Plate Geometry Research Articles

INVESTIGATE OF INFLUENCE PERFORATED PLATE ON DETERMINATION OF TRANSVERSAL PERMEABILITY ON REINFORCED FIBER

Polymeric composite materials can be build in different forms, resulting in different mechanical properties, with numerous industrial applications. Traditionally, they have been largely used in the automotive, naval and aerospace industries. A major concern in polymeric composites manufacture is related with the determination and control of the reinforcement and resin physical properties. They are responsible for the final composite mechanic properties and, if not correct defined, will result in defective composites. Reinforcement permeability is one of these physical properties that, in some cases, are difficult to be kept within the project specification. More specifically, for the case of the transverse permeability, its corrected determination is reported in literature as being considerably more difficult to experiment than the in-plane permeability. The most common experiment for transverse permeability determination is built with a cylindrical mold on which the reinforcement is positioned (and compressed) between two perforated plates. A fluid is forced transversely through the reinforcement, volumetric flow rate and pressure drop are measured, and the Darcy's Law is used to determine the permeability. In this experiment, flow is assumed rectilinear, and the holes of the perforated plates are ignored in the Darcy equation. It is known that size, number e position of these holes may influence the permeability determination, however this problem is not commonly discussed in literature. In this work it is presented a numerical study about the influence of the geometry of the perforated plates on the corrected determination of the reinforcement transverse permeability. The reinforcement region is molded as a porous medium and the two fluid flow (air + resin) is formulated with the Volume of Fluid (VoF) method. GMSH software was used to created and discretize the geometry and OpenFOAM software, more specifically using the interFoam solver, was used to solve the flow problem, determining pressure drop and flow rate inside the mold. Results have shown that correct determination of the transverse permeability is highly dependent on perforate plates geometry.

Predicting the fiber orientation of injection molded components and the geometry influence with neural networks

The injection molding simulation of short fiber reinforced plastics (SFRP) is time consuming. However, until now it is necessary for predicting the local fiber orientation, to optimize the molding process and to predict the mechanical behavior of the material. This research presents the capabilities of artificial neural networks (NN) in predicting fiber orientation tensor (FOT) during injection molding processes, with a focus on enhancing computational efficiency compared to traditional simulation methods. Three NN architectures are compared based on simulated injection molded plates, with the goal of predicting the effect of the plate geometry on the local fiber orientation. Results indicate that NN outperform the baseline assumption of aligned fibers and demonstrate significant potential for accurate FOT prediction. The computational efficiency of NN, especially during the prediction phase, showcases a reduction in processing time by a factor of 104 compared to traditional simulation methods. This research lays a foundation for further exploration into the feasibility of NN in partly replacing time-consuming simulations for practical applications in injection molding processes.

Modular Finite Element Modeling of Heavy Plate Rolling Processes Using Customized Model Reduction Approaches

Heavy plates are indispensable semi-finished products. Quality is strongly linked with production, so the rolling process must be performed within well-defined narrow tolerances. To meet this challenge, adequate modeling has become a necessity. In contrast to continuous strip rolling, where the workpiece can be modeled as a semi-infinite strip and 2D modeling can be argued quite well, this strategy is insufficient for the comprehensive modeling of heavy plate rolling. The geometry of the heavy plate favors an inhomogeneous distribution of relevant state variables, such as temperature. In addition, if the process involves longitudinal and spreading passes, the required plate rotation spoils the assumption of a symmetric arrangement that might have been acceptable before rotation. Consequently, the derivation of suitably reduced models is not trivial, and modeling tailored to the specific objective of investigation is of utmost importance. Models intended to resolve the evolution of inhomogeneities in the field variables are demanding and computationally expensive. An effective modular modeling strategy was developed for such models to be used offline. Mutually complementing and interchangeable modules may constitute an efficient modeling strategy valid for the specific subject of interest. The presented approach reduces the enormous cost of complete 3D simulation as much as the model purpose allows for.

A Generalized Townsend's Theory for Paschen Curves in Planar, Cylindrical, and Spherical Geometries in Planetary Atmospheres

AbstractIn this work, we focus on plasma discharges produced between two electrodes with a high potential difference, resulting in the ionization of the neutral particles supporting a current in a gaseous medium. At low currents and low temperatures, this process can create luminescent emissions: glow and corona discharges. The parallel plate geometry used in Townsend's theory lets us develop a theoretical formalism, with explicit solutions for the critical voltage effectively reproducing experimental Paschen curves. However, most discharge processes occur in non‐parallel plate geometries, such as discharges between particles in multiphase systems and between cylindrical conductors. Here, we propose a generalization of the classic parallel plate configurations to concentric spherical and coaxial cylindrical geometries in Earth, Mars, Titan, and Venus atmospheres. In a spherical case, a small radius effectively represents a sharp tip rod, while larger, centimeter‐scale radii represent blunted tips. In cylindrical geometries, small radii resemble thin wires. We solve continuity equations in the gap and estimate a critical radius and minimum breakdown voltage that allows the formation of a glow discharge. We show that glow coronæ form more easily in Mars's low‐pressure, CO2‐rich atmosphere than in Earth's high‐pressure, N2‐rich atmosphere. Additionally, we present breakdown criteria for Titan and Venus, two planets where discharge processes have been postulated. We further demonstrate that critical voltage minima occur at 0.5 cm⋅Torr for all three investigated geometries, suggesting easier initiation around millimeter‐size particles in dust and water clouds. This approach could be readily extended to examine other multiphase flows with inertial particles.

Design Of Tangentially Fired Pulverized Coal Burner Nozzle For Enhanced Erosion Resistance

Erosion-induced failure of pulverized coal burner nozzles (PCBN) presents a significant challenge in pulverized coal-based thermal power plants. Investigations have identified multiple causative factors leading to the accelerated degradation and consequent reduced lifespan of PCBN. These factors include the erosive impact of solid fuel particles carried at high velocities and angles, as well as the high-temperature conditions within the combustion zone. To mitigate erosion, strategies often revolve around enhancing material resistance or optimizing aerodynamic profiles to minimize drag forces. This study employs Computational Fluid Dynamics (CFD) via the CFX code to model and analyze the erosion dynamics within PCBN. By adjusting the geometry of the inner plates within the PCBN, simulations indicated a notable improvement in erosion resistance. The optimized design achieved this by expanding the flow area between the innermost bifurcated plates without altering their angle, leading to a more uniform flow distribution and favorable velocity and pressure gradients. These modifications have the potential not only to prolong nozzle life but also to contribute to more efficient combustion in tangentially fired furnaces.

Optimizing Plate Heat Exchanger Design for Steam Condensate Recovery Systems

Condensate water is typically generated as a by-product during the use of steam as a medium for heat transfer. In order to optimize the transfer area, the chemical industry often employs heat exchangers, such as the plate heat exchanger (PHE), which provides flexibility in adjusting the space area for heat transfer. This case study examines the optimization of plate geometry dimensions to enhance the heat transfer process of PHE equipment design. The optimization process involves mathematical equations and a literature review of the design of this type of heat exchanger. Improving the dimensional aspect of the plate geometry results in an increase in the overall heat transfer coefficient (U) and a reduction in the number of design requirements used. The study's estimation results suggest that the PHE design has a limitation on plate dimensions, which should be less than 0.3×0.6 m. Additionally, it is important to consider the pressure drop value, which should not exceed 29.07 kPa. A review of the chemical industry field provided estimated options for plate size and quantity, both of which support the optimization of heat transfer rate and design constraint thresholds. The implementation of the design has been found to enhance the performance of the planning process for recovering steam condensate water.

Assessing the effect of test parameters on the determination of the rheological behavior of calcium sulfoaluminate cement pastes

Calcium sulfoaluminate cement (CSA) is renowned for its application in technologies that require rapid setting and high initial strengths, such as 3D concrete printing and repairs. However, their rheological behavior needs to be more adequately explored. This study assesses the impact of rotational rheometer test conditions on CSA pastes with different water-to-cement ratios. For the determination of static yield stress (τ0s), stress growth test with shear rates between 0.01 and 0.05 s−1 were employed. The results revealed that higher shear rates anticipated the occurrence of the material's peak destructuring and resulted in lower values of τ0s. In addition, the effects of geometry and testing routine on the flow curve were analyzed. The results showed that the use of vane geometry provides more consistent results of the measured dynamic yield stress, viscosity, and hysteresis area of CSA pastes than parallel plate geometry.

New geochemical and geochronological insights on forearc magmatism across the Sanak-Baranof belt, southern Alaska: A tale of two belts

Abstract The Sanak-Baranof belt includes a series of near-trench plutons that intrude the outboard Chugach–Prince William terrane over ~2200 km along the southern Alaskan margin. We present new petrological, geochronological, and geochemical data for comagmatic microgranitoid enclaves and granitoid rocks from the Crawfish Inlet (ca. 53–47 Ma) and Krestof Island (ca. 52 Ma) plutons on Baranof and Krestof Islands, as well as the Mount Stamy (ca. 51 Ma) and Mount Draper (ca. 54–53 Ma) plutons and associated mafic rocks that intrude the Boundary block at Nunatak Fiord near Yakutat, Alaska, USA. These data suggest that intrusion of the Sanak-Baranof belt plutons is actually a tale of two distinct belts: a western belt with crystallization ages that young systematically from west to east (63–56 Ma) and an eastern belt with crystallization ages ranging from 55 to 47 Ma, but with no clear age progression along the margin. Hf isotope analyses of magmatic zircon from the western Sanak-Baranof belt become increasingly evolved toward the east with εHft = 9.3 ± 0.7 on Sanak Island versus εHft = 5.1 ± 0.5 for the Hive Island pluton in Resurrection Bay. The Hf isotope ratios of eastern Sanak-Baranof belt rocks also vary systematically with age but in reverse, with more evolved ratios in the oldest plutons (εHft = +4.7 ± 0.7) and more primitive ratios in the youngest plutons (εHft = +13.7 ± 0.7). We propose that these findings indicate distinct modes of origin and emplacement histories for the western and eastern segments of the Sanak-Baranof belt, and that the petrogenesis of eastern Sanak-Baranof belt plutons (emplaced subsequent to 57–55 Ma) was associated with an increasing mantle component supplied to the youngest eastern Sanak-Baranof belt magmas. These plutons reveal important information about offshore plate geometries and a dynamic period of plate reorganization ca. 57–55 Ma, but a clearer picture of the tectonic setting that facilitated these Sanak-Baranof belt intrusions cannot be resolved until the magnitude and significance of lateral translation of the Chugach–Prince William terrane are better understood.

The Impact of the Bohemian Spur on the Cooling and Exhumation Pattern of the Eastern Alpine Wedge of the European Alps

AbstractFold and thrust belt architecture may be influenced by basement geometry of the downgoing plate. This influence is notoriously difficult to assess due to a common lack of subsurface constraints and low resolution of exhumation estimates in space and time. The Bohemian Spur is a basement high at the transition from the Alps to the Carpathians. It coincides with narrowing of the foreland basin and an orogen‐scale change of strike. Its location in one of the best‐studied orogens in the world makes it an ideal case for understanding how basement topography influences fold and thrust belt tectonics. However, since thermochronological studies were mainly focused on the core of the Alps, timing and amount of exhumation remain poorly constrained in these peripheral parts of the orogen. We present new apatite (U‐Th)/He and fission track data from the wedge above the Bohemian Spur. Thermally reset ages monitor a so far un(der)appreciated phase of prominent Late Oligocene to Miocene cooling, associated with crustal thickening, uplift and erosion during wedge propagation. Pronounced exhumation on the order of 3–4.5 km can be related to basement steps beneath the advancing wedge. The spur acted as a buttress for foreland‐propagating thrusting, pinning deformation and nucleating antiformal stacking and duplexing and thus exhumation above it. We illustrate how along‐ and across‐strike changes of sub‐detachment topography impact wedge propagation and control fold and thrust belt geometries. The buttressing effect accounts for most of the exhumation, while deep‐seated slab dynamics are of subordinate importance for wedge uplift.

3D Local Earthquake Tomography of the Andaman–Nicobar Subduction Zone Using Ocean-Bottom Seismometer Data

ABSTRACT The Andaman–Nicobar (A–N) subduction zone is one of the most seismically active subduction zones of the world where the Indian plate subducts beneath the Burmese–Sunda plate. Imaging the subducting Indian plate (SIP) geometry in this region is important to understand the subduction process, earthquake genesis, and associated seismic hazards. Therefore, we imaged the SIP for the first time using local earthquake data recorded from a network of nine ocean-bottom seismometers and six surface seismic stations. We inverted 2819 P and 2171 S phases picked from 410 local earthquakes recorded between December 2013 and May 2014 to obtain the tomographic images in the A–N region. The images show high-VP and VP/VS anomalies linked to colder and thicker SIP in the A–N region. We also observed seismic signatures of strong structural heterogeneity all along the SIP. The low-velocity anomaly at 60–100 km depth beneath the Andaman back-arc spreading center indicates mantle upwelling. Likewise, low-VP anomalies beneath the active volcano Barren Island indicate production of arc magmas by slab dehydration and corner flow in the mantle wedge.

Continuous Purification of Biodiesel with Deep Eutectic Solvent in a Laboratory Karr Column

Following the trend of transport decarbonization, biodiesel has become a promising alternative fuel option. Its production includes multiple steps, all of which can be time-consuming and energy intensive. Improving any of these steps could bring considerable environmental and economic benefits. The utilization of deep eutectic solvents (DESs) for glycerol extraction from crude biodiesel has predominantly been explored as a batch process. This work provides insight into continuous column extraction. Different waste cooking oils were used to produce biodiesel via transesterification with methanol, and the selective solvent for purification was DES choline chloride–ethylene glycol (1:2.5, mol.). A laboratory Karr column at different pulsation frequencies and DES to biodiesel mass ratio was used for extraction. Plate material (steel and 3D printed PETG) and geometry influence on the efficiency of extraction were investigated. Contact angle measurement was used to measure the surface free energy of steel and PETG and the spreading ability of biodiesel and DESs on both materials. Extraction efficiency was analyzed by several analytical techniques. Higher efficiency was observed with steel plates of a triangular pitch hole arrangement. Increasing the mixing intensity and DES to biodiesel mass ratio further increased the efficiency of extraction.

Residual Stress Generation in Additive Manufacturing of Complex Lattice Geometries

Residual stresses developed during additive manufacturing (AM) can influence the mechanical performance of structural components in their intended applications. In this study, thermomechanical residual stress simulations of the laser powder bed fusion (LPBF) process are conducted for both simplified (plate and cube-shaped) geometries as well as five complex lattice geometries fabricated with Inconel 718. These simulations are conducted with the commercial software package Simufact Additive©, which uses a nonlinear finite element analysis and layer-by-layer averaging approach in determining residual stresses. To verify the efficacy of the Simufact Additive© simulations, numerical results for the plate and cube-shape geometries are analyzed for convergence and compared to experimental residual stress results available in the literature. Numerical residual stress results are subsequently compared for five complex lattice geometries. Results suggest that lattice geometry can play a significant role in the distribution and magnitude of residual stresses, which are significant in some applications.

Geometry Effects on Joint Strength and Failure Modes of Hybrid Aluminum-Composite Countersunk bolted Joints

This paper presents the effects of geometry parameters (width/hole diameter, and edge distance/hole diameter ratios) on the damage initiation and growth in the CFRP (Carbon Fiber Reinforced Polymer) composite-aluminum countersunk bolted joints. Strain gauge measurements conducted with an Instron testing machine along with a detailed 3D finite element model incorporating geometric, material, and friction-based contact nonlinearities were used to investigate the geometry parameters on the Progressive Damage Analysis (PDA) of the orthotropic material model. The PDA material model integrates the lamina nonlinear shear deformation, Hashin-type failure criteria, and strain-based continuum degradation rules, using the UMAT user subroutine in the MSC Software Corporation Patran-Nastran commercial software. The results showed that the geometry effects on damage initiation and failure modes are quite accurately predicted by the PDA material model, which proved to be computationally efficient, and therefore can predict failure propagation and damage mechanisms. Plate geometry is an important parameter in the design process of an adequate bolted joint while its effects on damage initiation and failure modes were quite accurately predicted by the analysis. The latter proved to be computationally efficient, and could successfully predict failure propagation and damage mechanism in hybrid metal-composite countersunk bolted joints.

Influence of visible light LEDs modulation techniques on photocatalytic degradation of ceftriaxone in a flat plate reactor

In this paper, the effect of light modulation on photocatalytic ceftriaxone (CEF) degradation in aqueous solution was investigated. The experimental set-up consisted of a fixed bed photocatalytic reactor with a flat plate geometry and visible LEDs for irradiation. Fe-N-codoped TiO2 photocatalyst was immobilized on a polystyrene plate (PS) by solvent casting method to achieve a structured photocatalyst (Fe-N-TiO2/PS), which was loaded in the photoreactor. Raman and UV–Vis diffuse reflectance spectroscopy confirmed the presence of Fe-N-TiO2 on the PS surface and its uniform distribution on the polymer support. Various LEDs dimming techniques were tested with fixed and variable duty-cycle values. In particular, the following modulations were used: fixed duty-cycle (FD), sinusoidal variable duty-cycle (S-VD), triangular variable duty-cycle (T-VD), square wave variable duty-cycle (SW-VD), saw-tooth variable duty-cycle (ST-VD), pulse variable duty-cycle (P-VD), and pseudo-sinusoidal variable duty-cycle (PS-VD). The optimal light modulation was the S-VD, with an average fed current between 25 and 75 mA and a period of 30 s. Indeed, by using S-VD modulation, the highest value of the apparent CEF degradation kinetic constant (resulting 0.0082 min−1) and the highest total organic carbon (TOC) removal (70 %) were achieved. By comparing the electric energy consumption (EE/O) with S-VD modulation used in this work with those found in other literature studies dealing with the photocatalytic ceftriaxone degradation, a significant decrease of EE/O was evidenced. Moreover, toxicity test showed that the photocatalytic treatment allowed to significantly reduce the toxicity of CEF solution when compared to untreated effluent.

Numerical simulation of bio-magnetic nanofluid flow in the human circulatory system

The investigation of the rheological properties of bio-magnetic nanofluid in the human circulatory system has attracted the attention of biomedical engineers, medical professionals and researchers in recent days to explore the potential of utilizing magnetic field in the diagnosis of cancer cells, thrombosis and cardiovascular diseases. The Eyring-Powell fluid model was employed in this investigation because it accurately captures the non-Newtonian features of blood owing to its shear thinning and stress relaxation qualities. The present study illustrates the importance of the induced magnetic field on Eyring-Powell nanofluid flow across three distinct geometries (stagnation point, plate, and wedge) with the presence of gyrotactic microorganisms. The investigation of different geometries provides essential information regarding their practical applications, such as the development of targeted therapies for localized drug delivery, the dissolution of blood clots to promote clot breakdown, the enhancement of drug delivery to specific regions, the prevention of biofilm formation on vessel walls, the promotion of improved blood flow, and the reduction of plaque for arterial health. The conversion of fluid transport equations into ordinary differential equations has been achieved through the utilization of appropriate self-similarity variables. The resulting equations have been solved with the use of the Runge-Kutta-Fehlberg (RKF) approach. The characteristics of numerous dimensionless parameters such as magnetic Prandtl number ( M mp = 0.5 , 1.0 , 1.5 ) , magnetic parameter ( β mp = 0.2 , 0.4 , 0.6 ) , fluid parameters ( ε , δ = 0.0 , 0.5 , 1.0 ) , chemical reaction parameter ( Kr = 0.0 , 0.5 , 1.0 ) , Eckert number ( Ec = 1.0 , 2.0 , 3.2 ) , Thermophoresis ( N T = 0.3 , 0.6 , 0.9 ) , Brownian motion ( N B = 0.3 , 0.6 , 0.9 ) , Biot number ( Bi = 0.5 , 1.0 , 1.5 ) , bioconvective constant ( σ 1 = 0.0 , 1.0 , 2.0 ) , bioconvective Schmidt number ( Sb = 0.1 , 0.3 , 0.5 ) , Peclet number ( Pe = 0.1 , 0.3 , 0.5 ) , temperature ratio ( θ w = 1.0 , 2.0 , 3.0 ) , Radiation ( Rd = 0.0 , 1.0 , 1.5 ) , Schmidt number ( Sc = 1.0 , 2.0 , 3.0 ) , and non-dimensional activation energy ( E = 0.0 , 0.5 , 1.0 ) are analyzed. The magnetic Prandtl number and the magnetic parameter both show a decrease with an increase in the induced magnetic field. The magnitude of concentration increases with the elevation of both the Bio convective constant and the Peclet number. The skin friction coefficient is increased to the higher values of the fluid parameter in all three geometries. Nusselt number and Sherwood number both increase to the higher values of the thermophoresis parameter across the plate, wedge, and stagnation point. The Peclet and bioconvective numbers increase the concentration of motile organisms across the plate, wedge, and stagnation point geometries.

An Experimental Database for the Analysis of Bursting of a Laminar Separation Bubble

The bursting phenomenon consists in the switch of a laminar separation bubble from a short to a long configuration. In the former case, reduced effects on profile pressure distribution are typically observed with respect to the attached condition. On the contrary, long bubbles provoke significant variations in the loading coefficient upstream of the separation position, with increased risk of stall of the lifting surfaces. The present work presents an experimental database describing separated boundary layers evolving under different Reynolds numbers, adverse pressure gradients and free-stream turbulence levels. Overall, more than 80 flow conditions were tested concerning short and long bubbles for the characterization of separated flows under turbine-like conditions. Measurements were performed on a flat plate geometry using a fast-response Particle Image Velocimetry (PIV) system. For each flow case, two sets of 6000 flow records were acquired with an acquisition frequency equal to 300 and 1000 Hz. Based on existing criteria for the identification of the bursting phenomenon, the flow cases were clustered in terms of short and long bubble states. Additionally, the kind of instability (i.e., convective or absolute) developing into the separated boundary layer was identified based on flow statistics. The present data captures the existing link between the bursting of a laminar separation bubble and the onset of the absolute instability of the separated shear layer, with stationary vortices forming in the dead air region.

Droplet manipulation on an adjustable closed-open digital microfluidic system utilizing asymmetric EWOD.

The closed-open digital microfluidic (DMF) system offers a versatile and powerful platform for various applications by combining the advantages of both closed and open structures. The current closed-open DMF system faces challenges in scaling up due to electrode structural differences between closed and open regions. Here we developed an adjustable closed-open DMF platform by utilizing the modified slippery liquid-infused porous surfaces (SLIPS) with asymmetric electrowetting on dielectric (AEWOD) as a hydrophobic dielectric layer. The consistent electrode structures of the bottom printed circuit board (PCB) electrode array on both the closed and open regions, and the utilization of a transparent acrylic with floating potential as the top plate allow a low-cost and easily scalable closed-open DMF system to be achieved. The impacts of applied voltage, parallel plate spacing, electrode switching interval, and electrode driving strategies on various droplet manipulations were investigated. The results show that the optimal plate spacings range from 340-510 μm within the closed region. Meanwhile, we also studied the influence of the thickness, geometry, and position of the top plate on the droplet movement at the closed-open boundary. Through force analysis and experimentation, it is found that a thin top plate and a bevel of ∼4° can effectively facilitate the movement of droplets at the boundary. Finally, we successfully achieved protein staining experiments on this platform and developed a customized smartphone application for the accurate detection of protein concentration. This innovative closed-open DMF system provides new possibilities for future applications in real-time biological sample processing and detection.

Visualizing flow dynamics and restart of Carbopol gel solutions in tube and parallel-plates geometries with wall slip.

The present study examines the impact of slip in Carbopol solutions during the restart flow in pipelines utilizing in situ visualization techniques. Rheological tests were conducted using smooth and hatched parallel plate geometries to obtain the rheological characteristics of the solutions. The behavior of the solutions in the creep tests is compared with those in the experimental unit. Three flow regimes were identified through rheological and experimental setup tests: non-flow, slip, and yielded. The slip regime allowed the establishment of a slip static yield stress value, indicating significant deformation states, and a restart pressure decrease of about 61% when compared to the static yield stress. The flow dynamics under the wall slip effect is captured by velocity profiles, velocity contour maps and velocity gradient. Transient correlations of the scaling law type were determined, with wall slip in proportion to the velocity gradient and wall shear stress. Additionally, the concentration of viscoplastic material in the solution increased the scaling law index. This research seeks to provide valuable findings by quantifying the effects of apparent wall slip through in situ measurements. Such insights are crucial for designing and managing pipeline transport systems that handle yield stress fluids, applicable across various industries including cosmetics, food processing, and the production of waxy oils.

Computational Modeling of Directed Energy Deposition of Titanium Aluminide Plate Geometries

In this work, transient thermomechanical analysis of the laser-based Directed Energy Deposition (DED) process was carried out to predict melt pool dimensions, thermal cycles and residual stress during Titanium Aluminide (TiAl) plate deposition. The predicted melt pool length, width, and depth increased as the laser power was increased from 250 W to 350 W at a constant travel speed of 15 mm/s. The melt pool length increased from 0.425 mm to 0.55 mm, while the depth increased from 0.1 to 0.29 mm, and the width increased from 0.412 to 0.5 mm. The plate's edges (tracks 1 and 6) were found to experience a slightly higher temperature than the middle tracks, which may contribute to higher thermal gradients at the edges. The highest Principal stress of 140 MPa was found in track 1. The magnitude of Principal stresses diminished as track deposition progressed from track 2 to 6 due to the variation of the thermal gradient along the tracks.

Performance of the porous media model for simulating flow through an electrostatic precipitator

An electrostatic precipitator (ESP), which filters the fine particles present in the exhaust gas generated from a power plant, has a better particle-collection efficiency when there exists a uniform flow in the dust collection chamber. However, most former investigations examined the flow distribution via numerical approaches that modeled the perforated plates within the inlet diffuser as porous media, which have not been adequately validated. Therefore, the aim of this study was to examine the performance of the porous media model for simulating the flow through perforated plates of an ESP diffuser by numerical simulation and experiment. Simulation results using the porous media model were compared with those obtained with a fully resolved mesh precisely describing the complete geometry of the entire perforated plate. The results obtained with both these methods were consistent with experimental results obtained upstream of the inlet diffuser, but the porous media model could not accurately simulate the flow distribution across the perforated plates. Overall, this model failed to predict the deflection of incoming flow on the solid bars and the wakes behind the bars, and could not reflect the vena contracta phenomenon occurring within the holes of the plate. As a result, the simulated flow distribution at the entrance of the main dust-collection chamber differed from that observed in the experiment, which resulted in poor prediction of the flow field inside the chamber. Therefore, this porous media model requires further improvement for wide-scale adoption in industrial practical applications, e.g., ESP for flue gas treatment in power plants.