the thread tip and the expanding rate of the dispersed neck decrease, and the peak value of the minimum width of the dispersed neck increases. The ferrofluid droplet size increases with increasing the magnetic flux density while decreases with increasing the two-phase flow rate ratio and the capillary number. A scaling law is proposed to predict the size of ferrofluid droplets, by taking the two-phase flow rate ratio, capillary number and magnetic Bond number into account.
研究领域:
物理学
·
流体力学
·
微流控技术
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产品关联
DOI
高影响因子
TRANSPORT IN POROUS MEDIA
·
2025
·Vol. 153
·期 1
·5
·
IF 2.6
Fu Pengyu,Wang Yuhang,Lu Wanjun,Ma Hao,Cao Yongqing,Guo Huirong
Spontaneous capillary imbibition in liquid–liquid systems with a shear-thinning wetting phase is crucial in natural and industrial processes yet remains underexplored. Shear-thinning fluids exhibit a continuous transition between power law and Newtonian behavior as the shear rate varies. To capture this rheological evolution during imbibition, we propose a Carreau–Yasuda-based transition function that quantitatively characterizes the relationship between wall shear rate and imbibition rate. Based on this function, we derive a governing equation, termed the transition model, to describe the capillary rise dynamics when Carreau–Yasuda fluid displaces a viscous liquid. The model is validated through multi-relaxation-time color-gradient lattice Boltzmann simulations. In parallel, capillary rise experiments using xanthan gum solutions and silicone oil are conducted to provide physical observations. The proposed transition function accurately captures the dynamic wall shear rate–imbibition rate relationship as Carreau–Yasuda fluids transition between power law and Newtonian behavior. Numerical solutions of the transition model closely align with experimental observation and lattice Boltzmann method simulation, whereas traditional power law model deviates at lower imbibition rates. Scaling analysis showed that, different from power law fluid, Carreau–Yasuda fluid imbibition in late viscous stage still obeys the classic square-root law when the imbibition rate falls below the critical value defined by the model and otherwise follows a power law scaling. This work provides new insights in shear-thinning fluids liquid–liquid imbibition and offers a robust framework for advancing the studies of non-Newtonian fluid imbibition in complex geometries.
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DOI
高影响因子
Applied Materials Today
·
2024
·
IF 7.2
Yaxuan Xiao,Xiong Zhao,Jinhua Zhang,Li Ma,Bin Fang,Nanjing Hao
The Phylum Porifera is one of the most primitive multicellular animals without a mouth, digestive cavity, or central nervous system. Its pores are strewn with flagella inside. Phylum Porifera wiggles its flagella to inhale the seawater, which brings in oxygen, bacteria, microscopic algae, and other organic debris to feed on. Inspired by this natural system, a microreactor based on sharp-edge has been developed and applied in microfluidics to achieve bidirectional pumping and mixing. Here we demonstrate a multifunctional microreactor for bidirectional pumping and mixing that mimics the internal flagella of the Phylum Porifera . The microreactor is designed based on microscale nonlinear acoustics to achieve functionalities via the acoustic streaming generated by the vibration of sharp-edge under the acoustic field. Numerical simulation is conducted to investigate the effect of sharp-edge numbers, dip angles, spreading angles, spacing of sharp-edges, and channel width on the pumping performance. And the bidirectional pumping is verified by experiments. Similarly, numerical simulation and experimental validation are conducted to investigate the effect of flow rate, amplitude, and sharp-edge density on mixing performance. Finally, to verify the application potential and good mixing performance of the developed microreactor, silica nanofluids were synthesized with excellent stability and uniform particle size distribution. These results not only provide important guidelines for the rational design of functional nanomaterials, but also shed new light on the development of efficient microreactors.
研究领域:
生物学
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微流体技术
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF CHEMICAL AND ENGINEERING DATA
·
2019
·
IF 2.298
Ben Li,Wei Guo,Edward D. Ramsey
The solubility of chloramphenicol in pure supercritical fluid carbon dioxide (SF-CO2) has been determined using a continuously stirred supercritical solubility vessel (SSV) directly interfaced with online supercritical fluid chromatography (SFC) using a single valve interface. Solubility measurements were performed at two temperatures of 313 and 333 K with pressures ranging from 10 to 26 MPa. For each individually loaded sample, a series of increasingly more saturated chloramphenicol solutions were prepared in situ by ramping the SF-CO2 pressure within the SSV in 2 or 3 MPa steps. Once equilibrium dissolution was established at each pressure step value, online SFC solubility measurements were performed. The combined SSV–SFC instrumentation and methodology enabled the rapid acquisition of chloramphenicol SF-CO2 solubility data. Chloramphenicol exhibited limited solubility in SF-CO2, providing mole fraction solubility values of 4.9 × 10–6 to 9.9 × 10–6 within the experimental range studied. All sets of SSV–SFC experimental solubility values obtained for chloramphenicol were successfully correlated in accordance with the semiempirical SF-CO2 density-based models developed by (i) Méndez-Santiago and Teja (MST) and (ii) Bartle.
研究领域:
药学
·
化学
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产品关联
DOI
高影响因子
Alexandria Engineering Journal
·
2023
·
IF 6.8
Sakinah Idris,Anuar Jamaludin,Roslinda Nazar,Ioan Pop
The heightened thermal efficiency of hybrid nanofluids presents substantial practical uses in diverse industrial and engineering fields. Thus, the aims of this research are i) to analyze the impact of pertinent parameters towards flow and heat transfer of hybrid Cu-Al 2 O 3 /water nanofluid over permeable moving surface with mutual effects of magnetohydrodynamic (MHD), thermal radiation, Joule heating, and thermal slip condition and ii) to examine the nature of dual solutions. The similarity transformation reduces the complexity of the PDEs to a system of ODEs, which are then numerically solved using bvp4c MATLAB. Two solutions are observable when the surface move approaches the origin ( λ < 0 ) which leads to a stability analysis and validates the first solution as a stable and physically reliable solution. It was discovered at a 1:1 ratio of Cu and Al 2 O 3 volume concentrations immersed in water; the hybrid nanofluid offers a remarkable heat transportation ability than nanofluid and water. An escalation of thermal radiation and magnetic parameters contributed to 79 % and 9.35 % enhancement to the heat transfer rate. The growth in magnetic parameters promotes a delay in boundary layer separation however insignificantly impacted by thermal slip parameter and Eckert number.
研究领域:
工程热物理
·
流体力学
✓ 已验证
DOI
高影响因子
SOLAR ENERGY MATERIALS AND SOLAR CELLS
·
2019
·
IF 6.019
Xue-Feng Shao,Chen-Lin Chen,Yong-Jian Yang,Xiao-Ke Ku,Li-Wu Fan
As potential candidates of solid−liquid phase change materials (PCM) for latent heat storage in the low-to-medium temperature range (80–250 °C), the temperature-dependent rheological behaviors of five select sugar alcohols were characterized over a wide range of shear rates from 10 −3 s −1 to 10 4 s −1 . It was found that the four linear-structured sugar alcohols, i.e., xylitol , erythritol , d-mannitol, and d-dulcitol, are Newtonian fluids above their respective critical shear rates, in both the molten and supercooled liquid states, and that they exhibit typical shear thinning behaviors below the critical shear rates. In particular, d-mannitol and d-dulcitol, with relatively higher melting points , behave like Herschel-Bulkley fluids, which experience slight yield under small yield stresses (0.0001–0.0099 Pa s and 0.0078–0.0528 Pa s for d-mannitol and d-dulcitol, respectively). Inositol , the only cyclic-structured sugar alcohol with the highest melting point (497.65 K), also behaves like a Herschel-Bulkley fluid in both the molten and supercooled liquid states. The dynamic viscosity curves of inositol were found to agree with the Cross model, leading to determination on its zero shear and infinite shear viscosities . An Arrhenius-type dynamic viscosity-temperature curve was observed for inositol over the entire temperature range at the highest shear rate of 10 4 s −1 .
研究领域:
材料科学
·
热能工程
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产品关联
DOI
高影响因子
ACS Omega
·
2025
·
IF 4.3
You-Peng Fang,Sheng-Hua Liu,Yan-Hong Liu,Ke-Xin Wang,Chun-Kui Hu,Chun-Xin Lu,Rusheng Qian,Xia-Chao Chen
Photoinduced transmembrane ion transport in organisms provides a distinctive perspective for exploiting the ocean enriched with both ions and solar energy. Artificial two-dimensional nanofluidic membranes for photothermal-driven ion transport are facing issues such as interrupted nanofluidic transport and much dissipated heat. Peristome surface of Nepenthes enables stable wetting and rapid directional water transport correlated with orientational sophisticated flow-guiding microstructures, inspiring amelioration of these issues by regulating membrane topographies. A conformal layer-by-layer assembly is adopted to construct superstructured positively charged graphene oxide (PGO)/MXene membranes (SGMMs) that differ from topographies. These membranes enable anion-selective transport enhanced by superstructure configurations via providing more and wider nanofluidic channels than planar PGO/MXene membrane (PGMM). SGMMs with orientational superstructures demonstrate superior wetting performance and directional transport of surface microfluidics compared to PGMM, inducing directional ion transport within nanochannels. Additionally, this superstructure design assists SGMMs to outshine PGMM in photothermal evaporation conspicuously, benefiting from an enlarged surface area and well-regulated surface microfluidic distribution. Eventually, SGMMs enable more remarkable photothermal evaporation-driven ion transport facilitated by directional transport of surface microfluidics and efficient photothermal evaporation. This work emphasizes the significance of membrane topography design for nanofluidic transport toward exploiting the ocean including sunlight, water resources, and ionic energy.
研究领域:
材料科学
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能源科学
·
仿生学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Microfluidics and Nanofluidics
·
2019
·Vol. 23
·期 5
·1-9
·
IF 2.437
Yang Xiaohan,Weldetsadik Netsanet Tesfaye,Hayat Zafar,Fu Taotao,Jiang Shaokun,Zhu Chunying,Ma Youguang
The aim of this work was to experimentally examine apparent rheological properties of fluids in microchannels based on pressure drop. Pressure drops of Newtonian and non-Newtonian fluids in microchannels were measured using pressure sensors. The effects of flow rate, Reynolds number, and viscosity of fluids on the pressure drop of single phase flow in microchannels were investigated, and the measurements of pressure drop were compared with prediction models. For Newtonian fluids, the friction factor in the laminar regime is f/ 2 = 26/ Re . The results show that the pressure drop of Newtonian fluid is in good agreement with the prediction formula proposed by Cornish. However, the pressure drop of non-Newtonian fluid deviates from the theoretical prediction. A power-law is proposed for the relationship between the apparent viscosity of non-Newtonian fluid and the characteristic shear rate in a microchannel based on the pressure drop measurement. This relationship between the apparent viscosity and the characteristic shear rate in a specific microchannel is completely different from the rheological curve measured by cone-and-plate rheometer, due to the heterogeneous distribution of shear rates at the radial direction for non-Newtonian fluids flowing in a microchannel.
研究领域:
流体力学
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微流控技术
·
工程学
✓ 已验证
产品关联
DOI
高影响因子
RSC Advances
·
2015
·Vol. 6
·期 1
·778-785
·
IF 3.84
Huajun Li,Yining Wu,Xiaoda Wang,Chunying Zhu,Taotao Fu,Youguang Ma
This paper is mainly focused on the investigation of the magnetofluidic control of the breakup of ferrofluid droplets in a symmetric Y-junction. The asymmetric breakup of the ferrofluid droplet or non-breakup with filtering the mother droplet into a desired branch to separate it from the satellite droplet was implemented by an external magnetic field. The breakup processes of ferrofluid droplets with and without the magnetic field were studied systematically. The influences of both the flow rate ratio between the continuous phase and dispersed phase and the magnetic flux density on the sizes of daughter droplets were determined. It was found that the attractive magnetic force shifted the mass center of mother droplet in the upstream main channel, which accordingly facilitated the asymmetric breakup of the droplet at the downstream Y-junction. A power function correlation for precisely predicting the sizes of daughter droplets was proposed by introducing the magnetic Bond number (Bom). Moreover, we also found that the controllable magnetic force could promote the pattern transition between the breakup and non-breakup of ferrofluid droplets.
研究领域:
微流体力学
·
材料科学
·
流体力学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF CHROMATOGRAPHY A
·
2023
·
IF 4.1
Qing Fu,Wenwen Dong,Dandan Ge,Yanxiong Ke,Yu Jin
The development of an approach based on simultaneous supercritical fluid extraction-sample cleanup, followed by supercritical fluid chromatography/tandem mass spectrometry (SFE-SFC-MS/MS) was as a tool for the extraction, separation and characterization of indole alkaloids of Uncaria rhynchophylla . A two-step SFE method was designed. A mixture of the U. rhynchophylla sample and an adsorbent named C18SCX with the ratio of 1:1 (w/w) was placed into an extraction cell. The extraction temperature was 40 °C and the pressure was 25 Mpa. In the first step, 10 % EtOH as the co-solvent was used to extract for 60 min, which was considered as a cleanup process to remove non-alkaloid components. In the second step, 0.1 % DEA was added to 10 % EtOH and it extracted for 60 min to obtain the desired extract. By introducing an additional adsorbent, the specificity of SFE towards alkaloids was greatly improved. An SFC-MS/MS method was then utilized for analysis of the SFE extract. Using 2-EP as stationary phase with the gradient elution of 0–10 min, 5–25 % EtOH (+0.05 % DEA) in CO 2 , column temperature 40 °C, and back pressure 13.8 Mpa, 10 peaks were separated within 8 min. Further MS/MS analysis confirmed that nine of the 10 peaks in the SFE extract were indole alkaloids. This study developed a supercritical fluid-based method specifically towards extraction and analysis of alkaloids, which is helpful to the study of alkaline compounds in complex samples.
研究领域:
植物化学
·
分析化学
·
药学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Small
·
2023
·Vol. 19
·期 34
·2300047
·
IF 13.3
Mingzhu Xie,Ziheng Zhan,Chengqi Zhang,Wanqing Xu,Ce Zhang,Yongping Chen,Zhichao Dong,Zhaolong Wang
Numerous structures have been functionally optimized for directional liquid transport in nature. Inspired by lush trees’ xylem that enable liquid directional transportation from rhizomes to the tip of trees, a new kind of programmable microfluidic porous matrices using projection micro-stereolithography (P µ SL) based 3D printing technique is fabricated. Structural matrices with internal superhydrophilicity and external hydrophobicity are assembled for ultra-fast liquid rising enabled by capillary force. Moreover, the unidirectional microfluidic performance of the bionic porous matrices can be theoretically optimized by adjusting its geometric parameters. Most significantly, the successive programmable flow of liquid in a preferred direction inside the bionic porous matrices with tailored wettability is achieved, validating by a precisely printed liquid displayer and a microfluidic logic chip. The programmable and functional microfluidic matrices promise applications of patterned liquid flow, displayer, logic chip, cell screening, gas–liquid separation, and so on.
研究领域:
材料科学
·
微流控技术
·
生物医学工程
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产品关联
DOI
PubMed
高影响因子
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