Flow Distributor Research Articles

Enhanced Hemodynamics of Anisometric TPMS Topology Reduce Blood Clotting in 3D Printed Blood Contactors.

Artificial organs, such as extracorporeal membrane oxygenators, dialyzers, and hemoadsorber cartridges, face persistent challenges related to the flow distribution within the cartridge. This uneven flow distribution leads to clot formation and inefficient mass transfer over the device's functional surface. In this work, a comprehensive methodology is presented for precisely integrating triply periodic minimal surfaces (TPMS) into module housings and question whether the internal surface topology determining the flow distribution affects blood coagulation. Three module types are compared with different internal topologies: tubular, isometric, and anisometric TPMS. First, this study includes a computational fluid dynamics (CFD) simulation of the internal hemodynamics, validated through experimental residence time distributions (RTD). Blood tests using human whole blood and subsequent visualization of blood clots by computed tomography, allow the quantification of structure-induced blood clotting. The results indicate that TPMS topologies, particularly anisometric ones, serve as effective flow distributors and significantly reduce and delay blood clotting compared to conventional tubular geometries. For these novel TPMS modules, the inner surfaces can be activated chemically or functionalized to function as a selective adsorption site or biocatalytic surface or made of a permeable material to facilitate masstransfer.

ПОВЫШЕНИЕ ЭФФЕКТИВНОСТИ КОНДИЦИОНИРОВАНИЯ ВОЗДУХА В КАБИНЕ ТРАНСПОРТНОГО СРЕДСТВА

The article presents the research aimed at creating a cooling system in a vehicle cabin that would have the fastest and most effective effect on the operator's body, while being environmentally friendly and cost-effective. It has been found that the efficiency of a vehicle operator's work is affected by the temperature and humidity parameters of the cabin (salon) microclimate. A multi-level approach has been applied to drawing up a heat balance for supplying and removing heat to the driver of a vehicle, taking into account the feasibility of cooling only a local area of his body. An analysis of the results of experiments on the possibility of using ventilation air flow distributors for local volumes with people there is given. It has been found that the operation of existing standard cooling and ventilation systems in a vehicle cabin is associated with significant energy costs, the consumption of a large amount of fuel, and a decrease in its environmental friendliness and efficiency. This is caused by the design complexity of the cooling system, its immobility relative to the operator's body, as a result of which the flow distributed in any direction exits the surface elements of the cabin, is washed out in the total volume, loses the required blowing speed, and, as a consequence, the cooling effect. It is possible to improve the air flow distributor of the vehicle cabin due to the channel having two truncated cones located one in the other, allowing to change the cross-section of the outlet opening and the direction of air flow distribution. The following were obtained: temperature distribution of round jets of the ventilation system of the MTZ-100 tractor at an outside air temperature of tн=29.5 °C without a cooler and with a cooler, a mathematical expression for determining the distance from the distributor. It was found that while maintaining the average heat transfer coefficient at the level of 6.5 W/m2 and the air outlet speed of 1 m/s, the total heat removal increases approximately 2.4 times.

Three-dimensional simulation of a proton exchange membrane fuel cell with non-integrated metal foam as flow distributor

In proton exchange membrane fuel cells (PEMFCs), the presence of metal foam in the flow channels improves the polarity diagram and increases the cell generated power, but this leads to an increase in pressure drop and, as a result, an increase in parasitic power. In this study, two types of non-integrated arrangements of metal foam are introduced, which, in addition to having high generated power, have lower pressure drop, and subsequently, lower parasitic power, and will also result in a more uniform distribution of temperature and current density. In the first arrangement, which is called IPTG, an abbreviation of Increased Porosity Toward the gas diffusion layer (GDL), the channels are divided into four equal parts with variable porosities from 0.65 to 0.95, in such a way that the metal foam layer with the highest porosity (0.95) is located in the closest area to the GDL. In the second arrangement which is called Reduced Porosity Toward the GDL, the metal foam layer with the least porosity (0.65) is located in the closest area to the GDL. To make a better comparison between the present model and the conventional one, the net power parameter with subtracting parasitic power from generated electrical power of the fuel cell is calculated for all models. The numerical study of this paper is conducted by developing a three-dimensional computational fluid dynamics model by employing user-defined functions. The results show that the net power of the PEMFC with IPTG arrangement is 3.8 % higher than that of the one with integrated metal foam arrangement with a porosity of 0.95. Also, the higher the pores per inch (PPI) of metal foam used in the non-integrated metal foam model, the greater the net power of the fuel cell, so that, the net power of PEMFC with IPTG arrangement with PPI=80 is 3.2 % more than that of PPI=20.

Concurrent arsenic, fluoride, and hydrated silica removal from deep well water by electrocoagulation: Comparison of sacrificial anodes (Al, Fe, and Al–Fe)

Some studies have reported the removal of As (As) and fluoride (F−) using different sacrificial anodes; however, they have been tested with a synthetic solution in a batch system without hydrated silica (SiO2) interaction. Due to the above, concurrent removal of As, F−, and SiO2 from natural deep well water was evaluated (initial concentration: 35.5 μg L−1 As, 1.1 mg L−1F−, 147 mg L−1 SiO2, pH 8.6, and conductivity 1024 μS cm−1), by electrocoagulation (EC) process in continuous mode comparing three different configurations of sacrificial anodes (Al, Fe, and Al–Fe). EC was performed in a new reactor equipped with a small flow distributor and turbulence promoter at the entrance of the first channel to homogenize the flow. The best removal was found at j = 5 mA cm−2 and u = 1.3 cm s−1, obtaining arsenic residual concentrations (CAs) of 1.33, 0.45, and 0.77 μg L−1, fluoride residual concentration (CF−) of 0.221, 0.495, and 0.622 mg L−1, and hydrated silica residual concentration (CSiO2) of 21, 34, and 56 mg L−1, with costs of approximately 0.304, 0.198, and 0.228 USD m−3 for the Al, Fe and Al–Fe anodes, respectively. Al anode outperforms Fe and Al–Fe anodes in concurrently removing As, F− and SiO2. The residual concentrations of As and F− complied with the recommendations of the World Health Organization (WHO) (As < 10 μg L−1 and F− < 1 mg L−1). The spectroscopic analyses of the Al, Fe, and Al–Fe aggregates showed the formation of aluminosilicates, iron oxyhydroxides and oxides, and calcium and sodium silicates involved in removing As, F−, and SiO2. It is concluded that Al would serve as the most suitable sacrificial anode.

Numerical study on performance enhancement of a solid oxide fuel cell using gas flow field with obstacles and metal foam

This study investigates the impact of gas flow field design on the performance of a solid oxide fuel cell (SOFC). A three-dimensional numerical model of the cell and channel is developed to simulate the use of metal foam as flow distributor, along with the presence of obstacles in the gas flow channels. The model is calibrated using experimental data and applied to simulate four relevant cases combining metal foam and obstacles, compared to a straight channel structure. The results demonstrate the positive impact of flow-field modifications on the distribution of species along the cell's active layers. It is found that, even though the pressure drops are affected, reactant gases are more uniformly distributed across the active electrode of the cell, reducing mass transport losses and enhancing current density. Simulations performed at a cell voltage of 0.7 V indicate that incorporating a metal foam as flow distributor increases the maximum current density by 26 % compared to the conventional straight flow design. Furthermore, combining metal foam with obstacles results in the best performance, achieving a 34 % increase in the maximum current density.

Research on flow, heat transfer, and solidification characteristics of flow distribution process in the twin-roll casting

Twin-roll casting (TRC) has seen a significant interest in recent years due to its short process, low energy consumption, and low emission. The research included both numerical simulation and experimental validation to examine the flow and temperature field distribution of the TRC process. The “U-shaped” buffer groove is identified as beneficial for maintaining a stable liquid level distribution in the molten pool through comparison with various flow distributor structures. The solidified billet shell dispersion around the casting roller in the molten pool is observed to undergo three distinct stages: stable growth, thickness fluctuation, and rapid growth. The inclusion of two circular side outlets, each with a diameter ranging from 8 to 10 mm, proves advantageous in maintaining a stable distribution of the liquid level within the molten pool. The edge outlet size ranges from 7 to 9 mm, and ensuring a U-shaped buffer groove width/flow distribution of 1.25–1.58 aids in enhancing casting stability.

Process intensification in flow chemistry using micro and millidevices: Numerical simulations of the syntheses of three different intermediate API compounds for diabetes mellitus drug production

Microreactor Technology (MRT) appears as an interesting alternative for process intensification, including the development of continuous synthesis of fine chemicals and Active Pharmaceutical Ingredients (API). The inherent proposal of MRT is to reduce the scale-up time by simply increasing the number of microreactors in parallel, the numbering-up concept using optimal designed micro or millidevices. Among the API, rosiglitazone and lobeglitazone are derivatives of thiazolidine-2,4-dione (TZD), which is used as a building block, for molecules with biological activity, sensitive to insulin and, thus, with its administration the body makes better use of the insulin it produces, being an important structural element in medicinal chemistry, especially for type 2 diabetes mellitus, one of the biggest concerns in the health area worldwide, affecting nowadays more than 180 million people. The numerical assessment of MRT for various API synthesis related to type 2 diabetes mellitus drugs indicates its comparable or superior performance compared to traditional batch process. Specifically, proposed micromixer designs facilitate successful scale-up to milliscale while maintaining microscale performance, with significantly lower pressure drops than commercial Asia microreactors. The proposed flow distributors offer good performance in ensuring uniform distribution across outlets due to their conical shape design and laminar flow regime, with low pressure drops. The flow distributor with eights outlet is preferred for higher flow rates due to its superior performance, minimizing the pressure drops. Efficient flow rate and molar concentration control at each reactor unit can be ensured by using one distributor for each reactant's feed stream. This approach guarantees accurate concentration, flow rate control and ideal residence time, ultimately facilitating higher total throughput for scale-up. The potential use of micromixer actuators lies in its ability to maintain or enhance performance while transitioning from micro to milli-scale, offering promising alternatives for process intensification and scale-up in pharmaceutical synthesis, particularly for medications targeting type 2 diabetes mellitus.

Toward Unrivaled Chromatographic Resolving Power in Proteomics: Design and Development of Comprehensive Spatial Three-Dimensional Liquid-Phase Separation Technology.

Spatial comprehensive three-dimensional chromatography (3D-LC) offers an innovative approach to achieve unprecedented resolving power in terms of peak capacity and sample throughput. This advanced technique separates components within a 3D separation space, where orthogonal retention mechanisms are incorporated. The parallel development of the second- and third-dimension stages effectively overcomes the inherent limitation of conventional multidimensional approaches, where sampled fractions are analyzed sequentially. This review focuses on the design aspects of the microchip for spatial 3D-LC and the selection of orthogonal separation modes to enable the analysis of intact proteins. The design considerations for the flow distributor and channel layout are discussed, along with various approaches to confine the flow during the subsequent development stages. Additionally, the integration of stationary phases into the microchip is addressed, and interfacing to mass spectrometry detection is discussed. According to Pareto optimality, the integration of isoelectric focusing, size-exclusion chromatography, and reversed-phase chromatography in a spatial 3D-LC approach is predicted to achieve an exceptional peak capacity of over 30,000 within a 1-h analysis, setting a new benchmark in chromatographic performance.

Table-top numbering-up 3D-printed miniaturized hydrocyclone for high-efficiency and high-throughput separation of oil-in-water emulsions

Oily wastewater from home and industrial effluents, as well as marine oil spills, poses significant environmental problems, such as water and soil contamination and ecosystem devastation. We here developed a parallelized miniaturized hydrocyclone (mHC) system consisting of multiple mHCs and a flow distributor for high-efficiency and high-throughput separation of oil-in-water emulsions. From a manufacturing perspective, our system can be easily and rapidly created using 3D printing technology. It was also specifically designed to provide simple and durable connections between tubes and components, eliminating the need for a time-consuming bonding process. Direct visualization of primary and secondary vortex flows generated within the mHC device was achieved, allowing the variation of the vortex flows as a function of the feed flow rates to be analyzed. Furthermore, we demonstrated that a single mHC was capable of separating six types of oil-in-water emulsions with different oil phases and a separation efficiency greater than 90 %, with olive oil-based emulsions achieving a remarkable separation efficiency of 98.3 % at the optimal feed rate of 200 mL/min. By numbering-up a single mHC and incorporating a 3D-printed flow distributor to ensure a uniform flow distribution into each individual mHC, we can construct a parallelized mHC system. The separation system can process an estimated 3,168 L (837 US gallons) of mineral oil-based emulsion per day with a separation efficiency of approximately 97 %. The results of this study can be further enhanced by modifying the flow distributor, increasing the number of single mHCs, and introducing high-performance pumps.

Unsteady three-dimensional multiphase modelling of anode flow distributor in PEM electrolysis cell

Unsteady three-dimensional multiphase modelling of anode flow distributor in PEM electrolysis cell

Effects of flow distributor structures and particle-wall interaction on baghouse gas-solid flow

The uniform distribution of gas–solid two-phase flow inside the baghouse is a key factor in its performance. The Discrete Phase Model (DPM) was applied to study the flow characteristics and uniform degree of the flow distribution. The effect of flow distributor structures, characteristics of particles (such as size and restitution coefficient), and the particle–wall interaction on gas–solid two-phase flow were investigated by experiments and simulations. Results show that flow distributors greatly improve the uniformity of fluid distribution, while showing little effect on the filtration resistance. The flow distributors effectively avoid the occurrence of jet phenomena within the baghouse and significantly reduce the quality of dust on the surface of the filter bag. The weight has decreased by approximately 24.6 % in Case B (a flow distributor with four baffles perpendicular to the flow direction) compared to Case A (without a flow distributor and baffle). More particles will deposit on the surface of the filter bag with the increasing of restitution coefficient. The particle–wall interaction has a significant impact on particle motion when the particle sizes are larger than 150 μm, while the impact on particle motion is small when the particle sizes are smaller than 10 μm. These studies provide a basis for improving the uniformity of gas–solid two-phase flow inside the baghouse.

Rapid flow synthesis of fenofibrate via scalable flash chemistry with in-line Li recovery

Flash chemistry controlled organolithium reactions allow redesigning the new economically affordable synthetic routes for life-saving drugs. However, microreactors limit their applications to extend industrial-level productivity. On the other hand, there has been little attention on recycling valuable elements from organic synthesis. In this work, a new compact monolithic metal microreactor was designed to successfully control the lifetime of short-lived organolithium intermediates at a large scale for sub-second scalable synthesis of fenofibrate as an FDA-approved drug for hypertriglyceridemia. Initially, the ultrafast chemistry of highly unstable ArLi intermediate was successfully explored for the synthesis of fenofibrate by its flow-controlled coupling reaction with 4-chlorobenzoyl chloride. As needed, by 3D metal printing of the CAD-CFD simulated works, eight laminated serpentine channels integrated with four flow distributors were constructed in a monolithic metal microreactor, leading to improved productivity up to 1.18 g min−1. At the in-line work-up step, the largely consumed Li was completely recovered for the potential recycling of valuable Li resources in a continuous-flow manner.

Effect of permeable spacer structure on energy loss and mass transfer in reverse osmosis membrane modules

This study used numerical simulation to investigate the effects of a novel permeable cylindrical-flow distributor on energy loss and mass transfer in reverse osmosis (RO) membrane modules. The analysis focused on variables, such as Reynolds number, inlet concentration and flow incidence angle, influencing the improvement of water production efficiency in RO membranes and the reduction of concentration polarisation on the membrane surface. The membrane surface shear stress, vorticity, permeate flux and concentration polarisation factor were used to describe these effects. To better explain the performance of the permeable flow distributor, the viscous resistance coefficient (Du) in the porous media model was used to measure the permeability of the flow distributor. Furthermore, a produced water energy consumption factor (JCP) was defined to represent the energy required for unit water production. The results indicate that the permeable flow distributor significantly reduces pressure loss in the membrane channels, avoiding the high energy consumption associated with traditional flow distributors in RO processes. The Du exhibits an optimal value in the range of 1e8 to 1e10, which maximises the JCP, leading to a 32.9 % improvement compared to traditional impermeable flow distributors. This achievement enables energy-efficient and effective desalination of seawater.

Study on Optimal Design of Constant Current Water Distributor

Daqing Field has entered the late stage of ultra-high water cut development. The number of subzones of water injection wells is increasing year by year, and the number of zones of high-efficiency annual survey has exceeded 240,000. The testing capacity has reached a bottleneck, the contradiction among test efficiency, test team and qualified rate of water injection is becoming more and more obvious. The constant flow water distributor can keep the water injection quantity of the applied layer basically unchanged under the frequent fluctuation of water injection pressure, the water injection zone will be changed from repeated adjustment to little adjustment or even no adjustment, greatly reducing the testing workload and improving the testing efficiency. In order to further improve the performance of constant-current water distributor, the stress simulation of valve spool of constant-current water distributor was carried out. Based on the mechanical analysis of the valve core of constant flow distributor, the force acting on the valve core of constant flow distributor is obtained by numerical simulation, and the accuracy of the simulation results is verified by laboratory experiments. According to the requirements of starting pressure difference and spring stiffness of constant current water distributor, the constant current water distributor is optimized and perfected. The experimental results show that the error is less than 5%, which meets the requirements of field application. This study provides a basis for further improving the design of constant-current water distributor. Up to now, 392 wells have been tested with constant-current distributor, the effect of constant-current is good, and the average efficiency of single well is increased by 28.3%.

(Invited) Submillimeter Bundled Microtubular Flow Battery Cells with Ultrahigh Volumetric Power Density

Flow batteries are a promising energy storage solution. However, the footprint and capital cost need further reduction for flow batteries to be commercially viable. The flow cell, where electron exchange takes place, is a central component of flow batteries. Improving the volumetric power density of the flow cell (W/Lcell) can reduce the size and cost of flow batteries. While significant progress has been made on flow battery redox, electrode, and membrane materials to improve energy density and durability, conventional flow batteries based on the planar cell configuration exhibit a large cell size with multiple bulky accessories such as flow distributors, resulting in low volumetric power density. In this talk, I will introduce a submillimeter bundled microtubular (SBMT) flow battery cell configuration that significantly improves volumetric power density by reducing the membrane-to-membrane distance by almost 100 times and eliminating the bulky flow distributors completely. Using zinc–iodide chemistry as a demonstration, our SBMT cell shows peak charge and discharge power densities of 1,322 W/Lcell and 306.1 W/Lcell, respectively, compared with average charge and discharge power densities of <60 W/Lcell and 45 W/Lcell, respectively, of conventional planar flow battery cells. The battery cycled for more than 220 h corresponding to >2,500 cycles at off-peak conditions. Furthermore, the SBMT cell is compatible with zinc–bromide, quinone–bromide, and all-vanadium chemistries. The SBMT flow cell represents a device-level innovation to enhance the volumetric power of flow batteries and potentially reduce the size and cost of the cells and the entire flow battery.(also see our publication: https://doi.org/10.1073/pnas.2213528120)

Experimental and numerical study of flow distributor of intermediate heat exchanger in high temperature gas-cooled reactor

The intermediate heat exchanger (IHX) is a key component in the heat-utilization system of a high temperature gas-cooled reactor. However, the elbow at the bottom of the IHX results in uneven flow and temperature fields among the heat exchange tube bundle, leading to fatigue damage to the IHX. This study experimentally and numerically investigates the mechanism by which a flow distributor improves the uniformity of the flow field, and selects the distributor with the best effect on improving the uniformity. The results show that the distributor divides the flow into two parts, and the length and the angle of the distributor influence the uniformity by influence the ratio of the two parts. As the length increases, the uniformity first increases and then decreases at any angle. When the length is short, the uniformity increases with the increasing angle. When the length is long, the uniformity decreases with the increasing angle. With an appropriate size of flow distributor, the squared coefficient of variation decreases from 0.35 to 0.034, and the non-uniformity decreases by 90.2%. This study also proposes a semi-empirical formula based on dimensionless numbers to predict the appropriate size for a flow distributor.

Hydrogen production in a proton exchange membrane electrolysis cell (PEMEC) with titanium meshes as flow distributors

The proton exchange membrane electrolysis cell (PEMEC) is a green and efficient method for producing hydrogen. The flow field structure is a critical factor affecting the performance of electrolysis. However, conventional processing of flow channels is complex and expensive, a novel PEMEC structure utilizing three-dimensional titanium meshes as flow distributors instead of flow channels is proposed. It is found to exhibit higher current density, pressure, hydrogen concentration, and lower temperature than the traditional parallel flow fields. The current density is improved by 88.2 mA/cm2 and the energy consumption is reduced by 0.15 kW h N−1·m−3 at 1.9 V. Based on the uniformity index, the new structure is found to improve the current and temperature uniformity by 20.6% and 13.4%, respectively, when compared to the parallel flow field structure. Additionally, the physical properties of the mesh layers are studied in terms of their influence on electrolysis performance. The increase in porosity and decrease in thickness can enhance the performance of the cell. The results show that a structure with titanium meshes is more beneficial for improving the heat and mass transfer performance and optimizing uniform distribution than the parallel channels, which provides a new direction for the design of electrolysis cell structures.

Performance analysis of avionics devices based on electro-thermal-stress multi-physics coupling under immersion cooling

The present study aims to analyze immersion cooling for the work reliability enhancement of avionics devices based on electro-thermal-stress multi-physics simulation. A comprehensive performance indicator considering the maximum DC IR-drop of the power supply network (PDN), the maximum temperature of the electronic elements and the maximum deformation of the printed circuit board (PCB) assembly is constructed to evaluate the effect of different flow distributor structure styles and Reynolds number (Re) on the work reliability of avionics devices. The results show that the maximum DC IR-drop of 2.0 V PDN was 73.83 mV which was the largest value among 1.5 V, 2.0 V, 3.3 V and 5.0 V PDN. The DC IR-drop of design A, design B and design C was smaller than the supply voltage fluctuation in a real design, this indicates that the flow distributor has no significant effect on enhancing the power delivery capability of PDN. The reflow in the middle part of design C makes the average temperature of PCB assembly lower than that of design A and design B by about 1–3 °C. The flow distributor has a significant effect on the maximum temperature of electronic elements and the pressure drop of avionics devices with Re increase, but not viable to decrease the maximum deformation of PCB assembly for design A and design B. The minimum of comprehensive evaluation function f is 0.038 when Re = 43,000 for design C, this means the comprehensive working reliability of the avionics server module is the best. Due to different flow patterns, the average temperature of PCB assembly for design C was lower which improve the electrical and mechanical properties, thus the value of f for design C was always smaller than that of design A and design B. The method and results herein revealed the advantages and potential limitations of immersion cooling on the working reliability of the avionics devices.

Effect of humidification and cell heating on the operational stability of polymer electrolyte membrane fuel cell

Because of its clean or zero-emission nature, the PEM fuel cell is considered a potential energy conversion device for power production. The performance of the PEM fuel cell is known to be influenced by many parameters, such as operating temperature, pressure, and humidification of the reactants. In addition, the operational stability of the PEM fuel cell under these conditions with the purging of water during its operation should also be studied to understand the performance of the PEM fuel cell. Therefore, this paper brings out the effects of cell humidification and cell heating on the performance, especially the operational stability concerning the liquid water removal of the PEM fuel cell. The experiments are conducted on a single PEM fuel cell with mixed flow distributors operating on different cell temperatures and humidification conditions. At dry feed operation of the PEM fuel cell at ambient condition, the cell utilizes around 80.3% of water generated for its membrane hydration, i.e., self-humidification. When the PEM fuel cell is operated at full humidification (100% RH) on both sides, the membrane is well hydrated, and the cell attains the maximum power density of 0.25 W/cm2, which is 56% more than dry feed operation. The results of the experiments at static current density demonstrate membrane hydration is the significant factor for both stable operation and efficient power output. External purging must periodically be carried out to stabilize the cell due to voltage fluctuations. The major outcome of the current study is to establish the connection between hydration and the stability of the PEM fuel cell.

ChannelCOMB Device for Mesostructured Reactors and Networks of Reactors

AbstractChannelCOMB, a consecutive flow distributor, was constructed by additive manufacturing (AM) for experimental validation. The feasibility of using AM was experimentally analyzed for two techniques: stereolithography (tolerance of 50 µm) and fused deposition modeling (tolerance of 100 µm). For the best ChannelCOMB configuration, SLA printing shows a maximum of ca. 4 % in flow deviation, while FDM has a maximum of ca. 15 %. Thus, the SLA technique promotes better flow uniformity due to the fabrication tolerance and material permeability. The results also show that the experimental flow distribution measured for the best ChannelCOMB configuration printed by SLA can be well predicted by both computational fluid dynamics simulations and a model based on resistance analogs proposed in a previous work.