Multiple Baffles Research Articles

Advancing subsurface analysis: Integrating computer vision and deep learning for the near real-time interpretation of borehole image logs in the Illinois Basin-Decatur Project

The accurate quantification and mapping of subsurface natural fracture systems using borehole imaging logs are critical for the success of CO2 sequestration in geologic formations, optimization of engineered geothermal systems, and hydrocarbon production enhancement. However, traditional interpretation processes suffer from time-consuming procedures and human bias. To address these challenges and expedite fracture analysis, we investigated the application of integrated computer vision and DL workflows to automate image log analysis. Specifically, the design of our workflow was crafted to swiftly detect fractures and baffles by using actual electrical resistivity of borehole wall from microresistivity imaging device alongside their binary representation. This novel approach significantly reduces computational time while providing invaluable insights. By incorporating conventional logging and microseismic data, we present a regional subsurface natural fracture mapping technique. Through the minimization of human bias in image log analysis, our automated workflow achieves reduced fracture interpretation time and costs while ensuring robust and reproducible results. We demonstrated the efficacy of our approach by applying the workflow to the Illinois Basin-Decatur Project site. The automated workflow successfully identified major fractured zones, multiple baffles, and an interbedded layer with a high resolution of 0.01 ft or 0.12 in. (0.3 cm) and can be upscaled to any desired resolution. Validation through microseismic and image log interpretations allows for accurate and near-real-time mapping of fractures and baffles, significantly enhancing CO2 pressure forecasting and postinjection site care. Our approach stands out due to its robustness, consistency, and reduced computational cost compared with alternative feature extraction technologies. It presents exciting possibilities for advancing CO2 sequestration and engineered geothermal efforts by offering comprehensive and efficient fracture mapping solutions. This technology can contribute significantly to the optimization of CO2 sequestration projects, facilitating sustainable environmental practices, and combating climate change.

The effect of baffles on vertical wall PCM to enhance natural convection

The objective of this study is to enhance convective heat transfer within phase change materials (PCM) using baffles on a vertical wall. PCMs have major drawbacks of low thermal conductivity, high viscosity, and limited natural convection. To address these issues, we investigated a passive approach to enhance natural convection with baffles. The new approach is to arrange multiple baffles with gaps on the opposite side of the heated vertical wall. This placement can minimize vertical temperature difference by blending upward-flowing hot liquid PCM with downward-flowing cold liquid PCM across the gaps and also increase circulating velocity by shortening path of circulation cell through sections divided by baffles. Visualization experiments of shadowgraphy and particle image velocimetry (PIV) were conducted to compare the case with baffle (WB) against the case without baffle (NB). The presence of the baffles lowered the average temperature difference in the horizontal direction by 40%. The WB case reduced the temperature difference in the vertical direction by 50%, compared with the NB case. Furthermore, comparison of the WB with NB showed that at the heat power levels of (4, 6, and 8) W, the convection coefficient increased by up to (28, 34, and 27)%, respectively. Therefore, by changing the internal flow pattern, the baffles on the vertical wall improved convective heat transfer performance.

A study on the designs of baffles-enhanced gas transfer inside Chlorella vulgaris airlift photobioreactors and flow visualisation modelling

Microalgae play a crucial role as bioresources, yet the culture systems of photobioreactors (PBR) encounter challenges. Many engineered PBRs tend to incorporate internals build-ups, serving photoautotroph production, and requiring substantial microalgal biomass. This study quantified the baffle effects on airlift flat plate PBRs based on the performance of Chlorella vulgaris. The impacts of baffle configurations, air velocity, and CO2 contents, three dominant parameters, on microalgae culture were investigated using culture experiments, numerical simulations, and flow visualisation techniques. The results demonstrate that multiple baffle design strategies enhance microalgae growth and production. On the 11th cultivation day, airflow rates of 6, 45, or 90 L/h produced 1.5, 3.0, or 1.9 times the biomass weight and 1.76 × 107 cell numbers/mL in PBRM with 24 baffles, compared to 1.44 × 107 cell numbers/mL in PBRC without baffles. Furthermore, it revealed an intensification in the generation potential of biocomponents with C–H, C = O, and C–O–C functional groups at a 45−50 L/h airflow rate and CO2 (20 %) aerated PBRM. Additionally, it presented the first visualisation explanation of the baffle-guided vortex flow pair symmetry PBRM. This study demonstrated enhancements by modelling newly proposed PBRs with baffles and high-valued bioproducts harvesting through the combination of culture parameters.

On abnormal noise generated from steam gas heater

When a steam gas heater set up in a town was operated, an abnormal noise with a sound pressure level (SPL) of 120 dB was generated at 32% of the rated flow rate. In order to solve this problem, We conducted a field survey to investigate the relationship between the operating conditions and the noise. First, I identified the source of noise and next, the noise level and the mode of sound pressure level (SPL) in a duct were measured and the FFT analysis was carried out to determine the dominant frequency. The results revealed that the abnormal noise was not a mere resonance but rather a self-sustained tone due to the interference of the vortex and the sound field. Furthermore, we measured the SPL outside the gas heater duct and found that the SPL was highest at the center of the gas heater duct. Typically, the first pressure mode should be minimum at the center and maximum at both ends, but the reason for this deviation was clarified in this paper. To address the issue, multiple baffle plates were inserted in a tube array and as a result, the abnormal noise completely disappeared. It was also found that the baffle plate should be inserted at the position where the particle velocity exceeds half of the maximum value.

Process intensification of biodiesel production using pilot-scale continuous multiple baffle reactor with feed distribution

This study aims to enhance biodiesel production through a pilot-scale continuous multiple baffle reactor. This reactor incorporates a baffle array with suitable dimension ratio into the conventional CSTR to create a series of complex flows that increase turbulence and mixing intensity, leading to an increased overall reaction rate. Additionally, this reactor also employed a method of distributing MeOH-KOCH3 solution into 5 streams to enhance mass transfer, reduce catalyst entrapment and ensure the reaction progression throughout the reactor. The investigated variables were the number of baffles, agitation speed, oil to methanol molar ratio, catalyst concentration, and residence time. Ester content of 97.70 wt. % was obtained with residence time of 10 min from single-step transesterification process. This achievement represents 6 times residence time reduction and 75 % reactor cost reduction compared to conventional CSTR with similar reaction conditions and equivalent production capabilities while maintaining simple and highly scalable design of traditional counterparts.

Thermogravitational Convection in a Multiple Baffled Enclosure Filled with Magneto-Hybrid Nanofluid Subjected to Magnetic Field Dependent Viscosity

This study explores the significant impacts of thin baffles and magnetic field dependent viscosity on magnetohydrodynamic (MHD) thermogravitational convection of Cu-Al2O3 (50%–50%) water hybrid nanoliquid in a cavity. Considering different arrangements of baffle sticks on both the vertical walls, four geometrical configurations (Case-I, Case-II, Case-III and Case-IV) have been analyzed. Numerical simulation has been performed for the governing Navier-Stokes (N-S) equations in streamfunction - vorticity form having energy equation. These coupled equations are solved by proposing a higher-order compact finite difference method. The combination of five important aspects (hybrid nanofluid, multiple baffles, magnetic field dependent viscosity (MFDV), magnetic field and compact computation) signifies the novelty of this work. Fluid flow and transportation of thermal energy within the stipulated domain are presented for various flow pertinent parameters. The outcomes show that the increase in number of baffles diminishes the average Nusselt number values. It is concluded here that an increase in Hartmann number from 0 to 90 leads to a decrease in average Nusselt number up to 23.7% for Case-I, 23.8% for Case-II, 21.2% for Case-III and 28% for Case-IV in presence of MFDV effects.

Mixing Performance of a Passive Micromixer Based on Multiple Baffles and Submergence Scheme.

A novel passive micromixer based on multiple baffles and a submergence scheme was designed, and its mixing performance was simulated over a wide range of Reynolds numbers ranging from 0.1 to 80. The degree of mixing (DOM) at the outlet and the pressure drop between the inlets and outlet were used to assess the mixing performance of the present micromixer. The mixing performance of the present micromixer showed a significant enhancement over a wide range of Reynolds numbers (0.1 ≤ Re ≤ 80). The DOM was further enhanced by using a specific submergence scheme. At low Reynolds numbers (Re < 5), submergence scheme Sub24 produced the highest DOM, approximately 0.57, which was 1.38 times higher than the case with no submergence. This enhancement was due to the fluid flowing from or toward the submerged space, creating strong upward or downward flow at the cross-section. At high Reynolds numbers (Re > 10), the DOM of Sub1234 became the highest, reaching approximately 0.93 for Re = 20, which was 2.75 times higher than the case with no submergence. This enhancement was caused by a large vortex formed across the whole cross-section, causing vigorous mixing between the two fluids. The large vortex dragged the interface between the two fluids along the vortex perimeter, elongating the interface. The amount of submergence was optimized in terms of DOM, and it was independent of the number of mixing units. The optimum submergence values were 90 μm for Sub24 and Re = 1, 100 μm for Sub234 and Re = 5, and 70 μm for Sub1234 and Re = 20.

Sloshing of Liquid in a Cylindrical Tank with Multiple Baffles and Considering Soil-Structure Interaction

In this study, the liquid sloshing in a cylindrical tank considering soil–structure interaction and undergoing horizontal excitation is investigated analytically. Multiple rigid annular baffles are positioned on the rigid wall to mitigate the liquid sloshing. Firstly, combined with the subdomain partition method for sloshing, the complex liquid domain is partitioned into simple subdomains with the single condition for boundary. Based on continuity conditions of velocity and pressure as well as the linear sloshing equation for free surface, the exact solution for convective velocity potential is derived with high accuracy. By yielding the similar hydrodynamic shear and moment as those of the original system, a mechanical model is developed to describe continuous sloshing, and parameters of the model are given in detail. Then, by means of the least squares approach, the Chebyshev polynomials are utilized to fit impedances for the circular surface foundation. A lumped parameter model is employed to represent influences of soil on the superstructure. Finally, by using the substructure method, a coupling model of the soil–tank system is developed to simplify the dynamic analysis. Comparison investigations are carried out to verify the effectiveness of the model. Detailed sloshing characteristics and dynamic responses of sloshing are analyzed with regard to different baffle sizes and positions as well as soil parameters, respectively. The novelty of the present study is that an equivalent analytical model for the soil–foundation–tank–liquid system with multiple baffles is firstly obtained and it allows the dynamic behaviors of the coupling system to be investigated with high computation efficiency and acceptable accuracy.

Slosh Damping in Rectangular Liquid Tank With Additional Blockage Effects Under Pitch Excitation

Abstract The quantification and damping of slosh responses are significant due to the increasing demand for safety of the liquid-based applications under severe external excitation. Recently, the solid or perforated baffle plates have been used to damp the slosh response of the liquid. However, there is uncertainty in the selection of an effective configuration of the baffle plates. In addition, most of the studies reported the slosh response under surge excitation. Therefore, this study focuses on the slosh response of the rectangular tank fitted with perforated baffle plates of different configurations under pitch excitation. For this, the liquid sloshing is simulated using the concepts of computational fluid dynamics (CFD) using pressure-based solver in the time domain. A detailed parametric study is carried out to develop an effective configuration of the perforated baffle plates considering the area of perforations, interperforation distance, size of perforations, distance between the perforated baffle plates, alignment of perforations, and the vertical position of perforated baffle plate as the parameters. The slosh responses are observed in terms of free surface elevation, hydrodynamic pressure, turbulence kinetic energy, velocity streamlines, power spectral density corresponding to the free surface elevation and the free surface deformation. The study developed a “zig-zag blocking alignment” of perforations for effective slosh damping, with the solid area between the perforations being 50%–60% of the area of perforations. In addition, “single-acting range” and “damping range” are identified to pilot the positioning of the multiple baffle plates in a rectangular tank under pitch excitation.

Flash Smelting Settler Design Modifications to Reduce Copper Losses Using Numerical Methods

A mathematical modeling approach was used to test different design modifications in a flash smelting settler to reduce the copper losses in slag, which is economically disadvantageous for copper processing using the pyrometallurgical route. The main purpose of this study was to find ways to reduce copper losses in slag by improving the settling and coalescence of copper matte droplets, in particular, the smallest droplet sizes of ≤100 µm. These improvements inside the flash smelting (FS) settler were targeted through different settler design modifications. Three different design schemes were tested using the commercial computational fluid dynamics (CFD) software, Ansys Fluent. These settler design modification schemes included the impact of various baffle types, positioning, the height inside the settler, and settler bottom inclinations. Simulations were carried out with and without coalescence and the results were compared with normal settler design. The results revealed that the settling phenomenon and coalescence efficiency were improved significantly with these design modifications. It was concluded that a single baffle design was optimal for reducing copper losses and increasing coalescence efficiency instead of using multiple baffle arrangements. The top-mounted baffle outperformed the bottom-mounted baffle and inclined settler design.

Numerical study on mass transfer in a falling film on structured plates with micro-baffles

• Falling film microreactors were structured with horizontal and inclined baffles. • Inclined baffles caused a pair of swirling flow vortices in a thin liquid film. • Mass transfer coefficient ( k L ) increased by 45% by decreasing baffle interval. • k L increased by 61 % by increasing baffle height. Falling film microreactors are applied to fast gas-liquid reactions to utilize a high interface area per liquid volume. The reaction rate in such reactors is still mass transfer-limited because the flow is laminar, and mass transfer occurs only by diffusion. Therefore, it is desirable to induce convective mixing in thin liquid films. In this study, multiple baffles with a predetermined height of 0.1–0.2 mm were constructed at equal intervals of 1–3 mm on a flat plate to induce a swirling flow, that is, convective mixing, in the liquid. Two types of microstructured plates with horizontal and alternately inclined baffles (IBs) with predetermined angles of 30–60° were designed, and CO 2 absorption into water was numerically investigated for the mass transfer coefficient on the liquid side ( k L ) at Reynolds numbers ranging from 28 to 111. The IB plates outperformed the standard plate without baffles because of the IB-induced swirling flow in a ∼0.2-mm-thick liquid film. k L was increased by 61%, as compared to the standard plate, by adopting a baffle height of 0.2 mm, angle of 45°, and interval of 2 mm, achieving process intensification.

Numerical Simulation and Design Optimization of Baffle Perforations for Better Noise Reduction

An increasing vehicle population always pressurizes to focus on environmental concerns for reduced noise level and harmful emissions. Even though many qualitatively optimized exhaust systems are developed during last two decades, still researchers focus on noise reduction and emission control. Abundant research and development activities are carried out to get a reasonable back pressure drop along with a significant noise reduction in the muffler. The development in computational coding leads to a realistic prediction of flow and acoustic characteristics inside the muffle. Hence the present research work focuses on computational simulation of muffler with single and multi-chambers separated by baffles along with porous pipes. The present work analyses a conventional single baffle muffler configuration and compares the flow behaviour with multi chambers separated by multiple baffle configurations. The shape of the baffle holes is also optimised to get better acoustic performance based on the transmission losses. The flow behaviour and its details are studied inside the muffler to identify the possibility of design improvements. Among the muffler configurations with single and multiple chambers, the overall pressure losses are calculated and compared to get an optimized design with reasonable sound attenuation.

Liquid Sloshing in a Cylindrical Tank with Multiple Baffles Under Horizontal and Pitching Motions

The sloshing response of fluid in a rigid circular cylindrical tank with multiple rigid annular baffles and subjected to horizontal and pitching excitations is investigated. The subdomain method for fluid sloshing is utilized to obtain exact solutions to the convective velocity potential of liquid. By substituting the velocity potential of liquid into free surface sloshing equation, the response equation under the horizontal excitation is constructed. According to producing the similar lateral force and moment as analytical solutions undergoing horizontal motion, an equivalent mass-spring model is developed to replace continuous liquid. Based on the model, dynamic response of liquid sloshing in the tank under the horizontal and pitching excitations is obtained. Compared with the reported results, the lateral force is in excellent agreement with literature solutions and the overturning moment shows good agreement with available solutions under the excitation with low frequency. The proposed model can be employed to simplify dynamics of complicated liquid-structure systems undergoing pitching motion without tedious derivation and great amount of calculation. The effects of the liquid height, the positions and sizes of the baffles on the influence coefficient factor of pitching motion and the steady-state response are revealed in detail.

Slosh-induced hydrodynamic force in a water tank with multiple baffles

This study uses laboratory experiments and a Large Eddy Simulation (LES) model to investigate the sloshing phenomenon in a rectangular water tank with multiple bottom-mounted baffles. The kinematic motion of the water surface was solved by the Volume of Fluid (VOF) method. The simulation results were verified by the measured wave heights in a water tank installed on a shaking table. The numerical model was employed to systematically determine the effects of the spacing and height of the baffles on the sloshing phenomenon. The simulation results indicate that the natural frequency of the tank was altered by the multiple baffles and was related to the effective water depth above the baffles. The diminishing effect of multiple baffles on the hydrodynamic force is better than that of a single baffle. In addition, the sloshing force on the sidewalls of the tank can be characterized by the excitation amplitude, frequency, and water depth. While the sloshing height and hydrodynamic force decrease as the baffle number or baffle height increase, the effect of baffles on the sloshing lessens when the relative baffle height hb/hw ≥ 0.75.

Conceptual design of laser transfer system of the JT-60SA Thomson scattering diagnostic

This paper provides a conceptual design of the laser transfer system to be installed for the JT-60SA Thomson scattering system. The optical design newly permits transferring two wavelength lasers, i.e., YAG (1064nm) and ruby (694nm) lasers, so that an in situ relative calibration for high-field edge measurements, where the scattering angle is close to 90°, is possible under severe radiation condition. Stray light generated from scattering at a vacuum window can be suppressed using multiple baffles. It is newly found that the baffles spaced at a geometric series, i.e., 40% of unit length, is an effective way and reduces the stray light. The amount of stray light can be reduced to ∼6% using only three baffles compared with the case of no-baffles.

Congenital Heart Disease in Adults

With advances in medical and surgical care, an increasing number of children with congenital diseases of the heart and vasculature now survive to adulthood. The proportion of adults who are affected by congenital heart disease is expected to continue to increase. Thus, it is important for clinicians to be knowledgeable about the care of these patients. This review examines acyanotic disorders (shunts and valvular lesions), vascular anomalies, cyanotic disorders, and women’s health issues. Figures show the anatomy of atrial septal defects, transcatheter closure of atrial septal defects, an anatomic cross section showing the atrioventricular septum, the anatomic positions of ventricular septal defects, a computed tomography scan of aortic coarctation, angiogram of a persistent left superior vena cava draining into the right atrium, systemic artery-to-pulmonary artery shunts, magnetic resonance image of a patient with repaired tetralogy of Fallot and long-standing pulmonary valve insufficiency, treatment of pulmonary valve regurgitation with a transcatheter pulmonary valve, computed tomographic images of a patient with atrial switch palliation of transposition of the great arteries and multiple baffle obstructions, stages in the repair of functional single ventricles, and echocardiograms of a patient with Ebstein anomaly. Tables list recommendations for pulmonary valve replacement in repaired tetralogy of Fallot, conditions in which pregnancy is high risk, and cardiac indications for fetal echocardiography. This review contains 12 highly rendered figures, 4 tables, and 62 references.

Congenital Heart Disease in Adults

With advances in medical and surgical care, an increasing number of children with congenital diseases of the heart and vasculature now survive to adulthood. The proportion of adults who are affected by congenital heart disease is expected to continue to increase. Thus, it is important for clinicians to be knowledgeable about the care of these patients. This review examines acyanotic disorders (shunts and valvular lesions), vascular anomalies, cyanotic disorders, and women’s health issues. Figures show the anatomy of atrial septal defects, transcatheter closure of atrial septal defects, an anatomic cross section showing the atrioventricular septum, the anatomic positions of ventricular septal defects, a computed tomography scan of aortic coarctation, angiogram of a persistent left superior vena cava draining into the right atrium, systemic artery-to-pulmonary artery shunts, magnetic resonance image of a patient with repaired tetralogy of Fallot and long-standing pulmonary valve insufficiency, treatment of pulmonary valve regurgitation with a transcatheter pulmonary valve, computed tomographic images of a patient with atrial switch palliation of transposition of the great arteries and multiple baffle obstructions, stages in the repair of functional single ventricles, and echocardiograms of a patient with Ebstein anomaly. Tables list recommendations for pulmonary valve replacement in repaired tetralogy of Fallot, conditions in which pregnancy is high risk, and cardiac indications for fetal echocardiography. This review contains 12 highly rendered figures, 4 tables, and 62 references.

Rocket‐borne measurements of electron temperature and density with the Electron Retarding Potential Analyzer instrument

AbstractDetermining electron temperature in the ionosphere is a fundamentally important measurement for space science. Obtaining measurements of electron temperatures at high altitudes (&gt;700 km) is difficult because of limitations on ground‐based radar and classic spacecraft instrumentation. In light of these limitations, the rocket‐borne Electron Retarding Potential Analyzer (ERPA) was developed to allow for accurate in situ measurement of ionospheric electron temperature with a simple and low‐resource instrument. The compact ERPA, a traditional retarding potential analyzer with multiple baffle collimators, allows for a straightforward calculation of electron temperature. Since its first mission in 2004, it has amassed significant flight heritage and obtained data used in multiple studies investigating a myriad of phenomena related to magnetosphere‐ionosphere coupling. In addition to highlighting the scientific contributions of the ERPA instrument, this paper outlines its theory and operation, the methodology used to obtain electron temperature measurements, and a comparative study suggesting that the ERPA can also provide electron density measurements.

Shape Optimisation of Multi-Chamber Acoustical Plenums Using BEM, Neural Networks, and GA Method

Abstract Research on plenums partitioned with multiple baffles in the industrial field has been exhaustive. Most researchers have explored noise reduction effects based on the transfer matrix method and the boundary element method. However, maximum noise reduction of a plenum within a constrained space, which frequently occurs in engineering problems, has been neglected. Therefore, the optimum design of multi-chamber plenums becomes essential. In this paper, two kinds of multi-chamber plenums (Case I: a two-chamber plenum that is partitioned with a centre-opening baffle; Case II: a three-chamber plenum that is partitioned with two centre-opening baffles) within a fixed space are assessed. In order to speed up the assessment of optimal plenums hybridized with multiple partitioned baffles, a simplified objective function (OBJ) is established by linking the boundary element model (BEM, developed using SYSNOISE) with a polynomial neural network fit with a series of real data – input design data (baffle dimensions) and output data approximated by BEM data in advance. To assess optimal plenums, a genetic algorithm (GA) is applied. The results reveal that the maximum value of the transmission loss (TL) can be improved at the desired frequencies. Consequently, the algorithm proposed in this study can provide an efficient way to develop optimal multi-chamber plenums for industry.

An Assessment of High-Order-Mode Analysis and Shape Optimization of Expansion Chamber Mufflers

Abstract A substantial quantity of research on muffler design has been restricted to a low frequency range using the plane wave theory. Based on this theory, which is a one-dimensional wave, no higher order wave has been considered. This has resulted in underestimating acoustical performances at higher frequencies when doing muffler analysis via the plane wave model. To overcome the above drawbacks, researchers have assessed a three-dimensional wave propagating for a simple expansion chamber muffler. Therefore, the acoustic effect of a higher order wave (a high frequency wave) is considered here. Unfortunately, there has been scant research on expansion chamber mufflers equipped with baffle plates that enhance noise elimination using a higher-order-mode analysis. Also, space-constrained conditions of industrial muffler designs have never been properly addressed. So, in order to improve the acoustical performance of an expansion chamber muffler within a constrained space, the optimization of an expansion chamber muffler hybridized with multiple baffle plates will be assessed. In this paper, the acoustical model of the expansion chamber muffler will be established by assuming that it is a rigid rectangular tube driven by a piston along the tube wall. Using an eigenfunction (higher-order-mode analysis), a four-pole system matrix for evaluating acoustic performance (STL) is derived. To improve the acoustic performance of the expansion chamber muffler, three kinds of expansion chamber mufflers (KA-KC) with different acoustic mechanisms are introduced and optimized for a targeted tone using a genetic algorithm (GA). Before the optimization process is performed, the higher-order-mode mathematical models of three expansion chamber mufflers (A-C) with various allocations of inlets/outlets and various chambers are also confirmed for accuracy. Results reveal that the STL of the expansion chamber mufflers at the targeted tone has been largely improved and the acoustic performance of a reverse expansion chamber muffler is more efficient than that of a straight expansion chamber muffler. Moreover, the STL of the expansion chamber mufflers will increase as the number of the chambers that separate with baffles increases.