Particle Flow Rate Research Articles

Microfluidics of nanoparticles using vibration-mediated regulation of aggregates evolution

Controlling the flow of particulate matter, especially nanoparticles, requires a deep understanding of particle structure and motion. In this study, we present experimental observations and intrinsic mechanisms for controlling the nanoparticle flow using vibration-mediated regulation of aggregates evolution. Our findings demonstrate that vibration could exert significant forces on the particles, causing them held apart or would touch with less force and then leads to re-breakup process of the aggregates. Furthermore, the relationship between the vibration parameter, aggregate size, the microchannel size and flow behavior has also been revealed. Notably, the outflowing aggregates have extremely small Stokes numbers due to their high porosity, and their motion is dominated by gas drag. The relationship between particles flow rate and the size of the microchannel and vibration parameters has been identified. These results have significant implications for precise control and assembly of nanoparticles.

Performance Optimization of Underwater Crushing Unit Based on AHP

An underwater crushing unit loaded on the underwater cleaning robot was intended to handle marine biofouling that adhered to the surface of the ship and the dam, and a prototype was initially built. A Computational Fluid Dynamics–Discrete Element Model (CFD-DEM) was created to boost the prototype’s crushing performance, and its rationale was validated by contrasting the simulation results with the results of experimental tests. Accordingly, the primary influences on crushing performance and the laws governing their influence were investigated. The Analytical Hierarchy Process (AHP) method was then used to establish a prediction model for the comprehensive evaluation indicator of crushing performance. The AHP was used, in this case, because of its ability to generate the weight of indicators. The prediction model was a quadratic polynomial function with the rotational speed, the normal velocity component at the outlet of the propeller, the mass flow rate of the particles at the inlet of the unit, and the thickness of the bushing as independent variables. The prediction model fitting effect met the requirements after the test. The primary elements influencing the underwater crushing unit’s performance were optimized using the prediction model. The average accumulation speed of particles in the crushing unit was reduced by 59.05%, and the mass flow rate of particles at the outlet was reduced by 11.93%. The maximum wear height of the bushing was reduced by 33.36%. The specific power was up 20.88%, and the overall crushing performance was up 9.87% when compared to before optimization.

A Pediatric Upper Airway Library to Evaluate Interpatient Variability of In Silico Aerosol Deposition

The airway of pediatric patients’ changes through development, presenting a challenge in developing pediatric-specific aerosol therapeutics. Our work aims to quantify geometric variations and aerosol deposition patterns during upper airway development in subjects between 3.5 months–6.9 years old using a library of 24 pediatric models and 4 adult models. Computational fluid–particle dynamics was performed with varying particle size (0.1–10 μm) and flow rate (10–120 Lpm), which was rigorously analyzed to compare anatomical metrics (epiglottis angle (θE), glottis to cricoid ring ratio (GC-ratio), and pediatric to adult trachea ratio (H-ratio)), inhaler metrics (particle diameter, {d}_{p}, and flow rate, Q), and clinical metrics (age, sex, height, and weight) against aerosol deposition. Multivariate non-linear regression indicated that all metrics were all significantly influential on resultant deposition, with varying influence of individual parameters. Additionally, principal component analysis was employed, indicating that {d}_{p}, Q, GC-ratio, θE, and sex accounted for 90% of variability between subject-specific deposition. Notably, age was not statistically significant among pediatric subjects but was influential in comparing adult subjects. Inhaler design metrics were hugely influential, thus supporting the critical need for pediatric-specific inhalable approaches. This work not only improves accuracy in prescribing inhalable therapeutics and informing pediatric aerosol optimization, but also provides a framework for future aerosol studies to continue to strive toward optimized and personalized pediatric medicine.Graphical

Optimisation of biochar filter for handwashing wastewater treatment and potential treated water reuse for handwashing

Portable handwashing facilities help fight the transmission of water-borne diseases. However, in places lacking piped drainage systems, handwashing wastewater (HW) is commonly discarded into the ground. This harms the environment and public health and wastes reusable water. This study optimised the biochar filtration parameters such as particle size (0.5–2 mm), filter depth (15–30 cm) and flow rate (1–2.5 L/h) to remove colour, turbidity, phosphates and E. coli from HW using Response Surface Methodology. Fifteen configurations studied the impact of filtration parameters on pollutant removal. Quadratic models provided the best fit for pollution removal data. Optimal conditions were 1.25 mm particle size, 30 cm filter depth and 1 L/h flow rate, with predicted removals of 97.06, 97.50, 82.67 and 73.06 % for colour, turbidity, phosphates and E. coli, respectively. Biochar filter performance under optimal conditions validated the models. Actual removal efficiencies of 97.63, 99.85, 85.94 and 76.08 % for colour, turbidity, phosphates and E. coli, respectively, aligned closely with predicted values. Treated HW quality complied with several international water quality standards. Optimising biochar filtration is crucial for integrating this technology into portable handwashing facilities with potential water reuse, benefiting communities in developing countries with limited handwashing infrastructure and access to water.

CFD-DPM modelling of solid particle erosion on weld reinforcement height in liquid-solid high shear flows

Liquid-solid two-phase flow erosion can lead to great economic losses and safety concerns in the oil & gas storage and transportation industry. The solid particle erosion on weld reinforcement height (WRH) in liquid-solid high shear flows were systematically investigated by coupling the computational fluid dynamics (CFD) and the discrete phase model (DPM) method. The effects of liquid velocity, WRH height, particle flow rate, and particle size on the particle erosion in the WRH region were analyzed. Increasing erosion rate was observed with increasing liquid velocity. The erosion rate first increased and then decreased with increasing WRH height. The increasing erosion rate was observed with both increasing particle flow rates and particle sizes. The existence of defects on the WRH surface significantly increased the maximum erosion rates. This work can provide scientific guidelines for the corrosion protection and safe operation of long-distance oil & gas pipelines.

Effects of electric field on the filtration characteristics of solid particles in oil

The presence of solid particles in oil can easily lead to surface failure of machine components. In order to reduce the harmful effects of solid particles, it is necessary to remove solid particles from oil. The electrostatic method is an efficient method for removal of solid particles under an applied electric field. However, the filtration mechanism for solid particles in mixed oil–solid systems using electrostatic methods has not been fully investigated. In view of this, an oil–solid separation method based on electric field enhancement is proposed. For this method, a numerical model of oil–solid separation under different electric field strengths is established by coupling the electric and flow field governing equation, the particle-wall collision equation, and the discrete phase tracking equation. Solved by finite element method, the influence of electric field on particle motion and filtration performance of the system is studied. The results indicated that in the mixed oil–solid system, the filtration efficiency is significantly increased by more than 32.97% when an electric field is used. When E > 1 kV/mm, the flow rate of particles into and out of the filter increased with increasing electric field intensity, the deposition became more dispersed, the highest deposition concentration was 3.69 times that without an electric field, and the filtration efficiency decreases but does not exceed 10% as the flow rate increases. When the particle size is greater than 30 µm, the filtration efficiency increases by at least 14.71% for every 1 kV/mm increase in electric field strength, up to a maximum of 97.65%.

Towards large size pixelized Micromegas for operation beyond 1 MHz/cm2

The R&D project being presented aims to improve the use of resistive Micromegas technology in high-energy physics experiments. The project focuses on achieving stable, reliable, and high-gain operation at particle flow rates above 1 MHz/cm2 on large surfaces. To achieve this, the project uses a configuration with small pads readout and requires innovative solutions for the spark protection resistive scheme. Different resistive patterns were investigated, and finally the solution based on a double layer of DLC foils was chosen, demonstrating the capability to perform equally for low and high rates under irradiation of X-rays on the full surface of 25 cm2 of the prototype detectors. With this technology and layout, a detector with an active area of 400 cm2 was recently built. In this work we present the results of high-rate capability, robustness, dependence on the irradiated area, obtained with high intensity X-rays measurements, as well as the results on efficiency and spatial resolution obtained, at low rates, at CERN SPS with high energy particle beams. Additionally, preliminary results of pixelized resistive Micromegas time response are reported. With the successful achievements of this detector and the construction of even larger small-pad resistive Micromegas next year, the project will establish the technology for future use in particle physics and other applications.

Hydraulic and Anti-clogging Performance Evaluation of a Novel Cylindrical Drip Emitter using CFD Techniques

An inline cylindrical drip emitter of 4 Lh-1 design flow rate is developed incorporating favourable geometric features against the physical clogging. The emitter model, with one-outlet and two-outlet variants, was tested for its hydraulic and anti-physical-clogging performance using Ansys Fluent 2022 software. The simulated flow rate of 3.988 and 3.992 Lh-1 is found to be very close to the design flow rate. The emitter exponent values of 0.4351 and 0.4406 for the one-outlet and two-outlet variants, respectively, are found to be within the stipulated limit of 0.5 by Bureau of India Standards (BIS) guidelines. The discrete particle modelling (DPM) simulation revealed that 100% of the particles entering the inlets of the emitter variants are escaping within an average residence time of 0.3779-1.036 s for the one-outlet variant and 0.2044-1.005 s for the two-outlet variant. The average residence time increased with increase in the particle size from 0.1 µm to 100 µm, however the same is not affected by the mass flow rate of particles. Overall, the novel cylindrical emitter developed is found to be satisfactory in its hydraulic and anti-physical-clogging performance. Index Terms: CFD, DPM, Ansys fluent, Drip Emitter, Anti- clogging, SST, k-ω Turbulence Model.

Tunable magnetophoretic method for distinguishing and separating wear debris particles in an Fe-PDMS-based microfluidic chip.

Wear debris analysis provides an early warning of mechanical transmission system aging and wear fault diagnosis, which has been widely used in machine health monitoring. The ability to detect and distinguish the ferromagnetic and nonmagnetic debris in oil is becoming an effective way to assess the health status of machinery. In this work, an Fe-poly(dimethylsiloxane) (PDMS)-based magnetophoretic method for the continuous separation of ferromagnetic iron particles by diameter and the isolation of ferromagnetic particles and nonmagnetic particles with similar diameter by type is developed. The particles experience magnetophoretic effects when passing through the vicinity of the Fe-PDMS where the strongest gradient of the magnetic fields exists. By choosing a relatively short distance between the magnet and the sidewall of the horizontal main channel and the length of Fe-PDMS with controlled particles flow rate, the diameter-dependent separation of ferromagnetic iron particles, that is, smaller than 7µm, in the range of 8-12µm, and larger than 14µm, and the isolation of ferromagnetic iron particles and nonmagnetic aluminum particles based on opposite magnetophoretic behaviors by types are demonstrated, providing a potential method for the detection of wear debris particles with a high sensitivity and resolution and the diagnostic of mechanical system.

Heat generation/absorption effects in thermally radiative mixed convective flow of [formula omitted] hybrid nanofluid

Investigation on hybrid nanofluids has increased significantly, and findings indicate that these fluids are effective heat transfer fluids for industrial applications. The thermal conductivity of nanoparticles, particle volume fractions, and mass flow rates play a major role in the enhancement of heat transfer of nanofluids. The enhancement in thermal transport only depends on the thermal conductivity of the nanoparticles when particle volume fractions and flow rates are constant. Therefore, the purpose of this article is to analyze the flow of Zn−TiO2/H2O hybrid nanofluid past an inclined shrinking surface. The PDEs of the flow model are converted into ODEs by using similarity conversions. The mathematical problem is tackled numerically by employing the bvp4c solver in Matlab software. The impacts of controlling parameters on fluid velocity, temperature distribution, skin friction coefficient, and local Nusselt number are studied and graphically depicted. The obtained results reveal that the mixed convection parameter is found to enhance friction drag and heat transport rate for the upper branch while it reduces the lower branch. Moreover, the kinetic energy is inclined as the heat sink/source, Eckert number, and temperature ratio parameters increase, causing the thermal distribution to rise for both branches.

Effects of input concentration, media particle size, and flow rate on fate of polystyrene nanoplastics in saturated porous media

Nanoplastics have gradually attracted widespread attention, but the studies in this area are still very scarce. In this research, the adsorption, transport, long-term release, and particle fracture of polystyrene nanoplastics (PS-NPs) in saturated porous media were investigated at different media particle sizes, input concentrations, and flow rates. The increased PS-NPs concentration and sand grain size promoted the adsorption of PS-NPs onto quartz sand. In transport tests, the peak breakthrough amounts of PS-NPs ranged from 0.5761 to 0.8497, demonstrating their high mobility in saturated quartz sand. Transport of PS-NPs in saturated porous media increased with decreasing input concentration and increasing media particle sizes. The effect of input concentration could be predicted by the Derjaguin-Landau-Verwey-Overbeek (DLVO) theory, in which adsorption played a dominant role. The effect of media particle size was mainly dominated by filtration rather than adsorption. As a result of higher shear force, increasing flow rate might boost transport of PS-NPs. With increasing media particle size and flow rate, more retained PS-NPs were released, which was in line with the findings of the transport tests on the mobility of PS-NPs. Notably, PS-NPs could be broken down into smaller PS-NPs during long-term release and the percentage of released PS-NPs (<100 nm) was gradually increased from 1st to 3rd PV effluent in all media particle sizes and flow rates. The fracture of released PS-NPs from medium quartz sand was the most in relation to fine and coarse and showed a decreased trend with increasing flow rate, which was likely to be governed by the force perpendicular to the contact surface with the media particle. This study showed that PS-NPs have strong mobility in porous media and are easily broken into smaller particles during long-term release. The findings of this research provided fundamental information for clarifying transport laws of nanoplastics in porous media.

Performance characterization and kinetic analysis of atmosphere-breathing electric propulsion intake device

An atmosphere-breathing electric propulsion (ABEP) system is designed to capture and compress the rarefied atmosphere through an intake device in very-low-Earth-orbit (VLEO). This study numerically characterizes the intake performance according to the design parameters, including the geometry of the tapered chamber, gas-surface interaction (GSI) models, surface temperature, aspect ratio, and sizing. The design of grid ducts is examined for different gaps, lengths, and yaw angles. The influence of intermolecular collisions is also investigated. The diffuse GSI model is chosen as a realistic model at VLEO due to the adsorption of atomic oxygen. The direct simulation Monte Carlo method is employed to calculate the capture efficiency, compression ratio, particle flow rate, and number density as the four indicators of intake performance. The flow conditions are obtained using the NRLMSISE-00 model, with a target altitude range of 180–220 km. In addition, a comprehensive design is proposed and the related propellant characteristics are investigated using kinetic analysis. Multi-modality is found in the particle velocity distribution, which implies non-equilibrium of the ABEP propellant.

Development of a Coal Dust Concentration Sensor Based on the Electrostatic Induction Method.

In order to solve the problems of easy blockage and difficult maintenance of the current coal dust concentration sensor, a coal dust concentration sensor based on the electrostatic induction method was designed. Based on the analysis of the principle of electrostatic induction dust concentration detection, an electrostatic induction dust concentration sensor composed of a electrostatic detection electrode, a dust extraction fan, an induction signal processing circuit, an insulator, a shield, and other parts was designed. The influence of the length and width of the electrostatic detection electrode and the particle flow rate on the standard deviation of the induction signal was analyzed through experiments to optimize them. The induction signals on the electrostatic detection electrode at different dust concentrations were determined in tests, and the mathematical relationship between the standard deviation of the induction signal and the dust concentration was obtained. According to segment multiple-curve height fitting, the maximum deviation between the detected value and actual dust concentration does not exceed 10%.

Experimental Study of an upflow Fluidized Bed: Identification of Fluidization Regimes

The concept of solar receiver using fluidized particles as heat transfer fluid is attractive from the point of view of its performance but also of the material used. In this concept, the receiver is composed of tubes subjected to concentrated solar radiation in which the fluidized particles circulate vertically. Circulation in the tubes, immersed in a “nurse” fluidized bed, is ensured thanks to a controlled pressure difference imposed on the latter and secondary aeration. This ventilation located at the bottom of the absorber tubes makes it possible to control the fluidization regimes. The latter strongly influence the parietal heat transfers and therefore the performance of the receiver. In order to better understand the conditions of appearance of these regimes and to better identify them, a study at room temperature was carried out with a tube 45 mm in internal diameter and 3.63 m in height. The tube is instrumented with several pressure sensors distributed over its height. More than 170 experiments have been performed exploring wide ranges of particle and aeration flow rates, with and without particle circulation. Signal processing methods, classically used in the scientific literature of fluidized beds, are applied. Combined together, these methods have enabled the identification of bubbling, pistoning (of the wall and axisymmetric), turbulent fluidization and rapid fluidization regimes. The pooling of all this information allows the establishment of a diagram of the fluidization regimes and their transition, showing that the local slip velocity is the key parameter governing the structure of the flow.

Femtosecond laser rapid prototyping and characterization of microfluidic device for particles sorting

Rapid prototyping methods for the fabrication of polymeric labs-on-a-chip (LoC) are on the rise, as they allow high degrees of precision and flexibility. In this contest, the flexibility of ultrafast laser technology enables the rapid prototyping and high-precision micromachining of 3D LoC devices with complex microfluidic channel networks. In this paper, we describe the realization process of a microfluidic tool for fully inertial particles sorting. The microfluidic network was realized in polymethyl methacrylate (PMMA), exploiting femtosecond laser technology. The multilayer device was assembled through a facile and low-cost solvent-assisted method. In particular, we studied the particle focusing in curved inertial microfluidic channel with trapezoidal cross section. A particles focusing along the walls of the device, sensitive to particle size and flow rate, was observed based on the principle of Dean-coupled inertial migration in spiral microchannel.

A review of applications of plasmonic and conventional nanofluids in solar heat collection

• The research progress of plasmonic nanofluids in recent ten years is reviewed. • Comparison of plasmonic nanofluids with conventional nanofluids. • The LSPR effect of plasmonic nanofluids enhances the light absorption. • Many factors affect the light absorption and photothermal conversion characteristics. • How to improve the light absorption properties of plasmonic nanofluids needs further discussion. With the development of solar energy utilization and nanotechnology, nanofluid heat collection has attracted significant attention. The solar plasmonic nanofluids with significant local surface plasmon resonance (LSPR) effect have exhibited superior behaviors in thermophysical properties, optical properties, and photothermal conversion efficiency. This paper reviews the research progress of plasmonic nanofluids in solar collectors and PV/T systems and compares them with conventional nanofluids for the first time. The plasmonic nanofluids exhibit excellent light absorption capacity and controllable light intensity and resonance frequency. Due to the existence of the LSPR effect, plasmonic nanofluids show significant absorption peak, which can meet the requirements of broadband solar energy absorption and have better usage value than conventional nanofluids in solar heat collection. Many factors affect the photothermal conversion efficiency of plasmonic nanofluids, such as particle size, concentration and flow rate. Using hybrid nanofluids can significantly broaden the extinction spectrum and further enhance light absorption. To clarify the specific mechanism of plasmonic nanofluids, improve their stability and make them more suitable for different types of solar heat collection, more experimental exploration is needed.

ОЦЕНКА ЭФФЕКТИВНОСТИ СЕПАРАТОРА С СООСНО РАСПОЛОЖЕННЫМИ ТРУБАМИ ПРИОБЕСПЫЛИВАНИИ ГАЗОВЫХ ВЫБРОСОВ ПРИ РАЗЛИЧНОМ УГЛЕ РАСКРЫТИЯ ПРЯМОУГОЛЬНЫХ ЩЕЛЕЙ

An important task in dedusting gas emissions at chemical industry enterprises is to achieve high efficiency. A complex of devices is used for this. Large particles are removed from gases in coarse cleaning devices. Fine particles are removed from gases in fine cleaning devices. However, fine filters are quickly clogged, which leads to an increase in hydraulic resistance and, in some cases, to a decrease in efficiency. An urgent task is to increase their service life and increase efficiency. For this purpose, the paper proposes the design of a separator with coaxially arranged pipes, which is proposed to be installed in front of fine filters. The aim of this work is to numerically investigate the effect of the angle of opening of rectangular slits on the efficiency and hydraulic resistance of a separator with coaxially arranged pipes. The article presents the design of the separator. The principle of operation is described. During numerical calculations, the inlet velocity of the gas flow was set at the inlet of the device, which varied from 3 to 10 m/s, and the mass flow rate of particles was 5 g/s. The particle density varied from 1000 to 3000 kg/m3. The particle diameter varied from 1 to 15 microns. The opening angle of the slits varied from 16 to 24 °. During the calculations, the following main conclusions were made: the structure of vortices in the inter-tube space determines the degree of efficiency of a separator with coaxially arranged pipes, with the angle of opening of rectangular slits α = 20 °, the maximum separation efficiency of fine particles up to 10 microns in size from a dusty stream is equal to an average of 40.3%, the separation efficiency of fine particles from a dusty stream is achieved. the flow rate increases with an increase in the input gas velocity and particle density, because they are easier to dislodge from the swirling gas, the pressure loss in the separator with coaxially arranged pipes is no more than 626 Pa.

Optimization Analysis of Particle Separation Parameters for a Standing Surface Acoustic Wave Acoustofluidic Chip.

Microparticle separation technology is an important technology in many biomedical and chemical engineering applications from sample detection to disease diagnosis. Although a variety of microparticle separation techniques have been developed thus far, surface acoustic wave (SAW)-based microfluidic separation technology shows great potential because of its high throughput, high precision, and integration with polydimethylsiloxane (PDMS) microchannels. In this work, we demonstrate an acoustofluidic separation chip that includes a piezoelectric device that generates tilted-angle standing SAWs and a permanently bonded PDMS microchannel. We established a mathematical model of particle motion in the microchannel, simulated the particle trajectory through finite element simulation and numerical simulation, and then verified the validity of the model through acoustophoresis experiments. To improve the performance of the separation chip, the influences of particle size, flow rate, and input power on the particle deflection distance were studied. These parameters are closely related to the separation purity and separation efficiency. By optimizing the control parameters, the separation of micron and submicron particles under different throughput conditions was achieved. Moreover, the separation samples were quantitatively analyzed by digital light scattering technology and flow cytometry, and the results showed that the maximum purity of the separated particles was ∼95%, while the maximum efficiency was ∼97%.

Exhaled phospholipid transfer protein and hepatocyte growth factor receptor in lung adenocarcinoma

BackgroundScreening decreases mortality among lung cancer patients but is not widely implemented, thus there is an unmet need for an easily accessible non-invasive method to enable early diagnosis. Particles in exhaled air offer a promising such diagnostic tool. We investigated the validity of a particles in exhaled air device (PExA) to measure the particle flow rate (PFR) and collect exhaled breath particles (EBP) to diagnose primary lung adenocarcinoma (LUAD).MethodsSeventeen patients listed for resection of LUAD stages IA–IIIA and 18 non-cancer surgical control patients were enrolled. EBP were collected before and after surgery for LUAD, and once for controls. Proteomic analysis was carried out using a proximity extension assay technology. Results were validated in both plasma from the same cohort and with microarray data from healthy lung tissue and LUAD tissue in the GSE10072 dataset.ResultsOf the 92 proteins analyzed, levels of five proteins in EBP were significantly higher in the LUAD patients compared to controls. Levels of phospholipid transfer protein (PLTP) and hepatocyte growth factor receptor (MET) decreased in LUAD patients after surgery compared to control patients. PFR was significantly higher in the LUAD cohort at all timepoints compared to the control group. MET in plasma correlated significantly with MET in EBP.ConclusionCollection of EBP and measuring of PFR has never been performed in patients with LUAD. In the present study PFR alone could distinguish between LUAD and patients without LUAD. PLTP and MET were identified as potential biomarkers to evaluate successful tumor excision.

Development of Medical Sensor Systems in Pulmonology Based on Electrical Impedance Measurement.

In order to experimentally confirm the dependence of the bioelectrical impedance on the flow rate of charged aerosol particles and the composition of bronchial secretions in small airways, the electrical impedance of an aerosol of 0.9% NaCl solution in polyethylene tubes of various diameters was studied. The electrical impedance was also measured in cylindrical chambers of various diameters and volumes filled with a 0.9% NaCl solution or a gelatin solution. The studies were carried out at frequencies of alternating electric current from 20 Hz to 150 kHz. It was shown that the electrical current is not recorded in the absence of a flow of aerosol particles, and the impedance decreases with an increase in the flow velocity. The impedance modulus and the phase angle of the electrical impedance has an expressed dependence on the composition of the conductive medium, the impedance modulus increases in the gelatin solution medium, with a decrease in the diameter of the electric current conductor, and decreases with an increase in the frequency of the probing alternating current. The obtained results confirmed the hypothesis about the influence of the speed of salty aerosol particles flow and the composition of bronchial secretions on the results of measuring electrical impedance.