Pressure Drop Reduction Research Articles

Optimizing CO2 Purification in a Negative CO2 Emission Power Plant

AbstractIn the pursuit of mitigating CO2 emissions, this study investigates the optimization of CO2 purification within a negative CO2 emission power plant using a spray ejector condenser (SEC) coupled with a separator. The approach involves direct‐contact condensation of vapor, primarily composed of an inert gas (CO2), facilitated by a subcooled liquid spray. A comprehensive analysis is presented, employing a numerical model to simulate a cyclone separator under various SEC outlet conditions. Methodologically, the simulation, conducted in Fluent, encompasses three‐dimensional, transient, and turbulent characteristics using the Reynolds stress model turbulent model and mixture model to replicate the turbulent two‐phase flow within a gas–liquid separator. Structural considerations are delved into, evaluating the efficacy of single‐ and dual‐inlet separators to enhance CO2 purification efficiency. The study reveals significant insights into the optimization process, highlighting a notable enhancement in separation efficiency within the dual‐inlet cyclone, compared to its single inlet counterpart. Specifically, a 90.7 % separation efficiency is observed in the former, characterized by symmetrical flow patterns devoid of wavering CO2 cores, whereas the latter exhibits less desirable velocity vectors. Furthermore, the investigation explores the influence of key parameters, such as liquid volume fraction (LVF) and water droplet diameter, on separation efficiency. It is ascertained that a 10 % LVF with a water droplet diameter of 10 µm yields the highest separation efficiency at 90.7 %, whereas a 20 % LVF with a water droplet diameter of 1 µm results in a reduced efficiency of 50.79 %. Moreover, the impact of structural modifications, such as the addition of vanes, on separation efficiency and pressure drop is explored. Remarkably, the incorporation of vanes leads to a 9.2 % improvement in separation efficiency and a 16.8 % reduction in pressure drop at a 10 % LVF. The findings underscore the significance of structural considerations and parameter optimization in advancing CO2 capture technologies, with implications for sustainable energy production and environmental conservation.

Influence of the pressure wire on the fractional flow reserve calculation: CFD analysis of an ideal vessel and clinical patients with stenosis

Background and objectiveFractional Flow Reserve (FFR) is generally considered the gold standard in hemodynamics to assess the impact of a stenosis on the blood flow. The standard procedure to measure involves the displacement of a pressure guide along the circulatory system until it is placed next to the lesion to be analyzed. The main objective of the present study is to analyze the influence of the pressure guide on the invasive FFR measurements and its implications in clinical practice. MethodsWe studied the influence of pressure wires on the measurement of Fractional Flow Reserve (FFR) through a combination of Computational Fluid Dynamics (CFD) simulations using 45 clinical patient data with 58 lesions and ideal geometries. The analysis is conducted considering patients that were subjected to a computer tomography and also have direct measurements using a pressure guide. Influence of the stenosis severity, degree of occlusion and blood viscosity has also been studied. ResultsThe influence of pressure wires specifically affects severe stenosis with a lumen diameter reduction of 50 % or greater. This type of stenosis leads to reduced hyperemic flow and increased coronary pressure drop. Thus, we identified that the placement of wires during FFR measurements results in partial obstruction of the coronary artery lumen, leading to increased pressure drop and subsequent reduction in blood flow. The severity of low FFR values associated with severe stenosis may be prone to overestimation when compared to stenosis without severe narrowing. These results have practical implications, particularly in the interpretation of lesions falling within the “gray zone” (0,75−0,80). ConclusionsThe pressure wire's presence significantly alters the flow on severe lesions, which has an impact on the FFR calculation. In contrast, the impact of the pressure wire appears to be reduced when the FFR is larger than 0.8. The findings provide critical information for physicians, emphasizing the need for cautious interpretation of FFR values, particularly in severe stenosis. It also offers insights into improving the correlation between FFRct models and invasive measurements by incorporating the influence of pressure wires.

Effect of high-intensity vibration parameter on droplet transport characteristics in gas channel of proton exchange membrane fuel cell

In aerospace applications, proton exchange membrane fuel cells are subject to high-intensity vibration. Vibration has a substantial effect on water transport in fuel cells. However, there is a lack of research on the effects of multi-directional and high-intensity vibration conditions on fuel cells. In this study, the droplet transport characteristics in the gas channel under high-intensity vibration conditions are investigated for the first time. Moreover, the effects of vibration direction and vibration frequency on the droplet dynamic transport process are specifically studied. The droplet transport state, drainage performance, and pressure drop variation in the gas channel under different vibration conditions are analyzed and interpreted. The results show that low-frequency vibration in the longitudinal direction is more conducive to the droplet discharge, and the pressure drop undergoes a periodic change corresponding to the vibration frequency. Vertical vibration promotes droplet detachment from the gas diffusion layer surface, which contributes to the reduction in water coverage ratio on its surface, despite an increase in the channel pressure drop. Under the influence of horizontal vibration, droplets are more susceptible to adsorption on the channel sidewalls and turn into a liquid film, which leads to a longer discharge time and a reduction in pressure drop.

Robot-LDA Plane Measurements And Smoke Investigations On A 30° Inclined Flat Plate In An Open Wind Channel With And Without Plasma Actuation Effect

Active flow control is a relatively new approach to influence the velocity vector field for plane airfoils or process engineering applications with a plasma source. The goal is to positively effect the point of separation to increase the lift/drag ratio or increase separation efficiency and to reduce pressure drop. In the presented study two approaches, the Robot-LDA measurements and smoke investigations, are chosen to find out whether the plasma source has an effect on the velocity vector field on a 30°inclined flat plate and the separation point. A flow rate of 250 m³/h resulting in a Reynolds number of 100 000 is chosen, since this is typical for already presented results within the field of plasma source investigations. With Robot-LDA in total 825 measurements points of the axial wind channel velocity components are captured twice, with and without activated plasma source. The measurement plane was set 80 mm x 50 mm orthogonal to the flat plate in the middle of the wind channel axis. The plasma source was powered with 14 kVp−p and 5 kHz. Due to stability of the plasma actuator, the LDA measurements were subdivided into eight regions. For the same configurations smoke investigations are performed. A chromium-nickel wire with a diameter of 0.213 mm is heated by an electronic circuit including capacitor and power source to vaporize liquid paraffin. The flow field is captured by a highspeed camera. Robot-LDA measurement results show a free-stream axial wind channel velocity component of about 15 m/s. In the shadow region of the 30°inclined flat plate a recirculation zone is found due to negative velocity components. At a distance up to 12 mm close to the plat plate, wall reflections dominated and to find valid LDA measurement results were not possible. With and without activated plasma source velocity differences between -0.5 m/s and 0.5 m/s are found. The biggest velocity differences are in the region of 15 mm to 45 mm relative to the tip of the inclined flat plate. For post-processing purposes, the 3D wind channel geometry and the Robot-LDA measurement results are loaded in ParaView 5.10.1. Smoke investigations show that the plasma source minimally attach the flow to the flat plate. This effect is higher with smaller flow rates (50 m³/h) than with 250 m³/h. Robot-LDA and smoke measurement results are promising that flow influence due to plasma has potential in various applications in future.

Numerical simulation and thermodynamic test analysis of plate heat exchanger based on topology optimization

Efficient heat transfer in PHEs relies on optimizing flow distribution to minimize thermal dead zones. Existing studies have predominantly focused on single-phase fluids as working media and employed density-based methods for structural optimization of microchannel heat exchangers at small scales. In this study, the Brinkman term from the porous media flow model is introduced in an innovative manner, along with the utilization of a material density interpolation model, which builds upon the density-based approach. A novel two-phase fluid topology optimization method is proposed, specifically tailored for large-scale PHE operating conditions, resulting in the successful design of a new PHE topology. To compare the performance of the two heat exchangers, finite element simulation, visualization experiments, and thermodynamic performance testing are conducted. The simulation results reveal that the heat transfer capacity of the topological PHE is 810 W with pressure drops of 18.8 kPa, while the dimple PHE exhibits heat transfer capacity of 652 W with pressure drops of 25.9 kPa. Compared to the dimple PHE, the topological PHE demonstrates 24.2 % improvement in heat transfer performance and 27.8 % reduction in pressure drop. The dimensionless comprehensive heat transfer coefficient (j/f) indicates that the overall performance of the topological PHE significantly surpasses that of the traditional PHE. Furthermore, the visualization experiment results demonstrate that the complex texture structure of the topological PHE effectively induces fluid motion, compelling the fluid to flow along the texture direction. This significantly mitigates the issue of uneven flow within the PHE, thus enhancing heat transfer efficiency. Specifically, the topological PHE exhibits inlet–outlet temperature difference of 10.3 °C and pressure drops of 11.2 kPa, while the dimple PHE shows inlet–outlet temperature difference of 6 °C and pressure drops of 12.9 kPa. The findings of this study provide guidance for future research endeavors aimed at evaluating potential solutions to advance heat transfer in PHEs and facilitate the implementation of thermal management strategies.

Synergistically controlling biofouling and improving membrane module permeability by using simultaneously structurally optimized and surface modified feed spacers

This study developed a new protocol to prepare feed spacers in the membrane module, by combining the optimization of spacers' geometrical parameters with subsequent chemical modification of the spacers’ surface, to enhance filtration performance comprehensively. Geometrical parameters of columnar spacers were optimized using an object-oriented and automatic optimization method based on computational fluid dynamics (CFD) simulation coupled with response surface optimization. In chemical modification, polydopamine was firstly used to provide anti-adhesive properties, followed by the even integration of silver nanoparticles (AgNPs) to exhibit antimicrobial activity. Anti-biofouling experiments involving Gram-negative (E. coli) and Gram-positive (S. aureus) bacteria demonstrated that the combined structurally optimized and chemically modified spacers resulted in over 10 % improvement in permeate flux and a 27 % reduction in feed channel pressure (FCP) drop. Chemical modification enhanced the structural optimization resistance to flux attenuation and FCP drop increase by over 220 % and 200 %, respectively. Analysis of the anti-biofouling behavior indicated that the primary mechanism of the integrated, optimized spacers lies in the increased wall shear, bactericidal activity of AgNPs, and improved interfacial interaction energy between the spacers and foulants. This study not only developed a novel modification method for anti-biofouling spacers, but also provides in-depth understanding of the roles of modified spacers, all of which are important for their practical applications in improving membrane filtration performance.

CFD Study of Novel Vortex Finder Pressure Drop Holes to Enhance Cyclone Separators Performance

Abstract Gas cyclones are widely employed for the removal of dust and suspended particles from gases, but they encounter challenges related to pressure drop (ΔP) and separation efficiency (ηSep). In addressing these issues, this study explores the impact of incorporating vortex finder pressure drop holes (VFPDH) in various configurations—single column, double columns, three columns, and four columns of holes—each column containing 15 holes. These holes are positioned equally distributed in clockwise order in the z-y plane starting from positive z to negative y-axis equally distributed. Computational fluid dynamics (CFD) analyses were conducted on 15 cases through different configurations, considering steady flow, isothermal properties, and incompressible turbulent flow with 8.809 m/s inlet velocity. The introduced modifications, involving the strategic use of VFPDH, lead to a significant reduction in (ΔP). Specifically, the single column of holes exhibited a remarkable 21% reduction in pressure drop compared to the case without holes. In contrast, the case with four columns of holes achieved a more modest 1.8% reduction. This underscores the substantial influence of VFPDH on the pattern of flow and overall gas cyclones performance. The study provides valuable insights into optimizing gas cyclone design for enhanced efficiency and reduced (ΔP), contributing to advancements in industrial dust and particle separation systems.

Design and Analysis of Gas Cyclone with Arc-Shaped Cone Using Bézier Curve for Improved Performance

Abstract The research investigates novel gas cyclone separators with curved conical sections, comparing eight configurations with varying curvature sizes. Gas cyclones are traditionally used as particle separators to remove dust from gas streams, aiming to achieve a dust-free gas flow at the exit pipe while recovering particles to the dust outlet. Computational fluid dynamics (CFD) was employed to model the gas cyclone using the Reynolds stress turbulence model (RSM); the study examines flow fields and pressure losses. It finds that increased curvature correlates with reduced pressure drop. The curved profile is derived from the Bézier curve, characterized by a set of control points determining its shape. This study examines eight cyclone configurations with the intermediate point placed at varying fractions of the main radius: 1/8, 1/4, 3/8, 1/2, 5/8, 3/4, 7/8, and the main radius itself. The investigation focuses on the impact of different conical segment shapes on cyclone performance, highlighting how convex variants outperform others at higher flow rates while concave variants exhibit higher pressure drop. The pressure drop in the convex variant with an intermediate point position equal to the main radius decreased by 50%. These findings suggest the potential of the convex variant in certain operating conditions over traditional designs with improved particle capture efficiency.

Influence of connecting a new gas pipeline to the operating gas pipeline on the flow rate of production wells

In some cases, it is necessary to connect new line to the pipeline. From this point of view, in the presented work, serious changes occurring in the pipeline as a result of connecting a new gas pipeline to the operating gas pipeline are investigated. The changes occurring in the pipeline are transmitted to the formations, which causes a violation of the stable operation of the wells in the initial period. After a certain period of time, the dynamic processes formed in the system as a result of changes in the transport line become stationary. From this point of view, it is of great practical importance to consider the stationary state of the processes occurring in the system. Therefore, in the presented work, as a result of the addition of a new line to the pipeline, the change in the production of gas wells in stationary regime conditions is studied. The effect of these changes on the operating mode of the wells, the effect on the change in production of operational wells is studied. Taking into account the interaction of the layer-pipeline system, a mathematical model of the movement process of gas and gas-liquid mixture is established, using the equations of motion and continuity, the resulting system of related differential equations is solved. With the help of the obtained formulas, the pressure drop and production reduction for each well are calculated during the connection of the new line. Numerical calculations are performed using various practical values of system parameters and the obtained results are analyzed. Keywords: production; layer; pressure; pipeline; stationary state; gas-liquid mixture; motion and continuity equation.

Optimization and mass transfer analysis under the ribs of multi-serpentine flow fields

This study aims to enhance the performance of Proton Exchange Membrane Fuel Cell (PEMFC) by optimizing the design of a three-channel serpentine flow field. The focus is on the introduction of sub-channels beneath the flow field ribs, utilizing the pressure differential between the main and sub-channels to strengthen lateral convection under the ribs, thus achieving uniform distribution of reaction gases. Using Computational Fluid Dynamics (CFD) methods, the performance of traditional and optimized flow fields were compared across various metrics. The results show that the introduction of sub-channels significantly improves gas mass transfer efficiency, enhances the uniformity of oxygen concentration and current density, and optimizes water content on the proton exchange membrane. At a voltage of 0.5 V, the Improved Serpentine Flow Field (ISCF) exhibits a notable enhancement in current density, increasing from 1.501 A/cm2 in the Traditional Serpentine Flow Field (TCSF) to 1.654 A/cm2 in the ISCF. This represents a significant 10 % increase in current density. Concurrently, the uniformity index climbs from 0.84 to 0.898, marking a 7 % improvement in uniformity. Furthermore, the ISCF design achieves a substantial reduction in pressure drop, decreasing from 1631 Pa to 1212 Pa, a reduction of 26 %. Additionally, the expansion of sub-channel width markedly boosts cell performance, whereas the Increase in sub-channel height reaches a saturation point beyond a certain threshold, indicating an optimal range for dimensional adjustments.

Bioinspired flow Fields: A numerical investigation into Nature-Mimicking designs for boosting vanadium redox flow batteries

Efficient flow field structures are crucial for improving the performance of all-vanadium redox flow batteries (VRFBs). Considering the large pressure drop and pump losses in traditional serpentine flow fields (SFF), this paper proposes a novel biomimetic flow field structure (BFF) for VRFB. A three-dimensional multiphysics model comparing SFF and BFF designs for VRFB is developed, the assessment was further enhanced by considering the impact of electrolyte flow rates on multiple performance indicators. The results show that BFF’s unique design substantially reduces pressure drop, especially at higher flow rates. For both SFF and BFF designs, at a low flow rate of 60 ml/min, the SFF has a slightly higher pump-based voltage efficiency, but as the flow rate increases to 120 ml/min and 180 ml/min, the BFF outperforms the SFF, demonstrating advantages of 2.057 % and 6.888 %, respectively. This comprehensive VRFB modeling analysis provides valuable insights into optimizing future flow battery designs.

Experimental investigation of pressure drop of spherical and non-spherical coarse particles in pneumatic conveying in horizontal pipes

In this work, the conveying flow pattern and pressure drop of spherical and non-spherical coarse particles in a horizontal pipe were measured experimentally. The experimental results show that when coarse particles are conveyed in stratified flow and sedimentation and dune formation, the rate of increase of pressure drop with superficial velocity is related only to the particles and not to the conveying conditions. The rate of increase of pressure drop with velocity is larger for spherical particles than for non-spherical particles in stratified flow, and the rate is smaller for spherical particles than for non-spherical particles in sedimentation and dune formation. The pressure drop varies linearly with the solid-gas ratio, and the slope of the linear relationship characterises the friction of the conveying pipe and the interaction parameters between the particles. The reduction in pressure drop for spherical particles is greater than that for non-spherical particles when the solid-gas ratio is increased by the same magnitude. In addition, to verify the experimental results of this work the data cited in the published literature were compared and the results were in good agreement. On the one hand, the variation rule of pressure drop with superficial velocity obtained in this investigation is an enrichment of the classical phase diagram. On the other hand, the experimental results are of guiding significance for the design and engineering application of coarse particle pneumatic conveying systems.

Heat transfer enhancement on a concave surface using sweeping impinging jets: Comparison of vortex-based and conventional oscillators

While the impinging sweeping jet generated by a conventional fluidic oscillator has been extensively investigated for its remarkable convective heat transfer performance, the cooling performance of the recently designed vortex-based fluidic oscillator on impinged hot plates remains unexplored. This study numerically investigates the cooling performance of oscillatory jets generated by the vortex-based fluidic oscillator compared to the conventional fluidic oscillator and a steady non-oscillatory jet impinging on a hot concave surface. The Fluent 2023R2 software was employed for solving the unsteady Reynolds-averaged Navier–Stokes equations with the k–ω SST model through the finite volume method. Numerical simulations were conducted at various dimensionless nozzle-to-surface distances (X/D = 2, 4, and 6) and Reynolds numbers (20,000, 30,000, and 40,000). The performances of both oscillators were assessed through the time-averaged velocity, temperature, and Nusselt number. The results demonstrated that the vortex-based fluidic oscillator, as an innovative type of fluidic oscillator, outperformed conventional fluidic oscillators by enhancing heat transfer and reducing pressure drop, attributed to its smaller size and higher operational frequency. At X/D values of 2, 4, and 6, the mean Nusselt number for the vortex-based oscillator exhibited respective increases of 19 %, 23 %, and 16 % compared to the conventional oscillator. In addition, these values were respectively 38 %, 34 %, and 24 % higher than those for the steady non-oscillatory jet. Furthermore, the thermal enhancement factor of the vortex-based oscillator demonstrated increases of 20 %, 23 %, and 21 %, respectively, in comparison with the conventional oscillator. These findings suggest that the novel vortex-based fluidic oscillator holds significant promise for replacing conventional oscillators in industrial cooling applications.

Significantly reduced pressure drop for flow boiling in finned microchannels through lowering the pin fin to channel height ratio

Pin fins have been widely applied in microchannels to enhance the heat transfer performance, however, they inevitably lead to a large increase in the pressure drop and the pump power consumption, which hinders their practical applications in microchannel heat sinks. In this work, we report that lowering the pin fin to channel height ratio can significantly reduce the pressure drop while largely maintaining the heat transfer enhancement for flow boiling in finned microchannels. A novel two-step deep reactive ion etching (DRIE) approach is developed to fabricate finned microchannel heat sinks with the controllable pin fin to channel height ratio. Our results show that at low to moderate heat flux, all the microchannel heat sinks with pin fins show nearly overlapping boiling curves, as pin fins elevate flow boiling heat transfer through enhanced bubble nucleation in this heat flux range, which is not affected by the height of pin fins. However, higher pin fins lead to a larger heat transfer coefficient (HTC) in the high heat flux range and a higher critical heat flux (CHF), which can be attributed to the enlarged surface area and the increased flow velocity. Importantly, compared to the microchannel heat sink with full-height pin fins, the pressure drop can be significantly reduced by 43.9 % through lowering the pin fin height ratio to 50 %, while the CHF is only slightly decreased by 10.1 %. The performance evaluation criterion (PEC) analysis shows that the calculated PEC is larger than 1 for lower pin fins at most heat flux conditions, which confirms that lowering the pin fin to channel height ratio is beneficial for flow boiling in finned microchannels. Moreover, flow reversal is effectively suppressed due to the increased flow resistance and the confinement of bubble growth by pin fins. This work sheds the light on the design of finned microchannel heat sinks with high flow boiling heat transfer performance and reduced pressure drop.

CO2 Capture with Polyethylenimine Supported on 3D-Printed Porous SiO2 Structures.

Amines supported on porous solid materials have a high CO2 adsorption capacity and low regeneration temperature. However, the high amine load on such substrates and the substrate itself may lead to substantial pressure drop across the reactor. Herein, we compare the CO2 adsorption capacity and pressure drop of fumed silica powder to 3D-printed monolithic fumed silica structures, both functionalized by polyethylenimine (PEI), and find a drastically reduced pressure drop for 3D-printed substrates (0.01 bar vs. 0.76 bar) in the sorption bed with equal CO2 adsorption capacity. Furthermore, the effect of 3D-printing nozzle diameter and PEI loading on the adsorption capacity are investigated and the highest capacities (2.0 mmol/g at 25 °C with 5000 ppm CO2) are achieved with 0.4 mm nozzle size and 34 wt% PEI loading. These high capacities are achieved since the 3D printing and subsequent sintering (700 °C) of monolithic samples does not compromise the surface area of the fumed silica. Finally, the comparison between 3D-printed monoliths and extruded granulate of varying diameter reveals that the ordered channel system of 3D-printed structures is superior to randomly oriented granulate in terms of CO2 adsorption capacity.

Single-phase and flow boiling heat transfer characteristics in staggered finned manifold microchannel heat sink

The investigation of staggered finned manifold microchannel (MMC) for addressing thermal management challenges in high heat flux electronic devices presents promising insights. The research indicates that staggered finned MMCs exhibit superior heat transfer characteristics in comparison to traditional rectangular microchannels, particularly under single-phase flow conditions. When staggered finned microchannels reduce the maximum temperature of the heating surface by around 10 K, the pressure drop is reduced by 1.3 kPa. Notably, as the heat flux escalates, the advantages of staggered finned MMCs become increasingly pronounced, while higher flow rates lead to a gradual diminishment of these advantages. Furthermore, in scenarios involving flow boiling with low heat flux and high flow conditions, staggered finned MMCs demonstrate enhanced heat transfer performance over traditional rectangular microchannels. When staggered finned microchannels reduce the maximum temperature of the heating surface by around 3 K, the pressure drop is improved by 1.2 kPa. Moreover, the study underscores that at lower flow rates, staggered finned MMCs experience a reduced pressure drop relative to traditional rectangular microchannels, whereas at higher flow rates, this trend is reversed. These findings carry significant implications for the optimization of thermal management strategies for electronic devices operating under high heat flux conditions.

Numerical investigation of the effect of perforated almond, tunnel, and bishop shaped pin fin heat sinks on the hydrothermal performance enhancement

The pin-fin design of the heat sink optimizes thermal dissipation by enhancing surface area and enabling efficient heat transfer in high-performance devices. The primary objective of the highly functionalized and convenient heat sink is to provide a competitive advantage in the field of efficient thermal management systems. The primary objective of this study is to investigate various designs of pin-fin heat sinks with unique shapes. These heat sinks are intended to operate in varying dynamic situations and necessitate an efficient convective heat transfer. The current technique has been thoroughly confirmed using earlier research, and computational investigations were conducted to improve the hydrothermal performance of staggered organized pin-fin heat sinks compared to the baseline case adopted from previous studies. Research is underway to examine the collective impact of the fin's unique structure, ideal aerodynamic form, and quality of perforations. A simulation of three-dimensional incompressible flow was conducted using the realizable k- ԑ model to generate turbulence flow that satisfies the relevant boundary conditions for solving the governing equations. When comparing fins shaped like a bishop to the standard hemispherical instance mentioned in recent work, the Nusselt number is 33 % higher. In addition, when the Reynolds number reaches 21,367, the presence of almond-shaped fins with circular perforations leads to a significant reduction in pressure drop, namely by 53.24 %. The almond-shaped hexagonal perforated fins, formed of a copper-diamond composite material, achieved the maximum hydrothermal performance factor (HTPF) of around 1.52 at a Reynolds number of 21,367. These layouts can be considered in various industrial applications.

Investigation of novel type of cylindrical lithium-ion battery heat exchangers based on topology optimization

The in-depth research on the heat exchanger for lithium-ion batteries is of significant importance due to its crucial role in ensuring the safe operation of electric vehicle (EV) power systems. To enhance the thermal and flow characteristic of the heat exchangers, the novel heat exchangers for 18650-cylinderical lithium-ion batteries have been proposed by topology optimization with the minimization of pressure drop and the lowest average temperature (∏1) and the minimization of pressure drop and the lowest temperature difference (∏2) as two different optimal goals. The topology optimization based on the variable density method is utilized to get two-dimensional (2D) optimal channels, and then the optimized results are extended to three-dimensional (3D) heat exchangers. The 3D heat exchangers are named TOHE-1 which is gotten by stretching the topology channels with ∏1 as optimal goal and TOHE-2 which is gotten by that with ∏2 as optimal goal. Subsequently, a detailed thermodynamic analysis is performed to assess the effect of the type of heat exchangers, channel heights, weight factor of topology optimization function, mass flow rates and discharge rates on the cooling effect of the batteries. The results show that compared with the traditional channel heat exchangers, the heat transfer coefficient of topological heat exchangers have increased by 49.92%, while reducing pressure drop by 27.81%. Meanwhile, compared to TOHE-1, heat transfer coefficient of TOHE-2 is increased by 9.70%, while pressure drop is saved by 4.70%. Other studies have indicated that for a 4 C discharge of the battery, a topological heat exchanger with a channel height of 1.5 mm, a thermal performance weight factor of 0.1, and a mass flow with 3.3 × 10−3 kg s−1 is the optimum heat dissipation scheme. Finally, the numerical studies are verified by conducting the convective heat transfer experimental tests.

Numerical simulation of all-vanadium redox flow battery performance optimization based on flow channel cross-sectional shape design

This paper numerically investigates optimizing trapezoidal flow channel cross-sectional shapes to improve all‑vanadium redox flow battery performance. A 3D steady-state multiphysics model coupling fluid dynamics, mass transfer, and electrochemistry was developed in COMSOL. Eight trapezoidal and one rectangular cross-section serpentine flow fields were simulated at varied flow rates. Results showed the TCS-T06 design reduced pressure drop by 12 % and pump power by 12 % versus the RCS. The concentration distribution of VO2+ was also improved, enhancing mass transfer. At 60 mA/cm2, TCS-T06 achieved 0.9 % higher pump power-based voltage efficiency. The optimized trapezoidal cross-section was proven to minimize losses, improve electrolyte distribution, and enhance VRFB performance. This work provides guidance for optimizing trapezoidal flow channel cross-sections to improve VRFB performance via enhanced mass transfer and reduced pressure drop.

Optimization of baffle and tapering integration in the PEM fuel cell flow field employing artificial intelligence

In this study, two surrogate models are developed to investigate and enhance the performance of parallel flow field Proton Exchange Membrane Fuel Cells (PEMFCs) with two modifications. The main channels are tapered, and baffles are inserted to enhance the mass transfer. A data set is generated by the multi-phase, three-dimensional CFD model. Two different data-driven models based on Artificial Intelligence (AI) and Modified Response Surface Methodology (MRSM) provide surrogate models. Subsequently, two multi-objective optimization methods are employed to reveal the optimum case. The results show that the AI model achieves superior accuracy, whereas the MRSM model has greater simplicity. An increased number of baffles and an optimal tapering ratio contribute to higher mass flux and improved uniformity in reactant distribution. The insertion of baffles and the tapering of main channels result in a remarkable 67 % increase in output power density. Optimum tapering also reduces pressure drop, whereas baffles, while improving performance, contribute to increased pressure drop and potential PEMFC degradation. The identified optimum configuration of baffles and tapering, along with the optimum values for voltage, pressure, and anode and cathode stoichiometries, results in an impressive output power density of 0.93 W cm−2 and a parasitic power ratio of 0.17, respectively.