Baffle Plate Research Articles

Improving Liquid Desiccant Dehumidifiers through Square Baffle Plate Design and Nanofluid Innovation

Enhancing the performance of the liquid desiccant dehumidifier (LDDs) is pivotal, with mass transfer playing a significant role. Compared to the previous method, using a baffles plate improved liquid desiccant dehumidification performance. The study utilized an aqueous solution containing nanocarbon tubes (NCTs) in LiCl/H2O as the desiccant, cascading over baffles plate with a square profile. The performance of this system was determined using numerical methods. The concentrations of NCTs ranged from 0.03% to 0.5% by weight. Furthermore, this paper investigates the impact of nanoparticles and parameters, including flow rates, solution concentration, humidity, solution temperature, etc. on the analysis through Computational Fluid Dynamics (CFD) simulation. The study shows a 29% increase in moisture removal and humidity change, along with a 15.57% improvement in film thickness. These findings are underpinned by the principle of a reduced in contact angle from 57° to 29°, resulting in reduced partial pressure of water vapor from the solution, thereby enhancing the mass transfer mechanism. Consequently, the utilization of baffles plate demonstrates a significant improvement in the moisture removal performance of the LDDs.

Investigation on the effect of vertical baffle plate on droplet size distribution and mixing efficiency in Taylor Reactor

The Taylor reactor is a dynamic mixer based on the principles of Taylor vortex flow. However, traditional Taylor reactors feature smooth inner and outer cylinder surfaces, presenting challenges in achieving uniform mixing and efficient mass transfer. These limitations do not meet the requirements of modern chemical processes for highly efficient mixing equipment. This article introduces a novel Taylor reactor equipped with vertical baffle plates, designed to overcome these challenges. A comprehensive methodology combining CFD-PBM and experimental techniques was employed to investigate both droplet size distribution and mixing performance in the annular gap. Compared to traditional designs, the new device demonstrates significantly lower COV at 0.018 and Sauter mean diameter at 38.3 μm. Optimal mixing efficiency is achieved at rotating Reynolds number (Re) of 1.17 × 105 and inlet Reynolds number (Rei) of 2.65 × 103. Numerical simulation results suggest that vertical baffles effectively enhance liquid-liquid interactions including collision, interface contact, and droplet residence time within the annular gap. Moreover, increased turbulent stress in the flow field contributes to greater vorticity, turbulence intensity, and turbulent kinetic energy resulting in smaller droplet sizes and improved mixing efficiency. These findings provide a theoretical foundation for hydraulic structural optimization design as well as widespread application of Taylor reactors.

Simulation study on flow field regulation of flotation column with stirring device

ABSTRACT Flow field regulation plays an important role in the optimization of column flotation units with agitation function. This paper aims to discuss the regulating effect of baffle design on the flow field in stirred column flotation units by numerical simulation. A series of geometric models of changing baffle structure and layout were established, and detailed flow field simulation analysis was carried out by using COMSOL software. The results show that the internal flow field of the traditional standard cylindrical tank will cause the solid particles to adhere to the wall movement and the bubbles to the middle area, resulting in the uneven distribution of particles and bubbles, and the internal flow field is not conducive to the mineralization process and the stability of the foam layer. This limitation can be significantly improved by introducing baffles. The results show different baffle shapes and layouts are as follows: wide and narrow on top, narrow on the bottom and wide on top, and only arranged at the bottom of the column body, can increase the average turbulent kinetic energy in the collision zone by 22%, 46% and 43%, and the average turbulent dissipation rate by 18%, 43% and 36%, respectively, while maintaining the turbulence intensity in the transport zone. Among them, the baffle plate with wide top and narrow bottom has the best effect. Arranging baffles with a length shorter than 2/3 of the height of the cylinder at the upper part inside the cylinder can also enhance the turbulence intensity in the collision zone, but at the same time, it also increases the turbulence intensity in the transport zone. Moreover, as the length of the baffle decreases, the enhancement effect becomes stronger. Since this method significantly affects the transport zone, it is more suitable for columnar mixing devices. The study also reveals that by adjusting the proportion of wide and narrow baffles, the center of the turbulent region can be laterally shifted to the short baffles, and the flow field distribution can be adjusted. Meanwhile, with the increase in the number of long baffles, the intensity of the flow field in the device will gradually decrease. By moving the center of the turbulent region to the side inlet, the particle dispersion can be accelerated, but in general, the particles will accumulate toward the region with lower turbulence intensity. These findings have important guiding significance for the design and optimization of the flow field of the stirred column flotation unit, which is helpful in improving the agitation uniformity and flotation efficiency.

Thermo-fluid performance of axially perforated multiple rectangular flow deflector-type baffle plate in an tubular heat exchanger

The study investigated an unconventional heat exchanger design that utilizes swirling airflow to enhance heat transfer over heated tubes. This innovative system incorporates a perforated round baffle plate, accompanied by multiple rectangular air deflectors oriented in opposite directions at varying inclination angles. These deflectors are symmetrically arranged at different pitch ratios alongside consistently spaced tubes forming a circular configuration, all subject to a uniform heat flux. Enclosed within a circular duct with longitudinal airflow, the combined baffle plate and tube assembly bring forth efficient heat transfer. The air-side turbulence intensified by the deflectors induces a chaotic motion, contributing to enhanced surface heat transfer. Each baffle plate has twelve opposite-oriented deflectors, resulting in opposing swirl flows that further promote flow recirculation and augment surface heat transfer. The performance of this heat exchanger was evaluated by considering different pitch ratios and inclination angles across a Reynolds number range of 16000-30000. The findings demonstrate that the heat exchanger with rectangular flow deflectors on the baffle plate exhibits significant improvements in thermo-fluid performance. Notably, an average enhancement of 1.88 was observed at an inclination angle of 50 degrees and a pitch ratio of 1.2 when compared to an exchanger without baffle plates, emphasizing the considerable impact of these design aspects.

Biohydrogen generation from distillery effluent using baffled up‐flow microbial electrolysis cell

AbstractMicrobial electrolysis cell (MEC) is gaining importance not only for effectively treating wastewater but also for producing hydrogen. The up‐flow microbial electrolysis cell (UPMEC) is an innovative approach to enhance the efficiency, and substrate degradation. In this study, a baffled UPMEC with an anode divided into three regions by inserting the baffle (sieve) plates at varying distances from the cathode was designed. The effect of process parameters, such as flow rate (10, 15, and 20 mL/min), electrode area (50, 100, and 150 cm2), and catholyte buffer concentration (50, 100, and 150 mM) were investigated using distillery wastewater as substrate. The experimental results showed a maximum of 0.6837 ± 0.02 mmol/L biohydrogen at 150 mM buffer, with 49 ± 1.0% COD reduction using an electrode of area 150 cm2. The maximum current density was 1335.94 mA/m2 for the flow rate of 15 mL/min and surface area of 150 cm2. The results showed that at optimized flow rate and buffer concentration, maximum hydrogen production and effective treatment of wastewater were achieved in the baffled UPMEC.Practitioner Points Biohydrogen production from distillery wastewater was investigated in a baffled UPMEC. Flowrate, concentration and electrode areas significantly influenced the hydrogen production. Maximum hydrogen (0.6837±0.02mmol/L.day) production and COD reduction (49±1.0%) was achieved at 15 mL/min. Highest CHR of 95.37±1.9 % and OHR of 4.6±0.09 % was observed at 150 mM buffer concentration.

Analysis of Inherent Frequencies to Mitigate Liquid Sloshing in Overhead Double-Baffle Damper

A disco-rectangular volume-fraction-of-fluid (VOF) model tank of a prismatic size is considered here for investigating the severe effect of overhead baffles made of three different materials, nylon, polyamide, and polylactic acid. In this work, the overdamped, undamped, and nominal damped motion of baffles and their effect are studied. In this research, the behaviour of different material baffles based on the sloshing effect and natural frequency of each baffle excited in damped, undamped, and overdamped cases is studied. VOF modelling is carried out in moving Yeoh model mesh with fluid–structure interaction between the water models for various baffle plates. The results of the water volume distribution and baffle displacement operating between a sloshing time of 0 and 1 s are recorded. Also, a strong investigation is carried out for the water volume suspended on overhead baffles by three different material selections.

Experimental investigations on thermo-fluid performance of perforated baffle aided with oppositely oriented sawtooth deflector in tubular heat exchanger

Purpose The investigation concentrated on studying a distinct category of tubular heat exchanger that uses swirling airflow over tube bundle maintained at constant heat flux. Swirl flow is achieved using a novel perforated baffle plate with rectangular openings and multiple adjustable opposite-oriented saw-tooth flow deflectors. These deflectors were strategically placed at the inlet of the heat exchanger to create a swirling flow downstream. Design/methodology/approach The custom-built axial flow heat exchanger consists of three baffle plates arranged longitudinally supporting tube bundle maintained at constant heat flux. The baffle plate equipped with saw-tooth flow deflector of various geometry represented by space height ratio(e/h). Next, ambient air was then directed over the tube bundle at varying Reynolds number and the effect of baffle spacing (PR), Space height ratio (e/h) and inclination angle(a) of deflectors on performance of heat exchanger was experimentally analyzed. Findings The heat transfer augmentation of heat exchanger for given operating condition is strongly dependent on geometry, inclination angle of deflector and baffle spacing. Originality/value An average improvement of 1.42 times in thermal enhancement factor was observed with inclination angle of 30°, space height ratio of 0.4 and a pitch ratio of 1.2 when compared to a heat exchanger without a baffle plate under similar operating conditions.

Enhancement of selenium removal in coal-fired flue gas across wet flue gas desulfurization spray tower by internal components-part 1: Demister and wall ring

Wet flue gas desulfurization (WFGD) device is a key piece of equipment used to control selenium, but its removal efficiency is highly variable (13%–95%). Adding internal components into WFGD can alter the gas-liquid flow pattern and is regarded as a promising technology for selenium removal. In this study, the demister and wall ring were adopted as internal components to investigate their feasibility on selenium removal and inherent mechanisms. Compared with the open tower (without internal components), the outlet selenium concentration was reduced by 52.2%–61.7% by installing a demister. This was because a liquid film was formed on the baffle plates of the demister after intercepting mists, which leaded a secondary absorption process for selenium. The lower plates of the demister made a major contribution to selenium removal, and increasing the plate area of the demister was beneficial to this process. The wall ring reduced the selenium emission by up to 56.5%, because it could force the flue gas and liquid column near/on the walls to flow towards the center, and significantly improve the gas-liquid contact. The enhanced method and mechanisms reported in this study can help to develop a low-cost technology to improve the selenium purification efficiency of existing WFGDs.

Experimental study on the effect of tube surface modifications and in-channel baffle plates on falling film evaporator heat transfer properties for sever cabinets

To effectively alleviate the high energy consumption associated with traditional cooling strategies in data centers, this research synoptically designs an innovative and energy-efficient integrated structure combining a falling film evaporator with a cabinet. An experimental setup with a water film tube in a rectangular channel is constructed, and the impacts of liquid film temperature, spray density, and inlet air Reynolds number on heat transfer properties in the cases of the tube's surface structure modifications and baffle plates presence in the channel are explored, respectively. Two significant findings that enable low energy consumption-oriented cooling strategy development are derived. (1) Decreasing the spray density can reduce energy consumption when liquid film integrity is maintained. Upon quadrupling the inlet spray density for the smooth and finned tubes, the heat transfer rate and heat transfer coefficient between the tubes and airflow in the baffled and unbaffled channels only increase by 23.1 to 29.9% and 18.6 to 28.3%, respectively. (2) The tube surface modifications and baffles presence can significantly improve the heat transfer performance. The performance evaluation criterion between the airflow and finned tube in the channel with baffles is 2.5–4.0 times higher than those between the airflow and smooth tube in the baffle-free channel.

Effect of Different Shapes of Nanoparticles on Mixed Convective Nanofluid Flow in a Darcy-Forchhiemer Porous Medium

The nanofluid has diverse applications in industries, engineering, and medicine due to its greater thermal characteristics. However, various factors such as the shape and size of nanoparticles, the base fluid, the porous medium, the quadratic drag force, and the viscous dissipation have significant effects on the flow and heat transfer characteristics of nanofluids. Therefore, it is crucial to study the influence of these factors. In this paper, a theoretical investigation is conducted to analyze the mechanisms of thermal conductivities of different shapes of nanoparticles, such as platelet, cylinder, brick and blade on the mixed convective nanofluid flow in a vertical channel saturated with porous medium. Consider ethylene glycol and water as base fluids for the nanoparticles, including copper, aluminum oxide, titanium oxide, silver, and iron oxide. A thin, movable baffle plate of negligible thickness is inserted in the channel and made into double passages. To define the porous matrix, the Darcy-Brinkaman-Forchhiemer model is used, and to define the nanofluid, the Tiwari and Das model is used. Robin boundary conditions are considered for the channel flow. The differential transform method (DTM) is applied to solve non-linear governing equations with inertia, and the perturbation method is applied to solve the problem without inertia. Velocity and temperature cantors are shown graphically using MATLAB and MATHEMATICA. The obtained values by DTM and the perturbation method are well validated and shown graphically. The Nusselt number was evaluated and tabulated for all governing parameters. The objective of this article is to investigate the effect of nonspherical shapes of nanoparticles, the base fluid, the inertial forces of the porous medium, and the buoyancy force on the thermal characteristics of flow and heat transfer of nanofluids. The main findings of this problem are that the optimum velocity and temperature cantor are found for platelet-shaped water-based silver nanofluid.

Modeling and Simulation of Drilling Gas Mixing Process with Various Conditions in Oil and Gas Pipeline Network

This research aims to model and simulate the gas drilling mixing process with various conditions in the inlet gas flow. This mixing process is very crucial because it can affect the phase stability in the storage tank. Based on this, the gas that has been mixed must be ensured that it is in a perfectly mixed condition before entering the storage tank. The simulation method used in this research is Computational Fluid Dynamics (CFD) with ANSYS Fluent software. The data used as input in this simulation includes flow velocity, temperature, pressure and drilling gas composition. The simulation results are expected to show that flow velocity and pressure have a significant effect on the drilling gas mixing process in the pipe flow. In addition, the differences in the composition of the drilling gas also have an impact on the mixing process, where the more diverse the composition of the drilling gas, the more difficult it is to mix the gas homogeneously. However, by using baffle plates as a barrier and agitator in the pipe, the simulation results show that the mixing of drilling gas can be significantly increased.

Investigation of structural parameters influencing vibration characteristics of heavy-duty truck diesel tanks.

The working conditions of heavy-duty trucks are very complicated as the diesel shaking and resonance problems, which causes weld tears, separators to fall off, and other failures occur. Through experiments and finite element simulation, the natural frequency and vibration mode of a given 400 L diesel tank were calculated to study the influences of structural parameters such as the fill ratio (0.1-0.9), the number of baffle plates (0, 1, 2), the spacing of the plates (240 mm, 400 mm, 560 mm) and the aperture (38 mm, 78 mm, 118 mm) on the modal parameters with the wet mode method. The results of the hammering mode test and the simulation modal analysis agree well with the maximum error is 4.8%; the natural frequency of the diesel tank will increase with fill ratio decrease; the increase of the baffle plate number (0, 1, 2) can effectively increase the first-order natural frequency of the diesel tank, but the change of the natural frequency is not obvious on the higher order; the higher plates spacing has a smaller natural frequency; increasing the aperture will highly increase the natural frequency, 188 mm has better vibration safety.

Correlating microstructure and mechanical properties of harvested high dose Zorita light water reactor internals

In this study, microstructural studies and micro-mechanical testing of an ex-plant material harvested from the decommissioned pressurized water reactor (PWR) is carried out. Irradiated 304 stainless steel (SS) components were harvested by the Electric Power Research Institute, U.S. Nuclear Regulatory Commission, and members of the José Cabrera Nuclear Power Station (Zorita) in Spain. The bi-crystalline micro-tensile specimens, atom probe tomography (APT) tips, and transmission electron microscopy (TEM) lamellae were fabricated from the baffle plate materials irradiated to 0.05, 15 and 50 dpa to elucidate microstructural, microchemical, and local mechanical properties changes as a function of dose. TEM and APT studies reveal radiation induced Ni, Cr, and Si rich precipitates in the 15 dpa sample that become smaller and partially redissolve into the matrix of the 50 dpa sample (decreasing size and number density). Dislocation loop and cavity number density and size were quantified as a function of dose as well as swelling. Intergranular Ni and Si enrichments with concomitant Fe and Cr depletion were observed in the 15 dpa sample and were more pronounced in the 50 dpa sample. Micro-tensile testing performed in the scanning electron microscope (SEM) at room temperature and 300 °C shows that the material's local yield strength and ultimate tensile strength decreases with increased dose and elevated test temperature and provides further insights via localized strain mapping. Current and previous mechanical data was compared with calculated values using the dispersed barrier hardening model with inputs of dislocation loops, precipitates, and cavities from microstructural characterization.

Thermal performance of tubular heat exchangers with the discontinuous swirl-inducing conical baffle with opposite-oriented flow deflectors

An experiment was conducted to analyze a tubular heat exchanger's turbulent heat transfer characteristics. The heat ex-changer was equipped with a newly designed perforated (rectangular) conical baffle plate consisting of two rectangular opposite-oriented flow deflectors with adjustable tilt angles. The baffle plate was installed at the entrance of the heat ex-changer, resulting in a counter-swirling flow pattern downstream. Three baffle plates were installed along the flow direction with different pitch ratios (spacing between baffle plates divided by the diameter of the heat exchanger). The experiment examined the effects of pitch ratio (ranging from 0.6 to 1.2), deflector tilt angle (ranging from 30° to 50°) and Reynolds numbers (ranging from 16 500 to 30 000) on the heat transfer performance. The results showed that the pitch ratio and tilt angle significantly affected the performance of the heat exchanger. In particular, a configuration with a tilt angle of 30° and a pitch ratio of 1 resulted in an average improvement of 26.9% in the heat exchanger's performance compared to a heat exchanger without a conical baffle plate under similar operating conditions.

Influence of combinational distortion generator geometrical parameters on the steady and dynamic components of the total pressure distortion

To construct a method for designing a total pressure distortion generator with adjustable, steady, and dynamic components, we experimentally investigated the influences of combinational distortion generator geometrical parameters on the steady and dynamic components of the total pressure distortion based on an indraft wind tunnel. Different types of annular plates and cylindrical rods were installed upstream of a traditional baffle total pressure distortion generator; the total pressure distortion was then measured using rotatable total pressure rakes. The installation of cylindrical rods upstream of the baffle plate could maximally reduce the ratio of steady and dynamic components of total pressure distortion by 30%. Increasing the number and height of the rods, as well as the axial distance between the rod and baffle plate, were effective methods of reducing the steady components of total pressure distortion. Similarly, changing the geometrical parameters of the annular plate was also an effective method for adjusting the ratio of steady and dynamic components of total pressure distortion. The ratio of the steady and dynamic components of total pressure distortion first experienced a decrease and then increased variance law with the increase in the height and circumferential scale of the annular plate. During this procedure, the steady and dynamic components ratio of total pressure distortion could be maximally reduced by 24% and maximally increased by 20%.

Suppression of the vortex-induced vibration of the cylinder by the baffle plates at different submerged depths

In this paper, the suppression effect of baffle on VIV of cylinder at different depths is studied. According to two-dimensional transient model and RANS equation, VIV responses of a cylinder with two baffle plates at a fixed distance and a fixed Angle at different depths are numerically simulated. The submersion depth radio h* is mainly 1.2, 1.5, 2.5 and 5. The experimental data and predicting results are compared to display the accuracy of numerical method. When h* is 2.5, the baffle plates have the best suppression effect on VIV. Compared to the bare cylinder, the amplitude is decreased by 69%. Meanwhile, the vibration of the cylinder at different depths shows instability, and the motion response has great jitter. The lower baffle plate is subject to a unidirectional force when h* = 1.5 and 1.2.

Multi-Objective Optimization of a Multi-Cavity, Significant Wall Thickness Difference Extrusion Profile Mold Design for New Energy Vehicles.

With the rapid development of the new energy vehicle market, the demand for extruded profiles for battery trays, mainly characterized by significant wall thickness differences in multiple chambers, is increasing, posing new challenges to production and quality control. This study examines the multi-objective optimization problem in the design process of aluminum profile dies with multi-cavity profiles and significant wall thickness differences. Using QFORM-extrusion professional aluminum extrusion finite element analysis software and the response surface analysis method, the standard deviation of the velocity (SDV), standard deviation of the pressure (SDP), and thick wall hydrostatic pressure (TWHP) on the profile section at the die exit are optimized. By analyzing the functional relationship between the key die structure parameters (the height of the baffle plates, the length of the bearing, and the height of the false mandrel) and the optimization objective, the optimal combination scheme of die structure parameters was obtained using the NSGA2 (non-dominated sorting genetic algorithm-2) multi-objective genetic optimization algorithm. The results show that, compared with the initial design scheme, the standard deviation of profile section velocity was reduced by 5.33%, the standard deviation of pressure was reduced by 11.16%, and the thick wall hydrostatic pressure was increased by 26.47%. The die designed and manufactured using this scheme successfully completed the hot extrusion production task, and the profile quality met the predetermined requirements, thus verifying the effectiveness of this study in optimizing the design of a multi-cavity aluminum profile die with significant differences in wall thickness for complex structures.

Gear-Shaped High-g Combustion Chamber for Micro Turbojet Engine Applications.

Enhancing combustion efficiency and optimizing the thrust-to-weight ratio are critical technical challenges encountered in the development, application, and growth of micro turbojet engines. The high-centrifugal (high-g) combustion chamber, as an innovative combustion chamber system, has the capability to replace the primary combustion chamber of the traditional turbojet engine, reducing the length of the combustion chamber while maintaining engine performance. Previous studies on the structure of the high-g combustor (HGC) have shown problems such as uneven temperature distribution of the turbojet rotor. To improve the feasibility of HGC integration into micro turbojet engines, this study conducts relevant experiments on a 120 N thrust engine. Subsequently, the results of these experiments were used to analyze the structural design of HGC through a simulation approach. Including six main configurations, the first four structural designs focused on establishing a suitable highly centrifugal environment to stabilize and improve the combustion performance, which was successfully achieved by designing the outer ring gear-shaped inlet with four different angles. Subsequent structural designs were based around improving the uniformity of the temperature distribution at the combustion chamber outlet. The final design of the HGC combustion efficiency is not much different from the original combustion chamber, and it can shorten the axial length of the combustion chamber by nearly 30%. The design of the air inlet holes and the baffle plate effectively improves the temperature uniformity at the outlet of the combustion chamber. Moreover, without changing the combustion chamber material, the corresponding engine weight can be reduced by about 10.7%, and the engine thrust-to-weight ratio can be improved by up to 12% with the same thrust, which provides design ideas for further lightweight applications.

Diseño de un sistema de agitación para un biorreactor de 1m3 de capacidad para la producción de ácido glicérico a partir de glicerol por fermentación microbiana de Acetobacter tropicalis

This work presents the design of an agitation system for a 1m3 capacity bioreactor intended to produce glyceric acid (GA) through microbial fermentation of A. tropicalis using 20% v/v glycerol as the primary substrate. Building on previous studies that evaluated ideal conditions for glyceric acid production, initial data were utilized to identify the impeller type and perform subsequent calculations, including impeller Reynolds number, power consumption, and mixing time. Once the agitator type was specified, standard geometric relationships were employed to size components of the agitation system, such as tank size, baffle plates, and agitator dimensions. Power consumption calculations were compared with results from other studies on fermentation media with similar rheological characteristics. The agitator's power consumption for mixing 1m3 of medium was determined to be 8.35 kW, achieving 95% homogenization in 5.14 seconds, with a mixing time error of approximately 10%, operating at an agitation speed of 500 rpm. Keywords: agitation system; glyceryc acid; bioreactor

Diseño de un sistema de agitación para un biorreactor de 1m3 de capacidad para la producción de ácido glicérico a partir de glicerol por fermentación microbiana de Acetobacter tropicalis

This work presents the design of an agitation system for a 1m3 capacity bioreactor intended to produce glyceric acid (GA) through microbial fermentation of A. tropicalis using 20% v/v glycerol as the primary substrate. Building on previous studies that evaluated ideal conditions for glyceric acid production, initial data were utilized to identify the impeller type and perform subsequent calculations, including impeller Reynolds number, power consumption, and mixing time. Once the agitator type was specified, standard geometric relationships were employed to size components of the agitation system, such as tank size, baffle plates, and agitator dimensions. Power consumption calculations were compared with results from other studies on fermentation media with similar rheological characteristics. The agitator's power consumption for mixing 1m3 of medium was determined to be 8.35 kW, achieving 95% homogenization in 5.14 seconds, with a mixing time error of approximately 10%, operating at an agitation speed of 500 rpm. Keywords: agitation system; glyceryc acid; bioreactor