Particle Volume Concentration Research Articles

Particles Transportation and Deposition Behavior During Horizontal Wellbore Exploitation

Abstract Particles deposition and plug-in wellbore cause lots of damage and efficiency reduction during oil and gas exploitation. Transportation has been a focus for safety and production improvement. The annular flow field and particles transport behavior have been investigated using computational fluid dynamics with an renormalization group k–ɛ method. Effects of particles volume concentration, washing fluid concentration with power-law shearing, annular eccentricity, flow rate, and rotation speed have been researched to get the mechanism of particles accumulation and transport behavior. The results show that an increase in eccentricity causes velocity reduction of the annular narrow gap area, particles easily deposit, accumulate, and are hard to transport; increasing flow rate and fluid concentration apparently improve particles transportation and reduce deposition, pressure loss increases; inlet particles volume concentration increases deposition starting position and deposition length, the inner pipe rotation facilitates particles’ second suspension.

SO2 enhances aerosol formation from anthropogenic volatile organic compound ozonolysis by producing sulfur-containing compounds

Abstract. Sulfur dioxide (SO2) can affect aerosol formation in the atmosphere, but the underlying mechanisms remain unclear. Here, we investigate aerosol formation and composition from the ozonolysis of cyclooctene with and without SO2 addition in a smog chamber. Liquid chromatography equipped with high-resolution tandem mass spectrometry measurements indicates that monomer carboxylic acids and corresponding dimers with acid anhydride and aldol structures are important components in particles formed in the absence of SO2. A 9.4–12.6-times increase in particle maximum number concentration is observed in the presence of 14–192 ppb SO2. This increase is largely attributed to sulfuric acid (H2SO4) formation from the reactions of stabilized Criegee intermediates with SO2. In addition, a number of organosulfates (OSs) are detected in the presence of SO2, which are likely products formed from the heterogeneous reactions of oxygenated species with H2SO4. The molecular structures of OSs are also identified based on tandem mass spectrometry analysis. It should be noted that some of these OSs have been found in previous field studies but were classified as compounds from unknown sources or of unknown structures. The observed OSs are less volatile than their precursors and are therefore more effective contributors to particle formation and growth, partially leading to the increase in particle volume concentration under SO2-presence conditions. Our results provide an in-depth molecular-level insight into how SO2 alters particle formation and composition.

The Effect of Glycerol-Based Suspensions on the Characteristics of Resonators Excited by a Longitudinal Electric Field

This study examines the effect of suspensions based on pure glycerol and diamond powder with different concentrations on the characteristics of resonators with a longitudinal electric field. We used two disk resonators made of the quartz and langasite plates with round electrodes on both sides of the plate and resonant frequencies of 4.4 and 4.1 MHz, operating in shear and longitudinal acoustic modes, respectively. Each resonator was mounted on the bottom of a 30 mL liquid container. During the experiments, the container was filled with the suspension under study in such a way that the resonator was completely immersed in the suspension, and the frequency dependences of the real and imaginary parts of the electrical impedance of the resonator were measured. As a result, the shear modulus of the elasticity and shear coefficient of the viscosity of the studied suspensions were determined. The material constants of the suspensions were found by fitting the theoretical frequency dependences of the real and imaginary parts of the electrical impedance of the resonator to the experimentally measured ones, which was calculated using Mason's equivalent circuit. As a result, the dependencies of the density, shear modulus of elasticity, shear viscosity coefficient, and velocity of the shear acoustic wave on the volume concentration of the diamond particles were constructed.

Разработка математической модели псевдоожижения частиц при наличии внутренних источников теплоты

Devices for heat treatment of bulk media due to the supply of high-temperature agent from an external source are widely used. In this case using the fluidization technique, the thermal agent also performs the function of a fluidizing medium. The ohmic heating of particles directly in the fluidized bed can be considered as an alternative and preferred technology in some cases. However, to organize such processes effectively we need reliable models to predict the structure of the fluidized bed itself, since it largely determines the conductivity, and, hence, the intensity of heating. The fluidized bed is an inhomogeneous heterogeneous system, therefore, mathematical models assuming its spatial discretization are necessary for its adequate description. Thus, the development of such models is an urgent task. The mathematical apparatus of the Markov chain theory is used as a mathematical basis to model the structure of a bulk medium in a fluidized bed. Parametric identification of the model is performed using the dependencies known from the literature. The transition matrices have been aligned with the physical parameters of the mass flows, which makes the proposed model nonlinear. The electrothermal process in the fluidized bed is described at a qualitative level with an assumption that the heating intensity of the representative volume of the bed is inversely proportional to the volume concentration of particles in it. The gas-particle heat and mass transfer process is a limiting factor that determine the asymptotic temperature in the bed. The authors have studied numerically the influence of the structure and expansion of the fluidized bed on the heating intensity of its phases in case we have internal heat sources, the intensity of which is inversely related to the concentration of the solid phase. The influence of various parameters of the model on the formation of the thermal regime in the apparatus is estimated. It is shown that for an appropriate description of processes in the apparatus, its analysis as an object with distributed spatial parameters is necessary. The paper shows that the methodology of the Markov chain approach is an acceptable tool to describe the structure of such particle systems as a fluidized bed. The obtained results of numerical experiments are in good qualitative agreement with the fluidized bed theory. They can be considered as a reliable scientific basis to calculate the system of ohmic heating of media in a fluidized bed.

Numerical investigation on dynamic performance of vertical hydraulic transport in deepsea mining

Owing to great demands of natural resource and huge reserves of seabed minerals, deepsea mining technology has been proposed in the past decades. The most promising way to convey the deepsea ores to the sea surface is vertical hydraulic transport (VHT). Numerical investigations on dynamic performances of VHT were conducted by Computational Fluid Dynamics and Discrete Element Method (CFD-DEM). The convergence study on the pipe length, simulation duration, spacial and temporal resolutions were carried out, followed by the method validation through the experiments. The characteristics of particle and fluid were analyzed from different aspects. In most conditions, the local volume concentration of particles in the pipe is larger than the feeding concentration owing to the velocity lag of particles in the upward flow, indicating that instantaneous particle characteristics should be considered in engineering applications. Sensitivity analyses of transporting parameters and particle properties were conducted. Flow velocity and feeding concentration are two key factors dominating the dynamics of the mixture. A special range of particle diameter was recognized in which the particle accumulation was severe, whereas a proper particle size distribution would benefit VHT. Based on the numerical simulations, empirical formulas were proposed to have a rough estimation of particle velocity, slip velocity and local concentration for the initial design of VHT.

Comparative studies on convective heat transfer behaviour of nanofluids under turbulent flow with inserts

ABSTRACT In this paper, the thermal performance of novel spiraled rod inserts in the turbulent flow of Al2O3/water, CuO/water, and TiO2/water nanofluids through a circular tube with constant heat flux boundary conditions is compared. The nanofluids used in this study contain particle volume concentrations of 0.25 and 0.5%. According to the study's findings, nanofluids have a greater Nusselt number than deionised water. Among the nanofluids used, CuO nanofluid with a spiraled rod insert of the lesser pitch gives the maximum enhancement in Nusselt number, and the enhancement value is 49.6% for 0.5% volune concentration compared to deionised water. The increase in friction factor for the above condItion is 17.59%. The maximum thermal performance factor value with a pitch of 30 mm spiraled rod insert and 0.5% volume concentration of CuO nanofluids is about 1.41.The novelty of this present study is the simple and easily manufactured inserts used to enhance heat transfer.

Thermal performance analysis of a double pipe heat exchanger using biosynthesised silicon carbide and carbon nanotubes

ABSTRACT A nanofluid is a solution of nanoparticles with diameters fewer than 100 nanometers suspended in a base fluid such as water, ethylene glycol, or oil. In the nanofluid, these nanoparticles are suspended. The goal of this research is to look at the functioning of a twin-pipe heat exchanger that uses counter flow arrangements and two different nanofluids as cooling fluids. Alkaline water is a basic fluid made up of silicon carbide (SiC) and carbon nanotubes (CNT). The goal of this research was to see how different compositions of SiC and CNT nanoparticles dispersed in water affected the heat transfer capacities of a twin pipe heat exchanger developed with a counterflow arrangement. The flow rate of the nanofluid and the particle volume concentration of alkaline water were (0.02) and (0.04), respectively. Fluids with constant intake temperatures of 60°C for water and 30°C for nanofluid flow at the same input velocity via a heat exchanger. Both fluids are traveling at the same rate. According to the findings, nanofluid absorbs more heat than water at a range of flow speeds. Because of the improved thermal properties of nanoscale fluids, this results in increased thermal efficiency in heat exchangers.

Size, concentration, and origin of human exhaled particles and their dependence on human factors with implications on infection transmission

Understanding infection transmission between individuals, as well as evaluating the efficacy of protective measures, are key issues in pandemics driven by human respiratory particles. The key is a quantitative understanding of the size and concentration of particles exhaled and their variability across the size range for a representative population of all ages, genders, and different activities. Here we present data from 132 healthy volunteers aged 5 to 80 years, measured over the entire particle size range for each individual. Conventional particle spectrometry was combined with in-line holography under well-controlled conditions for common activities such as breathing, speaking, singing, and shouting. We find age to be the most important parameter for the concentration of small exhale particles <5µm (PM5), which doubles over a 7-year period in adolescents and over a 30-year period in adults. Gender, body mass index, smoking or exercise habits have no discernible effect. We provide evidence that particles with a diameter of <5µm originate from the lower respiratory tract, 5–15µm from the larynx/pharynx, and >15µm from the oral cavity. PM5 concentration can vary by one order of magnitude within a person, while inter-person variability can span two orders of magnitude, largely explained by difference in age. We found no discernible inter-person variability for particles larger than 5µm. Our results show that cumulative volume of PM5 is 2–8 times higher in adults than in children. In contrast, number and volume concentration of larger particles, which are produced predominantly in the upper respiratory tract, is largely independent of age. Finally, we examined different types of airborne-transmissible respiratory diseases and provided insights into possible modes of infection transmission with and without several types/fits of face masks.

BORU YÜZEYİNDEKİ KAPSÜL TİPİ KABARTMANIN VE AL2O3 SU NANOAKIŞKANIN ISI TRANSFERİNE ETKİSİNİN SAYISAL ANALİZİ

This study aims to numerically investigate and evaluate the enhancement of heat transfer by new capsule dimples on tube surfaces for flow of water and Al2O3-water nanofluid with different concentrations, under uniform surface heat flux. The originality of this work lies in combining two passive heat transfer enhancement methods such as geometrical improvements and nanofluids together. Capsule dimples with different depths were considered. Al2O3-water nanofluid was modeled as a single-phase flow based on the mixture properties. The effects of dimple depth and nanoparticle concentrations on Nusselt number, friction factor and performance evaluation criteria (PEC) were studied. Numerical computations were performed using ANSYS Fluent commercial software for 2000 14000 Reynolds number range. It was found that when laminar, transient and fully developed turbulent flow cases are considered, increase in the dimple depth increases the Nusselt number and friction factor for both pure water and Al2O3-water nanofluids cases. Also, the friction factor increases as dimple depth increases. Results show that increase in PEC is more pronounced in the laminar region than in the transition region, it starts to decrease for turbulent flows. For nanofluid, PEC values are considerably higher than pure water cases. The variation of PEC for capsule dimpled tubes are dependent on flow regimes and dimple depths. Increasing the nano particle volume concentration and dimple depth in laminar flows increase the PEC significantly.

Heat transfer analysis of triple concentric tube heat exchanger using MWCNT/water nanofluids under parallel flow configurations

In this investigation, heat transfer characteristics of Multi-Walled Carbon Nanotubes/water nanofluids are studied experimentally in a triple concentric tube heat exchanger under parallel flow configurations and compared with water. The Multi-Walled Carbon Nanotubes/water nanofluids are formulated for 0.2, 0.4 and 0.6% nanoparticle volume concentrations using a two-step method by adding sodium dodecylbenzene sulfonate surfactant. At 0.6% particle volume concentration, the Nusselt number is found to be 10% higher compared with water at 7500 Reynolds number. In this experimental investigation, it is found that at Reynolds number 9500, the overall heat transfer coefficient is enhanced by 15% and pressure drop enhanced by 15% compared with water at 6500 Reynolds number and friction factor is enhanced by 16% compared with water at 0.6% Multi-Walled Carbon Nanotubes/water nanofluids concentration.

Performance investigation of flat plate solar collector with nanoparticle enhanced integrated thermal energy storage system

Since solar energy is unstable during the day, storage energy is essential to use this energy effectively. An experimental study on a newly designed, integrated solar collector with Nano enhanced-PCM-based energy storage has been carried out for solar collector application at night or when solar radiation is unstable. Before the collector design, performing a performance analysis on three different Nano-enhanced PCM was performed to select the nano-based PCM. To investigate the improvement in energy absorption performance, charging and discharging tests are performed at different flow rates. Amine functionalized paraffin wax (f-NH2-MWCNTs + PW)PCM has been selected due to high thermal conductivity and higher enthalpy gain among four samples, MWCNTS + PW, f-OH-MWCNTS + PW, and f-COOH-MWCNTS + PW. Finned triangular shape container designed for encapsulation of hybrid PCM, f-NH2-MWCNTs + PW. Fourteen triangular shape containers with rectangular profile fins are designed for PCM storage. PCM module has attached to the bottom of the trapezoidal absorber plate of the flat plate solar collector (FPSC). Experimental observation of charging and discharging shows that 21 % decrease in charging time while a 23 % decrease in discharging time observed for f-NH2-MWCNTs + PW compared to pure PCM, at 0.1 % particle volume concentration, flow rate 2.25 LPM and solar intensity 1010 W/m2. Instantaneous charging and discharging efficiencies are enhanced by 24 % and 28 %, respectively, compared to base PW PCM. Overall exergy gain for PCM enhanced system with respect to base FPSC is 12 %.The innovative design NePCM encapsulation and its attachment with the bottom of the trapezoidal absorber plate to utilize excess thermal energy that may go as waste through bottom insulation makes this work distinctive from past and contemporary research. This investigation aims to enhance energy utilization by storing excess amounts in the attached PCM storage. This system can be used for off-time hot water supply and milk pasteurization applications.

Evaluation of flat plate solar heater filling in nanofluid under climatic of Iraq conditions

In order to assess the performance efficiency of a flat plate solar collector. The current investigation focuses on a wide range of nanoparticles suspended in basefluid to create nanofluid. Additionally, the current investigation has been carried out with the best particle volume concentration possible based on our experimental results with varied mass flow rates along three months Feb, March and April 2020 from 10 a.m. to 3 p.m. The volume fractions of solid nanoparticles dispersed in water are 0.15, 0.25 and 0.35% with size diameter of 20 nm and mass flowrate are 0.021, 0.024 and 0.03 kg/s. According to experiments, the energy efficiency of a ZnO/water nanofluid is increased by 31% for a particle volume concentration of 0.35% at a mass flow rate of 0.03 kg/s. Increased system performance in terms of effective conversion of the available energy into useful functions is highlighted by the rise of energy and exergy efficiency. ZnO/water has the highest increase in energy efficiency of a collector, at 0.35%, followed by 0.25 then 0.15%, respectively.

Experimental measurement of respiratory particles dispersed by wind instruments and analysis of the associated risk of infection transmission

Activities such as singing or playing a wind instrument release respiratory particles into the air that may contain pathogens and thus pose a risk for infection transmission. Here we report measurements of the size distribution, number, and volume concentration of exhaled particles from 31 healthy musicians playing 20 types of wind instruments using aerosol size spectrometry complemented with in-line holography in a strictly controlled cleanroom environment. We find that playing wind instruments carries a lower risk of airborne disease transmission than speaking or singing. We attribute this to the fact that the resonators of wind instruments act as filters for particles >10µm in diameter, which were found in high abundance right after a brass mouthpiece but very rarely at the instrument bell end. We have also measured the size-dependent filtering properties of different types of filters that can be used as instrument masks. Based on these measurements, we calculated the risk of airborne transmission of SARS-CoV-2 in different near- and far-field scenarios with and without masking and/or distancing. We conclude that in all cases where there is a possibility that the musician is infectious, the only safe measure to prevent airborne transmission of the disease is the use of well-fitting and well-filtering masks for the instrument and the susceptible person.

Nanofluid applications in pressurized water reactors: A review

The main purpose of this paper was to review nanofluid applications as the main coolant of pressurized water reactors (PWRs) with both solid and dual-cooled annular fuel. In this regard, first, theoretical and experimental models for calculating thermo-physical properties of nanofluids including density, specific heat, thermal conductivity, viscosity, and heat transfer coefficient were reviewed and the effects of different variables such as particle volume concentration, particle size, shape, and temperature on these parameters were determined. In the following, research related to neutronic, thermal-hydraulic, and safety investigations of nanofluids as the main coolant of PWRs with solid and dual-cooled annular fuel were reviewed. Corresponding methods, codes, and results were discussed and compared. Based on studies, it was concluded that nanofluids' effects on key neutronic parameters (keff, neutron flux and radial and axial power peaking factor) depend on the used nanoparticle, volume concentration, and nanoparticle deposition on the cladding, while nanofluids can increase heat transfer, critical heat flux, and minimum departure from nuclear boiling ratio (MDNBR). Also, it was found that nanofluids with low volume concentration in reactor core with dual-cooled annular fuel can replicate the same advantages. Furthermore, using dual-cooled annular fuel instead of solid fuel increases MDNBR margin and reduces coolant flow which leads to a more compact design of the reactor core and a reduction of capital cost. Finally, incoming challenges and future works were presented.

Parametric optimization of friction stir process for developing high strength and wear-resistant chromium reinforced NiAl bronze composite

The present study focuses on fabricating a chromium-reinforced nickel aluminium bronze (NAB) composite using an optimized multi-pass friction stir processing (FSP) technique. The tool rotation, tool traverse speed, and volumetric concentration of the reinforcement were taken as input process parameters, whereas the ultimate tensile strength (UTS), yield strength (YS), percentage elongation (% E), microhardness, and sliding wear rate were taken as output responses. Taguchi-Grey relational analysis (GRA) was utilized for optimizing the input process parameters, which were 1000 r.p.m., 28 mm min−1 and 15.7%, respectively. The most significant parameter was traverse speed, followed by tool rotation and volumetric concentration of the reinforcement. FE-SEM, EDS, and XRD analyses were performed to characterize the as-cast NAB, chromium powder, and FS-processed composite. The tensile strength and wear resistance of the processed composite are enhanced compared to the base NAB alloy on account of significant grain refinement due to the stirring action of the tool pin in the processed zone and the dispersion of chromium reinforcement. The wear rate of the composite was reduced as the tool rotation, traverse speed, and Cr particle volume concentration were increased. The maximum UTS of the prepared composite was 701 MPa, whereas the UTS of the as-cast NAB was 620 MPa. It was observed that as-cast NAB exhibited a hardness value of 286 HV, which was improved to 385 in the FSPed prepared composite. It was found that as-cast NAB exhibited 7.0 × 10–6 gm m−1 of wear rate, whereas the FSPed composite showed a minimum wear rate of 5.5 × 10–6 gm m−1. The microstructural examination revealed that the wear mechanism in the case of as-cast NAB was primarily adhesion, whereas the abrasion was found to be the governing mechanism of material removal in the processed composite.

SIMULATION OF HOMOGENEOUS HYDROGEN-AIR DETONATION INTERACTION WITH POROUS FILTER

Calculations of the interaction of a cellular detonation wave (DW) with an inert porous filter were carried out based on the developed physical and mathematical model of the mechanics of heterogeneous medium which takes into account the detailed chemical kinetics of chemical reactions in the gas phase. Under an inert porous filter, a motionless lattice of inert particles is considered. The following flow regimes were revealed: propagation of attenuated cellular DW at velocities less than the Chapman-Jouguet velocity and detonation failure with the destruction of the cellular structure. Critical volume concentrations of filter particles corresponding to the detonation failure regime were calculated. Dependences of the normalized DW velocity and detonation cell size on the volume concentration of particles in filters were calculated. The concentration limits of detonation (critical volume concentrations of particles lead to detonation failure) in filters with diameters of 50, 100, and 200 µm were determined. The dependences of the normalized DW velocity and size of detonation cell on the volume concentration and diameter of particles in filters were calculated.

Light pollution and the concentration of anthropogenic photons in the terrestrial atmosphere

Light pollution can be rigorously described in terms of the volume concentration of anthropogenic photons (light quanta) in the terrestrial atmosphere. This formulation, consistent with the basic physics of the emission, scattering and absorption of light, allows one to express light pollution levels in terms of particle volume concentrations, in a completely analogous way as it is currently done with other classical pollutants, like particulate matter or molecular contaminants. In this work we provide the explicit conversion equations between the photon volume concentration and the traditional light photometry quantities. This equivalent description of the light pollution levels provides some relevant insights that help to identify artificial light at night as a standard pollutant. It also enables a complementary way of expressing artificial light exposures for environmental and public health research and regulatory purposes.

A study on energy transport performance of Microencapsulated Phase Change Materials (MPCM) slurry

Microencapsulated phase change materials (MPCM) slurry as a Heat Transfer Fluid (HTF) has been investigated due to the enhanced thermal energy storage capacity associated with the Phase Change Material (PCM). A numerical study employing the Eulerian-Eulerian flow model has been carried out to investigate the energy transport performance of MPCM slurry and water. Validation of the numerical model with the experimental work is first performed and further extended to identify the effects of temperature variations between the pipe inlet to outlet and volume concentrations of MPCM particles under a constant wall heat flux. Accordingly, it is found that water exhibits the highest pumping power demand over PCM-based HTFs to transport the corresponding thermal energy. The increase in temperature variation improves the energy capacity of both water and MPCM slurry; however, it affects the influence of the latent heat of the PCM. Pipe size and the latent heat of the phase change material significantly alter the ratio of energy transport by pumping power (Q/Wp) for MPCM slurry flow. Furthermore, it is observed that a flow of MPCM slurry with a low Reynolds number achieves a better value of Q/Wp under turbulent flow conditions.

Assessment of I/II fracture toughness of new magnetically guided stainless steel particle toughened carbon/epoxy composites

In this paper, a new kind composite, called the magnetically guided stainless steel particle toughened composite, is manufactured and its I/II fracture toughness is then experimentally investigated. The stainless steel particles can be arranged either vertically under the outside magnetic guidance during manufacturing process or randomly. Comparisons with the one without stainless steel particles, the GIC and GIIC can increase by 81.88% and 87.72%. Numerical simulations are also carried out. A theoretical prediction model is proposed for the interface parameters of mode I fracture toughness and verified by comparing simulation results with experimental ones. The trial-and-error inversion method is used to effectively simulate the mode II fracture toughness. Different interlaminar interface parameters are tried to determine the interface parameters which can yield mode II fracture toughness closest to the experimental one. A relational equation is fitted using the particle volume content and interlaminar interface parameters. Additional experiment and simulation for specimen with a different particle density are performed to demonstrate the accuracy of interface parameters obtained by the trial-and-error inversion method.

Micropolar Dusty Fluid: Coriolis Force Effects on Dynamics of MHD Rotating Fluid When Lorentz Force Is Significant

The main objective of this investigation to examine the momentum and thermal transportation of rotating dusty micropolar fluid flux with suspension of conducting dust particles across the stretched sheet. The novelty of the flow model is the exploration of the significance of boosting the volume concentration of dust particles in fluid dynamics. The governing PDEs of the problem for both phase models are transmuted into nonlinear coupled non-dimensional ODEs by utilizing suitable similarity modifications. The bvp4c technique was utilized in MATLAB script to acquire a graphical representation of the experimental results. This study illustrates the analysis of repercussions of pertinent parameters on non-Newtonian fluid and the dusty phase of fluid. By improving the volume concentration of dust particles and rotating parameters, the axial velocity for both phases depreciates, whereas temperature and transverse velocity for both phases have the opposite behavior. The micro-rotation distribution rises with higher contributions of rotating and material parameters, whereas it decreases against larger inputs of volume concentration of dust particles. The growing strength of the dust volume fraction (ϕd) caused the coefficient of skin friction to decrease along the x direction, and the skin friction coefficient is raised along the y direction.