Dual Fluid Research Articles

Metabolic Fingerprint of Dual Body Fluids Deciphers Diabetic Retinopathy.

Diabetic retinopathy (DR) is a microvascular complication of diabetes, affecting 34.6% of diabetes patients worldwide. Early detection and timely treatment can effectively improve the prognosis of DR. Metabolomic analysis provides a powerful tool for studying pathophysiological processes. Conducting metabolomic analyses on DR-related biofluids helps identify differential metabolic expressions during disease progression, thereby discovering potential biomarkers to support clinical diagnosis and treatment. Here, an innovative workflow for vitreous liquid analysis is established, and a machine learning-based DR analysis platform integrating vitreous liquid metabolic fingerprint (VL-MF) and plasma metabolic fingerprint (P-MF) derived via nanoparticle enhanced laser desorption/ionization mass spectrometry is developed. Direct VL-MF and P-MF are obtained with desirable reproducibility (coefficient of variation, CV <5%) and remarkable speed (3s per sample), and DR patients are distinguished from healthy controls applying dual biofluid-MF with an area under the curve (AUC) of 0.957. Moreover, a biomarker candidate panel from vitreous liquid and plasma with an AUC of 0.945 is constructed and the related metabolic pathways are identified by metabolomics pathway analysis (MetPA). This work offers a powerful multi-biofluid platform that can not only contribute to DR but also provide solid references for other clinical applications.

Enhancing Thermal-Hydraulic Modelling in Dual Fluid Reactor Demonstrator: The Impact of Variable Turbulent Prandtl Number

In response to the growing demand for advanced nuclear reactor technologies, this study addresses significant gaps in thermal-hydraulic modelling for dual fluid reactors (DFRs) by integrating Kays correlation to implement a variable turbulent Prandtl number in the Reynolds-averaged Navier–Stokes (RANS) simulations. Traditional approaches employing a constant value of the turbulent Prandtl number have proven inadequate, leading to inaccurate heat transfer predictions for low Prandtl number liquids. The study carefully selects the appropriate formula for the turbulent Prandtl number in the DFR context, enhancing the accuracy of thermal-hydraulic modelling. The simulations consider Reynolds numbers between 15,000 and 250,000, calculated based on the hydraulic diameters at different diameter pipes of the fuel and coolant loops. The molecular Prandtl number is equal to 0.025. Key findings reveal that uneven flow distributions within the fuel pipes result in variable temperature distribution throughout the reactor core, confirming earlier observations while highlighting significant differences in parameter values. These insights underscore the importance of model selection in CFD analysis for DFRs, revealing potential hotspots and high turbulence areas that necessitate further investigation into vibration and structural safety. The results provide a framework for improving reactor design and operational strategies, ensuring enhanced safety and efficiency in next-generation nuclear systems. Future work will apply this modelling approach to more complex geometries and flow scenarios to optimise thermal-hydraulic performance.

Comparison Study of Cascaded Organic Rankine Cycles with Single and Dual Working Fluids for Waste Heat Recovery

This study compares thermodynamics, economics, and environmental performance of cascaded ORCs operated under a single and dual fluids. In the single fluid cascaded ORC, toluene, benzene, acetone and cyclopentane are run in high and low temperature cycles, whereas in dual fluid cascaded ORC, toluene, benzene, acetone and cyclopentane are run in high temperature cycle and R601a in the low temperature cycle. The analysis compares variations in expander inlet temperature and condensation temperature. Thermodynamic performance involved net power output (Pnet) and thermal efficiency (ηth), while economic indicators included net present value (NPV) and levelized cost of electricity (LCOE). In environmental performance, the annual reduction in carbon dioxide emission (CO2-eq) is assessed. The findings revealed that dual fluid cascaded ORC generated the highest Pnet of 1245.11 kW while single fluid cascaded ORC reached 1170.27 kW. The dual fluid cascaded ORC showed the significant increase in Pnet (%DPnet) for about 43% at the lowest expander inlet temperature (500 K). In terms of ηth, dual fluid cascaded ORC attained 37.23 % while single fluid cascaded ORC reached 33.25%. It is further found that acetone+R601a performed well in dual fluid cascaded ORC, resulting in the highest Pnet and allowing system’s NPV to turn positive sooner than other fluids. Furthermore, cyclopentane+R601a had the lowest LCOE of 0.0158 US$/kWh, which is 1.1% lower compared to the single fluid cascaded ORC and competitive in the Thai electricity market. In environmental saving, dual fluid cascaded ORC reduced about 144.96 tCO2-eq/year, and outperformed single fluid cascaded ORC by roughly 6.39%.

Application of design of experiments for single-attribute optimization using response surface methodology for flow over non-linear curved stretching sheet

Optimizing the heat transmission rate of the flow through the statistically designed chain of experiments has major applications in product designing and improvising. Here, statistic design is framed by implementing response surface optimization methodology to contemplate the flow of dual non-Newtonian fluids allowed to flow over non-linear stretched geometry. The fluid flow model is designed under Cattaneo-Christov diffusion theory over a magnetized-radiative surface. The boundary condition is enriched with the slip regime and Newtonian heating. Numerical computations are acquired by employing the shooting technique approach in association with Runge-Kutta Fehlberg numerical scheme. Statistical and numerical consequences disclose that non-linear stretching index causes a depletion in velocity and temperature. When the Eckert number and the heat generating parameter are both large, the heat transfer rate is also large. Mass transport rate is lowest for higher ratios of diffusion coefficients. The 0.265365 is the maximum possible heat transport rate attained for the 8th experimental run with the key elements: Eckert number, heat source and radiation parameter. The critical point claimed by the Pareto chart shows that the slightest manipulation of the radiation parameter is critical for the heat transport rate, whereas the heat source parameter and Eckert number have almost similar influences on the response.

Numerical study on the flow and heat transfer performance of SCO2/molten salt in Z-type printed circuit heat exchangers

The utilization of a PCHE in conjunction with a SCO2 Brayton cycle and molten salt thermal storage demonstrates a high efficiency. Investigating the flow and heat transfer characteristics of SCO2 and molten salt within a Z-type PCHE is essential. However, this particular aspect has not been explored by previous researches. This study employs a Z-type PCHE to analyze the heat transfer and flow characteristics of SCO2 and molten salt under different inlet temperatures, mass fluxes, and outlet pressures. Furthermore, the heat transfer efficiency of a Z-type PCHE is evaluated and compared to that of a conventional straight-type PCHE. The results indicate that the flow pattern of SCO2 exhibits periodic behavior due to the periodic bending structure of Z-type PCHE, while the flow of molten salt is minimally affected. Furthermore, different SCO2 conditions lead to divergent patterns in flow and heat transfer efficiency compared to molten salt. Z-type channels help alleviate the decline in heat transfer that typically happens in the inlet section of straight channels. Nu for a dual working fluid in a straight-type PCHE is only 1.1 times greater than that of a single working fluid. In Z-type PCHE configuration, the ratio of the dual working fluid to the single working fluid Nu is 1.4. The sensitivity of SCO2/molten salt dual working fluid to the heat exchanger structure is significant, with Z-type PCHE demonstrating superior heat transfer capabilities. The results outlined in this study offer the prospect of improving the design and deployment of Z-type PCHE in molten salt energy storage systems that operate within SCO2 Brayton cycle.

Experimental investigation on the suitability of dual fluid system-assisted ECM (DF-ECM) and the influence of magnet in machining of SS304

Experimental investigation on the suitability of dual fluid system-assisted ECM (DF-ECM) and the influence of magnet in machining of SS304

Experimental study on the charge characteristics and dust reduction performance of inductive electrostatic dual-fluid nozzle for dust pollution control

Dust caused by production activities is the main reason for endangering the production safety and workers' health. To investigate the potential ability of electrostatic dual-fluid nozzles for efficient control of dust pollution, an inductive electrostatic dual-fluid nozzle using profiled electrodes has been designed. From the charge experimental results, the critical voltage of the nozzle is determined to be 12 kV. The maximum droplet charge to mass ratio is achieved when brass electrodes are used. Droplet size and dust reduction experiments show that electrostatic forces enhance the secondary atomization effect and achieve the best parameters at 0.3 MPa water pressure and 0.6 MPa air pressure compared to uncharged dual fluid spray. This nozzle offers a significant improvement in dust reduction efficiency, it can reach more than 78%, an improvement of 18.2% over the uncharged spray. The research results can provide theoretical support for the applications in dust control of inductive electrostatic dual-fluid nozzles.

Effects of dual Gemini-based fracturing fluid on the physicochemical properties of coking coal: Material preparation and wetting mechanism

In order to study the effects of fracturing fluid on the physicochemical properties of coking coal, and further improve the wetting effect of fracturing fluid on coal body. In this paper, an amphoteric surfactant (AS-22) was synthesized from erucic acid, and an amphoteric Gemini surfactant (GAS-22) was further synthesized by introducing 1,3-dichloro-2-propanol as a linker group. Then, the dual Gemini-based fracturing fluid (GAS-22/Gemini-3OH) that can be used for coal seam water injection to wet the coal body is prepared by combining with anionic Gemini surfactant (Gemini-3OH). The coal samples treated with fracturing fluid were analyzed by using characterization measurements, performance analysis and molecular dynamics simulation to reveal the mechanism of action of fracturing fluid wetting coal body. The results showed that four fracturing fluids, AS-22, GAS-22, AS-22/Gemini-3OH and GAS-22/Gemini-3OH, had different degrees of influence on the physicochemical properties of coking coal, and GAS-22/Gemini-3OH had the greatest influence on the element content, morphological structure, and compositional content of the coal samples. In addition, the contact angle experiments and molecular dynamics simulation showed that GAS-22/Gemini-3OH had better adsorption and wetting effect on coal body. This study provides theoretical guidance for developing efficient fracturing fluid to improve the wetting performance of coal bodies.

Experimental Investigation on Thermal Stability of Dual Particle Magnetorheological Fluid and Performance

Magnetorheological fluid and their properties are essential in Magnetorheological applications. The present study aims to obtain the thermally stable carrier fluid for Magnetorheological damper application through thermogravimetric analyses of three base fluids for higher stability fluid to synthesize Magnetorheological fluid. Scanning electron microscopic images of particles were also tested for their morphology. Magnetorheological fluid samples with 10%, 15%, and 20% by volume were prepared in-house with a 3% calcium base additive (base fluid). Sedimentation and thermal conductivity studies reveal that increasing particle concentration increases the settling time and thermal conductivity. The flow properties show an increase in yield stress with an increase in particle concentration and magnetic fields. The application part of the fluid consists of Magnetorheological damper fabrication and dynamic testing of 20% volume concentration particles at 10 mm amplitude, 2 Hertz frequency, and 0 Ampere and 0.5 Ampere currents, and the temperature of the system is captured with a K-type thermocouple. The results show an 8.2 °C rise at 0.5 Ampere with a 26.2% force decrease within 1000 cycles. The theoretical model based on the lumped parameter analysis predicts the temperature rise, similar to the experimental analysis with a 9.5% error.

The dynamical second-order transport coefficients of smeared Dp-brane

The smeared Dp-brane is constructed by having the black Dp-brane uniformly smeared over several transverse directions. After integrating the spherical directions and the smeared directions, the smeared Dp-brane turns out to be a Chamblin-Reall model with one background scalar field. Within the framework of the fluid/gravity correspondence, we not only prove the equivalence between the smeared Dp-brane and the compactified Dp-brane by explicitly calculating the 7 dynamical second-order transport coefficients of their dual relativistic fluids, but also revisit the Correlated Stability Conjecture for the smeared Dp-brane via the fluid/gravity correspondence.

Free surface and internal periodical waves generated by an oscillating floater in two-layer fluids using fully nonlinear numerical wave tank

This study simulated free-surface and internal periodical waves generated by an oscillating floater in two-layer fluids using a numerical wave tank (NWT) with dual-fluid domains. Each domain was based on the potential flow and boundary element method (BEM). To validate the present NWT, the simulated results were compared with Kashiwagi's theoretical and experimental data, which results in good agreement. The fully nonlinear NWT results were compared systematically with the linear results to quantify their differences through higher-order components in barotropic (or surface wave) and baroclinic (or internal wave) modes both in the surface and internal waves. Free-surface and internal waves were analyzed systematically in terms of the two wave modes, respective-order components, several density ratios, and body-oscillation amplitudes and frequencies. For the present NWT(FN-NWT) with dual fluid domains, three different approaches for updating the instantaneous free surface and interface in the mixed Eulerian-Lagrangian (MEL) method were compared to cross-check the robustness of the developed schemes. When the forced oscillation amplitude and density difference are large, both surface and internal waves have strong nonlinearity, especially in the low-frequency region mainly due to the increased effects of the baroclinic mode. On the other hand, for the surface wave, the increased effects of primary and higher-order components from the barotropic mode are observed, particularly in high frequencies.

Numerical Study of Flow and Heat Transfer Characteristics in a Simplified Dual Fluid Reactor

This study presents the design and computational fluid dynamics (CFD) analysis of a mini demonstrator for a dual fluid reactor (DFR). The DFR is a novel concept currently under investigation. The DFR is characterized by the implementation of two distinct liquid loops dedicated to fuel and coolant. It integrates the principles of molten salt reactors and liquid metal cooled reactors; thus, it operates in a high temperature and fast neutron spectrum, presenting a distinct approach in the field of advanced nuclear reactor design. The mini demonstrator serves as a scaled-down version of the actual reactor, primarily aimed at gaining insights into the CFD analysis intricacies of the reactor while minimizing computational costs. The CFD modeling of the MD intends to add valuable data for the purpose of modeling validation against experiments to be conducted on the MD. These experiments can be used for DFR licensing and design optimization. The coolant and fuel utilized in the mini demonstrator are of low Prandtl number (Pr = 0.01) liquid lead, operating at two distinct inlet temperatures, namely 873 K and 1473 K. The study showed a rapid increase in turbulence due to intense mixing and abrupt changes in flow areas and directions, despite the relatively low inlet velocities. Hot spots characterized by elevated temperatures were identified, analyzed, and justified based on their spatial distribution and flow conditions. Flow swirling within pipes was identified and a remedy approach was suggested. Inconsistent mass flow rates were observed among the fuel pipes, with higher rates observed in the lateral pipes. Although lower fuel temperatures were observed in the lateral pipes, they consistently exhibited higher heat exchange characteristics. The study concludes by giving physical insights into the heat transfer and flow behavior, and proposing design considerations for the dual fluid reactor to enhance structural safety and durability, based on the preliminary analysis conducted.

Seismoelectric Coupling Equations of Oil-Wetted Porous Medium Containing Oil and Water

For porous medium containing multiphase fluid, such as oil-wetted porous medium with oil–water dual phase fluid, its fluid interface will also produce electric double layer (EDL), which will play a role in the seismoelectric effects. At this time, the principle of seismoelectric effects is more complex. The existing theory for the seismoelectric effects is the Pride theory used in the water-saturated porous formation, which cannot meet the actual needs of the theoretical research of seismoelectric exploration in the porous formation with multiphase fluid. Carbonate porous formations are often oil-wetted; therefore, it is necessary to study the electrokinetic effects of oil-wetted porous medium containing multiphase fluid. In this paper, we treated the oil–water mixture as an effective fluid, and solved the effective elastic parameters and extended the Biot equations to the case of oil-wetted porous medium with oil–water dual phase fluid. We calculated the effective electromagnetic parameters and derived the macroscopic coupling equations of seismoelectric effects and electroseismic effects, and proposed the new electrokinetic coupling coefficients of the oil-wetted porous medium with dual phase fluid. We also deduced the coupling functions of electric and magnetic fields relative to the solid displacement in the homogeneous porous medium, and studied the polarization characteristics of the electric field. We use the derived coupling equations to simulate the seismoelectric logging while drilling in the model of oil-wetted porous formation with dual phase fluid under the excitation of multipole sources. The influence of drill collar wave on the acoustic field and electric field under the excitation of different sources was investigated, which has a certain guiding role in the selection of electrokinetic logging tools.

Novel methods to induce complex coacervation using dual fluid nozzle and metal membranes: Part II – Use of metal membrane technology to induce complex coacervation

In this follow up study, which is the extension of our previous work on the use of metal membranes for production of ginger oil emulsions with engineered droplet size (part I), we continue the exploration of membrane technology for production of complex coacervates. In this paper (part II) we introduced a novel method to induce multi core complex coacervation using metal membrane technology - which has been most used for drop-by-drop emulsification. Gelatin (4% and 10% w/w) and ginger oil (gelatin to ginger oil ratio 1:1) emulsions were produced using the high shear homogenization followed by injection through the metal membranes to induce complex coacervation using gum Arabic at pH 3.5 using a dispersion cell. The capsules (coacervates) produced using metal membrane (with 24 µm pore diameter) had spherical shape with diameters between 53 and 72 µm. Encapsulation efficiency ranged between 61% and 93% while the encapsulation yield varied from 15% to 90%, being significantly higher for emulsions with 4% (w/w) of gelatin. Complex coacervation by metal membrane was compared with coacervation induced by atomization and batch stirring. The methods discussed in this study can be potentially used in encapsulation of both lipophilic and hydrophilic compounds. Finally considering encapsulation properties and the possibility of engineering the capsules size, the use of membrane technology is a promising new configuration to induce complex coacervation, with real possibilities to allow scale up of the process of complex coacervation.

Simulation of battery simultaneous cooling based on the dual fluid medium system

The battery thermal management system (BTMS) based on refrigerant cooling can cope with high battery heat production even in the case of high ambient temperature, but the economy is poor. A novel BTMS called dual flow medium system (DFMS) had been proposed in previous studies to improve the economy of refrigerant-based BTMS, including refrigerant and coolant in parallel for battery cooling. Based on a validated simulation system, this study presents and analyzes a new operation mode of the DFMS called simultaneous cooling, in which the refrigerant and coolant cool the battery simultaneously. First, the transient cooling process was studied under different ambient temperatures, compressor speeds, and coolant flow rates. The results show that simultaneous cooling can reduce the average battery temperature by 2.66 °C more than using only refrigerant for battery cooling, and the maximum temperature difference between batteries can reach 0.33 °C. Then different coolant flow control methods are proposed and compared under the premise of constant temperature mode. The results show that compared with only refrigerant cooling, the optimal coolant flow control method can reduce the maximum temperature difference between the batteries by 31.94 % but with an extra 2.24 % power consumption.

Assessing the Potential Increase in the Energy Storage Density of Subsea Hydro-Pneumatic Accumulators Using Carbon Dioxide in Lieu of Air

Abstract The integration of energy storage systems (ESS) on a large scale is becoming essential to mitigate intermittency issues in power supply from offshore wind farms. This paper deals with an offshore hydro-pneumatic energy storage (HPES) system comprising of a subsea accumulator pre-charged with a compressed gas. The paper applies a simplified thermodynamic model to investigate the potential increase in the energy storage density of the proposed HPES system by replacing air with carbon dioxide (CO2) that is able to undergo a phase change (gas-liquid-gas) during the storage cycle when limiting the peak operating pressure below the critical point. The study is based on a numerical model for simulating the thermodynamics of the entire storage cycle. A sensitivity study is conducted to examine the influence of main operational parameters, primarily the seawater temperature, peak working pressure, and sea depth, on the storage density of the HPES system operating with a dual phase fluid. It is shown that the storage density of HPES accumulators can be increased substantially by using CO2 in lieu of air. The increase in density is found to depend considerably on the seawater temperature and sea depth.

Stable and unstable capillary fingering in porous media with a gradient in grain size

Multiphase flows in complex porous networks occur in many natural processes and engineering applications. We present an analytical, experimental and numerical investigation of slow drainage in porous media that exhibit a gradient in grain size. We show that the effect of such structural gradient is similar to that of an external force field on the obtained drainage patterns, when it either stabilises or destabilises the invasion front. For instance, gravity can enhance or reverse the drainage pattern in graded porous media. In particular, we show that the width of stable drainage fronts scales both with the spatial gradient of the necessary pressure for pore invasion and with the local distribution of this (disordered) threshold. The scaling exponent results from percolation theory and is − 0.57 for 2D systems. Overall, introducing a dimensionless Fluctuation number, we propose a unifying theory for the up-scaling of dual immiscible fluid flows covering most classical scenarii.

Modeling and Experimental Study of the Dual Cylinder Fluid Inerter

The fluid inerter is a new mechanical element which has received great attention in the field of vibration reduction. However, due to the influence of secondary flow in the curved channel, the damping force is too large and the inertia force is relatively small, which limits the engineering applications of the single-cylinder fluid inerter. To eliminate the influence of secondary flow in the single-cylinder fluid inerter, this paper proposes a dual-cylinder fluid inerter that has a straight tube instead of the spiral pipe or spiral groove. We Analyze the working principle, derive conditions of free movement, establish the damping force and inertia force model, and prove the validity of the model through bench testing. Contrastingly, it is found that the maximum parasitic damping force is only 40.32% of the single-cylinder structure, but the inertia force increases to 180.96% of the single-cylinder structure. The proposed inerter greatly increases the proportion of inertia force, and provides a new scheme for engineering applications.

A double-effect/two-stage absorption refrigeration and thermal energy storage hybrid cycle using dual working fluids

• The hybrid cycle can get a generation temperature of 385 K and a COP of 2.37. • This cycle can work below 273.15 K with a high ESD over 300 kJ·kg −1 . • It realized combined cooling and heating for 24 h using dual working fluids. To improve the flexibility of absorption thermal energy storage (ATES) cycle, including lower the generation temperature, larger the operating temperature region and combined cooling and heating for 24 h, a double-effect/two-stage absorption refrigeration and thermal energy storage hybrid cycle using LiBr/H 2 O and LiBr-[BMIM]Br/C 2 H 5 OH working fluids is proposed in this paper. The cycle includes an absorption heat pump (AHP) sub cycle and an ATES sub cycle. Based on the measured thermophysical properties, the thermodynamic performance of this new cycle under different working conditions was calculated by MATLAB. According to the results, the hybrid cycle obtained a low generation temperature of 385 K, attributed to the utilization of the low-temperature working fluid LiBr-[BMIM]Br/C 2 H 5 OH. Moreover, the evaporation temperature of 268.15 K expanded the operating region of the hybrid cycle, and the highest COP and ESD of 2.37 and 394 kJ·kg −1 were obtained at that temperature, respectively. More importantly, the cycle realized combined cooling and heating all day long, with a cooling output temperature range of 268.15–278.15 K and a heating output temperature range of 321–344 K, which can fully meet the demands of commercial and civilian applications. To further verify the feasibility of the cycle, the model sensitivity and chemical potential achieved in the hybrid cycle were analyzed.

An Improved Hydraulic Power Take-Off Unit Based on Dual Fluid Energy Storage for Reducing the Power Fluctuation Problem in the Wave Energy Conversion System

The power take-off (PTO) stability is one of the most important concerns for wave energy converters (WECs). The PTO unit converts the mechanical energy produced by the wave absorber (WA) unit into useful electrical energy. Due to the drastic input energy variation of real wave motions, the generated electrical power from the PTO unit significantly fluctuates and is potentially harmful to electrical and electronic appliances. This paper proposes an improved hydraulic PTO (HPTO) for the WECs. An improved HPTO unit comprises a dual high-pressure accumulator (HPA) module and fluid energy control (FEC) module, which significantly enhances the generated electrical power from the generator under irregular wave circumstances. A complete model of wave absorber device with conventional and improved HPTO units was built in MATLAB/Simulink using a Simscape fluids toolbox. The parameters of the FEC control strategy were optimized using a genetic algorithm. The improved HPTO unit model was simulated with five irregular wave inputs to evaluate its performance in irregular conditions. The effects of the HPA pressure constraints on the improved HPTO unit performance were also investigated. Overall, the simulation results indicate that the improved HPTO unit was able to generate a stable power up to 87.3% of WECs in an irregular sea state.