Multiphase System Research Articles

Multi-phase shear thickening fluid based on ionic liquid dispersion medium for impact resistance and wear protection

Shear thickening fluids (STFs) have attracted increasing attention as smart materials with unique rheological properties. However, the preparation of STFs usually relies on a composite system of spherical nanoparticles with polyethylene glycol. In this work, novel multi-phase STFs (ILSTFs) were prepared in an ionic liquid by incorporating nanosized SiO2 and rod-shaped calcium metasilicate (CaSiO3) particles as a dispersed phase. Compared to traditional STFs, ILSTFs demonstrate excellent thermal stability. Rheological tests indicate that ILSTFs exhibit continuous shear thickening behavior, resulting in excellent energy absorption and impact wear resistance. In addition, ILSTFs can serve as a new type of lubricant. The tribological properties and impact resistance of ILSTFs were highly correlated with the shear thickening effect, with the multi-phase ILSTF system with CaSiO3 demonstrating superior impact wear resistance compared to the single-phase system. In this study, finite element analysis (FEA) is further utilized to investigate the local damage evolution and energy absorption rate of STF under impact loading, providing insights into the underlying mechanism. This ionic liquid-based STF holds promise for applications as a flexible filling component in the fields of lubrication technology and impact protection structures.

Effect of the impeller blade outlet setting angle on the performance of the helical axial-flow multiphase pump

Effect of the impeller blade outlet setting angle on the performance of the helical axial-flow multiphase pump

Bacteria in clouds biodegrade atmospheric formic and acetic acids

Abstract. Formic and acetic acids are major organic species in cloud water and affect precipitation acidity. In atmospheric models, their losses are limited to chemical oxidation in the gas and aqueous phases and deposition processes. Previous lab studies suggest that these acids can be efficiently biodegraded in water by atmospherically relevant bacteria. However, the importance of biodegradation as a loss process in the atmospheric multiphase system has not been fully assessed. We implemented biodegradation as a sink of formic and acetic acids in a detailed atmospheric multiphase chemistry model. In our model, biodegradation is considered in 0.1 % of cloud droplets according to atmospheric bacteria concentrations of 0.1 cm−3. We predict that up to 20 ppt h−1 formic acid and 5 ppt h−1 acetic acid are biodegraded. This translates into a concentration change of 20 % and 3 % in addition to that caused by chemical losses. Our sensitivity studies suggest that acetic acid is most efficiently biodegraded at pH > 5, whereas biodegradation is least efficient for formic acid under such conditions. This trend can be explained by the fact that formic acid partitions more efficiently into the aqueous phase due to its higher Henry's law constant (KH,eff(HCOOH)=2×105 M atm−1 vs. KH,eff(CH3COOH)=3×104 M atm−1 at pH = 5). Therefore, under such conditions, formic acid evaporates less efficiently from bacteria-free droplets, resulting in less formic acid in the gas phase for dissolution bacteria-containing droplets to replenish biodegraded acid. Our analysis demonstrates that previous estimates of the importance of atmospheric biodegradation were often biased high as they did not correctly account for such uptake limitation in bacteria-containing droplets. The results suggest that, under specific conditions, biological processes can significantly affect atmospheric composition and concentrations in particular volatile, moderately soluble organics.

Modeling phase or chemical reaction equilibrium with an equation of state, an unrealistic modeling

The traditional chemical thermodynamics considered the chemical potential then fugacity of a component in a single-phase, open system is just the one of the component in a co-existing phase of an equilibrium, multi-component, multi-phase system or in an equilibrium, chemical reaction system and the fugacity can be calculated with the equation of state of the single-phase, open system. Therefore, the most common method to model phase or chemical reaction equilibrium is with an equation of state. Obviously, modeling phase or chemical reaction equilibrium with an equation of state requires to the single-phase, open system is equivalent to the co-existing phase or the equilibrium, chemical reaction system. However, there are significant differences in the thermodynamics properties between the single-phase, open system and the co-existing phase or the equilibrium, chemical reaction system. Therefore, the chemical potential then fugacity of a component in the single-phase, open system is impossible the one of the component in the co-existing phase or in the equilibrium, chemical reaction system. That is, the calculated fugacity of a component in a single-phase, open system with the equation of state of the single-phase, open system is impossibly the fugacity of the component in a co-existing phase of an equilibrium, multi-component, multi-phase system or in an equilibrium, chemical reaction system. Therefore, it is unrealistic to model phase or chemical reaction equilibrium with an equation of state. For this, we establish the chemical potential differential formula of a component in a co-existing phase and in an equilibrium, chemical reaction system to calculate phase or chemical reaction equilibrium. The calculated values of solubility in molar concentration within the framework of the present theory equals exactly the measured values of solubility in molar concentration by the experiments.

Pilot-scale testing on catalytic hydrolysis of carbonyl sulfur combined with absorption-oxidation of H2S for blast furnace gas purification

About 70 % of the flue gas in the iron-steel industry has achieved multi-pollutant ultra-low emissions in China until 2023, and then the blast furnace gas purification has become the control step and bottleneck. Our research group has designed and constructed the world's first blast furnace gas desulfurization pilot plant with the scale of 2000 Nm3/h in October 2021. The pilot plant is a two-step combined desulfurization device including catalytic hydrolysis of carbonyl sulfur (COS) and absorption-oxidation of H2S, continuously running for 120 days. In the hydrolysis system, one reason for catalyst deactivation has been verified from the sulfur deposition. HCN in blast furnace gas can be hydrolyzed on the hydrolysis catalyst to produce the nitrogen deposition, which is one of the reasons for catalyst deactivation and has never been found in previous studies. The deposition forms of S and N elements are determined, S element forms elemental sulfur and sulfate, while N element forms -NH2 and NH4+. In the absorption-oxidation system, the O2 loading and the residence time have been optimized to control the oxidation of HS− to produce elemental sulfur instead of by-product S2O32−. The balance and distribution of S and N elements have been calculated for the whole multi-phase system, approximately 84.4 % of the sulfur is converted to solid sulfur product, about 1.3 % of the sulfur and 19.2 % of N element are deposited on the hydrolysis catalyst. The pilot plant provides technical support for multi-pollutant control of blast furnace.

A numerical compass for experiment design in chemical kinetics and molecular property estimation

Kinetic process models are widely applied in science and engineering, including atmospheric, physiological and technical chemistry, reactor design, or process optimization. These models rely on numerous kinetic parameters such as reaction rate, diffusion or partitioning coefficients. Determining these properties by experiments can be challenging, especially for multiphase systems, and researchers often face the task of intuitively selecting experimental conditions to obtain insightful results. We developed a numerical compass (NC) method that integrates computational models, global optimization, ensemble methods, and machine learning to identify experimental conditions with the greatest potential to constrain model parameters. The approach is based on the quantification of model output variance in an ensemble of solutions that agree with experimental data. The utility of the NC method is demonstrated for the parameters of a multi-layer model describing the heterogeneous ozonolysis of oleic acid aerosols. We show how neural network surrogate models of the multiphase chemical reaction system can be used to accelerate the application of the NC for a comprehensive mapping and analysis of experimental conditions. The NC can also be applied for uncertainty quantification of quantitative structure–activity relationship (QSAR) models. We show that the uncertainty calculated for molecules that are used to extend training data correlates with the reduction of QSAR model error. The code is openly available as the Julia package KineticCompass.Graphical

Soluble and insoluble fractions of soy protein isolate affect the properties of its high-moisture extrudates

This research focused the impact of the variation in insoluble soy protein isolate (ISPI) and soluble soy protein isolate (SSPI) contents on the rheological properties of highly-concentrated SPI during extrusion-like conditions and the physiochemical, mechanical, and morphological characteristics of its extrudates. Results showed that increased ISPI content could resist great shear forces and increase the viscoelasticity of SPI samples. In addition, the increase of ISPI content in SPI samples also contributed to enhance the tensile strength and mechanical anisotropy, further created a distinct fibrous structures of extrudates. While higher SSPI content can form heat-induced reverseble aggregates via hydrophobic interaction and disulfide bonds, reduce the water mobility and facilitate the formation of a more uniform protein-water phase. The differences in solubility revealed the dominance of non-covalent bonds in ISS-40 extrudate (100% ISPI) and highlighted the important role of disulfide bonds in ISS-04 extrudate (100% SSPI). Possible mechanisms are proposed to explain the contrasting behavior of ISPI and SSPI under thermomechanical treatment. These insights explore the formation of protein multiphase system structures and offer valuable guidance for developing meat analogue products.

New model of linkage evolution for the transtensional fault systems in the Nanpu Sag of Bohai Bay Basin: Insight from seismic interpretation and analogue modelling

The evolution of faults within the same stress field is frequently influenced by numerous factors, involving the reactivation of pre-existing structures, stress transmission through ductile detachment layers, and the growth, interaction, as well as linkage of new fault segments. This study analyses a complex multi-phase oblique extension fault system in the Nanpu Sag (NPS) of the Bohai Bay Basin (BBB), China. High-resolution three-dimensional (3D) seismic data and analogue modelling indicate that the oblique extensional reactivation of pre-existing structures governs the sequential arrangement of fault segments in the caprock, and they dip synthetically to the reactivated fault at depth. During the NW–SE extension in the Eocene, the predominant movement of the pre-existing fault is strike-slip. Subsequently, during the N–S extension since the Oligocene, inclined at 20° to the pre-existing fault, forming splay fault segments and ultimately creating large en-échelon arcuate faults linked by relay ramps. Using fault throw-distance (T-D) and laser scanning, we reconstructed the fault evolution model of oblique extension reactivation in the presence of a ductile detachment basement. Our study illustrates that the arcuate faults can be categorized into linear master fault segments controlled by pre-existing structures, bending splay faults in the termination zone, and normal fault segments responding to the regional stress field. The interaction between faults occurs among normal faults and strike-slip faults, and the kinematic unification of the two fault systems is accomplished in the intersection zone. As the faults continue to evolve, the new fault segments tend to relinquish the control of pre-existing structures and concentrate more on the development of planar and continuous major faults. The ductile detachment layer significantly contributes to the uniform distribution of strain, resulting in narrow shear zones and discontinuous normal faults in its absence.

Prediction of ash content in coal slime flotation based on CNN-BP method with residual estimation

ABSTRACT Ash content is a key metric for assessing coal slime flotation performance. Traditional methods of sampling, combustion, and weighing lead to measurement delays, thus image-based real-time ash prediction during flotation has become meaningful. However, the complex characteristics of the multiphase system in flotation pulp images make the extraction of an effective dataset for ash recognition challenging. This paper introduces an image-based method for predicting ash content in solid-liquid pulp mixtures using Convolutional Neural Networks (CNNs). A CNN transfer learning method based on ImageNet is proposed, combined with a Backpropagation (BP) residual estimation module with specified feature filters, reducing the sample size requirement. Four classic CNN networks were utilized. Results indicate that introducing the BP residual estimation module improves the CNN network’s prediction accuracy in small samples, with total residuals consistent with the white noise distribution. Notably, the 5% accuracy (absolute error less than 5%) of VGG19 without the CNN classic residual structure improved significantly, reflecting the superior residual estimation of BP and the robust performance of the CNN-BP in predicting pulp ash content. This research offers a new option for transitioning previous dataset collection methods for ash detection in the coal slime flotation process.

Antioxidant-driven activity and stability enhancement in multiphase bicarbonate hydrogenation catalysis with a Ru-PNP pincer complex

Herein, we present a practical strategy to enhance the performance of a multiphase system for bicarbonate hydrogenation based on a molecular Ru-PNP pincer catalyst. This study demonstrates that the use of organic antioxidants not only mitigates catalyst degradation but also significantly boosts its intrinsic activity. This enables efficient catalyst recycling at ultra-low concentrations. Systematic screening and optimization of a range of organic antioxidants has identified TDTBP (tris(2,4-di-tert-butylphenyl) phosphite) as being exceptionally efficient in stabilizing and enhancing the performance of the Ru-PNP catalyst. With the optimized system an unprecedented integral turnover frequency (TOF) of 115,000 h−1 and a total turnover number (TTON) of 9.43×106 across four recycling tests were demonstrated, conducted at a reaction temperature of 90 ºC and H2 pressure of 50 bar. These findings represent a substantial advancement in sustainable formate/formic acid production, offering a scalable and highly efficient method suitable for industrial-scale application.

Microstructural evolution and performance analysis of WC-11Co reinforced iron matrix composites

This paper presents a new fabrication method utilizing lost foam casting as a processing technique to synthesize high-strength and ultra-wear-resistant particle reinforced iron matrix composites. The composite material incorporates large-sized WC-11Co reinforcement. The composite exhibits a multiphase microstructure composed of WC-11Co, α-Fe, and carbide precipitates that extend at different length scales. The precipitation of large-sized M3W3C (M = Fe, Co) type carbides at the WC-11Co/matrix interface is well controlled. A favorable reaction layer is formed between WC-11Co and the matrix. Nano-precipitates are pinned within the reaction layer, exhibiting a high degree of coherence with the iron matrix. The stress field at the interface is complex due to thermal stress, phase transformation stress, and microstress. The stress state between WC-11Co and the matrix consists of compressive residual stress-tensile residual stress-compressive residual stress, with compressive residual stress far exceeding tensile residual stress. The WC-11Co/Fe0.35C5CrMn composite exhibits outstanding compressive strength of 2.18 GPa and a fracture strain of approximately 24.6 %. Moreover, the composite demonstrates excellent wear resistance, with a threefold improvement compared to the matrix under severe wear conditions. The following mechanisms contribute to the enhanced mechanical properties: multiphase material system, coherent multiscale interfaces, grain refinement, dislocation strengthening, and residual stress strengthening.

Efficient hydraulic and thermal simulation model of the multi-phase natural gas production system with variable speed compressors

The natural gas production system is a very complex system, involving pipelines, compressors and valves with different structures and calculation parameters. It can be divided into two different parts: gas production and collection pipe networks. Fluid flow in the gas production pipe network is multi-phase flow. Fluid flow in the gas collection pipe network is single-phase flow. It is imperative to consider gas production and collection pipe networks in conjunction to ensure accurate operation simulation. The complexity of the network structures and flow statuses can cause computational instability or even divergence problems in simulations when coupling these two types of pipe networks. To address this issue, an automatic and practical node numbering method is proposed for the large-scale pipe network, which can ensure the full rank of the solution matrix and computational stability. On the other hand, due to the need for frequent adjustments of the pipe networks to satisfy the production demand, computational boundary treatments of constant inlet/outlet pressure, constant flow rate or constant pressure ratio for the compressor stations are not suitable. To address this issue, the characteristic curves of compressors are coupled into the simulation of pipe networks to represent the variable-speed centrifugal and reciprocating compressors.The accuracy and robustness of the proposed models and numerical methods are validated through comparisons with software results and field data. The simulation time is only within 0.5 s for the natural gas production system with 210 nodes and 176 pipelines. Our model has relative deviations within 3% in both pressure and flow rate compared to field data and within 10% compared to software.

Iterative real-time optimization of a reductive amination process in a thermomorphic multiphase system

In this paper, we discuss the optimization of the operation of a reductive amination (RA) reaction process in a miniplant without an accurate process model using iterative real-time optimization (RTO). The rhodium-catalyzed RA of undecanal with diethylamine produces a tertiary amine from a long-chain aldehyde and is performed in a thermomorphic multiphase system (TMS) to recover and reuse the expensive catalyst efficiently. An iterative RTO method called modifier adaptation with quadratic approximation (MAWQA) is used in combination with guaranteed model adequacy (GMA) to drive the RA process to its optimum iteratively. MAWQA utilizes online measurements to overcome model deficiencies. GMA ensures that the model used in MAWQA satisfies the model adequacy conditions. The optimal operating conditions of the RA process in the miniplant were identified during an experimental run of the plant, thereby validating the applicability and efficiency of MAWQA with GMA. The results illustrate the benefits of process optimization using iterative RTO methods without accurate process models.

Molten multi-phase catalytic system comprising Li–Zn alloy and LiCl–KCl salt for nitrogen fixation and ammonia synthesis at ambient pressure

Through combined experiments and simulations, we unraveled the molecular mechanisms of nitrogen fixation and ammonia synthesis in the molten catalytic systems.

Hydroaminomethylation of methyl 10-undecenoate with integrated catalyst recycling via thermomorphic multiphase system for the continuous production of renewable amines

The thermomorphic multiphase system (TMS) consisting of methanol and n-dodecane was successfully applied to the hydroaminomethylation (HAM) of the renewable methyl 10-undecenoate. By using different amine substrates, a variety of...

Mesoscopic modeling of silver particles melting process on silicon wafer in inkjet-printed solar cell metallization

Inkjet printing technology for solar cell metallization is considered as an important alternative with inherent non-contact characteristics. The melting process of silver particles plays the key role which determines the final structure of finger electrodes. To explore the melting of silver particles inside the silicon wafers, an enthalpy-based LB-FD model is presented to simulate the solid-liquid phase transitions in the multiphase system. In vertical thermal fields, silver particles melt from bottom to upper layers. The adhesion and coalescence behaviors of multiple particles are well captured in multiphase melting. The melting fluids near the sidewall are simulated with the interfacial tension and gravitational force. The effects of solid phase ratio and textured features of silicon wafers are also studied. The presented 3D enthalpy-based LB-FD model exhibits powerful capacities to solve the solid-liquid phase transitions in multiphase system. The numerical analysis provides a better insight to understand and improve the inkjet-printed solar cell metallization process.

Sizing and Selection of Pressure Relief Valves for High-Pressure Thermal–Hydraulic Systems

This study covers the critical concerns related to the sizing, selection, installation, maintenance, and testing of pressure safety valves (PSVs). The aim is to ensure the safety of pressurized systems, hydrostatic transmission systems, and hydraulic plants, including process plants, thermal power plants, and nuclear reactor systems. PSVs are devices that ensure the safety and reliability of pressurized vessels, lines, and systems during overpressure events. The task of selecting which PSV features are of greatest value for a specific purpose is complex—especially in the design of a high-pressure experimental thermal–hydraulic facility for hydrostatic and transient testing of the reactor system—when the systems are in the design and development phases and require qualification and demonstration to prove that they have reached a given level of technological readiness. The present study highlights the required steps for users to follow the associated rules, guidelines, and recommendations. As a part of this research, case studies are presented to help readers better understand the applicable strategy and standards. A discussion and a review of PSV performance degradation and failure are summarized to provide a better understanding of varied process applications and conditions, including fluid flow dynamics, boundary-layer formation and pressure drops, gas bubble formation and collapse, geometric configurations, inlet/outlet piping, abrupt pressure fluctuations, and acoustic resonance. Moreover, this study discusses the servicing and testing of PSVs in a multiphase pressurized system. Overall, it provides a basic overview of how PSVs ensure the safety of pressurized systems, supported by case studies and industrial practices.

New milk protein anisotropic structures formed by high moisture extrusion

In this work, the formation of anisotropic, layered structures from milk protein concentrates was investigated using high moisture extrusion. These structures were obtained in combination with three concentrations of starch (0 %, 14 %, and 33 %, d.b), and at three different moisture levels: 58 %, 63 %, and 68 %. Two different temperature profiles were investigated, reaching a maximum barrel temperature of 80 and 115 °C (and maximum melt temperature of 56 and 64 °C, respectively), with a constant screw speed and feed rate. In situ monitoring of torque, as well as the evaluation of water partitioning via proton relaxometry highlighted the interplay between moisture content and barrel temperature in starch transitions and water intake. For example, the presence of starch displayed water populations of distinct mobility, featured by higher relaxation times, and the apparition (or intensification) of new peaks representing free water in the system. The extruded samples showed a multi-phase system with swollen starch granules embedded in a protein network when 14 % starch was used, at moisture <63 %, as depicted by confocal microscopy. Tensile strength and cutting force tests showed a broad range of textures, from more brittle at high starch concentration, to softer and mushier when extruded at high moisture. Increasing starch and moisture content disrupted the protein network structure. This work demonstrated that milk protein concentrates show great potential to create novel anisotropic structures by extrusion, with tunable texture properties depending on starch, moisture and temperature conditions.

Quantification of powder phase transient accumulation behaviour in gas–powder–liquid flow through a packed bed with the cohesive zone of a blast furnace

Lower regions of industrial reactors, such as blast furnace, are complex multiphase system in which, gas, powder, and liquid flow co-, counter-, and cross-currently. Laboratory-scale experimental models are yet to consider this multiphase transport, even under chemically inert, cold conditions. In the iron-making blast furnace, the presence of fused metal and non-wetting nature of liquid iron towards coke bed challenges the simultaneous transport of gas, powder and liquid. Adverse conditions results in powder accumulation and liquid hold-up which decrease the coke bed’s permeability, and consequently, the furnace’s productivity. An experimental investigation on the aforementioned system is conducted for various flow conditions. Greater gas pressure drop, increase in raceway size, localized flooding of liquid, and distinct powder accumulation characteristics are observed as phases are introduced into the bed. Exploratory data analysis yields steady-state and transient correlations for powder hold-ups. The validity and functionality of these correlations are demonstrated.

Influence of dielectric properties of polybutylene terephthalate and respective foam beads on process behavior in radio‐frequency welding

AbstractRadio‐frequency welding shows great potential for a more sustainable manufacturing of lightweight bead foam products based on local dielectric heating of the part. This study provides the first insight into the material‐process interactions required to enable interdiffusion between foam particles and thus adhesion. The complex relative permittivity is analyzed by impedance spectroscopy of the bulk polymer and foam beads using specially designed measurement cells. Due to the increased flexibility of the polymer chains at elevated temperatures, the relaxation mechanisms are promoted, resulting in a shift of the curves to higher frequencies. At a fixed frequency, a peak in the imaginary part is observed above temperature, revealing the superposition of these two parameters. The foamed beads show similar trends with an attenuated signal due to the high volumetric fraction of air within the multiphase system. The linear dependence between and volumetric power as direct process feedback due to dielectric heating was observed during welding. Compared to the delayed signals from the shielded temperature sensors, the analysis of power consumption allows for higher quality real‐time monitoring throughout the process cycle. The correlation also allows prediction of power levels at defined temperatures.