Vapor Liquid Research Articles

Modeling the Vapor–Liquid Equilibria of Sustainable Aviation Fuel Components with Nitrogen Using the PC-SAFT Equation of State

Modeling the Vapor–Liquid Equilibria of Sustainable Aviation Fuel Components with Nitrogen Using the PC-SAFT Equation of State

Isobaric Vapor–Liquid Equilibria for Separation of the n-Propanol and Water Azeotropic System with the Addition of a Choline Chloride–Ethylene Glycol-Based Deep Eutectic Solvent as an Entrainer

Isobaric Vapor–Liquid Equilibria for Separation of the <i>n</i>-Propanol and Water Azeotropic System with the Addition of a Choline Chloride–Ethylene Glycol-Based Deep Eutectic Solvent as an Entrainer

Investigation of vapor liquid equilibria for HFO-1336mzz(E) + HFC-1234ze(E) binary system by a novel developed cyclic-analytical apparatus

Hydrofluoroolefins (HFOs), which have excellent thermophysical properties and environmental performance, are considered as the most promising environmentally friendly alternatives to the currently used refrigerants. The vapor-liquid equilibrium (VLE) properties of fluids are the basis for the design and optimization of chemical separation and refrigeration systems. In this work, a high-precision and visual VLE experimental apparatus was developed based on the cyclic-analytical method. which mainly includes thermostatic bath, VLE cell, temperature and pressure measurement system, and gas chromatograph, etc. The expanded uncertainties of temperature, pressure, and composition measurement are 0.06 K, 0.0086 MPa, and 0.056 mole fraction, respectively. By measuring the VLE data of the known binary system and comparing it with the literature, the reliability and accuracy of the experimental apparatus were verified. The VLE data of HFO-1336mzz(E) + HFC-1234ze(E) were measured in the temperature range of 293.15 to 358.15 K. The experimental data were correlated with the Peng Robinson (PR) equation of state (EoS) combined with Mathias-Copeman alpha function (MC) and van der Waals (vdW) mixing rule (PRMC-vdW model) in order to adjust the binary interaction parameters (BIP). The VLE data was also compared with the PPR78 predictive model. The VLE investigation provides a basis for further research on the cycle performance of the mixed working fluid.

Turbulent spray combustion modeling in reduced tabulation parameter space by similarity mapping

To overcome the modeling challenge from the coupling between liquid vaporization and chemical reaction in turbulent spray combustion, a similarity mapping approach is implemented to reduce the flamelet tabulation parameters. In the framework of Eulerian–Lagrangian multiphase large eddy simulations (LES), such a modelling idea is developed upon the conventional flamelet/progress variable model. The flamelet library is constructed from a series of quasi one-dimensional spray counterflow solutions, integrated with the multiple solution modes. Test cases, including the laminar spray counterflow flame and Sydney turbulent spray flame, indicate that this newly proposed model is in principle favorable to improve the numerical predictability with acceptable computational cost. Overall, the flame structure can be appropriately captured, showing better performance compared with some reported results. Novelty and significance statementA newly proposed similarity mapping spray flamelet/progress variable (SMFPV) model is implemented for turbulent spray combustion. In SMFPV, the number of entry parameters of the flamelet library is reasonably reduced and two-way coupling between flame and evaporation can be realized. Thus in principle, SMFPV is favorable to improve the numerical predictability with acceptable computational cost. Simulation results of test cases justify the modelling idea.

Phase equilibrium and separation process of byproduct vinyl acrylate in the ethylene vapor phase method producing vinyl acetate

Vinyl acrylate is one of the byproducts in the ethylene vapor phase method for the production of vinyl acetate (VAc), which not only has a toxic effect on the catalyst but also affects the purity of the product. Currently, phase equilibrium data for vinyl acrylate with water are missing, making the destination of vinyl acrylate in the distillation process uncertain. This has led to a lack of effective removal means, which restricts the optimization of the ethylene vapor phase method. This paper uses a method combining quantum chemistry and molecular dynamics simulation (MD) to investigate the existential form of the water molecule. And based on the ab initio calculation of the first principle, the force field parameters of the special water molecular structure are calculated, and the TIP4P-P force field that can describe the special water structure is established. Using the Gibbs Ensemble Monte Carlo (GEMC) method, the reliability of the improved water molecule force field for modeling the phase equilibrium of a binary system is first verified. Further, vapor–liquid phase equilibrium data for the vinyl acrylate-water binary system at 110 kPa and 150 kPa are calculated and the corresponding x-y and T-x-y phase diagrams are plotted. After performing the thermodynamic consistency test, the phase equilibrium data are fitted to obtain the binary interaction parameters of vinyl acrylate with water. The fitted parameters are applied to the process simulation of the VAc refining process to optimize the conditions and obtain an effective separation scheme for vinyl acrylate. The concentration distribution of vinyl acrylate in the distillation column is investigated, thus clarifying the destination of vinyl acrylate in the distillation process and facilitating the optimization of the ethylene vapor phase method.

Influence of liquid–vapor phase change on the self-propelled motion of droplets on wettability gradient surfaces

Self-propelled motion of sessile droplets on gradient surfaces is key to the advancement of microfluidic, nanofluidic, and surface fluidic technologies. Precise control over droplet dynamics, which often involves liquid–vapor phase transitions, is crucial for a variety of applications, including thermal management, self-cleaning surfaces, biochemical assays, and microreactors. Understanding how specific phase changes like condensation and evaporation affect droplet motion is essential for enhancing droplet manipulation and improving transport efficiency. We use the thermal Navier–Stokes–Korteweg equations to investigate the effects of condensation and evaporation on the motion and internal dynamics of droplets migrating across a surface with a linear surface energy profile. The study focuses on the early dynamics of self-propelled motion of a phase changing droplet at sub-micron scale before viscous forces are comparable with the gradient forces. Our results demonstrate that phase change significantly affects the self-propelled motion of droplets by reshaping interfacial mass flux distributions and internal flow dynamics. Condensation increases droplet volume and promotes extensive spreading toward regions of higher wettability, while evaporation reduces both volume and spreading. These changes in droplet shape and size directly affect the driving forces of motion, augmenting self-propulsion through condensation and suppressing it during evaporation. Additionally, each phase change type generates distinct internal flow patterns within the droplet, with condensation and evaporation exhibiting unique circulatory movements driven by localized phase changes near the contact lines.

Genesis of Cu deposits hosted by volcanic rocks in Yunxian-Jinggu Arc, Western Yunnan: Constraints from fluid inclusions and C-O-S isotopes

A series of vein-type Cu deposits have been preserved in the Triassic volcanic rocks of the Yunxian-Jinggu area. The Guanfang, Bazijie, and Minleyichang deposits are typical examples of regional Cu mineralization. The deposits are preserved in the intermediate-basic volcanic rocks, and the ore bodies are controlled by NNE-trending structures with similar alteration features and mineral assemblages. The fluid inclusions are recognized in quartz and calcite at the three deposits, dominated by aqueous inclusions (L) and liquid phase-rich vapor–liquid two-phase inclusions (L-V) with similar temperature (270-140℃) and salinity (14.0–20.2 wt% NaCl eq.). The three deposits have a medium–low temperature, moderate salinity, and higher oxidation rate than the volcanic host rocks, confirmed by the fluid inclusion, alteration, and mineral assemblage. The O isotope values for early quartz associated with sulfides in the three deposits are comparable (δ18OSMOW = 15.23 to 20.01 ‰). Late quartz in the Guanfang and Bazijie deposits shows a deficit in O isotope values compared to early quartz (δ18OSMOW = 9.89 to 13.98 ‰), indicating the incorporation of meteoric water or basin fluid during the late stage of mineralization. The early calcite in the Guanfang and Bazijie deposits have similar C-O isotopic signatures (δ13CV-PDB = −10.51 to −4.75 ‰, δ18OV-SMOW = 11.29 ‰ to 12.63 ‰), and δ18Ofluid (3.84 to 5.18 ‰) calculated from calcite is approximately the same as the δ18Ofluid (2.08 to 3.95 ‰) calculated from early quartz. The early calcite and early quartz in the Guanfang and Bazijie deposits may be connected to the same fluid source based on the similar δ18Ofluid signatures and salinities. The calcite C-O isotopic compositions of the Minleyichang deposit are 13CV-PDB = −23.03 to −17.74 ‰ and δ18OV-SMOW = 19.72 to 28.32 ‰, which exhibit the characteristics of biogenic carbon and indicate that the material originated from sedimentary layers in the Simao Basin. The sulfide δ34SV-CDT ranges from −17.2 to 3.2 ‰ in the three deposits, which is related to the addition of reduced S from the sedimentary strata in the Simao Basin. The fluid characteristics of medium to low temperature, moderate salinity, and the S-C isotope signatures indicate that the ore-forming fluids are the basin brine from the Simao Basin. The Cu mineralization in the Yunxian-Jinggu area is closely related to the thrust-fold structure system formed during the Late Cretaceous to the Cenozoic period. The ore-forming fluids may have come from the brine in the central part of the Simao Basin, which migrated through the thrust fault and assimilated the materials in the regional volcanic rocks and sedimentary rocks, forming Cu deposits in the Triassic volcanic rocks of Yunxian-Jinggu area.

Effect of Photolithographic Biomimetic Surface Microstructure on Wettability and Droplet Evaporation Process

In nature, engineering technology and daily life, wetting phenomena are widespread and have essential roles and significance. Bionics is becoming increasingly important nowadays and exploring the mechanism that influences biomimetic surface microstructure on droplet wetting process and heat and mass transfer characteristics is becoming more meaningful. In this paper, based on photolithography technology, SU-8 photoresist was used as raw material to prepare biomimetic surfaces with microstructures in various arrangements. The research results show that the wettability of biomimetic functional surfaces can be regulated by regulating the shape and arrangement of photoresist micro-pillars. At the same time, the effects of surface microstructure configuration and roughness on the heat and mass transfer processes within the droplets were also comprehensively studied. The results show that a biomimetic surface with cylindrical micro-pillars can effectively inhibit the evaporative cooling effect of the liquid–vapour interface. This effect becomes more evident with the increase in roughness, and the interface temperature difference can be reduced by up to 18%. Similarly, the biomimetic surface with cylindrical micro-pillars can also effectively promote the evaporation rate of sessile droplets, which can be increased by about 13%. In addition, the research also shows that regardless of the structure, substrate temperature changes will significantly impact the wetting phenomenon of the biomimetic surface. This study aims to guide the optimal design of biomimetic surfaces prepared based on photoresistance.

Vapor–Liquid Equilibrium Data and Thermodynamic Modeling for Binary Systems Consisting of Perfluorobutane (R610) with Oxygen or Nitrogen at (293, 313, and 333) K

Vapor–Liquid Equilibrium Data and Thermodynamic Modeling for Binary Systems Consisting of Perfluorobutane (R610) with Oxygen or Nitrogen at (293, 313, and 333) K

Study of a Cavitation Treatment in Kaplan Hydro-turbine

Abstract This research proposes an air-injection treatment for the cavitation phenomena in the Kaplan turbine. An unsteady numerical model is created to predict the cavitating flow through a 3-inch axial hydro turbine before and after the air injection. Pressurized air [jet-in-crossflow] injection is set to be through the turbine housing, and the configuration was altered between 1, 2, 4, and 12 circumferential jets to test the effects of air mass flow rate and injection distribution. Interactions between three fluids (liquid water, water vapor, and air) were considered by utilizing the physics models of Volume of Fluid (VOF) multiphase, Cavitation, and Large Eddy Simulation (LES) turbulence. Surface and time-average results are to be compared with a baseline case of pure cavitation. With the vapor volume fraction created on the rotor components during the cavitation, the absolute pressure scenes clarified the connection between the air treatment and cavitation reduction. While rotation causes negative pressure in the system, the injected air is sucked to such low-pressure zones, and consequently, increasing the absolute pressure above the vapor limit reduces the vapor formation. Preliminary outcomes at 1000 rpm show a 55 percent reduction in the formed vapor on the blades after air injection by a time corresponding to 6 cycles of the turbine. A corresponding mechanical power of 12 percent increase was observed. Moreover, the curve fitting of the data shows that the vapor reduction and power regain are in 2nd order correlation with the increased air volume.

A Diffuse Interface Model for Cavitation, Taking Into Account Capillary Forces

ABSTRACTWe consider the moving least squares method to solve compressible two‐phase water‐water vapor flow with surface tension. A diffuse interface model based on the Navier–Stokes and Korteweg equations is coupled with a suitable system of state equations that allows for a more realistic estimation of the pressure jump across the liquid–vapor interface as a function of temperature. We propose a simple formulation for computing the capillarity coefficient based on the surface tension and the thickness of the diffuse interface. A convergence analysis using pressure jump in the test case of static bubble is conducted to verify our solver. We present several numerical test cases that illustrate the ability of our model to reproduce qualitatively and quantitatively the effects of surface tension on cavitation bubbles in general situations.

Changes in fatty acids, vitamins, cholesterol and amino acid profiles of ram semen by freeze-thawing process

The objective of this study was to examine the impact of freeze-thawing on the levels of oxidative stress, fatty acids, vitamins A, D, E, and K, cholesterol, and amino acids, as well as on spermatological parameters, in ram semen. Semen was collected and pooled from each of the seven rams twice a week for three weeks. The mixed semen was diluted with tris + egg yolk diluent at 38 °C (Group 38 °C) and the temperature was reduced to 5 °C (Group 5 °C). Following the glycerolization-equilibration process (Group G-E), the samples were automatically frozen in liquid nitrogen vapor at −140 °C. The semen samples were thawed 24 h after freezing (Group Frozen-Thawed, F-T). A comparison of Group 38 °C with Group F-T revealed significant differences in several parameters. Motility rates, kinematic values, percentage of membrane integrity (HOS), some PUFA levels, ∑SFA and amino acid levels were significantly lower in Group F-T. Conversely, the ratio of dead and static spermatozoa, lipid peroxidation level, some PUFA levels, ∑MUFA, vitamins A, E and cholesterol levels were significantly higher in Group F-T. The majority of these alterations were also evident in semen samples subjected to G-E treatment. In conclusion, exposure of ram semen to G-E and F-T treatments results in modifications to semen, fatty acid, vitamin, and amino acid profiles, accompanied by elevated levels of lipid peroxidation. Moreover, this study demonstrated, for the first time, that oxidative stress was induced, some amino acid levels were altered, vitamin A and E levels were increased, vitamin D and K levels were not affected, and β-sitosterol levels were decreased after freeze-thawing in ram semen.

Investigation on vapour–liquid equilibrium (VLE) solubility of CO2 in aqueous solutions of amino sugars

AbstractAmino sugars, which are candidate CO2‐capturing solvents, react reversibly with CO2, thereby setting up vapour–liquid equilibrium (VLE). Knowing equilibrium data is useful for designing gas–liquid contactors for CO2 absorption. In this work, VLE data for two amino sugars, glucosamine (GA) and N‐methyl‐D‐glucamine (NMG), was measured and reported at 303, 308, and 313 K using a high‐pressure VLE setup for the first time. The equilibrium CO2 partial pressure was high (up to 1500 kPa). The molarity of sugar in the aqueous solution was in the 0.5–1.25 M range. It was found that the CO2 loading capacity of NMG was much higher than that of GA. For instance, 1.25 M NMG loaded 1.066 mol/mol at 303 K and 1500 kPa CO2 partial pressure. Using regression, empirical equations were developed to predict VLE data for GA and NMG. To enable comparison, VLE trials were also performed using two amines, monoethanolamine (MEA) and 2‐amino‐2‐methyl‐1‐propanol (AMP), and an amino acid salt potassium glycinate (PG). It was found that CO2 solubility (α, mol/mol) in NMG was comparable to that in MEA and higher than that in PG. Besides, it was also found that CO2 was most soluble in AMP. The effect of promoter addition on the loading capacity at T = 308 K was studied too. The value of CO2 solubility in GA solution (1 M) at = 1450 kPa was α = 0.298 mol CO2/mol amino sugar. It improved to α = 0.46 mol/mol in GA/NMG (1/0.5 M) mixtures. Similarly, the CO2 solubility in NMG solution (0.75 M) at = 250 kPa was α = 0.76 mol CO2/mol amino sugar. It improved to 0.94 and 0.93 mol/mol in NMG/PZ and NMG/AMP (0.75/0.25 M) mixtures (here, PZ denotes piperazine). In this way, this work provided new and useful VLE data for individual and blended sugar solutions.

Three-dimensional simulation of film boiling on a horizontal surface with magnetic field

This study conducts a numerical investigation into the three-dimensional film boiling of liquid under the influence of external magnetic fields. The numerical method incorporates a sharp phase-change model based on the volume-of-fluid approach to track the liquid–vapour interface. Additionally, a consistent and conservative scheme is employed to calculate the induced current densities and electromagnetic forces. We investigate the magnetohydrodynamic effects on film boiling, particularly examining the pattern transition of the vapour bubble and the evolution of heat transfer characteristics, exposed to either a vertical or horizontal magnetic field. In single-mode scenarios, film boiling under a vertical magnetic field displays an isotropic flow structure, forming a columnar vapour jet at higher magnetic field intensities. In contrast, horizontal magnetic fields result in anisotropic flow, creating a two-dimensional vapour sheet as the magnetic strength increases. In multi-mode scenarios, the patterns observed in single-mode film boiling persist, with the interaction of vapour bubbles introducing additional complexity to the magnetohydrodynamic flow. More importantly, our comprehensive analysis reveals how and why distinct boiling effects are generated by various orientations of magnetic fields, which induce directional electromagnetic forces to suppress flow vortices within the cross-sectional plane.

Investigation of the influence of rain on pitot-static measuring systems of unmanned aerial vehicles

AbstractFor unmanned aerial systems with a maximum take-off mass of up to 25 kg, simple pitot-static tubes are predominantly used to measure the aerodynamic speed. In this work, the influence of rain on this measurement is investigated using representative pitot tubes of different diameters. In wind tunnel tests, water droplets with a diameter of about 3 mm are generated at a flow velocity of 10 m/s, which hit the pitot tubes at the total pressure bore. The observed disturbances sometimes last several hours and are equivalent to a total failure of the measuring system during flight operations. Phenomena are identified that influence the measurement of dynamic pressure in rain. It can be shown that both capillarity and the momentum of the raindrops play a decisive role in the type, severity and duration of the disturbance due to their relative movement to the tube. The further course of the disturbance is also influenced by the evaporation of liquid, both on and in the tube. In flight tests under rain conditions, the findings of the wind tunnel tests were qualitatively confirmed and additional disturbance patterns were observed.

A consistent diffuse-interface model for two-phase flow problems with rapid evaporation

We present accurate and mathematically consistent formulations of a diffuse-interface model for two-phase flow problems involving rapid evaporation. The model addresses challenges including discontinuities in the density field by several orders of magnitude, leading to high velocity and pressure jumps across the liquid–vapor interface, along with dynamically changing interface topologies. To this end, we integrate an incompressible Navier–Stokes solver combined with a conservative level-set formulation and a regularized, i.e., diffuse, representation of discontinuities into a matrix-free adaptive finite element framework. The achievements are three-fold: First, we propose mathematically consistent definitions for the level-set transport velocity in the diffuse interface region by extrapolating the velocity from the liquid or gas phase. They exhibit superior prediction accuracy for the evaporated mass and the resulting interface dynamics compared to a local velocity evaluation, especially for strongly curved interfaces.Second, we show that accurate prediction of the evaporation-induced pressure jump requires a consistent, namely a reciprocal, density interpolation across the interface, which satisfies local mass conservation. Third, the combination of diffuse interface models for evaporation with standard Stokes-type constitutive relations for viscous flows leads to significant pressure artifacts in the diffuse interface region. To mitigate these, we propose to introduce a correction term for such constitutive model types. Through selected analytical and numerical examples, the aforementioned properties are validated. The presented model promises new insights in simulation-based prediction of melt–vapor interactions in thermal multiphase flows such as in laser-based powder bed fusion of metals.

Oscillations of Truncation in Vapor–Liquid–Solid Nanowires

Oscillations of Truncation in Vapor–Liquid–Solid Nanowires

Vapour–liquid equilibrium using quantum chemical molecular dynamics simulation and radial distribution function analysis

AbstractInstead of the classical molecular simulation widely implemented for estimating the vapour–liquid equilibrium (VLE), a quantum chemical (QC) molecular dynamics simulation was applied to the VLE estimation in three typical systems that include a deep eutectic solvent (DES) and an ionic liquid (IL). In addition, a radial distribution function (RDF) was derived from the QC simulation to examine the molecular behaviour in the liquid phase. A mean absolute error of 2.72% was obtained from the QC simulation compared to the experimental data. The RDF analysis explains the relative volatility increase of the acetic acid and water binary system with the propyl acetate solvent. This analysis indicated that the DES mixture comprising glycerol and choline chloride facilitated the separation of water and i‐propanol. The interaction between water and ethyl sulphate pair with the help of 1‐ethyl‐3‐methylimidazolium as an IL is stronger than that between ethanol and water, which explains how the IL improves ethanol and water separation in the vapour phase.

Vapor–liquid phase equilibrium prediction for mixtures of binary systems using graph neural networks

AbstractVapor–liquid phase equilibrium (VLE) plays a crucial role in chemical process design, process equipment control, and experimental process simulation. However, experimental acquisition of VLE data is a challenging and complex task. As an alternative to experimentation, VLE data prediction offers great convenience and utility. In this article, an artificial intelligence network is proposed to predict the temperature and the vapor phase composition of binary mixtures. We constructed a graph neural network (GNN) and designed an uncertainty‐aware learning and inference mechanism (UALF) in the prediction process. The model was tested on both a self‐constructed dataset and a publicly available dataset. The results demonstrate that the proposed method effectively reveals the phase equilibrium properties of the target data. This work presents a novel approach for predicting vapor–liquid phase equilibrium in binary systems and proposes innovative ideas for investigating phase equilibrium mechanisms and principles.

Vapor–Liquid Equilibrium Phase Behavior for Binary Mixtures Isopropyl Alcohol and Methyl Ethyl Ketone with Dimethyl Sulfoxide

Vapor–Liquid Equilibrium Phase Behavior for Binary Mixtures Isopropyl Alcohol and Methyl Ethyl Ketone with Dimethyl Sulfoxide