Flow Behavior Characteristics Research Articles

Investigating phytosterol as a potential functional component in milk through textural, flavour and oral perception study

Phytosterols (PS) are functional ingredients capable of providing health benefits. This study investigated the potential of incorporating different levels of PS ester (0.8, 1.2, 1.6 and 2.0 g/100 g) into skim milk (0.1 g/100 mL milk fat) to replace the milk fat. PS-enriched milk were analysed for its physical characteristics (colour, viscosity, tribology, particle size and microstructure) and compared to commercial milk (0.1, 1.3, 2 g/100 mL fat, and 1.3 g/100 mL fat with 0.3 g/100 mL PS). Furthermore, the flavour profiles and sensory acceptability of the PS-enriched milk were evaluated. All samples exhibited a characteristic shear-thinning flow behaviour, with 2 g/100 g PS ester milk displaying the highest viscosity (4.46 ± 1.93 mPa s) at 50/s shear rate and 35 °C. Confocal images and particle size distribution suggest fat coalescence resulting in larger fat globules (0.53 ± 0.14 μm) in 2 g/100 g PS ester milk. In general, the addition of PS ester increased the fatty acid and aldehyde compounds of PS-enriched milk, providing comparable lubrication properties and whiteness to commercial milk with the same fat levels. Sensory evaluation revealed that the PS-enriched milk did not possess any off-flavour and milk with 1.6 g/100 g PS ester were the most preferred.

Impact of external excitation on flow behavior of trapped oil blob

External excitation of oil reservoirs has shown promising potential in increasing residual oil recovery. Although several numerical, experimental, and pilot studies were conducted over the last decades, large-scale field application is not realized due to inconclusive results on its performance. This paper aims to investigate the effect of external excitation on the flow behavior of an oil blob trapped in a constricted capillary tube model. Flow evolution and characteristic flow behaviors were studied using computational fluid dynamics (CFD) simulations. An external excitation with a sinusoidal profile propagating in the axial direction was applied at the wall of the constricted capillary tube model. The excitation intensity and frequency were varied to identify the flow characteristics. The results show that under the influence of external excitation, three distinct flow regimes develop based on the excitation frequency and intensity; these are trapped, clear pass, and dispersed pass. Velocity profiles, streamlines, and pressure contours were used to examine the resulting flow behaviors. In addition, dimensional analysis was carried out, and the dominant factors in each flow regime were identified. The dominant dimensionless numbers are Euler number, Reynolds number, and Weber number. Accordingly, the three flow regimes were mapped in the domains of these dimensionless numbers. As such, under given flow conditions, fluid properties, and external excitation parameters, the subsequent flow behavior can be predicted using the characteristic flow behavior maps presented in the study. Moreover, any of these flow regimes can be induced for a given application by tuning the excitation parameters based on the dimensionless characteristic maps presented.

Numerical analysis and explore of asymmetrical fluid flow in a two-sided lid-driven cavity

The two-dimensional asymmetrical flow in a two-sided lid-driven square cavity is numerically analyzed by the finite volume method (FVM). The top and bottom walls slide in parallel and antiparallel motions with various velocity ratio (UT/Ub=λ) where |λ|=2, 4, 8, and 10. In this study, the Reynolds number Re1 = 200, 400, 800 and 1000 is applied for the upper side and Re2 = 100 constant on the lower side. The numerical results are presented in terms of streamlines, vorticity contours and velocity profiles. These results reveal the effect of varying the velocity ratio and consequently the Reynolds ratio on the flow behaviour and fluid characteristics inside the cavity. Unlike conventional symmetrical driven flows, asymmetrical flow patterns and velocity distributions distinct the bulk of the cavity with the rising Reynolds ratio. For λ>2, in addition to the main vortex, the parallel motion of the walls induces two secondary vortices near the bottom cavity corners. however, the antiparallel motion generates two secondary vortices on the bottom right corner. The parallel flow proves affected considerably compared to the antiparallel flow.

Rheological behavior and drag reduction characteristics of ice slurry flow in spiral pipes

This present study experimentally investigates the rheology and drag reduction characteristics of ice slurry flow in the spiral and circular pipes, to allow visualization of the flow regimes. For comparison, the tests were conducted for flow transition from laminar flow to turbulent flow in the spiral and circular pipes. During the tests, the ice mass fraction varied from 3% to 21%. The experimental results demonstrated that the ice slurry flow in the spiral pipe, considering turbulent flow, exhibited lower friction factor compared to that in the circular pipe. Additionally, the drag reduction rate of the spiral pipe was approximately 25%. Furthermore, visualization diagrams of the ice slurry flow in the circular and spiral pipes were also proposed. Concerning the transport prospect of the ice slurry flow, the experimental results showed that the spiral pipe produces the best drag reduction results for ice slurry flow in the turbulent regime due to engineered geometric patterns of the conduit.

Flow behavior characteristics and residual trapping of supercritical carbon dioxide in tight glutenite by MRI experiments

Whether flowback bottom water can form effective traps has a significant effect on the effective sequestration of injected supercritical carbon dioxide (SC–CO2) in anticline reservoirs. An in-depth core flooding experiment was conducted to investigate the flow behavior characteristics of SC-CO2 in a heterogeneous tight glutenite sample. Three NMR/MRI pulse sequences (CPMG, GR-HSE and SE-SPI) were used to monitor the flooding processes. The CPMG pulse sequence provided T2 spectra for the whole sample and the results show that the injected fluid always displaced the initial existing fluid from the larger macropores first. However, as water could form thin films on the pore surfaces or isolated beads in the middle of pores, the T2 spectra did not truly reflect the water distribution in different size pores during the drainage and imbibition processes. The GR-HSE sequence gave the saturation profiles as a function of lateral position along the core allowing the migration front of fluid along the flooding direction to be determined. These profiles provided direct evidence of the different influence of viscosity difference between SC-CO2 and water causing on heterogeneity-induced fingering during the drainage and imbibition processes. During the imbibition process, the extent of viscous fingering was reduced significantly. The SE-SPI sequence gave the T2 spectra for individual layers and provided a new perspective to determine the partial wettability of these layers. MRI imaging shows that the drainage and imbibition processes occurred mainly in the matrix, while the gravels were largely devoid of fluids. The displacement efficiencies during drainage and imbibition processes (calculated by averaging the values obtained from the CPMG and GR-HSE sequences) were 65.6% and 92.3%, respectively.

A novel experimental investigation on the occurrence state of fluids in microscale pores of tight reservoirs

Occurrence state of fluids in the microscale pores of tight reservoirs significantly affects the flow behavior and recoverability of reservoir fluid. Currently, microfluidic technique and CT (Computed Tomography) scanning have been widely applied on the reservoir pore structure evaluation and fluid flow behavior characterization due to their high resolution. In this study, combining a microfluidic chip test and a micro CT scanning test on tight rocks, the occurrence state of fluids in microscale pores is experimentally investigated. A set of tests on the microfluidic chips are performed to change the environment temperature, pore size and fluid compositions. Then, combining the results of micro CT scanning on real tight rocks and the results of microfluidic chips, the immobile and movable oil films in microscale pores can be obtained. Results indicates that the oil film thickness in microscale pores is negatively correlated with temperature and positively correlated with pore size. The effect of pore size can be neglected when it is above 15 μm. The higher the molar weight of fluids is, the thicker the oil film is. And the proportion of immobile and movable states are also closely related to the fluid compositions.

An alternative way to encapsulate probiotics within electrospun alginate nanofibers as monitored under simulated gastrointestinal conditions and in kefir

•In this study, Lactobacillus paracasei KS-199 was encapsulated within alginate-based electrospun nanofiber mats possessing uniform, well-defined, smooth and bead-free structure with an average size of 305 nm in diameter. Enhanced protection ability of the mats was observed in thermal degradation assays (weight loss from 93.4 to 84.5%). Probiotic and in situ viabilities were determined in simulated gastrointestinal and in vitro conditions, respectively, demonstrating that nanoencapsulation of the strain could enhance its survival in simulated gastric juice (the viability rate from 64.1 to 70.8 log cfu/mL) and improved its viability/survival (from 6.65 to 7.38 log cfu/mL) in kefir, respectively. Inoculation of kefir with encapsulated strain did not change the characteristic pseudoplastic flow behavior and viscoelastic nature (being predominantly elastic than viscous; G′ >G′′ values) of kefir. Given these results, it is possible to suggest that alginate can be an important tailor-made biopolymer playing an essential role for encapsulation of probiotics with increased viability.

Analysis of Transient Inhomogeneous Flow and Thermal Characteristics in a Drying Room via Large Eddy Simulation

AbstractTo optimize the flow structure in a soft‐capsule drying room, the notable inhomogeneous characteristics of flow behavior and thermal feature are numerically explored. An advanced three‐dimensional numerical model is established and a verified large eddy simulation (LES) model is adopted. The results indicated that there is a highly inhomogeneous flow structure especially approaching the bilateral region of the drying room, mainly caused by the large velocity gradient whereas a relatively uniform flow structure is observed in the middle region. In the drying process, the inhomogeneous flow feature is sensitive to the increased inlet velocity and aspect ratio λ. It was found that a suitable inlet velocity and a small aspect ratio λ can provide a better drying flow environment.

Influence of thermomechanical processing parameters on microstructural evolution of a gamma-prime strengthened cobalt based superalloy during high temperature deformation

Recent reports on γ′-L12 strengthened cobalt base superalloys showed the potential of this class of alloys to replace nickel-base superalloys for high-temperature applications. The studies on thermo-mechanical processing behavior of these new class of alloys are limited. Thus, the present study investigates the thermo-mechanical processing behavior of Co-30Ni-10Al-2Nb-4Ti-12Cr (all in at. %, referred to as Co10Al2Nb) γˈ strengthened cobalt base superalloy at different conditions of temperature and strain rates. The high temperature uniaxial compression tests were carried out using Gleeble 3800® in the temperature range of 1298–1448 K and the strain rate range of 0.001 to 10 s-1. The flow curves exhibited three distinct flow behavior characteristics: work hardening, softening, and steady state. Microstructures of deformed samples revealed the presence of fine strain-free dynamic recrystallization (DRX) grains in lower strain rate regime (0.001 to 0.1 s-1) and flow localization features like shear bands, cracks along the grain boundary in high strain rate regime (especially at 10 s-1) for all the temperatures. The strain rate sensitivity (m) map along with instability ( ξ(ε˙)) map revealed two distinct domains, one with m ~0.15 to 0.3 (0.001 to 1 s-1), and other domain with m < 0.13 ( >1 s-1) for the temperature range studied. DRX was observed to be the main restoration process at m ~ 0.15 to 0.3, whereas the flow localization was dominant at m < 0.13. The microstructure at different strain levels revealed that discontinuous dynamic recrystallization (DDRX) was the prevalent deformation mechanism for the present alloy. The strain field distribution obtained from the FEM simulation for different deformation conditions correlated with DRX microstructure evolution was also presented.

Chemically crosslinked xylan–β-Cyclodextrin hydrogel for the in vitro delivery of curcumin and 5-Fluorouracil

Novel hydrogels were synthesized from xylan and β-Cyclodextrin using Ethylene Glycol Diglycidyl Ether as a crosslinker in alkaline medium at different molar ratio. The physical characterization of hydrogels was carried out by the swelling study whereas the chemical characterization was performed in Fourier Transform Infrared Spectroscopy. The morphological analysis revealed the porous structure of hydrogel and the rheological study summarised the flow behavior and gelation characteristics of the hydrogels. Curcumin and 5-Fluorouracil (5-FU) were used as the model drugs to be loaded in hydrogel and subsequent studies involving the in vitro release in phosphate buffer saline (PBS, pH = 7.4). The hydrogels showed drug loading of 98% of 5-FU and 26% of curcumin. Furthermore, the gels showed the highest cumulative release of 56% 5-FU and 37% curcumin after 24 h. The kinetics of drug release was then analyzed by various kinetic models.

Application of irreversible thermodynamic model to a hollow fiber forward osmosis module in sodium chloride aqueous solution system

A forward osmosis (FO) module model including the membrane model based on the irreversible thermodynamic model was introduced, which considers the convective solute flux that the conventional solution diffusion model ignores, alongside the diffusive solute one. In addition, the membrane model was modified by coupling with the internal and the external concentration polarizations to form the overall membrane transport equation. The FO module model was also composed of correlation equations for the characteristics of flow behavior in the FO module. A parallel flow hollow fiber FO module very similar to a medical-use dialyzer was used for the performance analysis of the model. This module model was able to explain the experimental data in the sodium chloride solution systems well. Moreover, this model was superior to the conventional one in predicting the solute transfer. By the FO module model, specifically the solute convective coefficient appearing in this model, the effect of the convective solute flux on the FO performance was clearly demonstrated. Since there is a strong relationship between the water flux and the convective solute flux accompanying it, this model will be useful for the development of high permeable FO membranes in the future.

Study on the flow behaviour and aerodynamic noise characteristics of a high-speed pantograph under crosswinds

The aerodynamic noise of high-speed trains increases significantly under crosswinds. Researches have typically focused on the characteristics of aerodynamic loads and the corresponding safety issues, with less attention to flow-induced noise characteristics. In the present paper, the near-field unsteady flow behaviour around a pantograph was analysed using a large eddy simulation. The far-field aerodynamic noise from a pantograph was predicted using the Ffowcs Williams-Hawkings acoustic analogy. The results showed that asymmetric characteristics of the flow field could be observed using the turbulent kinetic energy and the instantaneous vortexes in crosswind conditions. Vortex shedding, flow separation and recombination around the pantograph were the key factors for aerodynamic noise generation. The directivity of the noise radiation was inclined towards the leeward side of the pantograph. The aerodynamic noise propagation pattern can be considered as a typical point source on spherical waves when the transverse distance from the pantograph geometrical centre is farther than 8 m. The sound pressure level grew approximately as the 6th power of the pantograph speed. The peak frequency exhibited a linear relationship with the crosswind velocity. The numerical simulation results and wind tunnel experiments had high consistency in the full frequency domain, namely, the peak frequency distribution range, the main frequency amplitude and the spectral distribution shape.

Flow Behavior and Microstructure of a Mo–V–Ti Micro-Alloyed High-Strength Steel

Flow behavior and microstructure characteristics of a Mo–V–Ti micro-alloyed high-strength steel were investigated through hot compression tests with two procedures. In group 1, the specimens were quenched after deformation at temperature range of 800–1100 °C, with strain rate of 10/s. Initiation of dynamic transformation (DT) and dynamic recrystallization (DRX) were confirmed by the evolution characteristics of work hardening rate (θ) during deformation. Critical stresses of both DT and DRX decreased with the increase in deformation temperature. The critical strain for DRX also decreased with the increase in temperature, while the critical strain of DT was less temperature dependent. In group 2, with different holding times at 630 °C after 3-pass deformation, complex precipitates were acquired from all the specimens. For the specimen that was water quenched after deformation, the particles were as fine as 20 nm. For the specimens that were held at 630 °C for 30–120 min, the particles were around 100–200 nm. Mo content in the precipitates decreased with holding time at 630 °C. V content in the particles is much less than Ti content because the Gibbs free energy of TiC is less than that of VC at the same temperature.

An OD Flow Clustering Method Based on Vector Constraints: A Case Study for Beijing Taxi Origin-Destination Data

Origin-destination (OD) flow pattern mining is an important research method of urban dynamics, in which OD flow clustering analysis discovers the activity patterns of urban residents and mine the coupling relationship of urban subspace and dynamic causes. The existing flow clustering methods are limited by the spatial constraints of OD points, rely on the spatial similarity of geographical points, and lack in-depth analysis of high-dimensional flow characteristics, and therefore it is difficult to find irregular flow clusters. In this paper, we propose an OD flow clustering method based on vector constraints (ODFCVC), which defines OD flow event point and OD flow vector to express the spatial location relationship and geometric flow behavior characteristics of OD flow. First, the OD flow vector coordinate system is normalized by the Euclidean distance-based OD flow event point spatial clustering, and then the OD flow clusters with similar flow patterns are mined using adjusted cosine similarity-based OD flow vector feature clustering. The transformation of OD data from point set space to vector space is realized by constraining the vector coordinate system and vector similarity through two-step clustering, which simplifies the calculation of high-dimensional similarity of OD flow and helps mining representative OD flow clusters in flow space. Due to the OD flow cluster property, the k-means algorithm is selected as the basic clustering logic in the two-step clustering method, and a sum of squared error perceptually important points algorithm considering silhouette coefficients (SSEPIP) is adopted to automatically extract the optimal cluster number without defining any parameters. Tested by origin-destination flow data in Beijing, China, new traffic flow communities based on traffic hubs are obtained by using the ODFCVC method, and irregular traffic flow clusters (including cluster mode, divergence mode, and convergence mode) with representative travel trends are found.

Internal Cavitating Flow and External Spray Behavior Characteristics According to Length-to-Width Ratio of Transparent Nozzle Orifice

The purpose of this study is to investigate effects of length-to-width (L/W) ratio on cavitation flow inside a transparent acrylic nozzle orifice, and its effects on spray angle. Three visualization nozzles with different geometries (L/W = 2.0, 2.67, and 4.0) are used, and the working fluid is water. In order to visualize the development process of cavitation, the injection pressure of the working fluid is changed, and a high-speed camera is used with a metal-halide lamp. From experiments and analysis, some important facts are determined. As the injection pressure increases, the cavitation length and thickness increase linearly until the hydraulic flip occurs. Although the cavitation width varies according to the orifice width, the maximum cavitation thickness relative to the orifice width is almost constant at approximately 25% ∼ 30%. When the nozzle shape ratio increases, the discharge coefficient tends to increase because of the decrease in friction area. When entering the hydraulic flip region, the discharge coefficient decreases due to the reduction of the exit section area. The spray angle is affected by the cavitation number, cavitation length, cavitation thickness, and Reynolds number. The higher the injection pressure, the higher the turbulence intensity, and the greater the instability of the fluid flow.

Effect of high pressure homogenization on mixed juice stability, rheology, physicochemical properties and microorganism reduction.

Cloud instability and loss of fresh-like appearance are important quality defects of cloudy mixed juices determining consumer acceptability. Therefore, the aim of this study was to investigate the feasibility of high pressure homogenization (HPH) for improving cloud stability, flow behavior and physicochemical characteristics as well as reducing spoilage microorganisms in a cloudy mixed juice, consisting of carrot, apple and peaches. HPH treatments included pressure of 25MPa, 100MPa, 140MPa and 180MPa, pass of 1 and 2 and inlet temperature of 25°C and 40°C, respectively. Results indicated that increasing pressure and pass improved cloud stability, while increasing temperature had negative effect. Herschel Bulkey model could be well fitted to viscosity related data. Compared with control (non-homogenized, NH) sample, HPH at 140MPa and 25°C for 1 pass resulted in three times higher flow behavior index. Increasing inlet temperature also resulted in enhancing flow behavior. Besides, total soluble solids content was not affected by HPH, even though pH and color showed slight changes. Compared with NH sample, HPH at 140MPa resulted in 4 log10 and 3 log10 reductions in total plate count and yeasts and molds count respectively. Thus, HPH at 140MPa could effectively be used for enhancing cloud stability, improving flow behavior and reducing microorganisms in cloudy mixed juices.

Discrete Element Modeling and Simulation of Soybean Seed Using Multi-Spheres and Super-Ellipsoids

The accuracy of particle shape characterization is the key to the study of particle dynamics. This study proposes two modeling methods, super-ellipsoid approach (SE) and multi-sphere approach (MS), to describe the discrete element method (DEM) model of soybean seeds with the goal of improving the accuracy of the discrete element analysis model of soybean seeds. The accumulation process, flow behavior, and mixing characteristics of soybean seeds were studied through experiments and DEM simulation. Three comparative verification tests were carried out to compare the accuracy and potential similarity of the SE particle model and the MS particle model: (1) angle of repose experiment; (2) slope screening experiment; and (3) horizontal rotating cylinder experiment. The simulation and experimental results indicated that when compared with the MS particle model, the soybean seed model established using the super-ellipsoid approach can make the described particle shape more accurate, and also reproduce the accumulation process, flow behavior, and mixing characteristics of soybean seeds more accurately. For the multi-sphere approach, the calculation cost for approximating the DEM model of soybean seeds can be saved when the number of sub-spheres is less, but the accuracy of the particle model will be reduced at the same time. In this paper, the DEM model established using the super-ellipsoid approach can accurately simulate the real movement of soybean seeds. Therefore, the model can provide a new numerical calculation method for the simulation of the particle system in the structure of agricultural machinery.

Research on Intelligent Configuration Method of Mine IoT Communication Resources Based on Data Flow Behavior

In order to ensure production safety and improve production efficiency, mining enterprises are constantly accelerating the construction of mine Internet of Things systems. In the context of a substantial increase in the number of devices with network communication capabilities in the mine, the mine network communication facilities are under tremendous pressure. We propose a device business classifier based on convolutional neural networks to improve the service quality of mine network communication infrastructure. The classifier uses wavelet transform to extract the data flow and construct behavior characteristics to classify device business categories. According to the classification results, the system flexibly adjusts the parameters of network services provided to the terminal equipment. In this way, the network resources of the system can be allocated reasonably. We evaluate the performance of the classifier model through the test data set. The performance evaluation results show that the comprehensive recognition rate of the classifier model reaches 97.2%. We optimize and adjust the classifier model according to the hardware environment in which the classifier is actually deployed.

Constitutive Relationship for Hot Deformation of TB18 Titanium Alloy

In the present work, the hot deformation behavior of TB18 titanium alloy was investigated by isothermal hot compression tests with temperatures from 650 to 880°C and strain rates from 0.001 to 10 s−1. The flow curves after friction and temperature correction show that the peak stress decreased with the temperature increase and the strain rate decrease. Three typical characteristics of flow behavior indicate the dynamic softening behavior during hot deformation. At a strain rate of 0.001∼0.01 s−1, the flow stress continues to decrease as the strain rate increases after the flow stress reaches the peak stress; the flow softening mechanism is dynamic recovery and dynamic recrystallization at a lower temperature and dynamic recrystallization at a higher temperature. The discontinuous yielding phenomenon could be seen at a strain rate of 1 s−1, dynamic recrystallization took place in the β single‐phase zone, and flow localization bands were observed in the α + β two‐phase zone. At a higher strain rate of 10 s−1, the flow instabilities were referred to as the occurrence of flow localization by adiabatic heat. Constitutive equation considering the compensation of strain was also established, and the results show high accuracy to predict the flow stress with the correlation coefficient of 99.2% and the AARE of 6.1%, respectively.

Identification of trapping in a peristaltic flow: A new approach using dynamical system theory

In this paper, we propose a new approach for the identification of characteristic peristaltic flow features such as “bolus” and “trapping.” Using dynamical system analysis, we relate the occurrence of a bolus to the existence of a center (an elliptic equilibrium point). Trapping occurs when centers exist under the wave crests along with a pair of saddles (hyperbolic equilibrium points) lying on the central line. For an augmented flow, centers form under the wave crests, whereas saddles lie above (below) the central line. The proposed approach works much better than the presently adopted approach in two ways: (1) it does not require random testing and (2) it characterizes the qualitative flow behavior for the complete range of parameter values. The literature is somewhat inconsistent with regard to the terminologies used for describing characteristic flow behaviors. We have addressed this issue by explicitly defining quantities such as “bolus,” “backward flow,” “trapping,” and “augmented flow.”