Axial Locations Research Articles

Automatic Vehicle Accident Detection and Messaging System Using GSM and GPS Module

Abstract: Our daily tasks are now simpler due to technological advances and infrastructure technological advances and infrastructures that are developing quickly. Road collisions, which incur significant destruction of life and assets, are on the rise daily as the number of vehicles grows. The World Health Organization's (WHO) study estimates that fifty million individuals are harmed and a total of 1.35 million individuals die each year in the world. The absence of medical help at the scene of an incident or the long response time during the rescue effort is the main causes of mortality. The majority of fatal accidents result from the lack of an appropriate medical facility at the scene. Most businesses now use various preinstalled smart sensing systems to monitor their cars' mechanical health and of already installed intelligent sensing systems to monitor their cars' mechanical health and to provide more individualized services to their valued clients. These systems also give clients access to vital smart recommendations enabling them to safely operate their cars them to operate their cars safely. We increase the security of the person by assessing their position while they are moving and keeping track of the cars by sending SMS by utilizing all of this preloaded smart monitoring equipment. With the help of the GSM module, our system would transmit the accident's precise location to the registered mobile numbers as well as the ambulance, the passengers' families, and the closest police station. The system that we propose in the automobile would first detect the accident using vibration detectors, and then detect the axial and latitudinal location of the site of the collision using GPS. Finally, it would determine the precise position of the car. In this study, an acceleration sensor can be employed as a vehicle rollover or crash detector both during and after a collision. A serious accident can be identified by keeping an eye on data collected by the accelerometer and vibration sensor. The major goal of this initiative is to reduce the amount of time it takes to get to the accident scene and deliver emergency medical care that can save lives. When an accident occurs in a remote place and no one is available to report it, this technique may prove to have been a lifeline. By responding quickly, emergency services can prevent an accident from happening and save a life. In this study, we looked at a number of articles about accidents detection devices and the effects of their use.

Multifocal intracranial meningioma coexiting with a transphenoidal meningocele of the Sella as seen on magnetic resonance imaging: A case report from a specialist hospital in Port Harcourt Rivers State, Nigeria

Meningiomas are frequently extra axial tumors and represent the most common tumor of the meninges. They are benign non- glial neoplasms which arise from meningothelial cells of the arachnoid membranes. However, they could be locally invasive and aggressive. They are classified into three grades according to the WHO, criteria, namely grade I (benign), grade II (atypical) and grade III (anaplastic). Atypical locations of meningioma (subcortical intra axial) have been reported. Our case study shows both the extra axial and intra axial locations. The latter represents a challenge in Radiological diagnosis because it could be taken as a metastatic tumor or a vascular malformation. Our case study, is a 57year old woman who presented to the Radiology department for a brain magnetic resonance imaging (MRI) investigation on account of a 3year history of seizure disorder, headache and occasional irrational behavior as explained by her relative. The seizures are inconsistent in pattern, it could be generalized tonic clonic or focal (facial or limb twitches or abnormal movement of the head). Magnetic Resonance Imaging of the brain revealed a dura based homogenously enhancing, isointense subcortical mass at the right occipital lobe with marked vasogenic perilesional oedema. A similar but smaller lesion is seen at the parasagittal area of the frontal lobe.

Quantum machine learning – A novel approach for hydrodynamics analysis and modeling of liquid-solid circulating fluidized bed risers

The Liquid-Solid Circulating Fluidized Bed (LSCFB) system is commonly employed in chemical and biochemical applications, serving as a reactor where solids act as catalysts or biofilm carriers. Mass and heat transfer heavily rely on the distribution of solids holdups, which are influenced by various operating conditions, including superficial liquid velocities and auxiliary liquid velocities. These operating conditions play a key role in controlling the hydrodynamics of solid distribution. Quantum machine learning (QML)-based modeling techniques are employed to investigate the solids holdup distribution in a Liquid-Solid Circulating Fluidized Bed (LSCFB) system. A novel application of quantum machine learning for the hydrodynamics analysis and modeling of the LSCFB riser. This work aims to lay the groundwork for investigating the applicability of QML for understanding and predicting the hydrodynamic behavior of CFB risers by leveraging the unique properties of quantum systems during the present Noisy Intermediate-Scale Quantum (NISQ) era. The unavailability of full-scale quantum infrastructure limits proper exploitation of different quantum computing opportunities including embedding. In this study glass beads particles with 500 µm used as the solid phase and water as liquid phase. At various axial locations (H = 1.0, 2.0, 3.0, and 3.8 m above the distributor) and with varying superficial liquid velocities, radial nonuniformity of solids holdup is observed. The derived models account for the impact of operating parameters, such as auxiliary and primary liquid velocities and superficial particulate velocity, on the radial phase distribution at various axial positions in the riser. By comparing the predicted solids holdup data with experimental data obtained from a pilot-scale LSCFB reactor, the accuracy of the models is determined. The models exhibit reasonable correlations with the experimental data and consistent phase distribution trends. The correlation coefficients between predicted outputs and experimental data for sequential and nonsequential QML models are 0.95 and 0.96, respectively.

CFD investigation on the radial heat transfer in a two stage co-axial pulse tube cooler working at liquid hydrogen temperature

Co-axial pulse tube coolers are very popular in practical applications due to their compactness, while radial heat transfer between regenerator and pulse tube due to temperature mismatch at the same axial location affects the cooling performance. Two stage pulse tube coolers are commonly used at liquid hydrogen temperature, and multiple radial heat transfer occurs in gas-coupled co-axial pulse tube cooler system due to the first stage annular pulse tube. CFD simulation models with and without radial heat transfer based on an actual gas-coupled two stage co-axial pulse tube cooler have been conducted to analyze the mechanism and effect. The heat transfer processes between the gas and pulse tube wall are analyzed and compared. Simulation results indicate that after introducing radial heat transfer, expansion efficiency of the second stage pulse tube is improved from 74% to 90.9% with radial heat flow from it to the regenerator and the first stage pulse tube. The cooling power at the second stage is notably increased compared to the model without radial heat transfer, while minor performance reduction at the first stage. This study may provide a valuable reference for the design of multi-stage pulse tube coolers.

Local instantaneous heat transfer characteristics around a rising single Taylor bubble and the temperature response of relatively thick pipe wall under local constant heat flux

A novel non-intrusive thermal diffusion measurement (TDM) method is proposed to measure the flow rate of gas–liquid two-phase flows under the slug flow state in our previous research. To improve the measurement accuracy of TDM by clarifying the real-time correspondence between wall temperature change and Taylor bubble (TB) location, the local instantaneous heat transfer characteristics around a rising single TB and the corresponding temperature response of the pipe wall are further investigated in detail by using the CFD tool in this paper. During the passage of TB, the local heat transfer between the pipe wall and fluid was analyzed based on the dynamic velocity field and temperature boundary layer, and the temperature on the fluid–solid interface presents the opposite trend with the heat transfer coefficient. For the zone upstream of the heat flux center, the lag time and increase of the wall temperature become large and weak along the radial direction, respectively, whereas the lag time is independent of the axial location, TB velocity, and TB length. Meanwhile, the increase in wall temperature shows an upward trend with the TB length for short TBs but is the same for long TBs.

Experimental design and analysis for film boiling heat transfer in a circular tube

In order to study the heat transfer of water during film boiling, stable film boiling heat transfer experiments are conducted in a circular tube. As the temperature of the heater surface sharply increases in a short period of time when critical heat flux (CHF) occurs, hot-patch technology is adopted to prevent damage to the test section. A complete experimental design, including the experimental facility, test section, experimental procedures, and the measurement of parameters, is developed. Two experimental schemes are used for testing, namely the post-CHF test and the quench test, respectively. These two schemes have been verified to achieve stable film boiling and yield consistent results. The effect of various parameters, including heat flux, pressure, mass flow and inlet subcooling, on the heat transfer coefficient has been analyzed. The experimental parameters range from an inlet subcooling of 10–50 K, a pressure of 0.1–2.5 MPa, and a mass flux of 100–1000kg/m2s. Through the analysis of the distribution of heat transfer coefficient along the axial location, three distinct heat transfer regions can be identified. Combined with heat transfer characteristics, three types of flow are considered: smooth inverted annular flow, rough inverted annular flow and inverted slug flow. Most of the data in this study is concentrated in the first two regions, namely the inversed annular flow. The data obtained in these tests is expected to provide important information for the study of inverted annular flow.

The VARIATION OF THE AXIAL LOCATION OF BRUCH’S MEMBRANE OPENING, GANGLION CELL INNER PLEXIFORM LAYER AND FLUX INDEX IN NORMAL TENSION GLAUCOMA AND PRIMARY OPEN ANGLE GLAUCOMA PATIENTS

Introduction. Bruch’s membrane opening (BMO) at the most anterior point of the neural canal for quantification of cup depth /based on retinal surface position, area and volume, laminar position, and prelaminar connective tissue volume. If these deep structural parameters are to be used effectively in glaucoma detection and identification of progression. Purpose. This study explores variation in the axial location of Bruch’s membrane opening (BMO) to determine if this reference plane varies with NTG and POAG patients. Methods This was a cross-sectional prospective descriptive study with purposive sampling. This study enrolled 72 eyes in Sardjito General Hospital underwent cirrus – OCT 5000 Ver 11.0.0.29946 between 1st March 2022 and 10th May 2022. Results. We evaluated 72 (25 NTG and 47 POAG) eyes on 37 outpatients service of Sardjito General Hospital. Median BMO, GCIPL, Flux index and CD ratio of NTG patients was 1.707 µm (1.387-2.182), 83,0µm (76-88), 0,40 (0.27-0,48), 0,64 (0,22-0,75). Median BMO, GCIPL, Flux index and CD ratio of POAG patients was 1.612 (1.028-2.031) µm, 79,00 (56-98) µm, 0,40 (0,26-0,47) and 0,64 (0,28-0,92) for CDR. Bruch’s membrane opening position was more posterior relative to the sclera in older subjects with negative correlation (P value = 0,07). Variable BMO and GCIPL tested between NTG and POAG group showed significant difference with BMO P value =0,04 and GCIPL P value=0,01 except Perfusion, flux index and RNFL. Conclusion. Bruch’s membrane opening is more posteriorly located in older individuals. There was significant difference p value of BMO between the mean of NTG and POAG.

Combining CdTe/CdS/ZnS Quantum Dot Fluorescence Temperature Measurements with Double-Helix Point Spread Function Axial Location for Intracellular 3D Thermograms

Combining CdTe/CdS/ZnS Quantum Dot Fluorescence Temperature Measurements with Double-Helix Point Spread Function Axial Location for Intracellular 3D Thermograms

Submarine-Channel Element Architecture Demonstrates Facies Heterogeneity in Both Strike and Dip Views: Miocene Modelo Formation, Lake Piru, California, USA

Submarine channels deliver vast quantities of sediment into ocean basins and the deposits left by these systems host important archives of paleoenvironmental change and are major targets for hydrocarbon production and carbon sequestration. However, similarities between channel subenvironments often make their identification difficult, particularly because some subenvironments are transitional or quite variable. While large channel complexes can often be resolved on seismic data, only outcrop data yields high-resolution detail of their internal heterogeneity. This study integrates 10 measured sections with drone-based photography to document lateral and vertical changes in depositional architecture in a well exposed outcrop of a submarine-channel element in the Miocene Modelo Formation at Lake Piru, California. The channel-element architecture is well constrained by erosional-surface mapping and lateral and vertical facies changes. The 3-dimensionality of the outcrop provides a unique example to demonstrate this heterogeneity in both strike (i.e., cross-sectional view) and dip orientations (i.e., longitudinal view). This channel element has a predictable vertical facies succession of thin sandstones and mudstones, mass transport deposits and amalgamated sandstones. The element is capped by a siliceous mudstones that provide a unique marker of hemipelagic deposition and the presence of an abandonment surface. The amalgamated sand packages are thickest in axial locations and thin over a distance of 500 m in the dip direction, but thin over 150 m in the strike direction toward two locations along the same margin. This thinning is used to constrain the dimensions and sinuosity of the channel element. We interpret a channel-element width of 550 m, a thickness of 29 m and an aspect ratio of 19:1, which is in agreement with previously published ranges of channel-element dimensions. With the documentation of lateral facies heterogeneity in orientations slightly oblique to both strike and dip, this study provides important data for understanding channelized sediment gravity flow dynamics in submarine channels and aids in evaluating reservoir-model volume and connectivity estimates.

Study of gas-liquid two-phase flow redistribution characteristics in the rod bundle channel using wire-mesh sensor

In subchannel analysis, the gas and liquid flow distribution phenomenon plays an important role in understanding rod bundle channels’ two-phase turbulent mixing mechanism. This paper obtained gas-liquid flow distribution data inside a vertical coupled subchannel rod bundle channel by utilizing a double-set wire-mesh sensor (WMS). To achieve evolutions of two-phase flow distributions, one subchannel was injected with gas and water called the donor channel, and the other injected with water is called the receptor channel. Four axial locations (Z/Dh = 28.95, 57.90, 86.86, and 115.81) were measured for each flow condition to obtain the evolution of the flow distribution. 36 flow conditions were acquired with 〈jg〉 from 0.073 to 1.02 m·s−1 and 〈jl〉 from 0.93 to 1.86 m·s−1 at Z/Dh = 115.81, including bubbly, cap-bubbly, and slug flow. The gas flow distributions were obtained by the cross-correlation calculation of the phase distribution data measured by a double-set WMS. The gas-phase flow rate relative errors acquired by WMS and rotameters are within ± 10%. To obtain the liquid flow distribution, the inter-subchannel equal-slip ratio assumption was introduced, which is according to the truth that two-phase flow characteristics between the adjacent subchannel are similar for most cases in this study. Further, obtained two-phase flow distribution data were verified and evaluated by Han et al.’s drift-flux model, and the relative errors for most cases are less than ± 20%. Results show that, under bubbly flow, the two-phase flow redistribution is weak. 90% of the gas was restricted in the donor channel, and the liquid flow was approximately distributed in both channels. With the increment of void fraction, two-phase flow redistributions are more severe. The liquid-phase recirculation flow was found in the receptor channel, under cap-bubbly and slug flow, which results in a higher gas-liquid flow in the donor channel than in the receptor channel. The rules of two-phase flow distributions indicate that the liquid-phase flow redistribution is more moderate than the gas phase. The drastic change in the gas-phase flow redistribution starts with the cap-bubbly flow. In addition, the current two-phase flow data indicates that the two-phase flow redistribution between the donor and the receptor channels does not follow the equal-volume principle postulated in the existing two-phase turbulent mixing model. Furthermore, current data also imply the relationship between void and mass flux distribution is not linear as assumed in the existing two-phase turbulent mixing model.

Flow Development of Multi-Annular Jets in a Confinement: Effect of Expansion Ratio

Confined coaxial jets have been widely used in gas turbine combustors, where the requirement is to achieve better mixing between two streams - fuel and air - prior to ignition so as to provide stable and complete combustion. Two shear layers, one between the central jet and the annular jet and other between the annular jet and the stagnant fluid outside the annular jet help in the mixing process for confined coaxial jets. Therefore, for improved mixing, a configuration of one central jet and two co-annular jets, called multi-annular or multicoaxial jets, has been considered. To understand mixing of these streams in a confinement (mixing chamber), the mean axial velocity profiles at different axial locations of the mixing chamber and the static pressure along the wall of the mixing chamber are measured for expansion ratio of 1 and 1.3. These quantities are also computed using CFD software, FLUENT, with Standard k-ε turbulence model. After validation of the CFD code, parametric studies have been carried out for different expansion ratios. The results provide a good understanding of the mixing process and flow development in expanding confinement.

Eulerian–Lagrangian fluid dynamics study on the effects of inlet radial angle on the performance and flow pattern of multi-inlet cyclone separator

This paper presents a study on the influence of inlet radial angle in a multi-inlet cyclone separator using Eulerian-Lagrangian (EL) fluid dynamics approach. The investigation focuses on the behavior of air and solid particles within the cyclone. Air circulation was simulated at velocities ranging from 2 to 6 m/s, with inlet radial angles of 15°, 32°, 45°, 61°, and 72°. To model the turbulent flow, the Reynolds stress model (RSM) and renormalization group k-model (RNG) were employed, while the particle trajectories were simulated using the discrete phase model (DPM) in ANSYS Fluent. The purpose of this study was to determine how the inlet radial angle impacts various parameters: collection efficiency, pressure drop, cut-off diameter, axial velocity, and tangential velocity. The numerical data obtained from the simulations were validated and found to be consistent with the existing literature. The results revealed interesting findings. In the case of an inlet velocity of 6 m/s, the highest pressure drop of 84.5 Pa was observed for the 15° inlet radial angle, while the lowest pressure drop of 77.42 Pa was observed for the 32° inlet radial angle. It was found that the collection efficiency varied according to the radial angle of the inlet, with values of 89.00%, 91.70%, 92.50%, 94.77%, and 94.83% for 32°, 45°, 15°, 72°, and 61°, respectively. Additionally, at an inlet velocity of 2 m/s and a radial angle of 72°, 61°, 15°, 45°, and 32°, the corresponding cut-off sizes were determined to be 1.17 μm, 1.19 μm, 1.25 μm, 1.33 μm, and 1.38 μm, respectively. At an inlet velocity of 6 m/s, the peak tangential velocities were found to be approximately 1.48, 1.44, 1.44, 1.39, and 1.34 times the inlet velocity for the 15°, 72°, 61°, 45°, and 32° radial angles, respectively, within the axial location range of z = 1.5D to z = 3.4D. The peak axial velocity values for the 32°, 72°, 45°, 15°, and 61° radial angles, were reported as 0.85, 0.89, 0.92, 0.94, and 0.96 times the inlet velocity respectively.

Numerical Investigation into the Temperature Profile of a PHWR Channel Containing a Disassembled Fuel Bundle During a Postulated Accident Condition

A reactor core overheats due to decay heat generated in the fuel when an effective cooling medium is unavailable, such as in a loss-of-coolant accident combined with a loss of emergency core coolant. If the heat generated is not effectively dissipated, then at extreme temperatures, the structural strength of the bundle assembly may deteriorate, leading to slumping of fuel elements onto the inner wall of the pressure tube. It is essential to examine the temperature behavior of the channel containing fuel pins in a disassembled state in order to comprehend the impact of further thermally induced deformations in the channel during postulated accident conditions. Capturing the temperature of channel components at each circumferential position from experiments is extremely difficult; thus, a modeling tool is necessary to obtain a thorough circumferential temperature profile. This paper presents a numerical study that aims to study the temperature distributions in a 1-m-long pressurized heavy water reactor (PHWR) channel containing a disassembled fuel bundle. The channel geometry and the boundary conditions implemented were obtained from the experiment. A temperature profile for each channel element at every circumferential and axial location was obtained. A thorough comparison of the predicted and the reported experimental values was performed, and it was found that the predicted temperature behavior of the channel was consistent with the experimental data. Further simulations with different fuel element configurations and decay powers may be carried out; in addition, the results obtained may be used for coupled thermal-mechanical and thermal-mechanical-chemical simulations.

Simulation Study on Axial Location Identification of Damage in Layered Pipeline Structures Based on Damage Index

This study investigates the feasibility of identifying the axial position of circumferential defects in laminated pipeline structures based on damage indices. Wavelet packet decomposition is combined with damage indices, and the effects of dual defects with the same circumferential position but different axial positions, as well as dual defects with different circumferential and axial positions, on damage indices are separately studied. Our aim was to determine the potential to use damage indices to identify the axial position of circumferential defects in laminated pipeline structures. ABAQUS finite element analysis software was used to establish models of laminated pipeline structures with single defects and dual defects (with the same circumferential position but different axial positions, and with different circumferential and axial positions). The laminated pipeline structure was composed of a steel pipe (structural layer), a rigid polyurethane foam (insulation layer), and a high-density polyethylene (anticorrosion layer). The received sensing signals were averaged, and subjected to 5-level wavelet packet decomposition, to calculate the damage index values, which were then organized into a damage index matrix. Based on the trend of changes in the damage index matrix, the effects of variations in the number and circumferential position of the defects on the identification of the axial position of the damage were analyzed. The results indicate that the trend in damage index changes is influenced by the number of defects, and the increase in the circumferential distance between the second and the piezoelectric element sensor. This study found that when 1.7λ≤PD≤3.4λ, Idouble defect 90°<Isingle defect<Idouble defect 0°; when 3.7λ≤PD≤4λ, Idouble defect 90°<0.3<Idouble defect 0°<Isingle defect. This article demonstrates that the identification of the axial position of damage in laminated pipeline structures can be achieved using the damage index values in the damage index matrix. Additionally, this damage identification method overcomes the limitation of the wavelet packet’s inability to identify dual defects with relatively small relative axial distances. This provides new ideas and methods for finite element analysis in identifying the axial position of damage in laminated pipeline structures.

Design Impacts on Ram Air Vane Cooling in an Ultra-Compact Combustor

Abstract The ultra-compact combustor (UCC) aims to decrease the length of gas turbine combustors using a unique design geometry which wraps a combustion chamber around the central axial flow. This distinctive design enables an out of the box type of cooling scheme to be investigated for the turbine inlet vanes, termed the hybrid guide vane (HGV) in the UCC. The leading edge of the HGV experiences only compressor exit air as combustion products do not interact with the vane upstream of the 14% axial chord location. Previous studies were conducted which computationally evaluated the viability of taking in freestream flow through the HGV stagnation region for use as coolant. Based on these studies, a six vane HGV was manufactured which incorporated a solid vane and five hollow vanes. Each of these vanes incorporated different features to vary the size of the internal plug, trailing edge exit, and film cooling holes. In the present study, the cooled HGV was experimentally analyzed using pressure, thermocouple, and infrared (IR) thermography measurements to evaluate internal coolant flowrates and pressure loss along with cooling performance. Furthermore, the vanes were compared to isolate the impact of design differences on vane cooling. It was found that the location of the internal plug and incorporation of film cooling holes had a minor impact on coolant flow and cooling. Additionally, results showed exit area had the largest impact on surface temperature and coolant mass flow where the largest exit area allowed less restricted coolant flow resulting in the lowest average surface temperature. However, completely blocking the exit slot forced coolant to exit only through film cooling holes, stagnating the majority of the internal flow, resulting in surface temperatures higher than the uncooled, solid vane.

Numerical investigation of the hydrogen, ammonia and methane fuel blends on the combustion emissions and performance

The co-combustion of traditional methane gas and alternative fuels importance to reduce emissions in combustion has increased in recent years. The literature proves the successful operations of ammonia and hydrogen as diesel engine fuels. However, there is not sufficient information about the combustion of methane along with ammonia and hydrogen. In this study, the effects of the combustion of methane-hydrogen and methane-ammonia-hydrogen fuel mixture on system performance and emissions are numerically investigated. Firstly, the effects of methane and 5%, 10%, and 15% hydrogen mixture are investigated. Then, methane and 5% fixed hydrogen ratio with 5% ammonia, 10% ammonia, and 15% ammonia mixtures are examined. The numerical model is validated against the literature data using the Sandia D model with a difference of 5.9% at x/d = 0.5. As a result of the study, 15% hydrogen addition to methane increased the maximum combustion chamber temperature by 100 K. However, with the addition of 15% of ammonia, the temperature is dropped by 200 K and the peak temperature location is slightly shifted away from the injection point. A 10% enhancement of hydrogen content rate will cause a 28% increase in thermal NOX emission and a 10% increment in the ammonia content of the fuel blend has caused to 3000 ppm enhancement in NOX emission. With the addition of %5, 10%, and %15 ammonia mass fraction to methane and hydrogen blend fuel at the axial location of x/d = 0.444, the NOx emission production rate has been increased by 1970, 3010, and 3790 ppm, respectively. In addition, the 15% hydrogen addition to methane (85% methane/15% hydrogen) and 5% hydrogen plus 15% ammonia addition to methane (80% methane/5% hydrogen/15% ammonia) reduced the CO2 emission by 30.7% and 14% compared to neat methane (100% methane) combustion. To sum up, this study shows that the use of methane-ammonia-hydrogen as a diesel engine fuel reduces combustion emissions.

Effects of ambient density and injection pressure on ignition and combustion characteristics in diesel spray under plateau cold-start conditions

Gaining insights into the multi-parameter coupling dominated in-cylinder combustion process takes on critical significance to controlling and enhancing the performance of diesel engines under plateau cold-start conditions. In this study, the effect of varying injection pressure and ambient density on ignition and combustion characteristics of No. -50 diesel spray was investigated through high-speed direct photography and the two-color imaging technique, respectively. Regarding ignition characteristics, the increase of the ambient density led to the variation of the non-monotonic trend of ignition delay time with the rise of the injection pressure to a monotonous decrease, whereas the correlation between the axial ignition location and the injection pressure remained unaffected. Under three different ambient densities, the transition modes of the flame structure varied with the increase of injection pressure, subsequently impacting combustion characteristics. For combustion characteristics, the average level of flame temperature and soot were inversely proportional to the injection pressure for all three ambient densities. Higher ambient density facilitated the heat release from combustion chemical reactions, influencing the impact of increasing turbulence intensity on the ignition and combustion processes of diesel spray. The overall temperature level of the flame displayed an inflection point with the rise of the injection pressure, and this inflection point is delayed with the increase of the ambient density. The local high-temperature regions in flames (＞2300 K) were identified under higher ambient densities, such that soot generation and oxidation were subjected to significant competition. At ρam = 16.6 kg/m3, the oxidation dominant time gradually decreased with the rise of the injection pressure, leading to the integral KL factor maximum at Pinj = 80 MPa case. The optimal fuel injection pressures for cold starting at different altitudes were determined by considering the ignition and combustion characteristics of the flames.

Effect of inlet gas and liquid velocity profiles on one-group interfacial area transport equation in a vertical large rectangular channel

Bubbly flows appear in many heat and mass transfer equipment. The interfacial area concentration is a critical parameter in determining the performance of the heat and mass transfer systems. The one-dimensional one-group interfacial area transport equation (IATE) was developed based on area-averaged bubbly flow data collected under uniform inlet flow boundary conditions. The applicability of the IATE to the flow systems with non-uniform inlet flow boundary conditions was not comprehensively examined. This study investigated the effect of inlet liquid and gas velocity profiles on measured interfacial area concentration changes along the flow direction. The data used in this study were collected for vertical upward air-water two-phase flow in a rectangular channel with a gap length of 10 mm and width of 200 mm. The test conditions were the superficial gas velocity ranging from 0.0870 to 0.288 m/s and the superficial liquid velocity ranging from 0.515 to 2.53 m/s. The interfacial area concentrations with uniform and non-uniform inlet flow boundary conditions measured in a large vertical rectangular channel were compared under the same area-averaged flow rate conditions. Then, the predictive capability of the IATE to the bubbly flow test data with uniform and non-uniform inlet flow boundary conditions was assessed. Some non-uniform inlet flow boundary conditions, including channel-center peaking of liquid flow (CPF), channel-center peaking of gas flow (CPG), single-side-wall peaking of liquid flow (SPF), and single-side-wall peaking of gas flow (SPG), significantly affected the interfacial area concentration changes along the axial location at relatively high superficial gas or liquid velocity conditions. The IATE's predictive capability deteriorated for several non-uniform inlet flow boundary conditions, including double-side-wall peaking of gas flow (DPG) and single-side-wall peaking of liquid flow (SPF), specifically at relatively high superficial liquid velocity conditions. The maximum percentage error of the interfacial area concentration prediction by the IATE for these non-uniform inlet flow boundary conditions reached 75%.

Influence of air swirl orientation on the spray characteristics of a micro-channel-based rotary (MCR) atomizer

In this work, we investigate the atomization and spray characteristics of a novel rotary atomizer with micro-channel grooves, using optical diagnostics. Micro-jets emanate from the grooves provided in the rotating injector. The spiraling liquid jets interact with the surrounding high-speed swirling air flow, resulting in the creation of a well-dispersed fine spray. Attention is focused on the effects of air swirler orientation with respect to that of injector rotation. Accordingly, the co- and counter-swirl cases are investigated. The primary jet breakup process is visualized using back-lit illumination technique, which also provides the measurement of jet breakup length. The jet break-up modes are identified for different air swirl strength and orientation and injector rotational speed. The size, number density and velocity components of the spray droplets are measured using PDPA technique at different axial and radial locations. Air velocity is also measured (in the absence of liquid injection) using the LDV technique. In addition, Laser Sheet Imaging (LSI) is employed to investigate the overall spray structure. Results show that the droplet size significantly reduces when air swirl strength or injector rotational speed is increased. Though not much difference is observed in the characteristic droplet size between the co- and counter-swirl cases, the droplet size distribution is narrower and droplet dispersion is improved for the latter. The current findings demonstrate the potential of the rotary injector to dynamically control the spray characteristics as per requirement.

Improved Performance of Lithium-Ion Batteries using a Multilayer Cathode of LiFePO4 and LiNi0.8Co0.1Mn0.1O2

<p>In Li-ion batteries, a thick electrode is advantageous for lowering the inactive current collector portion and obtaining a high energy density. One of the critical failure mechanisms of thick electrodes is inhomogeneous lithiation and delithiation owing to the axial location of the electrode. In this study, it was confirmed that the top layer of the composite electrode contributes more to the charging step owing to the high ionic transport from the electrolyte. A high-loading multilayered electrode containing LiFePO<sub>4</sub> (LFP) and LiNi<sub>0.8</sub>Co<sub>0.1</sub>Mn<sub>0.1</sub>O<sub>2</sub> (NCM811) was developed to overcome the inhomogeneous electrochemical reactions in the electrode. The electrode laminated with LFP on the top and NCM811 on the bottom showed superior cyclability compared to the electrode having the reverse stacking order or thoroughly mixed. This improvement is attributed to the structural and interfacial stability of LFP on top of the thick electrode in an electrochemically harsh environment.</p>