Baffle System Research Articles

Liquid Sloshing in Soil-Supported Multiple Cylindrical Tanks Equipped with Baffle under Horizontal Excitation

The dynamic behavior of liquid storage tanks is one of the research issues about fluid–structure interaction problems. The analysis errors of the dynamics of multiple adjacent tanks can exist if neglecting soil–tank interaction since tanks are typically supported on flexible soil. In the present paper, the dynamics of a group of baffled cylindrical storage tanks supported on a circular surface foundation and undergoing horizontal excitation are analytically examined. For upper multiple tank–liquid–baffle subsystems, accurate solutions to the velocity potential for liquid sloshing are acquired according to the subdomain partition technique. A theoretical model is utilized to portray the continuous sloshing of each tank. For the soil–foundation subsystem, a lumped-parameter model is used to characterize the impacts of soil on upper-tank structures using Chebyshev complex polynomials that present the fitting results of horizontal, rocking, and coupling impedance functions. Then, a model of the soil–foundation–tank–liquid–baffle system is constructed on the basis of the substructure approach. The present sloshing frequencies, sloshing height, and hydrodynamic shear as well as the moment under rigid/soft soil foundations are compared to the available exact results and the numerical results to prove the validity of the present model. The error of the maximum sloshing height between the present and the numerical solutions is within 5.27%; the solution efficiency of system dynamics from the present model is 40–50 times faster than that from the ADINA model. A detailed parameter analysis of the dynamic characteristics and earthquake responses of the coupling system is presented. The research novelty is that an equivalent analytical model is presented, and it allows for investigating the dynamics of soil-supported multiple cylindrical tanks with a baffle, providing acceptable accuracy and high calculation efficiency.

Sloshing mitigation in microgravity with moving baffles

We numerically investigate the effect on sloshing in microgravity of systems with passive, moving baffles whose motion is restricted by linear springs. The liquid is assumed to have physical properties similar to those of 5cSt silicone oil while the baffle is made of aluminium. Two kinds of numerical models are developed depending on whether the allowed baffle motion is translational or rotational. Simulations show that moving baffles significantly improve sloshing mitigation compared to fixed baffles, with decreases of up to 48% in the decay time and 23% in the fluid kinetic energy following excitation by a certain pulse-like acceleration. In all configurations considered, there exists an optimal spring stiffness that minimises the kinetic energy or decay time. Frequency analysis reveals two peaks in the range of 0.1–2Hz whose amplitudes vary as a function of spring stiffness, analogous to the behaviour of Tuned Mass Dampers (TMDs). The effectiveness of the moving baffle system is then assessed using a real microgravity perturbation measured during a reboosting manoeuvre of the International Space Station (ISS) and a significant reduction in decay time relative to the fixed baffle case is found: to 1.3s from 4s.

A novel framework for predicting active flow control by combining deep reinforcement learning and masked deep neural network

Active flow control (AFC) through deep reinforcement learning (DRL) is computationally demanding. To address this, a masked deep neural network (MDNN), aiming to replace the computational fluid dynamics (CFD) environment, is developed to predict unsteady flow fields under the influence of arbitrary object motion. Then, a novel DRL-MDNN framework that combines the MDNN-based environment with the DRL algorithm is proposed. To validate the reliability of the framework, a blind test in a pulsating baffle system is designed. Vibration damping is considered to be the objective, and a traditional DRL-CFD framework is constructed for comparison. After training, a spatiotemporal evolution of 200 time steps under the influence of arbitrary object motion is predicted by the MDNN. The details of the flow field are compared with the CFD results, and a relative error within 5% is achieved, which satisfies the accuracy of serving as an interactive environment for DRL algorithms. The DRL-MDNN and traditional DRL-CFD frameworks are then applied to the pulsating baffle system to find the optimal control strategy. The results indicate that both frameworks achieve similar control performance, reducing vibration by 90%. Considering the resources expended in establishing the database, the computational resource consumption of the DRL-MDNN framework is reduced by 95%, and the interactive response time during each episode is decreased by 98.84% compared to the traditional DRL-CFD framework.

An Analysis of Fuel Oil Sloshing in Partially Filled Cargo Tanker Trucks under Cornering Conditions Using Various Baffle Systems

Ethiopia imports all fuel and crude oils from abroad at high cost, and transportation of these fluids has been carried out by using various capacity of road transportation heavy-duty truck vehicle. Most tanker truck accidents happen during turning because of the fluid splashing in partially loaded tanks and of the uniqueness of the carrying liquids. This is a result of the fact that current baffle configurations are effective at reducing sloshing when braking or accelerating but ineffective at doing so when turning. Consequently, the primary goal of this thesis work is to investigate how different baffle systems affect lateral sloshing reduction. In this work, the optimal baffle configuration and its arrangements for modified oval tanks at 50% and 80% fill levels were tried, and the dynamic analysis of tanker trucks was researched. The tanker truck and baffle system are designed in CATIA V5 for the numerical analysis, and the CFD study is completed in ANSYS Fluent 2021. R2 and the dynamic analysis are carried out in ANSYS LS-DYNA to study the stability of truck. The computational simulation is carried out as a tank with eight types of baffle systems such as existing baffles (TB), TB with BMLB, UMLB, CLB, 2HLB, 2VHLB, 4HLB, and 4VHLB with similar meshing resolution, similar turbulence modeling, similar boundary conditions, and also similar solution strategies. Transverse baffles with bottom-mounted four holes longitudinal baffle with hole-varying position (4VHLB) are discovered to be the best baffle type after evaluating all baffle designs. This suggests that the quantity of sloshing is reduced as the number of holes with small diameters increases. Maximum lateral force and roll moment are reduced by the most, by 47.76% and 58.66%, respectively, at 50% fill level and by 58.08% and 22.52%, at 80% fill level. Consequently, the case tanker truck’s use of this revised design baffle will be crucial for enhancing rollover stability while cornering.

A microfluidic application for mass production of drug-loaded polymeric microspheres for a long-acting injectable with IVL-DrugFluidic®, a novel microfluidic microsphere manufacturing platform technology

Long acting injectables (LAIs) using polymeric microspheres has been developed to increase patient compliance and reduce side effects. Among many methods for manufacturing polymeric microspheres, microfluidics technology is known to have excellent characteristics in that the produced polymeric microspheres have perfect spherical shape without surface defect and uniform size, and thus have outstanding efficacy without initial burst. However, the mass production of polymeric microspheres was not realized by the inherent limitation that microfluidics is suitable for small quantity manufacturing. Overcoming such limitations, we could show mass production of finasteride-loaded polymeric microspheres (PLGA 7525) for LAIs using our microfluidic manufacturing platform technology, IVL-DrugFluidic®. The microfluidic channels used in manufacturing were optimized through computational fluid dynamics (CFD) simulation to minimize the flow variation between microchannels and eliminated disturbance outside of microchannels by resistance channels. In addition, the solvent removal was improved by applying the baffle and foam breaker system. Therefore, microspheres were mass-produced in the GMP manufacturing environment in perfect spherical shape, smooth surface, and even size distribution. The encapsulation efficiency was almost 100% and the residual solvent was under the Standard of regulation. In the clinical trial using microspheres mass-produced by IVL-DrugFluidic®, we confirmed that the drug release was stably maintained for a month, the target period without initial burst. It was also confirmed that the drug release by dose of microspheres was uniformly proportional. In conclusion, the microsphere manufacturing platform technology, IVL-DrugFluidic® has been proven to be an appropriate system for mass production of polymeric microspheres optimized for LAIs through physicochemical characteristics and clinical trial.

Reduced power consumption in stirred vessel with high solid loading by equipping punched baffles

Solid–liquid suspension in stirred tank is a common operation in the chemical industry. The power consumption, flow pattern and flow field instability of three systems named as unbaffled stirred tank, traditional baffled stirred tank and punched baffled stirred tank (Pun-BST) were studied by using the computational fluid dynamic analysis. Results showed that perforating holes in the baffles could reduce power consumption of mixing. Meanwhile, the punched baffle system could maintain the solids in suspension as traditional baffle system. The results also showed that the baffles could increase the “effective flow” of stirred tank even though the whole velocity of the vessel is lower than un-baffled vessel. In addition, both the solid–liquid suspension and “effective flow” were related to instability of the flow field. Perfect solid–liquid suspension results always along with obvious instability of the flow field. But, the strengthening effect of punched baffle on flow field instability mainly happened in the near-wall area. It’s because the collision and aggregation among sub-streams induced by holes intensified the unstable fluid flow. On the whole, the Pun-BST system provided much better mixing characteristics and recommended to apply in the industrial process.

Crown-Like Baffle System against Rock Avalanches: Energy Dissipation Mechanism and Numerical Verification

Crown-Like Baffle System against Rock Avalanches: Energy Dissipation Mechanism and Numerical Verification

Small telescopes being effective: MAGIC or not?

Abstract The paper describes the MAGIC multimode focal reducer (Monitoring of Active Galaxies by Investigation of their Cores), commissioned on the 1-m Zeiss-1000 telescope of the Special Astrophysical Observatory of the Russian Academy of Sciences in 2020 September. Three observational modes are currently realized: photometry, polarimetry, and long-slit spectroscopy. Reducing the focal length makes it possible to obtain a sufficiently large field of view for photometry and a large slit height for spectroscopy of ∼12′ , as well as a large field of view for polarimetry with a quadrupole Wollaston prism of ∼6${_{.}^{\prime}}$4. This feature makes the complex study of extended nebulae and galaxies efficient. The MAGIC capabilities are presented in examples of observations of various astronomical objects. The spectral mode in the range of 4000–7200 ÅÅ provides the spectral resolution R ∼ 1000; for a starlike target up to 14 mag in medium-band filters with a seeing of 1″ for 20 min of total exposure, the photometry accuracy is better than 0.01 mag and the polarization accuracy is better than 0.6 per cent. Especially for the new focal reducer, an offset guide and a position angle rotation system were implemented. The results of the modernization of the baffle system in the optical scheme of the telescope for the suppression of scattered light are also described.

Effect of stirring speeds on biodiesel yield using an innovative oscillatory reactor and conventional STR (A comparative study)

This paper aims to study the effect of stirring speed on biodiesel yield using an innovative oscillating reactor compared to the conventional stirring tank reactor. The efficiency of the invented reactor was compared with the conventional system, employing two catalysts (a homogeneous catalyst and a heterogeneous bio-catalyst). The obtained results showed that under low agitation speed of 50 rpm, the invented oscillating reactor is more efficient than the conventional system with a biodiesel yield of 93% compared to 90.13% using the heterogeneous catalyst and 93.53% compared to 92.7% using the homogeneous catalyst respectively. As for the higher stirring speeds, the conventional system was found to be slightly more efficient than the oscillating reactor when using the heterogeneous biocatalyst (96.03% against 94.42%) while the contrary was observed when using the homogeneous catalyst (94.43% against 95%). However, this slight increase in the biodiesel yield at higher speeds results in increasing production costs. This indicates that biodiesel production using the innovative oscillating reactor at low speeds is more economically viable. The characteristics of the produced biodiesel using the invented reactor were in agreement with the ASTM D6751 biodiesel standards. Moreover, a two-way ANOVA analysis was conducted to compare between groups that have been split on two independent variables as reactor type and stirring speed. The statistical analysis proved that the invented oscillating reactor performs better when using heterogeneous catalysts at low stirring speed levels. This study suggests that the biodiesel yield of the innovative reactor can be further enhanced by introducing a baffle system which provides a relatively larger contact surface area. Similarly, synthesis of other heterogeneous bio-catalysts derived from the date seed of another date palm cultivar can be tested to further improve the biodiesel yield.

Review of the Liquid Hydrogen Storage Tank and Insulation System for the High-Power Locomotive

Hydrogen has been attracting attention as a fuel in the transportation sector to achieve carbon neutrality. Hydrogen storage in liquid form is preferred in locomotives, ships, drones, and aircraft, because these require high power but have limited space. However, liquid hydrogen must be in a cryogenic state, wherein thermal insulation is a core problem. Inner materials, including glass bubbles, multi-layer insulation (MLI), high vacuum, and vapor-cooled shields, are used for thermal insulation. An analytic study is preferred and proceeds liquid hydrogen tanks due to safety regulations in each country. This study reviewed the relevant literature for thermodynamic modeling. The literature was divided into static, dynamic, and systematic studies. In summary, the authors summarized the following future research needs: The optimal design of the structure, including suspension, baffle, and insulation system, can be studied to minimize the boil-off gas (BOG). A dynamic study of the pressure, mass flow, and vaporizer can be completed. The change of the components arrangement from the conventional diesel–electric locomotive is necessary.

Perbandingan Pemilihan Antara Tipe Wellhead Conventional Dengan Wellhead Unihead

The wellhead is a surface well control device made of steel which forms a seal / baffle system to withstand bursts or leaks of liquid from the well to the surface composed of casing head (casing hanger) and tubing head (tubing hanger). Wellhead used in an oil or gas well must have a long runlife because an oil or gas well can last up to decades, and if it is necessary to replace the wellhead will take large costs. This paper determines the process in selecting the use and effectiveness of wellhead and comparing conventional wellhead versus unihead wellhead at W well that is efficient and safe during drilling well and optimal utilization during production process. Wellhead type selection process cover determining temperature class, material class, pressure rating, installation costs, and in terms of safety. Based on the selection process, W wellhead well has the temperature class used is class U, the material class used is the type FF-0.5 or HH-0.5, for a pressure rating of 3000 psi, and in terms of cost it is more economical to use unihead wellhead type.

Design and Analysis of Various Baffle System in Shell Tube Heat Exchanger

Heat exchangers are systems of thermal engineering in which its applications are occurred in different industries. Heat exchangers are the basic or heart of once organized plant since it transfers energy to the processing plant Shell and tube heat exchanger is the most common type heat exchanger widely use in refinery and other chemical process, because it suits high pressure application. The process in solving simulation consists of modeling and meshing the basic geometry of shell and tube heat exchanger using CFD package ANSYS 18.0. The objective of the project is design of shell and tube heat exchanger with various baffle structure and study the flow and temperature field inside the shell using ANSYS software tools. The heat exchanger with single, double, and with 10 and 20 degree inclined baffle will be defined. In simulation will show how the pressure varies in shell due to different double baffle angle and flow rate. The flow pattern in the shell side of the heat exchanger with angled baffles was forced to which results in a significant increase in heat transfer coefficient per unit pressure drop in the heat exchanger.

Optical system of a micro-nano high-precision star sensor based on combined stray light suppression technology.

The micro-nano design of a high-precision star sensor is studied. Point source transmittance (PST, the ratio of the irradiance generated by the external field source on the image surface to the irradiance at the entrance pupil) is used as the evaluation index of stray light suppression ability, the stray light suppression theory of star sensors is analyzed, and the mathematical model between stray light suppression ability and detectable magnitude is established. In view of the limited volume of micro-nano star sensors, a new design principle of combined anti-stray-light design of the baffle and optical system is proposed. The high stray light suppression of the micro-nano star sensor is realized by using the imaging optical path design of active stray light suppression and the design of a conical extinction cavity, which breaks through the technical problem of coupling system volume and stray light suppression ability. The results of the simulation and on-orbit experiments show that the star sensor based on the joint stray light technology can achieve a PST of 2×10-8 at the avoidance angle under the premise of limited optical system volume, and it has a stray light suppression ability of 6.5 magnitude stars.

New field wind manipulation methodology reveals adaptive responses of steppe plants to increased and reduced wind speed

BackgroundWind strongly impacts plant growth, leaf traits, biomass allocation, and stem mechanical properties. However, whether there are common whole-plant wind responses among different plant species is still unclear. We tested this null hypothesis by exposing four eudicot steppe species to three different wind treatments in a field experiment: reduced wind velocity using windbreaks, ambient wind velocity, and enhanced wind velocity through a novel methodology using wind-funneling baffles.ResultsAcross the four species, wind generally decreased plant height, projected crown area, and stepwise bifurcation ratio, and increased root length and stem base diameter. In contrast, the response patterns of shoot traits, especially mechanical properties, to wind velocity were idiosyncratic among species. There was no significant difference in total biomass among different treatments; this might be because the negative effects on heat dissipation and photosynthesis of low wind speed during hot periods, could counteract positive effects during favorable cooler periods.ConclusionsThere are common wind response patterns in plant-size-related traits across different steppe species, while the response patterns in shoot traits vary among species. This indicates the species-specific ways by which plants balance growth and mechanical support facing wind stress. Our new field wind manipulation methodology was effective in altering wind speed with the intended magnitude. Especially, our field wind-funneling baffle system showed a great potential for use in future field wind velocity enhancement. Further experiments are needed to reveal how negative and positive effects play out on whole-plant performance in response to different wind regimes, which is important as ongoing global climatic changes involve big changes in wind regimes.

Effects of different damping baffle configurations on the dynamic response of a liquid tank under seismic excitation

The dynamic motion of liquid sloshing in a container due to an external excitation can cause pressure pulses that severely damage the structure. In this study, a 2D rectangular tank was used to numerically model the hydrodynamic characteristics of sloshing and the pressure response in a typical industrial container. Harmonic and ground motion excitations were considered, and seven recorded ground motions were used to simulate the pressures at specified monitoring points. The contributions of the filling depth, ground motion components, and damping baffle to the pressure response history under impulsive and convective mode were examined. Based on the analysis of the dynamic response, a suitable damping baffle system was developed for all seismic excitations. The results of this work contribute toward improving tank design in earthquake-prone regions of the world.

Inorganic fouling mitigation using the baffle system in direct contact membrane distillation (DCMD)

Although membrane distillation (MD) has the potential for use in both desalination and industrial wastewater treatment, its widespread application has been hindered by its inherent limitations such as membrane fouling due to scale formation. One of the approaches to overcome this challenge is to develop novel membrane modules to mitigate the scale formation. Accordingly, this study sought to devise a way to control scale formation in MD systems using baffles in the modules. Moreover, the analysis based on computational fluid dynamics (CFD) was carried out together with bench-scale experiments to understand the hydrodynamic conditions in MD modules. CFD model was developed and applied to analyze flow velocity, shear stress, and vorticity. CFD analysis revealed that the baffled-modules can provide higher shear stress and generate both oscillatory mixing and vortices. Experimental results showed that fouling due to scale formation was more efficiently mitigated in the modules with the orifice baffles than the other modules. The final flux was increased from 2 L/m2-hr in the basic module to up to 19 L/m2-hr in the module with three orifice holes. According to the CFD results, it is attributed to the retardation of crystal deposition and cake formations by increased shear stress and vortices.

Research on the thermal performance of rack-level composite baffle diversion system for data centre

Airflow management plays an important role in ensuring secured and energy-efficient operation of data centres (DCs). Higher power density in DC is a risk resulting in serious deterioration of airflow distribution accompanied by the increasing cooling energy demand. In this study, the airflow optimization effects of rack baffles and server lower-side terminal baffles on the thermal environment are first validated by experiments. Then, the optimization mechanisms of the two baffle systems are analysed by numerical simulations. The results show that the optimization mechanisms of these two systems are different and the combination can contribute to better airflow distribution than separate baffles. The analysis is validated by altogether 12 cases in 3 scenarios where different combinations of the two systems were included. The results validated the combination of 8 cm × 45° server lower-side terminal baffles and 20 cm × 75° rack baffles can further improve the airflow distribution and relieve heat accumulation in the DC. The impacts of combined baffle system on the thermal environment in DC are analysed by experiments and simulations. The combined system superposes the airflow optimization functions of the two systems. The maximum temperature drop of the hotspot is 0.7 °C, which is 0.4 °C lower than that when only optimal rack baffles or server lower-side terminal baffles are installed.

Additive Aerodynamic and Thermal Effects of a Central Guide Post and Baffle Installed in a Solar Updraft Tower

The solar updraft tower (SUT) is a renewable power generation system that uses natural air convection from the ground that is heated by solar radiation. Placing flow-guide structures within the collector of the SUT can enhance aerodynamic performance, and hence, increase the kinetic power. Here, we propose a central guide post (CGP) structure in the SUT that controls updraft flow. The effect of the CGP geometry on aerodynamic performance was investigated using computational fluid dynamics modeling (ANSYS Fluent 19.2) to show that a CGP can play a positive role by preventing stagnation of the airflow at the center of the collector, resulting in increased kinetic power output (up to ~2%). However, excessively long CGPs retarded airflow, resulting in a dramatic decrease in kinetic power output. We also investigated a system with both a CGP (to improve aerodynamic performance and minimize energy loss) and a heat-exchange baffle (to maximize thermal energy transfer). When installed with a proper distance between components, the CGP and baffle showed a combined effect of increasing the kinetic power output by up to 10%. We expect that our proposed method using the CGP and baffle system will contribute to the development of better future SUT technology.

Effects of new baffles system under the impact of rock avalanches

To reduce the flow energy of rockfall in rmountain area, a baffle array is set up in the protection zone. The optimized design can enhance the efficiency of hazard source energy dissipation project. In the present study, the arc-shaped baffles were studied as compared with the conventional baffles (square baffles and cylindrical baffles) based on practical engineering. The comparison of three types of baffles was discussed in detail by experimental studies, which primarily focused on the blocking ability and effectivity. In particular, by determining the optimal case using those different types of baffles, the effects of the optimization of baffle system [column spacing, row spacing and Ld (distance between first baffle row and chute terminal)] were investigated. According to the results, the arc-shaped baffle is the best case among those three types of baffle, i.e. the deposit area and runout are all shorter than those of any other cases with the same value of Sr. Shape changing (cylindrical to arc-shaped) will up-regulate the fragment blockage degree; the following avalanches will take place close to the avalanche deposition, leading to a huge dissipation of kinetic energy. Moreover, by comparing deposition, dimensionless velocity (U*) and velocity reduction ratio (VRR), arc-shaped baffle system showed competitive blocking ability when Sc=3.5 and Sr=4.5. With the rise in the Ld, the energy dissipation efficiency can be enhanced through the particle collision and particle friction during the geo-disaster movement. Furthermore, it can effectively narrow the deposit area and reduce deposit depth and deposit width. The results obtained from this study are useful for facilitating design of baffles against rock avalanches.

Numerical investigation of effects of “baffles - deceleration strip” hybrid system on rock avalanches

Arrays of baffles are usually installed in front of protection site to attenuate the flow energy of rock avalanches in mountainous areas. Optimization design is crucial for efficiency promotion in hazard energy dissipation engineering. In this study, a deceleration strip was added in the baffles protection system to optimize the traditional baffles system. The effects of the "baffles - deceleration strip" hybrid protection system was discussed in detail with the nails number and nails angle. This study presents details of numerical experiments using the discrete element method (DEM). The effect of the optimization of hybrid protection system (nail angle and nail number) were investigated specifically, especially the impact force that avalanches exerted on structures. The results show that the maximum impact forces and kinetic energy of the rock avalanches decreases with the increase of the number and angle of the nail. Moreover, the distance between the toe and the bearing structure (L-m) is also a key factor. The shorter the distance L-m (30m) is, the higher the maximum impact force are. The longer the distance L-m (70m) is, the lower the maximum impact force are. Under the same size of the nails, increasing the numbers can enhance the dissipation ability of the hybrid protection system. Meanwhile, increasing its angle can also enhance the dissipation ability. There are three key ways for nails attenuate rock avalanches: (i) block the fine particles directly; (ii) form the particles bridge between nails and baffles; (iii) dissipate the coarse particles energy directly. The effect of segregation in rock avalanches is crucial for the energy dissipation mechanism, which is a key factor to optimize the traditional baffle system.