Increasing Flow Rate Research Articles

Experimental investigation on an innovative serpentine channel‐based nanofluid cooling technology for modular lithium‐ion battery thermal management

AbstractMany nations have committed to becoming carbon neutral by 2050 as a means of addressing the global warming challenge. To achieve carbon neutrality, transportation is one of the most essential and important tasks. Energy‐efficient pure electric vehicles (EVs) and hybrid electric vehicles (HEVs) with green energy power are being developed in response to the worldwide energy and environmental crises, as the potential replacements for the current generation of combustion‐engine automobiles. EVs require batteries more than ever before. In this perspective, lithium‐ion batteries (LIBs) stand out as remarkable energy storage technologies and have been widely used due to their numerous impressive benefits. Owing to LIBs sensitivity to temperature, EVs typically use the battery thermal management system (BTMS). The working temperature span of a lithium‐ion battery in an electric car is 15°C–35°C, which is achieved by the use of a BTMS. The production of internal heat during charging and discharging also affects how well lithium‐ion batteries work. A battery heat control system is therefore required. The temperature of the LIB pack might be efficiently controlled by liquid‐cooled systems in discharge and charge scenarios. Based on Al2O3 nanofluid (NF), the current experimental study suggests a novel active cooling technology for regulating the heat produced by the 18650‐format lithium‐ion batteries. A thorough analysis is conducted on the impact of charge/discharge C‐rates, Al2O3 nanoparticle (NP) volume fractions, inflow coolant velocity, and intake liquid temperature on the thermal efficiency of the LIB pack. By incorporating aluminum oxide NPs into the water at varying volume fractions of 0.3%, 0.5%, and 1%, the LIB pack's maximum temperature was significantly reduced by 7.9%, 18.09%, and 19.56%, respectively. With increase in mass flow rate of coolant from 0.0290 to 0.5810 kg/s, the maximum temperature has been substantially reduced by 3.7%–8.6%. Results show that using higher fluid inflow temperature significantly increased both the highest experienced temperature and temperature diversity throughout the discharge operation by about, 6°C and 5°C, respectively. The outcomes of the study indicate that NFs exhibit superior cooling performance compared to conventional coolants such as water and ethylene glycol.

CsxWO3 films with excellent infrared shielding ability and high visible light transmittance prepared via magnetron sputtering

Caesium tungsten bronze materials are widely used in various applications, such as architectural glass, medicine, insulation coating and textile fibre, owing to their excellent mechanical, optical and thermal properties. In this study, a caesium tungsten bronze (CsxWO3, x = 0.3–0.32) target with a relative density of 99.63 % and uniform microstructure was successfully prepared via hot-pressing sintering. CsxWO3 films were deposited on a quartz glass substrate via magnetron sputtering, and the mechanisms and effects of the substrate temperature and oxygen flow rate on the phase structure, microstructure and optical properties of CsxWO3 films were investigated. When the substrate temperature increased, the crystallinity and oxygen vacancy concentration of the CsxWO3 film improved. Consequently, the visible light transmittance of the film decreased, whereas the infrared blocking rate considerably increased, reaching up to 93.877 %. With the increase in the oxygen flow rate, the visible light transmittance exhibited an increasing trend, reaching a maximum value of 84.319 %, whereas the infrared blocking rate remained relatively stable. We successfully fabricated CsxWO3 films possessing a visible light transmittance of 66 % and infrared blocking rate of 94.97 % under the conditions of a substrate temperature of 300 °C and an oxygen flow rate of 2.5 sccm. Our study offers a method for the large-scale production of CsxWO3 films, which are excellent infrared shielding materials, rendering a substantial contribution to global energy conservation and emission reduction.

Exergy efficiency and sustainability indicators of forced convection mixed mode solar dryer system for drying process

The study investigates the effectiveness of a mixed-mode solar dryer (MSD) featuring two double-pass solar air collectors in series, with a focus on dehydrating cluster figs characterized by high moisture content and rapid deterioration. Exergy analysis is a powerful tool to assess the efficiency and sustainability of drying systems. The study involves experimental data obtained from the drying process under different air mass flow rates (0.018–0.062 kg/s). The solar radiation intensity ranged from 120 W/m2 to 750 W/m2 during these experiments. The solar air collectors and mixed mode dryer exergy efficiency is found to be dependent on solar radiation intensity, showing increased efficiency with higher air mass flow rates due to enhanced heat removal and reduced losses to the surroundings. The findings reveal that the optimal air mass flow rate of 0.062 kg/s yields the highest exergy efficiency in the solar air collectors. The overall exergy efficiency of the mixed-mode solar drying chamber increases with higher air mass flow rates, ranging from 18.8 % to 41.4 %. Improvement potential (IP) analysis indicates that, as the air mass flow rate increases, the potential for reducing exergy losses decreases. The sustainability index (SI), measures the environmental impact, and it ranges from 1.26 to 1.71, with higher values associated with higher exergy efficiency.

The effect of decoupling humidity control on aerosol drug delivery during HFNC for infants.

Aerosol therapy is commonly used during treatment with high-flow nasal cannula (HFNC) in the intensive care unit (ICU). Heated humidification inside the HFNC tubing circuit leads to unwanted condensation, which may greatly limit the efficiency of drug delivery. In this study, we aimed to investigate whether a novel humidification system, which decouples temperature and humidity control, can improve the delivered dose. In a bench study setup, fluorescein sodium solution was nebulized using a vibrating-mesh nebulizer in an infant HFNC circuit to measure the delivered dose, with a conventional versus a novel decoupled humidifier. The deposition of fluorescein inside each breathing circuit component and a final collection filter at the end of the nasal cannula was collected and quantified with a UV-vis spectrometer. Droplet sizes at different sections of the breathing circuit were measured by laser diffraction. Three air flow rates: 5, 10 and 15 L/min, and two nebulizer positions: (1) at the humidifier and (2) after the inspiratory tube, were tested. The delivered dose decreased with increasing flow rate for the conventional setup and was higher when the nebulizer was placed after the inspiratory tube. Turning off the conventional humidifier 10 minutes before and during nebulization did not improve the delivered dose. The decoupled humidifier achieved a significantly higher (p = .002) delivered dose than the conventional setup. The highest delivered dose obtained by the decoupled humidifier was 62.4% when the nebulizer was placed after the humidifier, while the highest dose obtained for the conventional humidifier was 36.3% by placing the nebulizer after the inspiratory tube. In this bench study, we found that the delivered dose for an infant HFNC nebulization setup could be improved significantly by decoupling temperature and humidity control inside the HFNC circuit, as it reduced drug deposition inside the breathing circuit.

Mass transfer of bilirubin and bovine serum albumin in hollow fiber membrane module of artificial liver

Understanding the mass transfer behaviors in hollow fiber membrane module of artificial liver is important for improving toxin removal efficiency. A three-dimensional numerical model was established to study the mass transfer of small molecule bilirubin and macromolecule bovine serum albumin (BSA) in the hollow fiber membrane module. Effects of tube-side flow rate, shell-side flow rate, and hollow fiber length on the mass transfer of bilirubin and BSA were discussed. The simulation results showed that the clearance of bilirubin was significantly affected by both convective and diffusive solute transport, while the clearance of macromolecule BSA was dominated by convective solute transport. The clearance rates of bilirubin and BSA increasd with the increase of tube-side flow rate and hollow fiber length. With the increase of shell-side flow rate, the clearance rate of bilirubin first rose rapidly, then slowly rose to an asymptotic value, while the clearance rate of BSA gradually decreased. The results can provide help for designing structures of hollow fiber membrane module and operation parameters of clinical treatment.

Analysis of refrigerant/lubricant distribution and operating characteristics of a rotary booster for data center free cooling

A booster-driven loop free cooling system plays a crucial role in enhancing data center energy efficiency and reducing emissions due to the special booster with low pressure ratio as a vital driving component. And the impact of lubricant and its fraction on the booster operation are the key points under low pressure ratio, as well as lubricant distribution. In this paper, the refrigerant/lubricant two-phase mixing flow in the working chamber of a booster was investigated under low pressure ratio for data center free cooling. The volume of fluid (VOF) multiphase flow model combining the working chamber of the rotary booster and discharge valve was built up to analyze the dynamic characteristics of the booster under free cooling conditions. The effect of lubricant fraction and its working frequency on the operating indexes (exhaust temperature/pressure, mass flow rate, volumetric efficiency, indicated specific work, energy efficiency ratio) were studied. The lubricant distribution and its changes for different angles and frequencies were presented. The results indicate that it can improve the thermal performance of the booster effectively with appropriate volume fraction of lubricant. The lubricant in the two-phase flow reduces the inner temperature and pressure in the booster working chamber, which changes the exhaust pressure and volumetric efficiency as well as the cooling capacity. The exhaust pressure and the mass flow rate increase notably for the refrigerant/oil mixture with the increasing lubricant volume fraction, while other performance indexes decrease. The exhaust pressure and the mass flow rate increase by 0.51 % and 47.14 %, separately, when the lubricant volume fraction raises from 0 to 5 % at operating frequency of 50 Hz. Whereas, the exhaust temperature, refrigerant mass flow rate, volumetric efficiency, indicated specific power, cooling capacity and EER decrease by 18.11 %, 4.81 %, 47.14 %, 38.94 %, 4.81 % and 26.36 %, respectively. The investigations can support the lubrication and sealing of the booster with low pressure ratio for free cooling to reach efficient and reliable operation.

Experimental Study on the Performance and Internal Flow Characteristics of Liquid–Gas Jet Pump with Square Nozzle

In order to ascertain the impact of working water flow rate and inlet pressure on the performance of the liquid–gas jet pump with square nozzle, the pumping volume ratio and efficiency of the liquid–gas jet pump with square nozzle were experimentally investigated at different inlet pressures and working water flow rates. Furthermore, the internal flow characteristics of the liquid–gas jet pump with square nozzle were explored through the utilization of visualization technology in the self-designed square-nozzle liquid–gas jet pump experimental setup. The findings indicate that the pumping ratio of the liquid–gas jet pump increases in conjunction with an elevation in the inlet pressure. Liquid–gas jet pump efficiency is higher at lower inlet pressures, up to 42.48%, and drops rapidly as inlet pressure increases. The pumping volume ratio of the liquid–gas jet pump increases significantly as the working water flow rate increases, and the working water flow rate exerts a minimal effect on the working efficiency of the liquid–gas jet pump. In the context of extreme vacuum conditions, a considerable number of droplets undergo substantial reflux in the posterior section of the throat, with a notable absence of bubbles in the diffusion tube. The size and number of bubbles diminish gradually along the axial direction. The objective of this paper is to provide a reference point for determining the optimal operational parameters for a square-nozzle liquid–gas jet pump in a practical context.

Gas–liquid mass-transfer characteristics during dissolution and evolution in quasi-static and dynamic processes

This study aims to understand the comprehensive behavior of the gas–liquid flow and dissolution–evolution mass transfer. A quasi-static closed-tank experiment was designed to measure the static mass-transfer coefficients of the dissolution and evolution processes using the diffusion equation. After a detailed uncertainty analysis, a dynamic ventilated-pipe experiment with different-sized orifice plates was designed to illustrate the relationship between the hydrodynamic parameters, physical structure, and gas–liquid mass-transfer characteristics. The results showed that, as the static pressure and liquid-level height increase, both the dissolution and evolution coefficients exhibit increasing trends. However, when the physical condition reaches the initial state after pressurization and depressurization, the gas absorbed by the solution cannot completely evolve from the solution; that is, the dissolution rate is always greater than or equal to the evolution rate. For the equal-diameter pipe, as the gas flow rate increases, the concentration increment decreases slightly after reaching the peak, owing to the reduction in mass-transfer time caused by the increase in liquid flow rate. In particular, the maximal dissolved concentration, an increment of 210.9 %, occurred in the double large-orifice plate with the ventilated condition, far exceeding the maximum value in the quasi-static process. Moreover, the concentration under the layout of two small-orifice plates decreases slightly, and the larger gas content enables the solution to have more gas nuclei, making it easier to induce the gas evolution. The current study provides guidance for the gas–liquid-mixture transportation and improvement of the dissolved efficiency.

Numerical investigation of corrosive gases absorption process by water injection in hydrogenation reaction effluent system

Abstract Water injection for absorbing corrosive gases NH3, HCl and H2S is a widely employed method to mitigate the risk of ammonium salt corrosion in the hydrogenation units. To ensure the efficient prevention of ammonium salt corrosion, a numerical model integrating the hydrodynamics of gas–liquid and the reaction of interphase mass transfer was built based on Euler–Lagrange method in this work. The flow and mass transfer characteristics of complex multi-component system in water injection pipeline were investigated, and the correlation between process operating conditions and gas removal performance was analyzed. The results reveal that the removal efficiencies of corrosive gases in pipeline are influenced by the characteristics of gas–liquid flow and mass transfer, with HCl showing higher removal efficiency compared to NH3 and H2S. Furthermore, the increasing flow rate of water injection, the reducing corrosive medium content and the decreasing droplet diameter have a positive impact on the removal efficiencies of corrosive gases, while the impact of gas-flow velocity on the removal efficiencies of corrosive gases primarily depends on the residence time of droplets. These results have important theoretical value and engineering guiding significance for intensifying the process of water injection in hydrogenation units.

Spatial characteristics study of hydrodynamics and bubble dynamics in baffled stirred tank based on CLSVOF method

The limited understanding of intricate mesoscale bubble structures in stirred tank reactors under forced convection poses significant challenges to the design and optimization of related agitation systems. In this study, the coupled level set with volume of fluid (CLSVOF) method is employed to investigate bubble dynamics and macroscopic hydrodynamics in a gas–liquid stirred tank after model validation. The results demonstrate that: i) based on the dynamics of bubble clusters within the system, the stirred tank can be categorized into four distinct regions: the dispersal region, accumulation region, rising wall-region, and reflex region; ii) in the dispersal region, the rear of impeller blade generates large-scale vortex. Two merging modes are identified during the bubble rupture process: the merging of bubbles at adjacent orifices and the merging of discrete bubbles with the back of impeller blade due to negative pressure. Two bubble breakup modes are observed: bubble breakup at the back of the impeller blade due to stretching and the breakup of bubbles growing at orifices due to disturbance caused by the impeller blade; iii) the inertial forces predominantly control most bubbles in the system. A predictive correlation for bubble velocity is proposed; iv) elevating the stirring speed increases bubble number in the accumulation region. Moreover, enlarging gas flow rate and fluid viscosity leads to a discernible augmentation of overall bubble size; v) at the macroscopic scale, the radial, axial, and tangential velocities of the system exhibit an increase with enlarging stirring speed, while showing no significant change with the increase in gas flow rate. Additionally, as fluid viscosity and density increase, the flow undergoes a transition from turbulent flow to laminar flow.

Study on the Flow and Heat Transfer Performance of Microchannel Heat Exchangers With Different Elliptical Concave Cavities

AbstractEllipticity has a significant impact on the flow and heat transfer performance of microchannel heat exchangers (MHEs) with elliptical concave cavities. In this study, five types of MHEs with different elliptical concave cavities (ellipticities of 0.4, 0.6, 0.8, 1.0, and 1.2) were designed. The influence of ellipticity on the flow and heat transfer performance of MHEs was numerically investigated using ANSYS Fluent 21.0 R1. Moreover, MHEs with corresponding elliptical concave cavities structures were processed and manufactured, and then an experimental platform was designed and built for experimental verification. The results showed that the fluid velocity distribution in MHEs with elliptical concave cavities was symmetrical, and the formation of secondary flow in the elliptical concave cavities led to the continuous destruction and reconstruction of the flow and thermal boundary layer in the microchannel, which is conducive to mass and heat transfer in the MHEs with elliptical concave cavities. The inlet and outlet pressure drop of MHEs with elliptical concave cavities increased as the inlet flow rate increased. At the same inlet flow rate, the inlet and outlet pressure drop of the MHE with elliptical concave cavities first increased and then decreased with increasing ellipticity. At an ellipticity of 1.0, the inlet and outlet of MHE exhibited the lowest pressure drop indicating that the MHE with an ellipticity of 1.0 featured the highest pressure drop performance. The cold‐water outlet temperature of the MHEs with elliptical concave cavities first decreased and then increased as the inlet flow rate increased. At the same inlet flow rate, the cold‐water outlet temperature of the MHEs with elliptical concave cavities first increased and then decreased with increasing ellipticity, while the hot‐water outlet temperature of the MHEs first decreased and then increased with increasing flow rate. This indicated that the MHE with an ellipticity of 1.0 exhibited excellent heat transfer performance.

Optimization of Oil Bores on Connecting Rod Small End to Prevent Bushing Failures at Maximum Speed

Abstract The bushing of connecting rod small end is one of the most prone components to failure in diesel engines. According to previous study, the oil flowrate and storage of small end bearing with splash lubrication are both minimal at maximum speed. Thus the optimization of oil bores was performed using a model based on smooth particle hydrodynamics. By adjusting the angle between the axes of two oil bores to 90°, the oil flowrate and storage increase from 0.036 mL/s and 0.04 mL to 0.094 mL/s and 0.045 mL, respectively. A semicolumn baffle above oil bore away from piston cooling nozzle further increases them to 3.564 mL/s and 0.8 mL. The optimization greatly enhances the cooling intensity and oil supply stability of small end bearing, conducing to prevent bushing failures.

Global self‐similarity of dense granular flow in silo: The role of silo width

AbstractThe influence of silo width on dense granular flow in a two‐dimensional silo is investigated through experiments and simulations. Though the flow rate remains stable for larger silo widths, a slight reduction in silo width results in a significant increase in flow rate for smaller silo widths. Both Beverloo's and Janda's formula accurately capture the relationship between the flow rate and outlet size. Flow characteristics in the regions near the outlet exhibit local self‐similarity, supporting Beverloo and Janda's principles. Moreover, global self‐similarity is analyzed, indicated by the transition in flow state from mass flow in regions far from the outlet to funnel flow near the outlet. The earlier occurrence of this transition favors to enhance the grain velocity and consequently increases the dense flow rate. An exponential scaling law is proposed to describe the dependencies of flow rate, grain velocity, and transition height on silo width.

Effects of the Water Diversion Project from the Three Gorges Reservoir to the Hanjiang River on diatom blooms in Middle and Lower reaches of the Hanjiang River

ABSTRACT The algal blooms in the Middle and Lower reaches of the Hanjiang River (MLHR) have become a great aquatic eco-environmental problem over recent years. The planned implementation of the Water Diversion Project from the Three Gorges Reservoir to the Hanjiang River (WDP-TH) would influence the growth and propagation of diatoms and the development of algal blooms. In this paper, a dynamic model of diatom growth is developed that considers factors such as light exposure, water temperature, total phosphorus, and flow velocity. The effects of the WDP-TH on algal density and blooms in the MLHR were predicted for a typical median year, a typical dry year, and an extremely dry year. The results showed that following the water recharge in a typical median year, the propagation of diatoms in the MLHR was significantly promoted because of an increase in total phosphorus concentration. However, following the water recharge in typical dry and extremely dry years, increased flow rate and improved hydrodynamic conditions significantly inhibited diatom growth and accelerated the transport process. The results of the hypothetical simulation showed that after the initiation of the WDP-TH, inhibition effects of improved hydrodynamic force on algae were more apparent than promotion effects of increased total phosphorus concentration in the MLHR.

A Navier-slip model for liquid film thickness in gas–liquid slug flow in capillaries

ABSTRACT The motion of a long gas bubble in a continuous liquid phase in a small diameter channel results in a thin liquid film between the bubble and the channel wall. Generally, a free-slip (zero shear) boundary condition is applied at the gas–liquid interphase boundary which is applicable only at low gas velocities. However, at increased flow rates of gas phase, shear stress at the gas–liquid interface is non-negligible. Applying non-zero shear at the interface requires knowledge of velocity profile in the gas phase. In this work, we circumvent this problem by using a slip length like parameter to take into account the velocity gradient in the gas phase. The slip length is infinite for the free-slip condition at the interface and zero for the no-slip condition. An expression is derived for the film thickness in terms of slip length and capillary number and is compared with the experimental data and other correlations available in the literature.

Prediction of technological indicators of selective water isolation of water-watered wells by nanostructured gel

In this work the composition forming nanostructured gel, which does not change phase permeability of oil, easily penetrating into water-saturated depth of the formation in watered wells, effectively closing the drainage channels, is established, the possibilities of its rapid heating up to formation temperature, gel formation within a certain time in contact with water depending on the concentration of the selected composition and with its use of involvement in the development of residual oil reserves, which are in watered wells, are investigated at injection of this composition into the well. As an optimal variant of well isolation in terrigenous reservoirs of oil fields it is suggested to use nanocomposite on the basis of silicate gel (with the content of liquid glass 4 % (modulus 3.1), 0.6 % of hydrochloric acid and 0.063 % of metal nanoparticles). The mechanism of selective isolation of water flow in production wells is based on the fact that when the composition is injected into the production well, part of its volume gets into the oil-saturated layer, and the rest – into the water-saturated layer. The composition is distributed in proportion to the permeability of the layers. In the process of well development the composition in the oil-saturated layer is removed, and in the water-saturated layer it retains its isolating properties. The greater the volume of injected fluid, the greater the isolation factor and pressure gradient. The isolation factor is directly proportional to the volume injected. Gel formed in the water-saturated layer corresponding to the volume of the injected composition reduces the phase conductivity on water at least 30 times. Practically does not change the phase conductivity by oil. On the basis of the calculation model including physical and chemical characteristics of selective isolation process taking into account real field conditions, the influence of possibility to isolate bottomhole zone of wells by gel on technological indicators of its operation was estimated. Thus, when putting into operation a well after isolation by water, the production of which was flooded with water, in the initial moments there was a sharp increase in oil flow rate (2–3 times), and at the subsequent stage – a slight decrease in the rate, compared to the flow rate before isolation, the effective time of development or flushing was about 150 days.

Study on performance of a multi-heat source heat pump coupled energy storage system for plant factory heating system

CO2 air source heat pump (CASHP) faces challenges of performance degradation caused by the high return water temperature and the low ambient temperature for building heating. This study proposed a novel multi-heat source heat pump system (MHSHP) that combined with a CO2 air source heat pumps (CASHP) and ground source heat pumps (GSHP) with the implementation of a thermal storage tank. The performance and CO2 emissions of both CASHP and MHSHP systems were investigated by applying a plant factory located in Beijing, China. The effects of user-side parameters and ambient temperature were explored with the storage water temperatures ranging from 20 °C to 40 °C. The results demonstrated that the heating performance of the CASHP improved with an increase of user water flow rate and ambient temperatures, while it decreased as the storage water temperature increased. At the flow rate of 1.1 m3/h, the increase of the compressor frequency from 40 Hz to 60 Hz led to a significant improvement in heating capacity by 53.3 %, and a reduction in COP by 23.3 %. When the user-side water flow ratio decreased or the total flow rate increased, the COP of the MHSHP system showed improvement and outperformed that of the CASHP system, with an increase ranging from 46.9 % to 61.5 %. Additionally, it exhibits reduced sensitivity to ambient temperature fluctuations, resulting in a decrease in COP variability from 33.3 % to 20.6 %. Moreover, the CO2 emissions of the system decrease as the COP increases, with significant reduction of 69.2 %.

Parameter optimization of ultrafine molybdenum powder during hydrogen reduction of MoO2 based on central composite design method

The hydrogen reduction of MoO2 is a common method for preparing ultrafine molybdenum powder, which is an important basic material for manufacturing high-performance Mo-based alloys. However, its preparation parameters are usually hard to be controlled. To address this issue, the work conducted the parameter optimization research during the hydrogen reduction process with using central composite design method, and the influence of different parameters such as reaction temperature, yttrium content, and hydrogen flow rate, on the particle size and oxygen content of the prepared molybdenum powder were investigated. The findings showed that the particle size of the prepared molybdenum powder is gradually decreased with the increase of reaction temperature and yttrium content, while gradually increased with the increase of hydrogen flow rate. The oxygen content of the prepared molybdenum powder is gradually decreased with the increase of reaction temperature and hydrogen flow rate, while gradually increased with the increase of yttrium content. Reaction temperature and yttrium content have significant interactions on the particle size and oxygen content are also concluded, and their respective regression model equations are obtained. The result also demonstrated that the particle size and oxygen content of the prepared molybdenum powder had a certain contradictory relationship. Through the comprehensive analysis, the optimal parameters for preparing ultrafine molybdenum powder with a low oxygen content are deduced, that is, reaction temperature: 1200 K, yttrium content: 0.1 mass%, and hydrogen flow rate: 1000 mL/min. Under the conditions, the average particle size and oxygen content of the prepared molybdenum powder are 320 nm and 0.456 mass%, respectively.

In-use stability of Rituximab and IVIG during intravenous infusion: Impact of peristaltic pump, IV bags, flow rate, and plastic syringes

This study investigates the impact of intravenous (IV) infusion protocols on the stability of Intravenous Immunoglobulin G (IVIG) and Rituximab, with a particular focus on subvisible particle generation. Infusion set based on peristaltic movement (Medifusion DI-2000 pump) was compared to a gravity-based infusion system (Accu-Drip) at different flow rates. The impacts of different diluents (0.9 % saline and 5.0 % dextrose) and plastic syringes with or without silicone oil (SO) were also investigated. The results from the aforementioned particular case demonstrated that peristaltic pumps generated high levels of subvisible particles (prominently < 25 µm), exacerbated by increasing flow rates, specifically in formulations lacking surfactants. Other factors, such as diluent type and syringe composition, also increased the number of subvisible particles. Strategies that can help overcome these complications include surfactant addition as well as the use of SO-free syringes and a gravity infusion system, which aid in reducing particle formation and preserving antibody monomer during administration. Altogether, these findings highlight the importance of the careful selection of formulations and infusion protocols to minimize particle generation during IV infusion both for patients’ safety and treatment efficacy.

Numerical investigation of particle behavior and erosion wear in a centrifugal pump using coarse-grained Discrete Element Method

Erosion wear presents a significant challenge in the operation of hydrodynamic systems, particularly in centrifugal pumps. To address this issue, this study employs the coarse-grained Discrete Element Method (CGDEM) coupled with Computational Fluid Dynamics (CFD) to predict erosion wear areas and elucidate particle behavior dynamics. The simulation considers spherical solid particles (brown corundum) with diameters ranging from 0.3 mm to 1 mm and volume fractions of 15% and 5%. The flow field is calculated using the Navier-Stokes equations and the shear-stress-transport (SST) k-ω model. Particle movement is tracked using Newton’s second law, considering drag and gravitational forces. Results indicate that the highest turbulent kinetic energy (TKE) occurs at a flow rate of Q = 15 m3/h. Moreover, the pressure reduces slightly when the flow rate increases, although flow velocity might increase with volumetric discharge. Additionally, increased particle diameter leads to greater erosion wear, particularly on blade leading edges, the volute tongue area, and the volute casing belly region. As particle mass concentration intensifies, wear rates on the volute wall and inner hub edge also increase. The study’s robustness is demonstrated through alignment between experimental and numerical data. This investigation offers valuable insights into erosion dynamics in centrifugal pumps, crucial for enhancing operational efficiency and mitigating erosion-induced challenges in these critical systems.