Liquid Flow Rate Research Articles

Synthesis of solid NMC622 particles by spray drying, post-annealing and lithiation

Layered lithium-nickel-manganese-cobalt oxide (NMC) cathode materials are widely used in Li-ion batteries that require high energy densities, such as those used in plug-in hybrid electric vehicles (PHEVs) and electric vehicles (EVs). Here we studied the synthesis of NMC622 particles by spray pyrolysis, which is a simple one-step process for production of spherical particles. However, synthesising NMC powder using spray pyrolysis has a tendency to produce hollow NMC particles. To gain insight into the mechanism behind the formation of the hollow particles, one dimensional numerical simulation of the physical and chemical phenomena taking place during spray drying were carried out. The effects of several process parameters, including drying air temperature, drying air mass flow rate, and liquid feed mass flow rate, on the evaporation and particle formation process were studied. The increased evaporation rate at higher temperatures was found to result in crust formation on the droplet surface during the particle formation, and thus, in lower solid volume fractions in the dried particles. However, by optimizing the process parameters production of solid NMC622 sulphate particles by spray drying was achieved. The produced NMC622 sulphate particles were then oxidised and lithiated in air at 850 °C via the conventional thermal treatment process. Four lithium precursors, LiOH, Li2CO3, Li2SO4 and LiNO3, were tested for the lithiation of the oxidized NMC particles. The degree of lithiation and the crystalline phase of the powders were determined using ICP-OES and XRD, respectively.

Rapid evaluation of capillary pressure and relative permeability for oil–water flow in tight sandstone based on a physics-informed neural network

Efficient and accurate evaluation of capillary pressure and relative permeability of oil–water flow in tight sandstone with limited routinely obtainable parameters is a crucial problem in tight oil reservoir modeling and petroleum engineering. Due to the multiscale pore structure, there is complex nonlinear multiphase flow in tight sandstone. Additionally, wetting behavior caused by mineral components remarkably influences oil–water displacement in multiscale pores. All this makes predicting capillary pressure and relative permeability in tight sandstone extremely difficult. This paper proposes a physics-informed neural network, integrating five important physical models, the improved parallel genetic algorithm (PGA), and the neural network to simulate the two-phase capillary pressure and relative permeability of tight sandstone. To describe the nonlinear multiphase flow and the wettability behavior, five physical models, including the non-Darcy liquid flow rate formula, apparent permeability (AP) formula, and contact angle-capillary pressure relationship, are coupled into the neural network to improve the prediction accuracy. In addition, the input parameters and the structure of the physics-informed neural network are simplified based on analyzing the change rule of the oil–water flow with the main controlling factors, which can also save training time and improve the accuracy of the neural network. To obtain the data for training the coupled neural network, the dataset of tight sandstone in Ordos Basin is constructed with experimentally measured data and various fluid flow properties as constraints. The test results demonstrate that the estimated capillary pressure and relative permeability from the physics-informed neural network are in good agreement with the test ones. Finally, we have compared the physics-informed neural network with the quasi-static pore network model (QSPNM), dynamic pore network model (DPNM), and conventional artificial neural network (ANN). The calculation time of QSPNM and DPNM are hundreds of times longer than that of the physics-informed neural network. The coupled neural network has also performed much better than the conventional ANN. As the heterogeneity of pore spaces in tight sandstone increases, the advantages of the physics-informed neural network over ANN are more prominent. The prediction models generated in this study can estimate the capillary pressure and relative permeability based on only four routine parameters in a few seconds. Therefore, the physics-informed neural network in this paper can provide the potential parameters for large-scale reservoir simulation.

Thermal management of large-sized LiFePO4 pouch cell using simplified mini-channel cold plates

An efficient, simplified mini-channel cooling plate-based thermal management system is presented for LiFePO4 pouch cell. The proposed design improves the uniformity in surface temperature difference by more than 100% compared to existing literature data on similar designs. The proposed coolant design is tested for temperature distribution and cooling efficiency parameters by varying the cooling fluid volume flow rate and inlet temperatures from 15 ml/min to 150 ml/min and 5 °C to 35 °C, respectively. The proposed design maintains the maximum temperature in the cell well below 40 °C even under a 4C discharge rate and a high coolant inlet temperature of 35 °C. Increasing the coolant temperature is observed to positively impact the temperature homogeneity in the pouch cell. Further, an increase in the cooling liquid flow rate is observed to have a reduced impact on the maximum temperature reduction at all discharge rates. In comparison with the existing minichannel-based study, the proposed cooling system improved the temperature uniformity of the pouch cell by more than 140%. The proposed simple design is easily scalable to modular packs of pouch cells.

Enhanced CO2 removal in hollow fiber membrane contactors using amine-based nanofluids

Increasing the mass transfer coefficient, improving the rheological properties of the liquid, reducing the possibility of wetting, and reducing the consumption of the absorbent are among the significant effects of using nanofluids in membrane contactors as chemical absorbents. The use of nanofluids allows the system to use higher transmembrane pressures and higher liquid flow rates. In this work, stable amine-based nanofluid were prepared by adding different amounts (0–0.4 wt%) of three nanoparticles (Al2O3, Fe3O4, and MWCNT-COOH) to MEA aqueous solution. Amine-based nanofluids were then used in a membrane contactor to remove CO2 from the gas mixtures. The influence of effective parameters on the separation performance was evaluated in order to better understand how NPs affect CO2 removal. The findings of this work show that the use of nanofluids can improve CO2 removal performance by 5% and thus reduce adsorbent consumption by 20%. The effect of nanoparticle dispersion on mass transfer flux was evaluated using a new enhancement factor (Rnano). Numerical methods were used to provide a suitable equation for Rnano so that it can be combined with general mass transfer equations. The Rnano values obtained for the NPs used in this work were in the range of 0.03–0.05.

The high-throughput atomization of polymer solutions for fiber synthesis in a single step aided with corona ionizers

Polymer microfibers are ubiquitous structures across virtually all technological fields. Their applications include, for instance, filter media, tissue regeneration, wound healing and dressing, and reinforcement materials. The most effective methods for fabrication of fibrous micro and nanomaterials rely on electric fields to spin a liquid jet into an ultrafine thread that rapidly dries up forming a fiber. Continuous spinning and collection leads to formation of fiber mats. Here we report a robust yet simple approach for the massive production of liquid threads, which upon acquiring electrical charges in-flight are collected downstream in the form of fibers. The entire process takes place on-line in a single step. The liquid threads are produced through the fragmentation of a polymer solution bulk due to a turbulent interaction of a gas–liquid interface in the interior of an engineered device, a so-called Flow Blurring atomizer. The particularity of this approach consists precisely in such vigorous interaction, at the micrometer scale, which triggers a bubbly motion in the interior of the device, that is a “micro-mixing”. Subsequently, the threads are passed through ionized air currents, at ambient conditions, and then stretched to sub-micrometer dimensions by electric fields. Polyvinylpyrrolidone (PVP) as well as carbon nanotubes (CNTs) or graphene oxide sheets (GOSs)-containing PVP fibers, with diameters in the range 100–900 nm, were synthesized via this approach. In the cases studied herein the method was operated at liquid flow rates (i.e. production rates) of 0.2 mL/min but it could be readily increased up to a few tens of mL/min. The method requires further improvement and optimization, nevertheless it is a promising alternative for mass production of polymer fibers.

Experimental and numerical study on the falling film flow process on the outer wall of dome cylinder

The passive containment cooling system (PCCS) is crucial for ensuring the safety of nuclear power plants, and the thickness and temperature of the falling film on its outer wall are important parameters that determine the heat and mass transfer performances. In this paper, a compact liquid film thickness and temperature simultaneous measurement system was developed to provide a measurement method, which is based on the absorption spectroscopy technology, and then the measurement accuracy was verified by using a calibration tool. The results showed that the mean relative error of the liquid film thickness and temperature measurements from the known values were about 3.4% and 0.4%, respectively. On this basis, this system was used to study the falling film process on the outer wall of the dome cylinder analogous to the containment under different working conditions and combined with numerical simulation for comparison. The results showed that the two methods have good consistency. The variation of the liquid film heat transfer coefficient for various operating conditions was further analyzed. It was found that the average thickness of the falling film is positively correlated with the liquid flow rate, but negatively correlated with the temperature and heat transfer coefficient. In summary, this system can accurately study the falling film process on the outer wall of the dome cylinder, which is expected to accurately analyze the heat and mass transfer process in the PCCS and provide data support for its design and optimization.

Liquid flow in heap leaching using the discrete liquid flow model and graph-based void search algorithm

The liquid flow in many heap leaching processes is discontinuous in nature as it occurs either as droplets or rivulets or in combination. Therefore, it cannot be represented correctly using continuum-based models at very low liquid flow rates, such as in heap leaching, or in non-wetting conditions, where liquid flow is discrete in nature. Many researchers have modelled the liquid flow through the heap packing using continuum models. However, this directly contradicts the experimental observations made by various researchers. In the current study, liquid flow is considered discrete in nature as rivulets and droplets with their rupture and merging phenomena. A single vertical layer of particles is considered for the study. A novel void search algorithm is devised to detect the position, shape, and size of the voids in a heap. The liquid flow behaviour is studied in terms of particle size, tortuosity, liquid distribution, breakthrough time, and contact angle. The study shows that heap leaching processes can be modelled more accurately using Discrete Liquid Flow (DLF) theory by avoiding uncertain experimental parameters such as bed permeability. It is found that particle size in the heap structure has significant effect on the liquid-solid contact area, which is an important parameter to determine the efficiency of the leaching process at an industrial scale.

Optimizing the parameters of the air disc atomizer for the low volume desalination spraying of cotton crops

The article presents the results of a multi-factorial experiment to justify the parameters of a rotating sprayer. Optimization of the parameters of the pneumatic disk atomizer shows that with the correct choice of the specific liquid flow rate (qi), disk radius (r) and the number of radial channels (η r) at a constant air flow rate, it leads to obtaining the required median-mass droplet diameter. Therefore, when justifying the diameter of sprayed drops, it is necessary to consider a combination of the specific flow rate of the liquid and the radius of the disk. To obtain a monodisperse spray of drops with a median-mass diameter d= 80…120 µm, the disc radius should be in the aisles r=75.8…83.4 mm, the specific liquid flow rate qi= 0.61…0.96 l/min and the number of radial channels for pairs of disks in the aisles η p = 4.59… 5.75 things.

Reusability of Discarded Tubular Ceramic Membranes for CO2 Removal: A Case Study for Membrane Circularity.

Discarded polymeric or ceramic membranes are currently in need of appropriate and sustainable management. In the present study, the direct reuse of discarded ceramic membranes in membrane contactor (MC) systems for CO2 removal was investigated for the first time. The hydrophobic surface modification of the discarded ceramic membrane was done by using macromolecule additive coating. The influence of operational parameters (absorbent liquid flow rate (QL), feed gas flow rate (Qg), and different NaOH concentrations) of the MC on CO2 removal was investigated to prove the technical feasibility of reused ceramic membranes. The CO2 absorption flux was 7.9 × 10-4 mol/m2 s at optimal conditions of 2 M NaOH, QL (20 mL/min), and Qg (300 mL/min) with a removal efficiency of 98%, which lasted for 8 h. This study demonstrates a potential alternative for the reuse of discarded ceramic membranes and avoids their disposal in landfills. The proposed approach will also bring membrane technology into the circular economy and achieve sustainability goals by reducing the amount of waste from discarded ceramic membranes in the future and combating global warming by absorbing CO2.

Numerical study on the effect of co-current gas flow on the falling film flow characteristics outside the horizontal tube

Gas-liquid interactions are a ubiquitous feature of falling film exchangers in the nuclear industry. In the current research, a 2D model is established to explore the impact of co-current gas flow on the hydrodynamic characteristics of the falling film outside the horizontal pipes. This study examines different factors, including film flow rate, tube diameter, co-current gas flow velocity, transverse pitch ratio, distributor height, and inlet liquid temperature. The results revealed that the co-current gas flow significantly reduces the film thickness in the strong gas-liquid interaction zone and intensifies the fluctuating motion in the weak portion. Lead to the location of the minimum film thickness shifting upwards to around 90°, which highlights the need to monitor this region to prevent the occurrence of film rupture or dry spots that negatively impact heat transfer performance. When the gas flow velocity is constant, the lower liquid film flow rate, the larger tube diameter, and the distributor height enhance the impact of gas flow velocity on the falling film, resulting in reduced liquid film thickness. A film thickness correlation applicable to both with and without co-current gas flow is established, and 91% of 900 prediction data fell within ±15% of the numerical results.

The international space station packed bed reactor experiment: capillary effects in gas-liquid two-phase flows

Experimental data on flow patterns and pressure drop in two-phase gas-liquid flows through a packed bed obtained aboard the International Space Station (ISS) are analyzed in the limit of low flow rates. Four distinct flow regimes (dispersed bubble, pulse, elongated or large bubble, and gas continuous) are observed and the transition boundaries are identified by a change in the slope of the pressure gradient versus flow rate. It is found that the pressure drop is a function of flow history with the relative magnitude of the hysteresis decreasing with increasing gas or liquid flow rates. Pressure drop (or friction factor) correlations are presented for each of the flow regimes. The capillary or interfacial contribution to the pressure gradient is found to be dominant in the gas channeling regime but comparable to the viscous contribution in the large bubble regime. Preliminary data indicating the slow accumulation of the gas in the bed in the large bubble regime over a longer time period and the intermittent nature of this regime are also presented.

Enhancement of CO2 Absorption Process Using High-Frequency Ultrasonic Waves

The advancement of efficient carbon capture technology is vital for the transition to a net-zero carbon future. Critical developments in ultrasonic irradiation can be used to enhance the conventional CO2 absorption process. For example, sonophysical effects such as acoustic streaming, acoustic cavitation, acoustic fountain and atomization induced by the propagation of high-frequency ultrasonic waves in a liquid medium can enhance the mixing and create a larger interfacial area for gas–liquid mass transfer. In this study, the performance of a continuous ultrasonic-assisted CO2 absorption process using MDEA was investigated. The design of experiment (DOE) was used to study the effect of the gas flowrate, liquid flowrate and ultrasonic power on CO2 absorption performance. Based on the findings, ultrasonic power was the most significant parameter affecting the CO2 outlet concentration, liquid-to-gas ratio (L/G) and mass transfer coefficient (KGa), which confirmed that ultrasonic irradiation has a significant impact on the intensification of the CO2 absorption process. The optimum condition to achieve the target CO2 absorption performance was numerically determined and validated with experimental tests. The results from the verification runs were in good agreement with the predicted values, and the average error was less than 10%.

Natural extract-polymer monodisperse submicron particles from Plateau-Rayleigh microjets

Particles of interest in food, pharmaceutical, and nutraceutical sectors are often formulated with a polymer and one or more natural or synthetic active compound. The two components frequently have distinct hydrophilicity. Submicrometric particles with narrow size dispersion can be made by the droplet-to-particle route by electrospray. In the steady cone-jet mode a liquid Taylor cone (TC) continuously emits a Plateau-Rayleigh microjet which breaks up spontaneously and periodically into tiny droplets, which later dry up to form solid particles. To achieve a stable process of this kind, we argue that it is necessary to: (i) operate near the minimum solution flow rate compatible with TC stability, (ii) prevent the drying of the TC by surrounding it with a gentle gas stream saturated in solvent vapor, and (iii) monitor the electric current and image the TC. We demonstrate this process in the preparation of curcumin (CUR) loaded polyvinylpyrrolidone (PVP) submicrometric particles as a function of solution composition and ambient relative humidity. In the atomization step (jet and droplet formation), the initial droplet size and charge are determined by the liquid properties and flow rate. The particles’ shapes were spherical (with or without internal voids), corrugated due to shell buckling (with compact interiors), and filamented due to Coulombic instabilities, depending on the interplay of different factors at the droplet drying step. These included the droplet size and charge, solvent evaporation, solute diffusion, water uptake from the ambient, mechanical forces, and solution thermodynamics. The electric current and droplet size are suitably predicted by scaling laws developed for simple Newtonian fluids. Hence, our particle sizes lie always between the predicted droplet and compact-sphere sizes, at a distance which depends on the particle morphology. CUR-loaded PVP quasi-monodisperse submicron particles could be an interesting model for drug delivery and biomedical applications.

Hydrodynamics and electrical insulation of PbLi flow with SiC flow channel inserts in a strong magnetic field

Experimental and numerical research in a strong magnetic field is described in this article testing silicon carbide (SiC) flow channel inserts (FCI) in lead-lithium (PbLi) liquid metal flow. The study aims to further develop the High-Temperature Dual-Coolant Lead-Lithium nuclear fusion blanket concept by testing new variations of SiC inserts operating in the relevant electromagnetic conditions. These inserts act as electrical insulators in magnetohydrodynamic lead-lithium flow and can also play the role of the thermal insulator in the potentially real fusion environment. The liquid metal pressure and integral flowrate measurements were performed on up to 5T DC magnetic field created by a superconducting magnet at high temperatures up to 700 °C, which is close to the real fusion environment. Comparisons of several cases with and without inserts are provided, demonstrating their impact on hydraulic resistance. Additionally, electrical potential distribution is recorded on the lead-lithium channel walls, which can be used to evaluate the character of liquid metal velocity distribution in the lead-lithium channel.

The growth of capillary networks by branching for maximum fluid access

Here we document the deterministic evolution of capillary networks that morph by connecting more and more branches to water sources. The network grows with the objective of extracting in steady state higher and higher liquid flow rates. Growth happens through the generation of tree-shaped structures and the geometrical configuration of the dendritic network evolves as the number of connected sources increases. We present a novel methodology to generate capillary architectures and show how the evolution of the network leads to pump higher volumetric flow rates by capillary suction. The results suggest that networks generated within a plane lead to higher flow rates than networks generated within a three-dimensional domain, for the same volume of fluid.

ИССЛЕДОВАНИЕ РАБОТЫ ВИХРЕВОГО ПНЕВМАТИЧЕСКОГО РАСПЫЛИТЕЛЯ ДЕЗИНФИЦИРУЮЩИХ ЖИДКОСТЕЙ

The production of high-quality livestock products is achieved not only by breeding productive livestock breeds, but also by observing zootechnical requirements and ensuring sanitary well-being in livestock buildings. To maintain the proper sanitary condition of livestock buildings, modern technologies, technical means and preparations for disinfecting surfaces are used, and non-compliance with the requirements for the operation of technical means and the consumption rates of disinfectant liquids leads to an increase in the resistance of microorganisms to antimicrobial drugs. The effectiveness of disinfection largely depends on the technical capabilities of disinfection units, and to a greater extent on spray devices. Many researchers solve complex problems of optimizing the design and technological parameters of spray devices, thereby improving their spray quality. In this regard, a vortex pneumatic liquid sprayer has been developed to perform various technologies and disinfection modes. The dispersed composition of aerosols of disinfecting liquids was obtained under various operating modes by the proposed design of the sprayer. Based on the experimental data, graphical dependencies are constructed that affect the degree of dispersion of the working pressures of the disinfectant liquid and compressed air in the channels of their supply. The values of flow rates of a vortex pneumatic atomizer during its operation in various modes are obtained. Graphic dependences of the disinfectant liquid flow rate through the sprayer are plotted at different pressure ratios in the media supply channels (disinfectant liquid and compressed air) and the angles between them. Based on the obtained technical characteristics, the rational design parameters of the new design of the vortex pneumatic atomizer were determined, namely, the angle between the pneumatic and liquid inlet channels α=90o, the diameter of the outlet d=2.0 mm.

Sustainable irrigation of pipeline fluid flow rate regulation based on traveling wave magnetic field

To adjust the flow rate of liquid in the pipeline in real-time in the process of crop drip irrigation, to achieve sustainable agricultural irrigation. This paper designs and develops a kind of liquid speed-regulating device for drip irrigation based on traveling wave magnetic field. This paper aims to use the electromagnetic driving force generated by the traveling wave magnetic field to realize the soft control of liquid flow rate in drip irrigation pipelines. First of all, the structure of the combined traveling wave magnetic field generator was designed. COMSOL physical field simulation software was used to build the traveling wave magnetic field simulation model, and the magnetic field distribution diagram and the variation curve of the magnetic field intensity were generated in the time domain. Then, through the analysis of the simulation model, the harmonic interference of a single row and combined traveling-wave magnetic field generator is compared, and the optimal spacing between the traveling-wave magnetic field generator units is determined. Finally, the water-fertilizer fusion liquid used in the process of agricultural irrigation was selected and the liquid speed regulation experiment was carried out. The experimental results show that the combined liquid speed regulating device can effectively reduce the number of traveling wave field harmonics, compared with the single wave field generator at the same power, the magnetic field intensity is increased by 33.9 %. When the excitation current is 2 A and the initial flow rate is 0.5 m/s, the device can increase the flow rate of water-fertilizer fusion liquid for agricultural drip irrigation by 2.27 % and decrease by 2.13 %, which can meet the real-time and effective speed regulation requirements of water-fertilizer fusion liquid in the process of agricultural drip irrigation.

Efficient CO2 absorption through wet and falling film membrane contactors: insights from modeling and simulation

The release of excessive carbon dioxide (CO2) into the atmosphere poses potential threats to the well-being of various species on Earth as it contributes to global working. Therefore, it is necessary to implement appropriate actions to moderate CO2 emissions. A hollow fiber membrane contactor is an emerging technology that combines the advantages of separation processes and chemical absorptions. This study investigates the efficacy of wet and falling film membrane contactors (FFMC) in enhancing CO2 absorption in a monoethanolamine (MEA) aqueous solution. By analyzing factors such as membrane surface area, gas flow rate, liquid inlet flow rates, gas–liquid contact time, and solvent loading, we examine the CO2 absorption process in both contactors. Our results reveal a clear advantage of FFMC, achieving an impressive 85% CO2 removal efficiency compared to 60% with wet membranes. We employ COMSOL Multiphysics 6.1 simulation software and finite element analysis to validate our findings, demonstrating a close agreement between predicted and experimental values, with an average relative error of approximately 4.3%. These findings highlight the significant promise of FFMC for applications in CO2 capture.

Polymeric hollow fiber heat transfer surface for heat exchanger

Polymeric heat transfer surfaces (HTS) offer numerous advantages, such as flexibility, fouling resistance, corrosion and chemical resistance, and good recyclability. Moreover, polymeric materials have a lower carbon footprint than commonly used metal materials in the heat exchanger industry, making them an environmentally-friendly choice. In this study, we propose a novel nonwoven fabric technology for the fabrication of HTS. This technology enables the production of three-dimensional objects with precisely separated hollow polymeric fibers, resulting in highly efficient polymeric heat exchangers (HE). The fabrication process is based on the hot melt technique, where the polymeric melt (helmitin 42048) is perpendicularly applied to the longitudinal hollow fibers (polyamide 612). To evaluate the performance of the developed HTS, polymeric HE was produced and compared with a conventional aluminum HE, which served as a heater core in a gas-to-liquid application. The polymeric HE exhibited similar pressure losses on the liquid side and slightly higher losses on the gas side while achieving comparable thermal performance. For a liquid flow rate of 150 l·h−1 and an air velocity of 4 m·s−1, the polymeric HE reached a maximum thermal performance of almost 0.8 kW. The results demonstrate the functionality of the developed HTS technology and its potential as an advancement in heat transfer processes. The utilization of polymeric HTS in heat exchangers shows promising prospects for enhanced thermal performance, paving the way for sustainable and efficient heat transfer applications.

Experimental investigation of bubble size evolution released from a fine bubble ejector

AbstractThe effects of gas flow rate, liquid flow rate, and liquid properties on the bubble size evolution at the outlet zone of an ejector have been investigated systemically. The liquid properties, including surface tension and viscosity, were changed by adding glycerol, ethanol, or Carbopol 2020 into tap water. It was found that increasing the liquid flow rate is beneficial for producing smaller bubbles with a narrower size distribution in the ejector, while the gas flow rate investigated here shows less influence on the generated fine bubble diameter. An intense bubble coalescence phenomenon, which has a negative effect on mass transfer, was first observed at the small outlet zone of the ejector by exploring the bubble size evolution along the axial height. It was found that the mean diameter of the fine bubbles could increase by 48% ~ 90% when they rose only 25 cm from the ejector outlet, and the bubble coalescence could be effectively suppressed by adding a small amount of glycerol to water. The bubble diameter could be reduced by 32% ~ 43% by using a 2 wt.% glycerol solution under the experimental conditions. A comparative study with tap water, glycerol solution, Carbopol solution, and ethanol solution was taken, and the underlying mechanism of reducing the generated bubble size by changing the liquid properties was revealed.