Computational Fluid Dynamics Software Research Articles

An Analysis and Comparison of the Hydrodynamic Behavior of Ships Using Mesh-Based and Meshless Computational Fluid Dynamics Simulations

This paper presents a comparison of two turbulence models implemented in two different frameworks (Eulerian and Lagrangian) in order to simulate the motion in calm water of a displacement hull. The hydrodynamic resistance is calculated using two open-source Computational Fluid Dynamics (CFD) software packages: OpenFOAM and DualSPHysics. These two packages are employed with two different numerical treatments to introduce turbulence closure effects. The methodology includes rigorous validation using a Wigley hull with experimental data taken from the literature. Then, the validated frameworks are applied to model a ship hull with a 30 m length overall (LOA), and their results discussed, outlining the advantages and disadvantages of the two turbulence treatments. In conclusion, the resistance calculated with OpenFOAM offers the best compactness of results and a shorter simulation time, whereas DualSPHysics can better capture the free-surface deformations, preserving similar accuracy.

Aerodynamic Optimization Method for Propeller Airfoil Based on DBO-BP and NSWOA

To address the issues of tedious optimization processes, insufficient fitting accuracy of surrogate models, and low optimization efficiency in drone propeller airfoil design, this paper proposes an aerodynamic optimization method for propeller airfoils based on DBO-BP (Dum Beetle Optimizer-Back-Propagation) and NSWOA (Non-Dominated Sorting Whale Optimization Algorithm). The NACA4412 airfoil is selected as the research subject, optimizing the original airfoil at three angles of attack (2°, 5° and 10°). The CST (Class Function/Shape Function Transformation) airfoil parametrization method is used to parameterize the original airfoil, and Latin hypercube sampling is employed to perturb the original airfoil within a certain range to generate a sample space. CFD (Computational Fluid Dynamics) software (2024.1) is used to perform aerodynamic analysis on the airfoil shapes within the sample space to construct a sample dataset. Subsequently, the DBO algorithm optimizes the initial weights and thresholds of the BP neural network surrogate model to establish the DBO-BP neural network surrogate model. Finally, the NSWOA algorithm is utilized for multi-objective optimization, and CFD software verifies and analyzes the optimization results. The results show that at the angles of attack of 2°, 5° and 10°, the test accuracy of the lift coefficient is increased by 45.35%, 13.4% and 49.3%, and the test accuracy of the drag coefficient is increased by 12.5%, 39.1% and 13.7%. This significantly enhances the prediction accuracy of the BP neural network surrogate model for aerodynamic analysis results, making the optimization outcomes more reliable. The lift coefficient of the airfoil is increased by 0.04342, 0.01156 and 0.03603, the drag coefficient is reduced by 0.00018, 0.00038 and 0.00027, respectively, and the lift-to-drag ratio is improved by 2.95892, 2.96548 and 2.55199, enhancing the convenience of airfoil aerodynamic optimization and improving the aerodynamic performance of the original airfoil.

Research on the thermal comfort of vertical radiant cold plate coupling with a new dual cold source dehumidification air conditioning system

Radiant cooling provides a completely novel air conditioning terminal that could provide better thermal comfort for the resident. However, the radiative system may encounter condensation issues under high-humidity environments. This article studies a radiant air conditioning system with dual-cold-source dehumidification which comprises a plate heat exchanger, a dual-cold fresh air dehumidifier, a capillary radiant cooling wall, and an air-source heat pump. The experimental results demonstrate a positive correlation between the temperature profile of the indoor air and the temperature distribution of the radiant cooling wall. Simulations were conducted to analyze the office’s air temperature and airflow velocity distributions under different supply air volumes and to assess thermal comfort employing computational fluid dynamics (CFD) software. The comfort levels with different air inlet positions are discussed. The simulation results demonstrate that the air conditioning system can maintain a high standard of comfort under an air supply of 350 m³/h.

Coupling analysis between wave resonance in the moonpool and heave motion of the twin hulls with mooring effect

Fluid resonance in the moonpool formed by two identical rectangular hulls in water waves is investigated by employing the Computational Fluid Dynamics (CFD) package OpenFOAMⓇ. The influence of vertical stiffness on the behavior of moonpool resonance coupling with the heave motion response is presented. Numerical simulations show that the free surface oscillation in the moonpool exhibits a two-peak variation with the incident wave frequency, defined as the first and second peak frequencies. A local Keulegan–Carpenter (KC) number is introduced for describing the influence of fluid viscosity and flow rotation on the fluid resonance and heave motion resonance. At the first peak frequency, the free surface oscillation and heave motion response show an in-phase relationship, where increase in the vertical stiffness can increase the relative motion between them. This finally leads to an increase in the KC number, indicating the increased effect of energy dissipation with increase in the vertical stiffness. At the second peak frequency with an out-of-phase relationship between the free surface oscillation and heave motion response, the variation of the KC number is not sensitive to the vertical stiffness. Correspondingly, the influence of energy dissipation is not strongly dependent on the vertical stiffness.

Numerical simulation of fuselage sliding on calm water for an amphibious aircraft based on global moving mesh method

Abstract Aiming at the large motion fluctuation of fuselage sliding on calm water, a numerical simulation method based on the global moving mesh method is introduced by using the computational fluid dynamics software of STAR-CCM+, the two equations SST k-w turbulence model to solve the RANS equations, the VOF method to capture free surface, the DFBI module to simulate the movement of the fuselage. We established a simulation scheme on the sliding movement of the fuselage on calm water, which effectively solves the problem of calculation divergence caused by the excessive stretching deformation of the mesh. Comparison between calculation results and model test results shows that the trends of resistance and attitude angles changing with velocity are basically the same, and the relative errors are around 10%, which indicates that the global moving mesh method is feasible in the simulation of fuselage sliding on calm water.

Enhancing thermal performance in power electronic modules through a novel micro-nozzle model and hybrid nanoparticles with varied shape factors

Temperature uniformity in high-heat-flux electronic devices is an important concern in the field of micro-scale heat transfer. The present study recommends four novel configurations of cone-shaped nozzles to reduce the temperature of Si-IGBT electrical modules. Moreover, the thermal characteristics of working fluid (H2O) improved using a 1 % to 5 % volume fraction of Fe3O4 –Ag (50 % -50 %) nanoparticles with Spherical, Blades, and Lamina synthetic shapes. The constant heat flux ranging from 110 W/cm2 to 240 W/cm2 was considered a boundary condition for the top of the module, i.e. IGBT and the Diode. The simulation was conducted by computational fluid dynamic software ANSYS-FLUENT-18.2 which employed the Realizable k-ε model for turbulence flow. The outputs indicated that the spiral nozzles (Case 4) increase the turbulent kinetic energy (TKE) compared to simple cone-shaped nozzles (Case 1). It was also found that the use of hybrid nanoparticles causes an increase in the cooling of the fluid and moves away from the critical point (393.15 K). On the other hand, the synthetic forms of Lamina have caused a reduction of the temperature by almost 2.3 % relative to other forms of nanoparticles because of their higher thermal permeability.

Numerical Simulation of an Isolated N-Heptane Pool Fire

Refineries are industrial complexes of great economic importance which are located close to major cities. A pool fire accident that can occur from an oil leak combined with wind can result in disastrous consequences for such an industry. This study investigates the characteristics of an isolated n-heptane square pool fire of 36 m2 under the influence of a cross wind. The pool fire characteristics are numerically studied using open-source Computational Fluid Dynamics (CFD) software, such as FireFoam (v4.1) and Fire Dynamic Simulator (FDS) (version 6.9.0). The turbulent flow field and the fire characteristics were simulated with the LES Method. The crucial parameters of the pool fire, such as (a) the temperature and velocity fields, (b) the flame length and height, (c) the surface emissive power, and (d) the flame tilt angles, were computed. Comparisons against experimental data for both small and large-area pool fires from the literature were made successfully. The flame tilt angle is shown to correlate very well with the reciprocal of the Richardson number, which was approximated within a multiplication constant to the Froude number. Thus, both the reciprocal Richardson number and Froude number can be used for correlating the flame tilt angle. It is shown that both of these numbers are used to correlate the tilt angle of experimental pool fires with effective diameters from a fraction of a meter to approximately 16 m, and wind speeds up to 7 m/s. The goodness of a linear fit based on the sum of the residual squares is 0.91.

Computational fluid dynamics analysis of flat plate type solar collector under different fin variables to enhance air-based heat transfer

Purpose This study begins by outlining the core principles of how flat plate solar collectors (FPSC) operate and the underlying mechanisms of heat transfer. It underscores the pivotal role of fin patterns in enhancing convective heat transfer. Design/methodology/approach The primary objective is to examine the impact of diverse fin patterns on the thermal performance of FPSCs. The study involves the development of a 3D-CFD model for FPSC using the computational fluid dynamics (CFD) software ANSYS FLUENT. The analysis is conducted for variable mass flow rates (mf) ranging from 0.01 to 0.05 kg/s with an interval of 0.02 kg/s. Each flow rate is assessed for three distinct fin patterns: straight plate fins, V-shaped fins and wavy fins. Recognizing the variation in solar radiation intensity throughout the day, the analysis is executed at six different time points ranging 10:00 a.m. to 03.00 p.m. with a time interval of 1.00 h. Findings It is observed that the wavy fin pattern with a mass flow rate of 0.01 kg/s exhibited the highest outlet temperature, showing a significant temperature difference of 12.4 K at noon. Conversely, the V-shaped fin pattern with a mf of 0.05 kg/s has the lowest temperature difference value, measuring only 3 K. The analysis included the calculation of thermal efficiency for each case, revealing that the V-shaped fin pattern at a mf of 0.05 kg/s and a sun radiation intensity of 885.42 W/m2 achieved the maximum instantaneous thermal efficiency (ηth) of 34.7%. The study records the outlet air temperature for all of these combinations and presents the data graphically in the paper. Originality/value The findings of the simulations indicate that the thermal performance that is ηth and maximum temperature of outlet air of FPSCs can be improved through the utilization of variable fin patterns.

Virtual physiological analysis of non-culprit disease in patients with STEMI and multivessel disease: a substudy of the COMPLETE trial

Abstract Background In the Complete Revascularization with Multivessel PCI for Myocardial Infarction (COMPLETE) trial, patients with ST-segment-elevation myocardial infarction (MI) who underwent staged revascularization of non-culprit coronary stenoses experienced fewer major adverse cardiovascular events than those who underwent a culprit-only approach (1). Inclusion was, however, based on angiographic and not physiological criteria. Purpose To analyse, using computational modelling, the physiological significance of non-culprit lesions included in the COMPLETE trial, to compare these against angiographic measures of severity, and investigate interactions between physiology and the benefits of complete revascularization. Methods Angiograms with appropriate digital imaging and communications in medicine (DICOM) data from the COMPLETE trial (n=1327) underwent software-based 3-dimensional (3D) arterial reconstruction and analysis of 3D-quantitative coronary angiography (QCA) and virtual fractional flow reserve (vFFR) using computational fluid dynamics software. Physiological lesion significance was defined as vFFR ≤0.80 and was compared with operators’ visual angiographic analysis, core-laboratory 2D-QCA and 3D-QCA. Results vFFR was computed successfully in 635 patients (710 lesions). The median vFFR was 0.82 (interquartile range 0.73–0.91). 302 patients (48%) had at least one physiologically significant lesion and 333 (52%) had none. 321 (45%) lesions were physiologically significant and 389 (55%) were not. Physiologically significant lesions were angiographically more severe than non-significant lesions according to the operator’s visual angiographic assessment (mean stenosis 80% vs. 75%, P<0.0001), 2D-QCA (69% vs. 59%, p<0.0001), and 3D-QCA (56% vs. 43, P<0.0001). Percentage lesion stenosis was significantly different when measured visually, with 2D-QCA and with 3D-QCA (80% vs 62% vs 49%, P<0.0001). vFFR was weakly correlated with operators’ visual angiographic severity (Figure 1) and 2D-QCA, but more strongly with 3D-QCA (r=-0.21, -0.21, and -0.60, respectively; all p<0.0001). 3D-QCA predicted vFFR significance more accurately than visual and 2D-QCA (concordance 73% vs 49% vs 59%, respectively). There was no statistically significant interaction between physiological lesion significance and any of the trial coprimary or key secondary clinical outcomes, or on an exploratory outcome of ischaemia-driven revascularization without preceding MI (all interactions P>0.30) (Figure 2). Conclusions In this virtual physiological substudy of the COMPLETE trial, 52% of patients lacked any physiologically-significant lesions, 3D-QCA was a better predictor of physiological significance than either 2D-QCA or operator visual analysis, and the benefits of complete revascularization appeared to be independent of physiological lesion significance. Further research is warranted to compare angiography-guided and physiology-guided complete revascularization strategies.Figure 1.Figure 2.

Development of a Custom Fluid Flow Chamber for Investigating the Effects of Shear Stress on Periodontal Ligament Cells.

The periodontal ligament (PDL) is crucial for maintaining the integrity and functionality of tooth-supporting structures. Mechanical forces applied to the tooth during orthodontic tooth movement generate pore pressure gradients, leading to interstitial fluid movement within the PDL. The generated fluid shear stress (FSS) stimulates the remodeling of PDL and alveolar bone. Herein, we present the construction of a parallel fluid-flow apparatus to determine the effect of FSS on PDL cells. The chamber was designed and optimized using computer-aided and computational fluid dynamics software. The chamber was formed by PDMS using a negative molding technique. hPDLCs from two donors were seeded on microscopic slides and exposed to FSS of 6 dyn/cm2 for 1 h. The effect of FSS on gene and protein expression was determined using RT-qPCR and Western blot. FSS upregulated genes responsible for mechanosensing (FOS), tissue formation (RUNX2, VEGFA), and inflammation (PTGS2/COX2, CXCL8/IL8, IL6) in both donors, with donor 2 showing higher gene upregulation. Protein expression of PTGS2/COX2 was higher in donor 2 but not in donor 1. RUNX2 protein was not expressed in either donor after FSS. In summary, FSS is crucial in regulating gene expression linked to PDL remodeling and inflammation, with donor variability potentially affecting outcomes.

Study on Atomization Mechanism of Oil Injection Lubrication for Rolling Bearing Based on Stratified Method

The atomization mechanism of lubrication fluid in rolling bearings under high-speed airflow between the rings was investigated. A simulation model of gas–liquid two-phase flow in angular contact ball bearings was developed, and the jet lubrication process between the bearing rings was simulated using FLUENT computational fluid dynamics software (Ansys 19.2). The complex motion boundary conditions of the rolling elements were addressed through a layered approach. We can obtain more accurate boundary layer flow field changes and statistics of the diameter of oil particles in lubricating oil atomization, which lays the foundation for analyzing the law of influence on lubricating oil atomization. The results show that as the number of boundary layer layers increases, the influence of the boundary layer flow field on the lubricating oil is more obvious. The oil particle size is excessively flat, and the concentration of large particles of oil appears to decrease. As the speed increases, the amount of oil in the cavity decreases, but the oil droplets are also fragmented, which intensifies the atomization and reduces the particle diameter. This reduces the Sauter Mean Diameter (SMD), which is not conducive to the lubrication of the bearing. Under different injection pressures, when the injection pressure is large, it is beneficial to the lubrication of the bearing.

The impact of fire source location on hot gas layer temperature in multi-compartment pre-flashover fires: Analysis and semi-empirical model development

A numerical study of a two-room structure (multi-compartment) subjected to fire in the inner room was carried out, employing the CFD (Computational Fluid Dynamics) software called FDS (Fire Dynamics Simulator), to (i) analyze the influence of the fire source position on the hot gas layer temperature, Tu, and its behavior in a multi-compartment fire, and (ii) develop a semi-empirical engineering calculation model to predict Tu in the adjacent room to a pre-flashover well-ventilated fire room, taking into account the fire source position. The results showed that when the fire origin occurs close to walls or elevated above the floor level, a reduced air entrainment is observed in the fire plume and flame, causing an increase in the Tu and a reduction of the smoke production in the fire room. This reduction in the smoke production led to a lower increase in the Tu of the adjacent room in relation to the case when the fire source was at the center of the fire room. It was also observed that the Tu in both rooms was inversely proportional to the ventilation factor (A.H0.5), with a significant increase observed as the ventilation factor decreases, depending on the fire source position. Furthermore, a semi-empirical engineering calculation model was developed to predict the Tu in the adjacent room, considering different fire source locations at ground level and elevated. The model was validated against experimental data from the literature, showing a good agreement (deviation of ≈20 %), thus demonstrating its applicability to other cases.

Induction of Controllable Vortical Flow in a Dual-Stenosis Aorta Model: A Replication of Disordered Eddies Flow in Aneurysms.

This paper presents a two-stenosis aorta model mimicking vortical flow in vascular aneurysms. More specifically, we propose to virtually induce two adjacent stenoses in the abdominal aorta to develop various vortical flow zones post stenoses. Computational fluid dynamics (CFD) simulations were conducted for the virtual two-stenosis model based on physiological and anatomical data (i.e., diameters, flow rate waveforms) from adult rabbits. The virtual model includes adult rabbits' infra-renal portion of the aorta and iliac arteries. 3D CFD simulations in five different dual-stenosis configurations were performed using a commercial CFD package (FLUENT). In-house software assessed the evolution of flow vortices. Notably, spatial-temporally averaged wall shear stress (STA-WSS) and oscillatory shear index (OSI), the total volume of vortex flow, the number of vortices, and the phase-to-phase overlap of vortex flow within each region were evaluated. In all models, we found consistent patterns of the vortex flow parameters, indicating that the adjacent stenoses induced three different hemodynamic zones, namely, stable vortical flow (after the first stenosis), transient vortical flow (after the second stenosis), and unstable vortical flow (further distal to the second stenosis). Also, different degrees of flow disturbance can be achieved in these three zones. It is significant to note that, although the 'dual-stenosis' geometry is completely hypothetical, it allows us to create various vortical flows in consecutive vessel segments for the first time. As a result, if implemented as a pre-clinical model, the proposed two-stenosis model offers an attractive, tunable environment to investigate the interplays between subject-specific hemodynamics and vascular remodeling. This aspect remains in our future directions.

CFD analysis of the erosion wear through 90° bend of different area ratio at high slurry concentration

Using the commercial computational fluid dynamics package ANSYS FLUENT, the behaviour of slurry erosion wear at 90° pipe bends was studied with varied area ratios (AR = 1–2). In this investigation, two influencing parameters have also been selected, such as slurry flow velocity (4−10 m/s) and the low to high slurry concentration of the fly ash (2.5%–40% by volume). To make a slurry, fly ash particles (150 µm) were mixed with water. Euler–Lagrange was used to forecast slurry erosion wear accurately. Simulations of the slurry flow within the bend pipeline were conducted with the help of a standard k-ɛ turbulence model and a two-way coupling approach. The findings of the simulation were validated against the existing research to ensure their accuracy. The study observed that the average erosion rate was directly proportional to the flow velocity and solid concentration of the slurry, while the average erosion rate was inversely proportional to the AR at all flow parameters. The findings indicate that the minimum and maximum erosion wear are found in AR = 2 and AR = 1, respectively. In the case of AR = 2, the average erosion rate is reduced by an average of 5.47 and 2.5 times at given flow parameters (slurry velocity and solid concentration) as compared to the AR = 1 and 1.5, respectively.

CFD Analysis of the Effects of a Barrier in a Hydrogen Refueling Station Mock-Up Facility during a Vapor Cloud Explosion Using the radXiFoam v2.0 Code

A CFD (computational fluid dynamics) analysis to investigate the effects of the installation of a barrier in a hydrogen refueling station (HRS) mock-up facility, with a dummy vehicle and dispensers in the vapor cloud region, during a hydrogen-air explosion using a gas mixture volume of 70.16 m3 was conducted to determine whether the radXiFoam v2.0 code with the established analysis methodology to predict the peak overpressure can be utilized to evaluate the safety of a HRS with such a barrier installed in a large city in the Republic of Korea. The radXiFoam v2.0 code was developed on the basis of the XiFoam solver in the open-source CFD software OpenFOAM-v2112 by modifying C++ source codes in several libraries and governing equations so as to ensure effective calculations of the hydrogen-air chemical reaction and radiative heat transfer through water vapor in a humid air environment and to remove unnecessary warning messages that arise when using the radXiFoam v1.0 code. First, we conducted a validation analysis on the basis of measured overpressure datasets from a near field to a far field of a vapor cloud explosion (VCE) site in the HRS mock-up facility to evaluate the uncertainty in prediction datasets by radXiFoam v2.0. After this validation analysis, we undertook CFD sensitivity calculations by installing barriers with heights of 2.1 m and 4.2 m at a horizontal distance of 2.3 m from the VCE region in the grid model used for the validation analysis to assess the effects of these barriers on reducing the peak overpressure of the blast wave. From these calculations, we judged that the radXiFoam v2.0 code can accurately simulate the effects of the barrier during a VCE, as the calculated overpressure reduction values according to the barrier height are reasonable on the basis of previous validation results from Stanford Research Institute’s explosion test with such a barrier. The results herein imply that the radXiFoam v2.0 code is feasible for use in HRS safety when barrier installation must meet the technical regulations of the Korea Gas Safety Corporation in a large city.

Numerical Simulation of Gas-suspended Proppant Migration Based on Equivalent Principle

Abstract The gas-suspended proppant is composed of conventional proppant particles and hydrophobic aerophilic coating. The surface coating changes the surface wettability of the proppant and increases the adhesion of the proppant surface to the gas, changing the traditional liquid-carried proppant into a gas-carried proppant. The sand carrying capacity of low concentration polymer fracturing fluid can be greatly improved by using air-suspended proppant carrying technology. At present, there is no numerical simulation method aiming at the migration law of gas-suspended proppant. Based on the principle of equivalent substitution, the density of gas and particles is set as the calculated equivalent density during simulation. Similarly, the diameter of gas-suspended proppant is set as the calculated equivalent diameter during simulation. Then computational fluid dynamics software was used to simulate the Euler-Euler method. It is found that Euler-Euler method can simulate the placement of gas-suspended proppant in fractures. Compared with conventional proppant, gas-suspended proppant is not easy to settle during migration, and the settling sand bed still has fluidity and can be re-suspended. When gas suspension proppant density increases, the proppant sedimentation trend increased. Increase the injection rate of proppant, and the shape of long and high sand dunes will become shorter and lower. As the sand rate increases, the height of the sand bank rapidly increases.

Numerical Investigation of Vertical-Axis Hydrokinetic Turbine on Side-by-Side Configuration

Abstract Indonesia, a maritime country, has a renewable energy source that has not been utilized to date, which is ocean current energy, with a potential reaching 17.9 GW. Ocean current energy conversion can be harnessed by using a turbine. A turbine farm is one of the solutions that can be applied to harvest energy and utilize the full potential of the energy available. The arrangements of the turbine on a turbine farm become crucial because the wake generated may affect the performance of the turbines. In this study, numerical simulation will be carried out to find the best y/D distance for twin turbine in low-velocity ocean currents. The simulation is carried out using Computational Fluid Dynamics software with different variations of lateral spacing (y/D 1.2, 1.5, and 2.0). The performance of each turbine, such as torque and Cp, is obtained and compared to a single turbine arrangement. At y/D 1.5 peak Cp achieved at 0.45, a 53% increase from single turbine arrangement. Using a twin turbine arrangement may be beneficial in developing ocean current turbine farms in the future.

Numerical simulation of miniature high-speed aviation fuel pump using immersed solid method

Abstract Aviation fuel pumps are developing toward lightweight design and high rotational speeds at the same time that vehicles, such as missiles and unmanned aerial vehicles (UAVs), gradually get smaller. To investigate the internal flow field characteristics of a miniature aviation gear pump under conditions of high rotational speed, three-dimensional numerical simulations are conducted using computational fluid dynamics (CFD) software ANSYS CFX. The simulations use the immersed-solid method and employ the SST k-ω turbulence model. The findings reveal that under identical conditions, augmenting the tooth width by 1mm leads to a notable 27.32% increase in the average outlet flow rate and a corresponding enhancement of 7.22% in maximum efficiency. Furthermore, a 2mm increment in tooth width results in a substantial surge of 62.74% in the average outlet flow rate and a significant enhancement of 14.61% in maximum efficiency. Nevertheless, concurrently, the augmentation of tooth width corresponds with a gradual rise in trapped oil pressure and significant deterioration of the internal flow field. The study findings offer valuable insights into the integrated design of the oil supply system and engine components of aerospace engines.

Development of a novel concentrated solar-powered material extrusion system for producing printed circuit assemblies

A novel material extrusion system powered by Concentrated Solar Energy (CSE) for functional small-scale applications is proposed. The open literature has reported that any other system employs CSE to heat the extruding needle directly, which is the main component and function of any material extrusion device and the one that allows the building of the desired product or prototype. Polycaprolactone (PCL) is selected as the depositing material that gives shape to the substrates sheltering electric traces, resulting in a printed circuit assembly (PCA). A set of 15 experiments with different shapes allows the compilation of enough data to identify the exposure time and the direct radiation received as the main variables for obtaining the needed temperature for converting the depositing material to its rubbery state. Examples of functional circuits obtained by this device are included, showing his capabilities and potential. This information and the help of simulations on Computational Fluid Dynamics (CFD) software allow finding an expression of the material temperature at the depositing needle's exit as a function of the abovementioned variables. The obtained function describes the experimental equipment's behavior and has an average relative error of 12.6 % compared with the measured material's temperature at the depositing needle's exit. This proposal is expected to summarize the evidence of the CSE's potential for powering some manufacturing systems to obtain consumer goods and that a melt casting system mainly powered by CSE will be plausible shortly.

Numerical study of swirl core-annular flow and factors influencing pressure drop in vertical pipelines for oil-water two-phase flow

As oil field production progresses, the water content of the produced fluid increases and wax deposits form on the pipe wall as the crude oil is transported vertically through the pipeline. This causes the cross-sectional area of the pipeline to decrease, the flow resistance to increase and the pipeline pressure to decrease. As a result, production from oil wells declines and extraction costs rise. Therefore, in the current study, a vortex structure is utilized to generate a vertical core-annular flow for oil production and transportation in high-water-content oil wells. This study uses computational fluid dynamics (CFD) software to investigate the influence of various oil properties on the oil phase distribution and pressure drop in core-annular flow in vertical pipes. The findings demonstrate that the ring-forming effect of the core-annular flow increases with larger oil droplet sizes and lower oil phase densities, while it becomes weaker with higher inlet oil phase volume fraction and lower inlet velocities. As the size and density of the oil droplets grow and decrease, respectively, the pressure drop reduces. On the other hand, the pressure drop increases with higher inlet oil phase volume fraction and viscosity. When the oil droplet size is greater than 0.2 mm, the density is less than 850 kg/m3, the oil phase volume fraction is less than 30% and the inlet velocity is greater than 1 m/s, the annular flow works better. When the inlet oil phase volume fraction is above 30%, and the ring formation effect decreases significantly. The utilization of swirl core-annular fluid significantly mitigates the pressure drop in pipelines compared to pure oil transport downhole, rendering it highly suitable for conveying crude oil in high-water-content oil wells.