Mesh Count Research Articles

Unlocking electrodialysis efficiency with spacer mesh geometry and material conductivity via finite element analysis

AbstractSpacer meshes in electrodialysis (ED) play a crucial role in influencing fluid and electric field distributions during mass transfer. This study employed finite element analysis using real‐world parameters to explore how spacer mesh geometry and material affect mass transport. Comparisons among different wire mesh configurations revealed increased fluid velocity near mesh wires and reduced electric field intensity nearby, enhancing overall transport efficiency. Increasing mesh count or wire diameter notably improves transport, with optimal results achieved when wire orientation aligns with fluid flow. Additionally, the study showed that spacer mesh conductivity significantly influences ED transport, particularly when it exceeds the conductivity of the solution. These findings advance the design and application of spacer meshes, offering valuable insights for future developments in ED technology.

Optimizing thermal efficiency: Advancements in flat plate heat exchanger performance through baffle integration

Compact heat exchangers have been gaining popularity in many industrial applications. Various types of passive turbulising structures such as corrugations, protrusions and ribs are introduced in the flow path to increase the effective heat transfer area and the level of turbulence in the flow path. This study investigates the impact of introduction of baffles on the performance of PHEs in terms of flow characteristics, pressure drop, and heat transfer. Two distinct types of baffle structures, namely wedge and aerofoil configurations, were introduced at varying numbers - 1, 3, and 5. An extensive experimentation is conducted for a FPHE in a thermal power plant of 500 × 2 MW and various flow and thermal parameters are measured. Computational Fluid Dynamics is utilized in this study to find the optimum baffle configuration. A detailed validation study is executed to obtain the correct computational algorithm, that is the right mesh count, optimum turbulence model, and precise numerical algorithm by comparing the numerical results with the available experimental results. Wedge- type baffles create increased turbulence and pressure drop, while aerofoil-type baffles minimize stagnation and exhibit lower pressure drop. Both baffle configurations lead to a substantial increase in heat transfer, with the 5-wedge-baffle setup showing the highest up to a 55% enhancement of Nusselt number. The Performance Evaluation Criterion (PEC) of wedge and aerofoil type is about 1.24 to 1.3 and 1.22 to 1.24 to that of conventional one respectively.

Print Quality Analysis of Stone Paper and Coated Sticker Paper Used in Screen Printing

The sustainable use of natural resources is becoming an increasingly important issue today. Stone paper, produced as an alternative to cellulose-based paper from the forest, is rich in minerals and produced without cellulose and water. This study focuses on the behavior of screen-printing ink on two different papers, stone paper and coated sticker paper. Properties such as ink adhesion, rubbing resistance, optical printing ink density, ink consumption, and lightfastness were measured on these surfaces. Solvent- and UV-based inks were used, and printing was carried out on cellulose-based (coated sticker paper) and mineral-based (stone paper) paper layers using three different mesh counts (90, 120, and 140 tpc). The rubbing resistance and lightfastness of the papers were also measured. The present findings revealed that stone paper had the same printability properties as cellulose-based paper. The study concluded that using a 140 tpc mesh with both types of ink results in a high-lightfastness ink layer and lower ink consumption. UV-based inks exhibited high rub resistance across all mesh counts. Additionally, when printing with stone paper, there will be a reduction in ink consumption, thereby achieving cost savings. Based on the present findings, it was concluded that water- and oil-resistant stone paper can be considered an essential alternative in many fields, including the printing industry.

Application of polyhedral meshes in large-eddy simulation of building array flow fields within neutral and unstable boundary layers

Urbanization has intensified the urban heat island phenomenon, a critical concern for human habitation in recent decades. Analyzing flow fields around building arrays is vital for mitigating issues such as heatstroke and air pollution, thereby enhancing human comfort in urban environments. However, challenges in accuracy and computational efficiency persist in simulating urban thermal environments. This study evaluates how boundary layer meshes in polyhedral meshes affect wind and temperature distributions in neutral and unstable boundary layers, utilizing large-eddy simulation (LES). A total of ten cases were examined, including eight with local mesh refinement and two without. The study demonstrates that local mesh refinement is an effective strategy to reduce mesh count by approximately 60 %, thereby reducing computational time by 60 % using the same computational configuration. The performance of the polyhedral meshes was found to be comparable to that of the hexahedral meshes. For the mean velocity and temperature, the discrepancies between the hexahedral and polyhedral cases were within 10 %, while for the second-order statistics, the discrepancies were within 20 %. Within the neutral boundary layer, boundary layer meshes on the ground and building surfaces had minimal impact on the wind field. However, these meshes enhanced the accuracy of low percentile wind speed estimations by approximately 20 % within the unstable boundary layer. Moreover, this study lays the foundation for research on the thermal environment in actual urban areas and contributes to the guidelines for LES with non-isothermal inflow conditions.

Numerical study of heat transfer characteristics of phase change materials reinforced with porous media based on hybrid mesh

To address the drawbacks of inadequate energy density as well as utilization effectiveness in solar energy utilization, phase change energy storage offers a possible option. However, the low thermal conductivity of traditional phase change materials (PCMs) restricts the extent to which solar energy utilization can be enhanced. In this paper, the impact of the metal foam (MF) on the solid–liquid interface, the flow field, the enhancement heat transfer mechanism during the paraffin wax (PX) melting process and thermal storage characteristics was analyzed. Besides, a three-dimensional mathematical model of MF-PX using the hybrid mesh technique was established and software ANSYS-FLUENT was used for simulation. The results indicated that, the hybrid mesh exhibited a reduction of 52.75 % in mesh count compared to the unstructured mesh, resulting in 45 % reduction in computational time. Moreover, the hybrid mesh also showcased improved mesh quality that the unstructured mesh was mainly distributed in the range of 0.48–0.6, while within the range of 0.84–1.0 for the hybrid mesh. More important, the maximum relative error between experimental and simulation was 8.67 %, indicating that the model can make a reasonable prediction. With the proportions of MF increased from 0.11 % to 0.43 %, both the Rayleigh number (Ra) and its amplification decreased. At 800 s, the Ra decreased from 1.76E+07 to 1.20E+07, while the amplification of the Ra was reduced from 1.88E+07 to 1.30E+07. In addition, the natural convection proportions of CMF decreased from 96.31 % to 80.65 %. These observations indicated that natural convection was the primary heat transfer mechanism, and the conduction was enhanced by the increasing proportion of MF. Finally, in terms of heat storage characteristics, the heat storage capacity and heat storage rate of the composite PCM slightly decreased. The heat storage values decreased from 19.30 kJ to 18.66 kJ. Similarly, the heat storage rates decreased from 19.86 J/s to 18.81 J/s.

Anode surface pretreatment to optimize electrochemical performance of aqueous zinc-ion batteries

The aqueous zinc-ion batteries (AZIBs) exhibit promising potential as a viable solution for large energy storage. Solving dendrite growth the surface of zinc metal anode in AZIBs is of great significance for its application in energy storage field. Among the many strategies for solving the zinc anode problem, the influence of zinc anode pretreatment is often ignored. The effect of sandpaper physical polishing on the performance of zinc anode was studied in this paper. The striated grooves formed on the surface of the zinc anode after sandpaper treatment make the zinc anode have a large specific surface area and a high zinc plating/stripping kinetics. It was found that sandpaper with larger mesh count (the finer the sandpaper) could reduce roughness and had the higher the electrochemical performance of zinc anodes. Consequently, the cycle life of 2000 M-Zn symmetric battery can reach 900 h under the current density of 0.5 mA cm−2. In the application of energy storage, the full battery composed of 2000 M-Zn and sodium doped V2O5 cathode (NVO) still has a specific capacity of 148.6 mAh g−1 after 500 cycles, and has a stable rate performance. The pretreatment strategy of zinc anode holds significant importance in the applications of AZIBs.

Effect of wire mesh casing treatment on axial compressor performance and stability

In this paper, a kind of Wire Mesh Casing Treatment (WMCT) is proposed to improve the stable operating range of the compressor. In contrast to the traditional circumferential groove, as for WMCT, a layer of wire mesh is laid on the surface of the circumferential groove. Parametric studies were conducted on the low-speed axial flow compressor, including the groove width, axial location, and mesh count. The optimum axial location for WMCT is related to its groove width. A higher wire mesh count results in a smaller compressor stall margin improvement. Steady simulations were carried out to study the effect of WMCT on the flow structure of the compressor. The wire mesh in the WMCT has a certain flow resistance, which restricts the flow into and out of the groove. Due to the WMCT, the flow parameter in the tip region of the rotor is less sensitive to changes in the operating conditions of the compressor. The WMCT causes the rotor tip blade loading to shift backward, inhibiting the formation of spill forward of the leakage flow, and thus improving the stability of the compressor. The flow resistance on the groove surface is a new degree-of-freedom for the casing treatment designer.

Extracellular shuttling miR-21 contributes to esophageal cancers and human umbilical vein endothelial cell communication in the tumor microenvironment and promotes tumor angiogenesis by targeting phosphatase and tensinhomolog.

Cell-cell communication by carcinoma-derived exosomes can influence the tumor microenvironment (TME) and regulate cancer progression. Based on the overexpression of microRNA-21-5p (miR-21) in plasma from patients diagnosed with esophageal squamous cell carcinoma (ESCC) and exosomes from ESCC cell lines identified earlier, this study aimed to explore the influence of exosomal miR-21 within the TME. ScRNA-Seq and Bulk RNA-Seq were integrated to elucidate the communication between cancer and endothelial cells. The functionality and mechanisms by which exo-miR-21 derived from carcinoma regulate endothelial cell-mediated angiogenesis were assessed using a cocultivation model of EC9706 cells and recipient human umbilical vein endothelial cells (HUVECs), through blood vessel formation experiments, luciferase reporter assays, RT-qPCR, and western blot analysis. A total of 3842 endothelial cells were extracted from the scRNA-seq data of ESCC samples and reclustered into five cell subtype. Cell-cell communication analysis revealed cancer cells presented a strong interaction with angiogenesis-like endothelial cells in secreted signaling. MiR-21 was unregulated in ESCC and the carcinoma-derived exo-miR-21 was significantly raised in HUVECs. The exo-miR-21 promoted the proliferation and migration of HUVECs while also enhancing, closed mesh count, and junction number in HUVECs. Mechanistically, dual-luciferase reporter assay revealed that PTEN was the target of miR-21. Meanwhile, p-Akt was significantly increased and suppressed by inhibition of miR-21 and PI3K inhibitor LY294002. Exo-miR-21-mediated communication between endothelial and cancer cells plays a pivotal role in promoting the angiogenesis of ESCC. Therefore, controlling exo-miR-21 could serve as a novel therapeutic strategy for ESCC by targeting angiogenesis.

Liquid nitrogen wicking rate experiments for screen channel liquid acquisition devices

A screen channel liquid acquisition device (LAD) commonly employed in microgravity space applications uses a finely woven mesh of metal wires along with capillary forces to separate liquid and vapor phases in storage tanks used for propellant transfer. Successful implementation of LADs in flight propulsion systems, particularly for cryogenic systems, depends on analytical design models that are anchored to experimental data. Screens are characterized using parameters such as bubble point pressure, flow-through-screen pressure drop, and wicking rate. The last parameter is especially important to cryogenic LAD systems due to the high propensity for screens to experience evaporation dry out during a mission. This paper presents new experimental wicking rate data for 12 screens covering a wide range of weave types, mesh counts, and metal type with liquid nitrogen (LN2) as a working fluid using a continuous flow method. The horizontal wicking rate data is used to validate the room temperature fluid-based wicking rate model from Grebenyuk and Dreyer (2016) with the gravitational term neglected. Results are examined parametrically, with respect to the effect of wicking rate direction, dewar test pressure, fineness of the screen, shute to warp wire ratio, warp wire orientation, and using cryogenic vs. room temperature fluid. The main takeaway from the current work is that the effective wicking diameter from cryogenic testing lies within experimental uncertainty as wicking diameters from room temperature data for all screens, implying that the room temperature based-model from Grebenyuk and Dreyer (2016) can be used to compute wicking velocities for cryogenic nitrogen for most screen types.

Tailoring the Porosity and Breathability of Nanofiber Webs with Mesh Size of the Deposition Material

Nano and micro-pores of the electrospun webs provide good moisture vapor transmission rate, while it maintains resistance to pressured air and resistance to liquid for some type of clothing. Laminating a nanofiber web to any textile structure could improve the desired resistance to air permeability with providing excellent breathability. In the present study, hydrophobic thermoplastic polyurethane (TPU) and hydrophilic poly (vinyl alcohol) (PVA) nanofiber webs were produced onto three different chromium sieve wires and then laminated to an interlining fabric and compared in means of pore size, breathability and air permeability. Mesh count of the wires affected the pore size and smallest pore size are belong to 90 mesh wire. The water vapor permeability of the samples varied between 80% and 90% as well as providing relatively low air permeability values. With increasing nanofiber amount, air permeability decreased dramatically.

Two-scale solution for tripped turbulent boundary layer

Recent findings on the Reynolds-number-dependent behaviour of near-wall turbulence in terms of the ‘foot-printing’ of outer large-scale structures call for a new modelling development. A two-scale framework was proposed to couple a local fine-mesh solution with a global coarse-mesh solution by He (Intl J. Numer. Meth. Fluids, vol. 86, 2018, pp. 655–677). The methodology was implemented and demonstrated by Chen & He (J. Fluid Mech, vol. 933, 2022, p. A47) for a canonical turbulent channel flow, where the mesh-count scaling with Reynolds number is potentially reduced from $O(R{e^2})$ for a conventional wall-resolved large-eddy simulation (WRLES) to $O(R{e^1})$ . The present work extends the two-scale method to turbulent boundary layers. A two-dimensional roughness element is used to trip a turbulent boundary layer. It is observed that large-scale disturbances originating at the trip have a much shorter lifetime and weaker foot-printing signatures on near-wall flow compared to those long streaky coherent structures in well-developed wall-bounded turbulent flows. Modal analyses show that the impact of trip-induced large scales can be adequately captured by a locally embedded fine-mesh block. For the tripped turbulent boundary layer, a Chebyshev block-spectral mapping is adopted to propagate source terms from the local fine-mesh blocks to the global coarse-mesh domain, driving to a target solution for the upscaled equations. The computed mean statistics and energy spectra are in good agreement with corresponding experimental data, WRLES and direct numerical simulation (DNS) results. The overall mesh count– $Re$ scaling is estimated to reduce from $O(R{e^{1.8}})$ for the full wall-resolved LES to $O(R{e^{0.9}})$ for the present two-scale solution.

EFFECT OF MESH COUNT AND PERCENTAGE OPEN AREA ON THROUGHPUT CAPACITY IN DEVELOPING CASSAVA CAKE SCREENING MEDIUM

The screen is a medium for breaking cassava cake lump into fine particles before the heating process that turns the fine particles into garri. The objective of this research is ascertain the effect of mesh count and percentage open area on throughput capacity of cassava cake screening medium, with respect to two methods of development. To this end, six screens each of diameters 1.5, 3, 4.5, 6, 7.5 and 9mm were developed using perforated and the traditional woven wire mesh method respectively. Measurement was made of the mesh count and open area of the screens and screening was done with 2kg of cassava cake across each screening medium. Data was obtained from the mesh count and open area of the screens as well as the throughput capacities. The data obtained were analyzed using t test and regression analysis. Result showed that the mesh count for 3mm screen for the woven wire mesh was approximately 3 while the mesh count for a smaller diameter of 1.5mm for the perforated screen was 10.6. This resulted to percentage open area of 11 and 28.3 respectively. Also screening time was 4.1min for 3mm against 3.4min for 1.5mm, given throughput capacity of 24kg/hr and 35.6kh/hr, for the woven wire and perforated mesh respectively. The t-test showed that there is a statistical significant difference in the throughput capacity of the two methods. The perforated method has advantage of higher throughput capacity, lower time and energy input and hence is recommended for manual and motorized screening process.

Influence of Wafer Thickness and Screen-Printing Mesh Counts on the Al-BSF in Crystalline Silicon Solar Cells

Influence of Wafer Thickness and Screen-Printing Mesh Counts on the Al-BSF in Crystalline Silicon Solar Cells

Temperature estimation of a receiver equipped with a 3D compound parabolic concentrator

Solar Tower Power Plant (STPP) require a high concentration ratio to provide high working fluid temperatures for power generation. Three-dimensional Compound Parabolic Concentrator (3D-CPC) can be used to increase the concentration ratio in the receiver. This paper estimates the air outlet temperature of an indirectly irradiated solar receiver equipped with a 3D-CPC for STPP. For this purpose, the STPP subsystems such as the heliostat field, the 3D-CPC and the receiver are sized for an electrical power of 30 kW. An in-house Matlab code is developed and executed the configuration of the heliostats in the field. The result of the Monte Carlo ray tracing (MCRT) method is used to provide boundary conditions to the Computational Fluids Dynamics (CFD) model. The CFD model is used to simulate the conjugate heat transfer in the receiver. Based on this, a heat source is created from the solar rays absorbed in the receiver. This heat source is implemented as a volumetric heat source in Ansys Fluent by UDFs functions. Thus, the in-house Matlab code is validated by simulating the PS-10 heliostat field and the CFD model is also validated by simulating the Weizmann heliostat field. The results show that the solar field is consisted of 175 heliostats of 2 m2 surface area and 1.5 m height each. The 3D-CPC truncated at 35° increased the concentration ratio by a factor of 4.91 for an optical efficiency of 80.66 %. A receiver mesh count of 1,076,958 gave convergence of the air outlet temperature. 1.5 × 106 rays are found to get independence of the absorbed heat flux in the receiver. The temperature found on the heated solid is 1063.4 K. For a porosity of 56.02 % and a mass flow rate of 0.11 kg/s, a temperature of 1218 K is reached at the outlet of the receiver. The results show that the use of a 3D-CPC increase the concentration ratio and, consequently improve the thermal performance of the receiver. It is important to note that, parameters such as mass flow rate and porosity have a strong influence on the air outlet temperature.

Solution-Based Mesh Adaption Criteria Development for Accelerating Flame Tracking Simulations

Abstract Solution-based mesh adaption approaches have been widely studied and tested by different research groups to generate the required finer meshes in the critical regions on the fly while keeping the overall mesh count to a manageable level. However, these approaches are typically applicable for a set of problems, and therefore, there is a need for a generic approach suitable for a broader range of problems. This work explores various parameters and specific weightage factors to predict correct flame-tracking outcomes for different types of flames. The selections of flow quantities (flow variables, their gradients, curvatures) are performed using simple flames and flow configurations. The functions based on selected flow-quantities derived from these studies are then tested to predict the results for the more complex set of published flames like the Engine Combustion Network (ECN) spray flame and Knowledge for Ignition, Acoustics, and Instabilities (KIAI) five-burner configuration (liquid and gas fuel). Derived adaption criteria are found to predict the correct flame tracking behavior in terms of transient evolution of flame front, flame propagation, and ignition timing of burners. The parameters used for the study are identified keeping genericity as the key point, and thus making sure that the derived adaption functions can be applied across different types of fuel blends, combustion systems (gaseous or liquid fuel-based systems) and combustion models, for example, species transport or mixture fraction-based models.

Numerical simulation of convective heat transfer coefficient in wire mesh absorbers with fixed porosity

Convective heat transfer is one of the main thermal mechanisms in volumetric absorbers technology. There is a lack of literature on the behaviour of convective heat transfer in dense wire meshes. In this research, numerical simulations are used to determine the influence of geometrical parameters of dense wire meshes, such as wire diameter and mesh count, in obtaining the local volumetric Nusselt coefficient. In order to achieve that aim, a sensitivity study of the inlet air velocity (0.5–5 m/s) and wire temperature (700 K, 1100 K and 1500 K) has been performed with different staggered stacked wire mesh configurations. The fixed single screen and staggered porosity of the studied configurations are 80% and 64% respectively, however the wire diameters in each configuration range from 0.1 mm to 0.7 mm. As a result of this study, the effect of the convection heat transfer is more emphasized in larger wire diameters than in smaller ones. In summary, the flow and heat transfer can be modified without changing the porosity.

Research on abrasive pool machining method based on gas–solid two-phase flow

For complex curved difficult-to-machine parts, a new method based on pneumatic suspension abrasive pool bright finishing processing is proposed, using the mixing of pneumatic suspension abrasive, the workpiece surface, and fluidized abrasive to produce relative motion velocity, so that the solid particles and workpiece surface microscopic two-body abrasive wear to achieve the effect of precision machining. The experimental test material is the widely used Q235 steel plate. The experimental parameters include workpiece shape (round tube, square tube, cylindrical), abrasive particle size (24, 80, 120 mesh count), gas–solid two-phase flow pattern (dispersion fluidization state, turbulent fluidization state, spurting fluidization state), abrasive particle shape (sphere, irregular), and spindle speed (600, 900, 1200 rpm). An orthogonal test was designed according to the experimental parameters, and the degree of influence of each parameter on the processing of the abrasive cell was evaluated by the roughness of the workpiece surface together with the scanning electron microscope (SEM) micrograph of the workpiece surface, and the optimal combination of parameters was judged using the extreme difference method as well as the factor trend diagram. The results show that under the present experimental conditions, the workpiece surface roughness (Ra) can reach a minimum value of 0.4 μm. The feasibility of gas–solid two-phase flow processing is demonstrated from an experimental point of view, and the advantages of abrasive cell processing are explored.

Exploring the art of screen printing asphaltum for etching on medals and trophies for the indigenous metal art industry

Etching remains a primeval craft used to produce interesting images on metal surfaces. The mode of applying resists onto these surfaces presents a challenge for metalsmiths in the indigenous metal art industry to achieve accuracy, precision and details. Recent studies have outlined improved resist application methods developed in the industrial sector as compared to the indigenous metal art industry. This studio practice research explores screen printing as an alternative method to print asphaltum onto metal surfaces for etching. Experimentation at the studio and chemistry laboratory aided in achieving the preparatory stages or variables like ideal consistency of the resist, ratio of acid to water for etching, the mesh count for screen printing the resist and the best squeegee type to use. Relevant results from the studio experiments proved the possibility of screen printing asphaltum which match the viscosity of toothpaste onto the surface of a metal for etching.

Numerical Simulations of a Lifted Hydrogen Jet Flame Using Flamelet Generated Manifold Approach

Abstract A turbulent lifted H2/N2 jet flame in a vitiating coflow environment is numerically investigated, using the Flamelet generated manifold (FGM) combustion model with large eddy simulations (LES). Due to the hot vitiated H2/air coflow, the primary stabilization mechanism is the auto-ignition followed by a premixed flame. In addition to using H2 as a fuel, this flame poses two other modeling challenges: (i) the auto-ignition, which is a transient chemistry-driven phenomenon; (ii) the existence of multiple combustion regimes, e.g., diffusion at auto-ignition location but premixed in the postflame. A series of LES/FGM simulations are completed in this work by reducing the coflow temperature from 1045 K to 1000 K. The FGM model can predict the characteristics of the flame by showing a lifted flame. It also accurately predicts the trend in the flame lift-off distance with a change in the coflow temperature. The current results are compared for mixture fraction, temperature, and OH mass fraction at multiple locations, which have also been correctly captured. It is noted that for a high coflow temperature (and hence a low lift-off distance), the flame's lift-off is highly sensitive to the inlet boundary conditions and the mesh resolution near the jet entry. A relatively coarse mesh is used for all the simulations, which is generated using a careful strategy that not only resolves the jet instabilities near the fuel inlet but also keeps the overall mesh count low and allows for a large computational time step. A systematic sensitivity analysis of the computational speed is also performed. This work provides some useful guidelines for simulating the H2 diluted flames using the FGM model, which may be valuable to the gas turbine industry.

Exploring the art of screen printing asphaltum for etching on medals and trophies for the indigenous metal art industry

Etching remains a primeval craft used to produce interesting images on metal surfaces. The mode of applying resists onto these surfaces presents a challenge for metalsmiths in the indigenous metal art industry to achieve accuracy, precision and details. Recent studies have outlined improved resist application methods developed in the industrial sector as compared to the indigenous metal art industry. This studio practice research explores screen printing as an alternative method to print asphaltum onto metal surfaces for etching. Experimentation at the studio and chemistry laboratory aided in achieving the preparatory stages or variables like ideal consistency of the resist, ratio of acid to water for etching, the mesh count for screen printing the resist and the best squeegee type to use. Relevant results from the studio experiments proved the possibility of screen printing asphaltum which match the viscosity of toothpaste onto the surface of a metal for etching.