Baffle Position Research Articles

Terminal sequence consistency verification method for small diameter abreast optical fibers based on computer vision

In a kind of precision industrial equipment, small diameter abreast optical fibers are used for high-speed communication among functional nodes. The arrangement order at both terminals of the abreast optical fibers need to comply with communication protocols. In this paper, we propose an automatic terminal sequence consistency verification method based on computer vision. The Hue Saturation Value (HSV) color space is used for improving the image feature extraction capability. An abreast optical fiber sequence dictionary which converts the protocol logic into an input-output mapping table is provided to follow protocol confidentiality and improve inspecting speed. A light control baffle position adaptive algorithm is designed for improving the accuracy of optical fiber incident light control. The experimental results show that the method can achieve the conductivity inspection of 1 optical fiber every 50 seconds, and the inspection accuracy is over 96.5%, which generally improves the inspection efficiency by 45% compared with manual inspection.

Novel concept for 3D-printed, baffled micro-fluidized beds for the regulation of bubble behavior and the suppression of solid back-mixing: Experiments and simulations

In Micro-Fluidized Beds (MFBs), large bubbles (or slugs) and strong solid back-mixing might hinder good mixing, heat and mass transfer, while reducing conversion rates, and limiting selectivity in certain gas–solid reactions. In this study, a series of novel baffled MFBs were produced using 3D-printing. The influence of the number and position of baffles on the regulation of bubble performance and solid back-mixing in MFBs was investigated through fluidization experiments and Two-Fluid Model (TFM) simulations. The results show that the introduction of baffles effectively suppress slug formation and expand the bubbling regime. Baffles placed at mid-height disrupt fully developed slugs more effectively than those at the bottom. Increasing the number of baffles enhances bubble-breaking efficiency. Numerical simulations suggest that baffles positioned in the lower portion of the bed are more effective for the inhibition of global solid back-mixing. This study shed new light on the design and optimization of baffled MFBs.

Equivalent analytical model for liquid sloshing in a 2-D rectangular container with multiple vertical baffles by subdomain partition approach

An equivalent analytical model of sloshing in a two-dimensional (2-D) rigid rectangular container equipped with multiple vertical baffles is presented. Firstly, according to the subdomain partition approach, the total liquid domain is partitioned into subdomains with the pure interface and boundary conditions. The separation of variables is utilized to achieve the velocity potential for subdomains. Then, sloshing characteristics are solved according to continuity and free surface conditions. According to the mode orthogonality of sloshing, the governing motion equation for sloshing under horizontal excitation is given by introducing generalized time coordinates. Besides, by producing the same hydrodynamic shear and overturning moment as those from the original container-liquid-baffle system, a mass-spring analytical model of the continuous liquid sloshing is established. The equivalent masses and corresponding locations are presented in the model. The feasibility of the present approach is verified by conducting comparative investigations. Finally, by utilizing normalized equivalent model parameters, the sloshing behaviors of the baffled container are investigated regarding baffle positions and heights as well as the liquid height, respectively.

Experimental and numerical investigation on energy efficiency improvement of methane/propane added of hydrogen-fueled micro power generation

The micro-thermal power generation presents several challenges including reaction instability, large heat loss, and energy conversion. So, a micro-planar with multi-hole baffle for micro power generation is proposed with C3H8/CH4 blended and reaction sensitivity analyzed. Effects of fuel sensitivities, baffle settings, operating conditions on combustion characteristics and performance of thermal are analyzed. Experimental results revealed the thermal performance of H2-fueled combustion with blended CH4 and C3H8 can be improved, while the H2/CH4/air burning obtains a higher improvement by promoting flame anchoring and reducing heat losses. Thermal reflux and high temperature zones can be generated at appropriate baffle positions and hole sizes to enhance the operating micro-combustor performance. Optimized baffles and CH4 blending ratios significantly improved combustor output power and system efficiency. For instance, the maximum mean radiation temperature of 1347 K can be obtained in combustor C8-0.8 at mc = 25 % and mf = 4.08 × 10−5 kg/s. Meanwhile, micro-thermophotovoltaic (MTPV) system equipped with InGaAsSb cell can achieve a 3.4 W electrical power output and a system efficiency of 3.5 %. It provides solutions for recovering energy from exhaust gases and improving energy efficiency to develop efficient and sustainable micro-energy sources.

Improved performance evaluation of a dual passage solar thermal collector using staggered turbulators

Energy exists in various forms and plays a crucial role in global economic development and modernization. Solar energy is a prominent choice among several alternatives as an energy source to meet the demand. To harness solar energy for heating applications, the most basic approach is to transform it into thermal energy through the use of solar thermal collectors (STC). The thermal effectiveness of the dual passage solar thermal collector (DP-STC) is particularly poor. An effective approach to enhancing its thermohydraulic performance (ηTHPP) involves employing turbulators on the absorber plate (AP). This study investigates the impact on ηTHPP of DP-STC providedwith single V-shaped staggered baffles (SVSSBs). The impact of various geometrical elements, such as relative staggered baffle position (PB′/PB) ranging from 0.45 to 0.75, relative staggered baffle size (B/HB) from 2.5 to 4.0, and relative roughness pitch (PB/HB) from 1.0 to 2.5, are investigated for Reynolds numbers (ReX) ranging from 3000 to 19000. The remaining geometrical parameters, including the relative roughness height (HB/HC) = 0.40, relative gap position (Gd/Lv) = 0.67, relative gap size g/HB = 1, and angle of attack (αB) = 60°, remained fixed. Notable among the findings of this research is the fact that, SVSSBs performed best in comparison to other turbulators reported in the literature review. The ηTHPP reached its maximum value of 3.67 for the case with SVSSBs with PB/HB = 1.5, PB′/PB = 0.65, andB/HB = 3.5 atReX = 17000. The correlations are also developed for the Nusselt number (NuBP) and friction factor (fBP), using experimental data.

Design and Optimization of Cross-Corrugated Triangular Ducts with Trapezoidal Baffles Based on Response Surface Methodology and CFD

Plate heat exchangers are widely used in the Heating, Ventilation, and Air Conditioning (HVAC) field. Cross-corrugated triangular ducts are commonly employed in plate heat exchangers. Inserting baffles into the cross-corrugated triangular ducts can improve the heat transfer performance of the plate heat exchangers. This study focuses on intricate interdependencies among the flow channel apex angle, the trapezoidal baffle inclination angle, baffle position, and Reynolds number (Re) on heat transfer and pressure drop using response surface methodology (RSM) and computational fluid dynamic (CFD). To identify the factors that maximize the Nusselt number (Nu) and minimize friction factor (f), the RSM is used to design factors, conduct numerical studies, and establish regression equations. The results show that the apex angle, baffle angle, X-direction position, and Re have significantly affected Nu and f. Compared to a non-baffled channel with the same apex angle and Re conditions, the optimized channel enhances heat transfer by 1.54 times and has an almost identical pressure drop. The inclined baffle significantly enhances comprehensive performance at low Re. The synergistic effect of the heat transfer and pressure drop is most optimal when the apex angle of the flow channel is 90°, the trapezoidal baffle inclination angle is 52.5°, and the Re is 1000, with the baffle position at 0.625H in the X-direction.

Effect of inside Surface Baffle Conditions on Just Drawdown Impeller Rotational Speed

The effect of inside surface baffle installation conditions on the minimum impeller rotational speed for just the drawdown of floating solid NJD was investigated. The inside surface baffle condition is the condition in which a partial baffle is placed with a clearance between the baffle and the vessel wall. In this study, a baffle with an insertion length of 0.2 times the liquid height was used. Moreover, the effect of baffle angle on NJD was investigated. The NJD was measured visually at least three times. The results showed that the effect of the radial installation position of the inside surface baffle on NJD depended on the impeller position. In addition, even baffles placed parallel to the tangential flow were found to decrease NJD.

Effects of baffle position in serpentine flow channel on the performance of proton exchange membrane fuel cells

This study used a three-dimensional numerical model of a proton exchange membrane fuel cell with five types of channels: a smooth channel (Case 1); eight rectangular baffles were arranged in the upstream (Case 2), midstream (Case 3), downstream (Case 4), and entire cathode flow channel (Case 5) to study the effects of baffle position on mass transport, power density, net power, etc. Moreover, the effects of back pressure and humidity on the voltage were investigated. Results showed that compared to smooth channels, the oxygen and water transport facilitation at the GDL-Channel interface were added 11.53%−20.60% and 7.81%−9.80% at 1.68 A·cm−2 by adding baffles. The closer the baffles were to upstream, the higher the total oxygen flux, but the lower the flux uniformity and the worse the water removal. The oxygen flux of upstream baffles was 8.14% higher than that of downstream baffles, but oxygen flux uniformity decreased by 18.96% at 1.68 A·cm−2. The order of water removal and voltage improvement was Case 4 > Case 5 > Case 3 > Case 2 > Case 1. Net power of Case 4 was 9.87% higher than smooth channel. To the Case 4, when the cell worked under low back pressure or high humidity, the voltage increments were higher. The potential increment for the backpressure of 0 atm was 0.9% higher than that of 2 atm. The potential increment for the humidity of 100% was 7.89% higher than that of 50%.

Micro T-mixer with Baffles (Effect of Baffle Position on Mixing)

Micro T-mixer with Baffles (Effect of Baffle Position on Mixing)

A comprehensive investigation on liquid sloshing of rectangular water tank with vertical baffles

Although numerical method is used to analyze the liquid sloshing-induced wave height and control force, it is worth noting that the effects of vertical baffle on liquid sloshing of rectangular water tanks have not been thoroughly explored. Further research in this domain would be invaluable for gaining a more profound understanding of liquid sloshing in such tanks. Therefore, the CFD method and finite volume model are employed in this paper, and the effects of vertical baffle on the liquid sloshing behaviors are comprehensively investigated, including wave height of free surface, horizontal control force, damping ratio of liquid sloshing, natural frequency, and free surface deformation. Then, the influences of excitation amplitude, water depth, number of baffles, baffle position, and baffle height are extensively explored. The accuracy of the modeling is confirmed through rigorous comparisons with existing experimental results. The number of baffles has a considerable influence on the behaviors of liquid sloshing. The effectiveness of the baffle in reducing liquid sloshing is closely tied to its position. Exceeding the baffle height beyond the water depth causes a transformation of the working mechanism and inherent properties of the rectangular water tank. The natural frequency is generally overestimated by linear potential flow theory.

Numerical investigation of nanofluid buoyant flow behavior and heat transfer characteristics in annular-shaped enclosure with internal baffle

PurposeNatural convection in finite enclosures is a common phenomenon in various thermal applications. To provide the thermal design guidelines, this study aims to numerically explore the potential of using internal baffles and nanofluids to either enhance or suppress heat transport in a vertical annulus. Furthermore, the annular-shaped enclosure is filled with aqueous-silver nanofluid and the effects of five distinct nanoparticle shapes are examined. In addition, the influence of baffle design parameters, including baffle position, thickness and length, is thoroughly analyzed.Design/methodology/approachThe finite difference method is used in conjunction with the alternating direction implicit and successive line over relaxation techniques to solve nonlinear and coupled partial differential equations. The single phase model is used for nanofluid which is considered as a homogeneous fluid with improved thermal properties. The independence tests are carried out for assessing the sufficiency of grid size and time step for obtaining results accurately.FindingsThe baffle dimension parameters and nanoparticle shape exhibit significant impact on the convective flow and heat transfer characteristics, leading to the following results: sphere- and blade-shaped nanoparticles demonstrate around 30% enhancement in the heat transport capability compared with platelet-shaped nanoparticles, which exhibit the least. When considering the baffle design parameter, either a decrease in the baffle length and thickness or an increase in baffle height leads to an improvement in heat transport rate. Consequently, a threefold increase in baffle height yields a 40% improvement in thermal performance.Originality/valueUnderstanding the impact of nanoparticle shapes and baffle design parameters on flow and thermal behavior will enable engineers to provide valuable insight on thermal management and overall system efficiency. Therefore, the current work focuses on exploring buoyant nanofluid flow and thermal mechanism in a baffled annular-shaped enclosure. Specifically, an internal baffle that exhibits conductive heat transfer through it is considered, and the impact of baffle dimensions (thickness, length and position) on the fluid flow behavior and thermal characteristics is investigated. In addition, the current study also addresses the influence of five distinct nanoparticle shapes (e.g. spherical, cylindrical, platelet, blade and brick) on the flow and thermal behavior in the baffled annular geometry. In addition to deepening the understanding of nanofluid behavior in a baffled vertical annulus, the current study contributes to the ongoing advancements in thermal applications by providing certain guidelines to design application-specific enclosures.

Steady Jeffery Fluid through Porous Media in Presence of a Baffle in a Vertical Channel

In this paper we have studied the Jeffrey fluid flow through a porous medium in a vertical channel with baffle. The channel is divided into two phases by a thin perfectly conductive plate and governing equations are simplified analytically by using boundary and interface condition at different baffle position, result are plotted for various important parameters and exposed graphically. We found that, the expression for increases in porous parameter, chemical reaction parameter which decrease the velocity and temperatures in both the regions. And also an increase in Thermal Grashof number leads to increases in both velocity and temperature profiles.

Optimized Geometric Structure of a Rotational Hydrodynamic Cavitation Reactor

The objective of this paper is to obtain an excellent structure of a rotational hydrodynamic cavitation reactor (RHCR) by a numerical method and then to investigate the cavitating flow characteristics of the optimized RHCR experimentally. The RNG k-ε turbulence model combined with the Zwart cavitation model was applied to analyze the influence of the straight blade number, the baffle position and the baffle shape on the pressure field, bubble distribution and turbulence kinetic energy of the RHCR. The results show that compared to the original model, an RHCR with a straight blade number of 6, a baffle position of 0.74 and a triangular baffle offers better cavitation performance. Moreover, the energy performance and the cavitation development process of the optimized RHCR were studied experimentally. The results indicate that the multiscale bubbles are induced by straight blades and baffles of the optimized RHCR, accompanied by the twice quasi-periodic shedding dynamics in one cycle. The findings of this study have positive significance for the design and optimization of RHCRs.

Application of residence time distribution (RTD) to enhance the performance of perforated baffled constructed wetland under unsteady flow

The perforated baffle can significantly enhance the performance of the constructed wetland. In the present study, the effects of perforation shape, number of baffles, baffle position and perforation location on the flow pattern of wetlands were investigated using NaCl impulse-response tracer test, and perforated baffles were used to improve the nitrogen removal rate of the constructed wetland. The perforated baffle optimizes the flow pattern by reducing the peak height of the RTD curve and delaying the peak occurrence time. Triangle perforation exhibits better flow pattern optimization due to its smaller area. When the inlet flow rate is 100 mL/min, the mean residence time (Tm) increases by 0.25 h. The position of the perforated baffle has a more significant effect on the flow pattern, being able to better extend hydraulic residence time (HRT) when located at the height of H/2 substrate. In addition, the perforation locations of two adjacent baffles are not on the same vertical line, which can increase the horizontal water flow velocity and improve the space utilization of the wetland. Compared to the control check constructed wetland (CKCW) without baffles, the perforated baffled constructed wetland (PBCW) exhibited a higher NH4+-N removal rate of 84.53 ± 7.48 % during stable operation. This is mainly because the perforated baffle improves the utilization of dissolved oxygen (DO) while improving the water flow distribution and extending the HRT. In conclusion, perforated baffles have considerable potential to alleviate shock loading and enhance the performance of constructed wetlands.

Semi-analytical method for liquid sloshing in the rigid super-elliptical tank with the ring baffle

Tanks with super-elliptical cross-sections can improve space utilization. The effect of the submerged ring baffle on liquid sloshing in the tank is studied. The semi-analytical method is developed to solve the three-dimensional (3D) sloshing problem in the baffled non-axisymmetric tank, using linear potential theory by dividing the liquid domain into sub-domains. The formal solutions are obtained analytically for the 3D non-axisymmetric sub-domains with arbitrary cross-sections, allowing for the determination of natural frequencies and modes by substituting the formal solutions into the linearized free surface condition, the boundary conditions on the baffle and tank wall and the continuity conditions at the interfaces of the interconnecting sub-domains. The dynamic response equation is derived using the mode superposition method with the damping term for swaying excitation. The obtained solution is validated by comparing it with a numerical model, demonstrating excellent accuracy and efficiency. Parametric studies are performed to determine the effect of the baffle on liquid sloshing, indicating that the baffle can considerably reduce the liquid sloshing when considering an optimal baffle position and width. This technique can be extended to investigate the sloshing reduction in vertical containers with arbitrary cross-sections.

Investigation of Sloshing with Vertical and Horizontal Baffle in the Prismatic Tank using Meshfree CFD

Sloshing is a phenomenon where the tank experiences an external oscillating motion due to the interaction of fluid with tank. The most appropriate way to prevent instability from the sloshing movement is to add baffles or anti-sloshing. This paper was conducted with the 3D simulation of sloshing roll motion on the prismatic tank with a simulation time of 28 seconds. Vertical and Horizontal baffles were used to mitigate sloshing in the prismatic tank. The ratio of baffle height and water depth is 0.7, 0.8 and 0.9. Moreover, horizontal baffle position is 0.1, 0.2, 0.3, and 0.4 respectively, with the tank filling water ratio is 25%. The numerical study was carried out using meshfree CFD, i.e., Smoothed Particle Hydrodynamics. In addition, advanced post-processing was conducted with Blender. The aims of this study were found out the effective baffle configuration ​​to reduce sloshing using vertical and horizontal in the prismatic tank. The results showed the most effective baffle variation for roll motion is 0.9 for vertical baffle and a horizontal baffle height is 0.1 from the water surface. It showed baffles effectively reduces dynamic pressure, hydrodynamic force and free surface deformation

Passive control of, energy storage of NePCM, heat and mass transfer with gamma-shaped baffle in a thermo-bioconvection system using CFD and artificial intelligence

The passive control of energy storage of Nano Enhanced Phase Change Material (NePCM), heat and mass transfer in a closed space was investigated using a Gamma-Shaped baffle in this numerical study. The Galerkin Finite Element Method was used to conduct a numerical study of the thermos-bioconvection system. The CFD data was used to calculate additional data using the Artificial Intelligence technique. The study was carried out for various parameters such as Darcy number, baffle position, Hartmann number, Lewis and Peclet numbers. The position of the L-shaped closed space is observed to be a control element for bioconvection heat transfer in a partially heated closed space, with an optimal value around ω = 150o. Artificial intelligence prediction algorithms, as they do in many other industries today, produce very useful results in the energy sector. In this study, we attempted to estimate the results of three different decision tree algorithms on the created datasets. In most of the datasets, we achieved 100% estimation accuracy using the single decision tree, random forest, and gradient boosted tree. We plotted a graph of the actual and predicted values for the dataset to compare the results. We believe that the successful outcomes will pave the way for exciting developments in the use of artificial intelligence prediction algorithms in the field of CFD.

Proton Exchange Membrane Fuel Cell as an Alternative to the Internal Combustion Engine for Emission Reduction: A Review on the Effect of Gas Flow Channel Structures

Proton exchange membrane fuel cells are a new energy technology with great potential due to advantages such as high efficiency and no pollution. The structure of the gas flow channels has a profound impact on the overall performance of the fuel cell. Different flow channel geometries have their own advantages and disadvantages, and a good understanding of the influence of these structures on performance can provide a reference for the design and improvement of flow channel geometries in various application contexts. Numerical models can be used as a reasonable and reliable tool to evaluate the influence of operating and structural parameters on cell performance and service time by simulating the transport processes of substances and heat as well as electrochemical reactions inside the fuel cell and can be used for the optimisation of cell design. This paper reviews the recent models of proton exchange membrane fuel cells, summarises and analyses the effect of gas flow channels on fuel cells, and organises and concludes efficient design of flow channel structures to enhance PEMFC performance in terms of the cross-section shape, length, width, number of flow channels, and baffle position.

Stray light analysis of diamond-turned image slicers

We describe the process through which stray light analysis should be performed in optical systems involving image slicers. We detail how scattering models should be used depending on how the image slicer assembly will be fabricated. Our work describes how to determine all ray paths, compute cross-talk on the pupil mirrors due to scattering, quantify the ghost images’ intensity, and determine baffle positions. In the example given, an ABg model is applied to all mirror arrays separately, before considering their contributions altogether. We also consider diffraction due to the image slicer’s narrow slice apertures, which contribute to unwanted light in the system by causing cross-talk on the pupil mirrors. Using Fourier optics, this quantity is computed and compared with cross-talk caused by scattering. Our work represents a useful asset for optical engineers who work on image slicer-based systems and want to analyze stray light, by providing a clear and exhaustive procedure to follow to obtain accurate estimates.

Design of Integrating Sphere Uniform Light System for Solar Simulator

In the process of designing and adjusting the solar simulator, the side lobe effect and aberration of the optical integrator affect the irradiation uniformity, an integrating sphere is proposed to replace the optical integrator for uniform light and the compound parabolic reflector for beam shaping. First, based on the equal illuminance theorem and the radiation transfer theory, the calculation formula of the energy transmission efficiency of the porous integrating sphere is derived; Then, the light hole illuminance interference factor is introduced, and the effects of the aperture size of the integrating sphere, the radius of the integrating sphere, and the size and position of the baffle on the energy transmission efficiency and irradiation uniformity are analyzed. Finally, an integrating sphere uniform light system with high energy transmission efficiency and uniformity is designed and simulated with LightTools software. The simulation results show that: the average difference of irradiation uniformity and the range difference of irradiation uniformity are closest to 1 in the area where the ratio of the opening size and radius of the integrating sphere is 36%–40%, and the light is evenly distributed; When the baffle position is 0.8 times of integrating sphere radius away from the light entrance hole, irradiation non-uniformity at the outlet hole is 1.99%, which is the best position of the baffle; In the effective irradiation surface of Φ1032 mm, the irradiation non-uniformity is 1.98%, and the maximum irradiance is 0.62 solar constants, the spot simulation with high irradiation uniformity on large irradiation surface is realized.