Bubble Pressure Research Articles

Isochoric bubble point data for binary systems of 1 (ethane) in 2 (decane, undecane, dodecane and tridecane)

In this communication, a new set of vapour liquid equilibrium (bubble point) data were obtained for ethane-decane, ethane-undecane, ethane-dodecane and ethane-tridecane binary systems. The datasets were obtained using constant-volume (isochoric) method. The datasets cover temperatures from 260 to 373 K and pressures from 0.6 to 10 MPa for all binary systems. A total of five compositions were studied for each of the binary systems ranging from ethane rich compositions to compositions rich in decane, undecane, dodecane and tridecane respectively. Datasets obtained were used to adjust the binary interaction parameters (BIP) for Peng-Robinson (PR), Perturbed Chain Statistical Associating Fluid Theory (PC-SAFT) and the Multi-Fluid Helmholtz Energy Approximation (MFHEA) equations of state (EoS). Quadratic temperature dependent BIP functions were obtained for PR-EoS using a combination of datasets from this work and those published in the literature for the ethane-decane and ethane-dodecane binary systems. Correlation of the datapoints from this work with the PR-EoS, PC-SAFT-EoS and MFHEA EoS yielded very low average absolute deviations (AADs) of less than 5 % for all the datasets. Expanded uncertainties associated with each of the bubble point temperatures and pressures obtained are also reported at 95 % confidence interval. Expanded uncertainties in all the compositions studied were found to be less than 0.002 at 95 % confidence interval.

Prediction and Deformation Mechanism Analysis of High Porosity in U–10Mo Monolithic Fuels at High Burnup

High porosity phenomena of U-10Mo fuel foil appear in the U–Mo/Al monolithic fuel plate under deep burnup. In this study, the fuel skeleton creep-based bubble growth model is further improved with the intrusion effect of solid fission products, multiplying the reduction factor in the bubble volume to obtain the bubble pressure. With the locally enhanced irradiation creep of the Mo-depleted region considered, a simulation of the thermo-mechanical coupling behaviors of the monolithic fuel plate L1P7A0 is carried out, based on the commercial finite element (FE) analysis code ABAQUS. A fission-induced creep rate coefficient of 250 × 10−22 mm3/(fission·MPa) is identified for the Mo-depleted region, with the predictions of porosity and the thickness deformation of U–Mo fuel foil agreeing well with the experimental data. The research results indicate that: (1) the locally enhanced fuel skeleton creep ability is responsible for the higher porosities near the U–Mo/Zr interface; (2) the entrance of solid fission products into the fission bubbles at high burnup is the dominant factor in inducing high porosity in the regions of the most heavily irradiated fuel foil, especially near the fuel foil edge bearing the elevated external hydrostatic pressures; (3) with the intrusion effect of solid fission products considered, the prediction of the porosity increases from ~15% to ~35% near the fuel foil edge; (4) the intrusion of solid fission products leads to extra differences between the bubble pressure and the external pressure, and simultaneously results in the strengthened fuel skeleton creep deformation contributions to the bubble growth.

Evaluation of hydrogen peroxide wetting properties in the context of safe application in aseptic milk filling

Introduction: In aseptic filling systems, packaging materials are sterilized using various methods to eliminate microorganisms. One of the most popular methods for sterilizing packaging materials is the use of hydrogen peroxide. The wetting property of the surface plays a crucial role in ensuring effective inactivation of microorganisms and uniform treatment of the aseptic packaging. Improving the wetting properties of hydrogen peroxide solutions by adding surfactants will enhance the contact of the sterilant with the lyophobic multilayer packaging material's treated surface, providing the necessary sterilizing ability and disinfectant action during the aseptic filling of milk and dairy products.Purpose: To study the wetting properties of concentrated hydrogen peroxide solutions on various substrates and the possibility of their correction with surfactants to ensure better packaging wetting and safe disinfection processes.Materials and Methods: The objects of the study included the disinfecting substance and sterilant - hydrogen peroxide, surfactants used as technological aids in the food industry, and combined multilayer packaging materials based on paper, cardboard, aluminum foil, and polymer materials used in aseptic milk filling processes. Wetting ability was evaluated by the contact angle in a 3-phase system: adhesive (hydrogen peroxide, water, surfactant solutions) - substrate (packaging material, steel plate, glass) - air using the drop shape analysis based on the Young-Laplace method; surface tension was determined by the optical drop shape analysis using the DSA25S device; surface tension of solutions at temperatures ranging from 30 to 70 °C was determined using the maximum bubble pressure method. The presence of residual amounts of the surfactant polysorbate on the sterilized packaging material was analyzed by HPLC.Results: The Tetra Brik®Aseptic packaging material exhibits pronounced lyophobic properties. The introduction of 0.1% polysorbate surfactant into the hydrogen peroxide solution (~35% w/w) reduced the contact angle by more than 50%, from 93.75° to 40.99°, and significantly decreased the surface tension (45-48%).Conclusion: Improving the wetting properties of hydrogen peroxide solutions will enhance the contact of the sterilant with the treated surface of the lyophobic multilayer packaging material by adding a surfactant, ensuring the necessary sterilizing ability and disinfectant action during the aseptic filling of milk and dairy products. The application conditions of hydrogen peroxide solutions with the addition of 0.1% nonionic surfactant polysorbate in aseptic filling, considering both effectiveness in disinfecting packaging material and safety related to the removal of its residual amounts, allow considering it as a technological aid.

Flow Turbulence and Pressure Fluctuations in a Hydraulic Jump

Turbulence and pressure fluctuations are key elements in the bed protection design of hydraulic structures. However, their roles in a hydraulic jump are not yet fully understood, and the nature of their relationships are not conclusive. In order to better understand the relationships between pressure fluctuations and flow characteristics of a hydraulic jump downstream of a weir, detailed measurements of flow kinematics using the nonintrusive techniques of particle image velocimetry and bubble image velocimetry and pressure using voltage-type pressure gauges were carried out in this study. The physical modeling of the hydraulic jump was carried out using the simultaneous measurements of pressure and turbulent flow properties. The distributions of flow properties, such as water level and velocity, were assessed in each case. Based on the measurements, the correlations between the pressure fluctuations and the variables were investigated by coupling the statistical values of the variables at the same points. The analysis results show that the water level and turbulence intensity are the main factors influencing the pressure fluctuations in the hydraulic jump. Using these factors, an empirical formula and dimensionless numbers are proposed to show that the pressure fluctuations depend on the bubble flow behavior.

Effect of diameter and inclination of steam injection pipe on chugging dynamics in direct contact condensation

Low mass flux of steam and high degree of subcooling are the prominent factors for occurrence of unstable direct contact condensation, commonly known as chugging, when steam is injected into a subcooled water pool. Such an arrangement is typically used in the pressure suppression pool of the primary containment vessel in a boiling water reactor. With an attempt to identify the conditions of minimum pressure oscillations during the chugging regime, the present study investigates the effect of internal diameter (0.5–1 in.) and inclination (8.75˚) of steam injection pipe on steam bubble dynamics, pressure transients and heat transfer characteristics at different steam mass flow rates (5–25 kg/hr) and submergence depths of steam pipe (1–13 cm) within the water pool. The study reveals that the condensation cycle time decreases with a decrease in the internal diameter of the pipe. Furthermore, the frequencies of fluctuations in the interfacial area of the steam bubble and pressure transients in the steam pipe exhibit an increasing trend with an increase in steam mass flow rate and a decrease in internal diameter of the steam injection pipe. The chugging frequencies in the inclined and vertical orientation of steam injection pipe lie within the range of 0.5–3 Hz. The average heat transfer coefficient increases with an increase in the internal diameter of pipe and steam mass flow rate. The amplitude of pressure oscillations has decreased significantly whereas heat transfer coefficient has increased marginally upon changing the orientation of steam injection pipe from vertical to inclined. Therefore, smaller diameter and inclined orientation of steam injection pipe are favourable for mitigation of pressure oscillations in applications of direct contact condensation.

Optimal design of the diphasic flow pattern in water electrolyzers with CFD-independent multiphysics model

The diphasic flow in the flow channel in water electrolyzers is one of the most significant phenomena affecting the efficiency of power-to-hydrogen. The produced bubbles during electrolysis will cover the catalyst layer, isolating the contact between the electrolyte and the catalyst. The topology of the flow channel, determining the bubble distribution on the catalyst, should be well-designed to attenuate the insulated bubble effect. Aiming at maximizing the hydrogen production rate from flow topology optimization, a CFD-independent multiphysics model is proposed in this paper considering the bidirectional coupling between electrochemical reaction and diphasic flow. Unlike the traditional diphasic models whose resolving depends on CFD methods, the proposed model features a node association matrix recording the topology of the flow channel, so that the multiphysics fields can be obtained through a set of matrix equations. By comparing the results with the CFD model, the resolving of the proposed model accelerates over 50 times at maximum, while the multiphysics fields can be obtained with different flow topologies at an accuracy loss within 5% by increasing the differencing segments. Therefore, the model can be applied to the optimization of the flow topology due to outperforming mathematical properties. By weighing the bubble accumulation and pressure drop in the paralleled flow channel, the optimal topology can be acquired for minimized bubble effect with various structural parameters of the flow channel in pursuit of maximum power-to-hydrogen efficiency.

Atomistic simulation of brittle-to-ductile transition in silicon carbide embedded with nano-sized helium bubbles

The tensile response of cubic silicon carbide (SiC) bulk containing cavities (voids and He bubbles) has been investigated using molecular dynamic simulations. The formation of cavities in SiC leads to a significant degradation in the mechanical properties of SiC with more influence on material fracture than initial elastic deformation. The brittle-to-ductile transition occurs in cavity-embedded SiC as the pressure in He bubbles increases. This is associated with the deformation mechanism that bond breaking at a low He bubble pressure transfers to extensive dislocation activities at a higher He bubble pressure. The cavities can effectively concentrate stress around them in the direction perpendicular to the tension, which leads to preferred cracking in the region with a higher tensile stress. The failure mechanism as revealed by this study improves understanding of property degradation in SiC that may be useful for applications of SiC in advanced nuclear energy systems.

Nonlinear modeling of sparkling drink bubbles using a physics informed long short term memory network

Bubble dynamics exist in many physical phenomena from the interaction between atmosphere and ocean, to food science of champagne bubbles. Bubble sound has recently been found to be a new way to understand bubbles and bubble dynamics. In this paper, we collect bubble sounds of different types of sparkling drinks, namely, sparkling water, beer, and champagne, and use the experimental data to construct a data driven model for sparkling bubbles. We apply dynamical reconstruction theory to the measured data and use false nearest neighbor, correlation dimension, and largest Lyapunov exponent to verify that the sparkling drink bubble dynamic is nonlinear and chaotic. Based on the derived physical principle on bubble pressure, we propose a novel physics informed long short term memory (PI-LSTM) neural network as a time series predictor to form a data driven with physics guidance model for bubble dynamics. It is shown here that the proposed PI-LSTM is effective in modeling the bubble sound data with improved accuracy compared to standard predictors including LSTM, multi-layer neural network and decision tree. The predictive analysis supports the nonlinear behavior of the bubble sound signals and demonstrates results consistent with the chaotic analysis.

Numerical study of liquid jet and shock wave induced by two-bubble collapse in open field

The shock waves and high-speed jets induced by the violent collapse of bubbles can cause serious damage to nearby structures. To fully understand the shock wave and jet characteristics induced by bubble-bubble interaction, we developed a diffuse-interface method for the simulation of compressible two-phase flow, which combined interface compression technique with interface sharpening technique to keep the sharpness of the shock wave and phase interface. The thermodynamically consistent five-equation model was improved using interface compression technique to maintain a constant thickness of the phase interface. To further suppress numerical dissipation, the high-order scheme WENO (Weighted Essentially Non-Oscillatory) and interface sharpening function THINC (Tangent of Hyperbola for INterface Capturing) were used for the flux reconstruction at the grid boundary to ensure that the total variation at the cell boundary was minimized (Boundary Variation Diminishing, BVD), thus the spatial reconstruction scheme, named WENO-THINC-BVD, was developed. Moreover, we extended the present method to a block-structured adaptive mesh refinement framework to improve grid resolution and save computing resources. Numerical results of several benchmark tests fully demonstrated the advantages of the present method in simulating complex compressible flows containing shock-shock and shock-interface interactions. Based on the present high-fidelity numerical methods, we investigated the shock wave and liquid jet induced by the two-bubble interaction in an open space. A phase diagram of the liquid jet propagation direction as a function of the initial bubble pressure and the inter-bubble distance was summarized. Finally, according to the bubble-bubble interaction process, an empirical formula for the collapse strength and another for the attenuation of shock waves were developed.

Experimental study of underwater explosions below a free surface: Bubble dynamics and pressure wave emission

The current work experimentally studies the complex interaction between underwater explosion (UNDEX) bubbles and a free surface. We aim to reveal the dependence of the associated physics on the key factor, namely, the dimensionless detonation depth γ (scaled by the maximum equivalent bubble radius). Four typical bubble behavior patterns are identified with the respective range of γ: (i) bubble bursting at the free surface, (ii) bubble jetting downward, (iii) neutral collapse of the bubble, and (iv) quasi-free-field motion. By comparison of the jet direction and the migration of the bubble centroid, a critical value of γ is vital for ignoring the effects of the free surface on UNDEX bubbles. Good agreements are obtained between the experimental data and Zhang equation [Zhang et al., “A unified theory for bubble dynamics,” Phys. Fluids 35, 033323 (2023)]. Additionally, the dependence of the pressure signals in the flow field on γ is investigated. The peak pressure, impulse, and energy dissipation in the UNDEX are investigated.

Pressure drop and bubble length prediction for gas-non-newtonian fluid two-phase flow in a curved microchannel

The control mechanism of the pressure drop and bubble size has a guiding significance for selecting the micropump, the pressure resistance design, and the precise control of the microfluidics. In this study, single-phase flows and gas-non-Newtonian fluid two-phase flows are studied in a microchannel containing curved structures. Sodium carboxymethyl cellulose solutions are used as the non-Newtonian fluids; water and nitrogen are used as Newtonian fluid and gas phases, respectively. The pressure drop and the bubble length are measured. The influences of operating conditions are discussed. The non-Newtonian properties of the solutions are found to affect the parameters measured significantly. The experimental results are compared with the existing models, and the fanning friction factor is used to evaluate the pressure drop. The two-phase flow pressure drop can be predicted by the Lockhart-Martinelli method with a newly developed C-coefficient as a function of the fluid characteristic parameters and microchannel structure parameters. The new correlation for two-phase pressure drop prediction has an error within 18%, smaller than existing models. A new prediction method for the dimensionless bubble length containing the two-phase friction multiplier is also given with an error of 16%.

Constructing a composite microfiltration carbon membrane by TiO2 and Fe2O3 for efficient separation of oil-water emulsions.

Membrane-based separation technology has attracted enormous attention for oil/water emulsion treatment. Here, composite microfiltration carbon membranes (MCMs) were prepared from the precursor of phenolic resin doping with TiO2 and Fe2O3 via the processes of stereotype and pyrolysis. The functional groups, thermal stability, porous structure, microstructure, morphology, and hydrophilicity of the membrane samples were analyzed by Fourier-transform infrared spectroscopy, thermogravimetric analysis, bubble pressure method, X-ray diffraction, scanning electron microscope, and water contact angle, respectively. The effect of dopant amount on the separation performance of MCMs was investigated. The results show that a mixed matrix system is constructed by TiO2 and Fe2O3 in MCMs, which is beneficial for further optimizing the pore size, porosity, and hydrophilicity of MCMs for oily wastewater treatment by varying the dopant amount. The maximum oil rejections are achieved at 98.9% and 99.6% for MCMs with a dopant content of TiO2 and Fe2O3 at 25%, respectively. In brief, this study offers an attractive strategy for improving the separation performance of MCMs for oily wastewater.

Estimation of excess Gibbs free energy of multicomponent biofuel mixtures of Butan-1-ol using machine learning methods based on modified Raoults law models

In biofuels, the excess Gibbs free energy of mixing is a very important thermodynamic property as it is used in evaluating the efficiency and sustainability in terms of energy conversion. Multiple biofuel systems containing butan-1-ol were examined with oxygenate ether additives such as MTBE and DIPE using isothermal vapour-liquid equilibrium data at different temperatures (298.15K, 313.15K, 318.15K). Two activity coefficient models, Wilson and van Laar model were compared by determining the bubble pressure and vapor mole fractions of each system using Modified Raoults Law and Machine Learning techniques. Besides, mole fractions and activity coefficients were used to identify the excess property. Results showed that Wilson model is appropriate for all the biofuel systems when using the Artificial Neural Network (ANN) resulting in an MSE of 3.2010e-09, 4.6792e-10, 1.6186e-10, and 5.3461e-07. In addition, van Laar model is more acceptable when Rational Quadratic GPR or Fine Tree algorithm were used with an average RMSE of 0.005820.01 and 0.020950.03 respectively. Lastly, the generated data for both activity coefficient models were also used to estimate the systems excess Gibbs free energy of mixing across varying mole fraction of its components.

Direct Measurement of the Internal Pressure of Ultrafine Bubbles Using Radioactive Nuclei

Direct Measurement of the Internal Pressure of Ultrafine Bubbles Using Radioactive Nuclei

The influence of divalent cations on the dynamic surface tension of sodium dodecylbenzenesulfonate solutions

The kinetics of surfactant adsorption at interfaces is crucial in many industrial settings. Maximum bubble pressure tensiometry allows accessing the adsorption at time scales of tens of ms to uncover the initial stages of surfactant diffusion to the interface. This method was used to investigate electrolyte solutions of sodium dodecylbenzenesulfonate (SDBS), specifically targeting how the presence of small amounts of divalent cations (Mg2+, Ca2+, Sr2+ and Ba2+) influenced the adsorption kinetics and equilibrium. The dynamic surface tensions revealed that the adsorption of SDBS was strongly influenced by the presence of divalent cations due to strong interactions with the anionic surfactant. In addition, the type (i.e. size) of cations played a role. The strong divalent cation-surfactant interactions lead to distinct lowering of surfactant diffusion coefficients, calculated using the short-time approximation solution of the Ward-Tordai equation. The diffusion coefficients were slightly and similarly lowered for all types of divalent cations when the surfactant concentration was increased up to the critical micelle concentration (CMC). Above CMC, the diffusion coefficients increased steadily depending on the divalent cation. It was speculated that this could be due to differences in structure and aggregation numbers of micelles and slower disassembly of micelles to supply monomers for adsorption. Furthermore, CMC of SDBS was reduced according to the Hofmeister series in the presence of divalent cations.

The density and pressure of helium nano-bubbles encapsulated in silicon

The 1 s 2 → 1 s 2 p ( 1 P ) excitation in compressed helium atoms in either the bulk material or encapsulated in a bubble is shifted to energies higher than in the free atom. For bulk helium, energy shifts predicted from non-empirical electronic structure computations are in excellent agreement with experimentally determined values. However, there are significant discrepancies both between the results of experiments on different bubbles and between these and the well established descriptions of the bulk. A critique is presented of previous analyses of earlier scanning transmission electron microscope measurements that are untrustworthy because the density dependence of the electron impact excitation cross section was neglected. Experimental electron energy loss data from an earlier study of helium encapsulated in silicon are reanalysed and it is shown that the properties of the helium in these bubbles do not differ significantly from those in the bulk, thereby enabling the densities in the bubbles to be determined. These enable bubble pressures to be deduced from a well established experimentally derived equation of state. It is shown that the errors of up to 80% in the incorrectly determined densities are greatly magnified in the predicted pressures which can be too large by factors of over seven.

Insights into the bubble formation dynamics in converging shape microchannels using CLSVOF method

Abstract Bubble formation in a square microchannel having a converging shape merging junction has been studied using the Coupled Level-Set and Volume-of-Fluid (CLSVOF) method. The influence of variations in merging junction angles, fluid properties, and operating conditions on the bubble length and pressure drop has been analyzed. The results show a direct relationship between surface tension, gas-liquid flow ratio, and the inverse relation of continuous phase viscosity with the bubble length. Moreover, opposite variations of these parameters are observed for pressure drop. This work reveals a discerning influence of the angle variations of merging junction on the interplay between inertial, viscous, and surface tension forces in the bubble formation mechanism. We envisage that this numerical work will be of significant interest for the process intensification in various industries that deal with gas-liquid microfluidic systems.

Properties of liquid CaO–SiO2 and CaO–SiO2-‘Fe2O3’tot slags measured by a combination of maximum bubble pressure and rotating bob methods

Liquid slag properties are essential for understanding complex mass and momentum phenomena in metallurgical operations. The density, surface tension and viscosity were measured in six silicate-rich slags of the CaO–SiO2 and CaO–SiO2-‘Fe2O3’tot systems by combining the maximum bubble pressure and rotating bob methods. The properties investigated were sensitive to the temperature, SiO2 and Fe2O3 contents. Different experimental trends were derived due to the amphoteric properties of Fe2O3. The slags with ferric oxide were denser than the silicate melts. Surface tension gradually decreased with temperature and indicated firstly a rise and then decline with further Fe2O3 addition. Raman spectra were analyzed to provide structural information of the polymer melt and indicated an enhancement in the polymerization degree with Fe3+. The derived experimental trends and role of Fe3+ in the silicates were attributed to the interplay of complex factors: different bonding in the melt, cation interactions and the oxidation state of iron. The influence of Fe3+/Fe2+ on the melt properties was discussed.

Ensuring consistency in VLE and density modelling of (CO2 + H2) mixtures that are relevant in CCS pipeline transport: fitting BIPs for various EoS implemented in ‘off-the-shelf’ property packages

The impact of impurities in the physical properties of CO2 is now widely acknowledged by industry. In particular, the presence of H2 in CO2 mixtures has a significant effect on the saturation pressure (bubble point) and bulk (liquid) density. Both physical properties are key in the many engineering tasks, for example, in calculating the closed-in tubing head pressure of an injection well or in defining operating pressures to avoid two-phase region in transport systems. If there are large uncertainties in the estimated properties, then, significant design margins will be required making the system less cost-effective.The reliability of Equations of State (EoS) implemented in property packages used in industry is limited to the availability and quality of the experimental data that was used to calibrate the model. For the pair CO2H2, there is lack of validation at conditions of CCS systems. Thus, the performance of EoS is unsatisfactory for many CO2H2 mixtures. An additional complication is that there is large discrepancy not only between models but also between the ‘same’ model implemented across different platforms. For the practitioner, this poses quite a conundrum: ‘What EoS and package should be used?’.In this work, an attempt to homogenize various EoS implemented in commercial software is presented. To calibrate the models, a subset of available of experimental data with content of up to 5%mol of H2 is used. A different subset of data is used to assess the performance of the fitted models. In the parameter estimation problem, the EoS are tuned via Binary Interaction Parameters (BIPs) or departure parameters. To improve liquid density calculations, an additional step is used to regress cubic EoS via volume shift parameters.The resulting optimized EoS can be readily available in commercial simulators, and it is hope that they will be part of a growing databank/toolbox for engineering design activities of CCS systems.

The comparative modeling of solubility of carbon dioxide in amine solutions using SAFT-HR and PC-SAFT equation of state

In this paper, we applied PC-SAFT and SAFT-HR equations of state so as to reproduce the solubility of carbon dioxide in aqueous diethanolamine solution. By using these equations, we have been able to model the solubility of carbon dioxide in aqueous amine solution in more than 350 experimental data points with wide range of amine molar concentration (0.01–0.12), temperature (300 K –478 K), carbon dioxide partial pressure (0.0001 KPa –5473 KPa), and carbon dioxide loading (0.04 –1.1). Ternary systems including water, carbon dioxide and diethanolamine have also been modeled by PC-SAFT and SAFT-HR equations of state based on bubble pressure algorithm. Binary interaction parameters are set to zero to show the genuine capability of equations of state in reproducing such experimental data. Provided modeling results have been obtained from MATLAB R2019b software for PC-SAFT equation of state are less deviated with experimental data. Overall average relative deviation of SAFT-HR and PC-SAFT are 45.452% and 4.374% respectively which show that PC-SAFT is a robust equation of state in predicting the solubility data of carbon dioxide in aqueous alkanolamine solutions.