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Energy quality in each country is one of the important indicators of economic development, Which affects the economic growth of that country. Exergy analysis, considering all flow properties including pressure, temperature, composition, is a powerful way to evaluate the energy consumption of equipment such as natural gas and liquefied gas plants. Inefficiency of a system can be defined by the conventional exergy analysis method, While, irreversible resources and real potentials for system improvement can only be identified by the advanced exergy analysis method. This analysis splits conventional exergy destruction into two exogenous and endogenous parts according to origin, and also unavoidable and avoidable parts according to the ability to remove and modifications. In this method, the exergy concept was separated by considering the ideal and avoidable condition assumptions. As a real case study, a natural gas liquid plant 800, from National Iranian South Oil Company located in southwest of Iran was considered to be investigated by conventional exergy analysis, advanced exergy analysis methods. The results of conventional exergy analysis illustrated that the highest amount of exergy destruction belonged to compressor and heat exchanger with 509.99 and 629.04 kW, respectively. However, in the case of heat exchanger, despite having the highest rate of exergy destruction, it is not considered in modification priorities due to its low avoidable exergy destruction value. Also, advanced exergy analysis suggested that the exergy destruction of the compressor and heat exchanger will be reduced by improving performance of these components.

In this study, the lattice Boltzmann method was used to simulate the three-dimensional intrusion process of liquid water in the gas diffusion layer (GDL) of a polymer electrolyte membrane fuel cell (PEMFC). The GDL was reconstructed by the stochastic method and used to investigate fiber orientation's influence on liquid water transport in the GDL of a PEMFC. The fiber orientation can be described by the angle between a single fiber and the in-plane direction; three different samples were simulated for three different fiber orientation ranges. The simulated permeability correlated well with the anisotropic characteristics of reconstructed carbon papers. It was concluded that the fiber orientation had a significant effect on the liquid invasion pattern in the GDL by changing the pore shape and distribution of the GDL. The results indicated that the stochastically reconstructed GDL, taking into account the fiber orientation, better demonstrates the mass transport properties of the GDL.

Grid spacers installed in subchannels of fuel assemblies for nuclear reactors can promote heat transfer. However, the fluid velocity and bubble behavior are greatly affected as the cross-sectional area of the flow passage changes. Therefore, the void fraction distribution behind the obstacle that simulates the grid spacer shape simply was measured by using a wire mesh sensor (WMS) system. Moreover, a two-phase flow analysis was performed to investigate the effect of the obstacle on the bubble behavior in a vertical duct.

Storage of liquefied gas in an underground cavity created in hard rocks is a promising new technology that can significantly reduce the dimensions of a storage facility. The intense heat transfer between the cryogenic fluid and the surrounding rocks leads to the formation of an ice ring in water-saturated rocks, which acts as a natural protective barrier. In this paper, we provide a general theoretical analysis of the existence and evolution of the freezing ring. The analysis is based on solving the problem of heat transport in heterogeneous domain with two thermal waves initiated inside the domain and propagating into two opposite directions. The analytical solution was obtained by the modified Karman–Pohlhausen integral method. We have developed the extension of this method to a heterogeneous medium, in which the effect of the temperature semi-stabilization occurs. It has been shown that the propagation of the freezing front is non-monotonic and changes direction, so that the lifetime of the ice ring is finite. General analytical formulae have been obtained that describe all process parameters depending on the thickness of the insulating layer, in particular: the maximum thickness of the ice ring, its lifetime, conditions of existence, the critical thickness of the insulation above which the ice ring does not arise, as well as the global evolution of the temperature field. These results enable to select an optimal thickness of the insulation.

Infrastructures such as prestressed concrete containment vessels (PCCVs) and liquid gas storage tanks are constructed as bi-directional prestressed concrete (PSC) structures to ensure outstanding leak-tight storage and shielding performance. However, PSC structures exhibit severe vulnerability to high-temperature fire due to the high-strength concrete used and the application of prestressing (PS) stresses to increase the strength of the structures. The PCCV of a 1400 MW advanced power reactor was selected as the target for study. A scaled-down model of the PCCV outer wall was fabricated and tested to determine its resistance to a standard fire-loading scenario. Furthermore, different PS forces were applied to the specimens to evaluate the effect of concrete confinement on the fire resistance. Test data of temperature distribution, PS force loss and residual strength capacity were obtained. The experimental data were used for calibration of a commercial finite-element simulation program (Midas FEA) for structural fire analysis of real-scale concrete structure and infrastructure. The simulation and test results showed significant similarity and the result trends were accurate.

Liquid–gas ejector as a key component of jet loop reactor (JLR), plays an important role in the continuous production of gas–liquid mixing reaction. In this paper, a formula for estimating the gas induction of the ejector is presented. The effects of nozzle radius and mixing length on gas induction of liquid–gas ejector for gas–liquid mixing are simulated, and the formula is verified. Focusing on the efficiency and gas induction, the geometrical parameters are analyzed for the same cases, so that the performance of the ejector can be thoroughly understood. The results show that the optimum mixing section length to diameter ratio (LDR) is about 5–7, and the decrease of nozzle outlet radius can increase the gas induction, which provides a reference for the evaluation of gas induction for liquid–gas ejector and has crucial guiding significance for the design of nozzle and mixing section of liquid–gas ejector in industry.

The accidental releases of pressurized liquefied gases from tanks involve violent phase transformation, which would generate two-phase releases and flashing jets. To investigate the evolution of leakage behaviors and make an analysis of near-field jet flow characteristics, a small-scale liquefied gas release experiment has been established. Leakage holes with different length-diameter ratio (LDR) have been used to analyze interactions between the leakage holes and release behaviors. Morphological characteristics of jet expansion angles have been obtained by high-speed camera, and jet velocities have been measured by particle image velocimetry (PIV). Meanwhile, the depressurization process, variation of temperature in the tank and mass outflow rates were obtained. Results show that, despite the LDR is varying, expansion angles and jet velocities behavior in the same tendency: decreases in the initial and maintains in a stable value for a period. The stable velocity status was worked by the balanced pressure drop. Thereafter, an empirical two-phase mass outflow rate model is developed based on the experimental data, which is related to the nozzle geometric parameter and upstream pressure, 90 % of the experimental data are within ±12 % of the prediction. Therefore, the empirical two-phase model can be supported in the mass flow rate evaluation, especially for the release cases that LDR are smaller than 5.00 but larger than 2.00. The experimental data is beneficial for providing further insight into the prediction of accidental release and risk assessment for the liquefied gas transportation and storage.

Renewable energy contributes to the energy portfolios of many countries. One form of renewable energy is syngas which is generated from bio-residues. The focus of this paper is the biomass transportation and conversion network that covers the entire syngas (synthesis gas) production process from different biomass feedstocks to the end products. Specifically, we focus on the resource planning and management problem (a) to allocate different feedstocks to anaerobic digesters (reactors), (b) to determine number and locations of reactors in each region, (c) to determine number and locations of the condensers to liquefy syngas, and finally (d) to determine distribution network of syngas to demand points. We developed a mixed-integer, non-linear programming (MINLP) cost model to describe this resource planning wherein the constrained cost is minimized to find the optimal solutions for reactors and condensers locations. We identify optimal allocation of feedstocks to all reactors and the distribution of liquefied gas to distribution centers. We propose a new algorithm to search for an alternative between two sub-problems of the original MINLP. We verify the convergence of the algorithm to an optimal or sub-optimal solution by conducting various sets of numerical experiments using some real-world parameters.

Tunable antennas have become research hotspots due to their applicability and practicability. To get rid of complex peripheral facilities, a novel design featuring an efficient actuating strategy b...

Metal storage tanks for liquid gas are unstable at low temperature (below zero degreecentigrade), because the metal tends to be brittle and susceptible to crack. In this researchstudying some physical properties such as shrinkage, adhesion force and coating layer thicknessof aluminum powder with ethyl silicate as a binder were performed. The results shown, that thecoating with such layer has excellent resistance to low temperature and impermeable to liquidgas for example, propane, methane and nitrogen a suitable coating layer thickness is (5mm). Thedata and results were optimized by using Taguchi / ANOVA Technique

The gas suction rate of a conventional liquid–gas ejector pump was measured on a modular pilot plant unit utilizing convergent nozzles and a water–air system. Hydraulic characteristics were measured for various water flow rates, suction and discharge pressures, and ejector geometries, covering a wide range of configurations and operating conditions. The device configurations, providing the most stable and reproducible results, were identified. The air flow rates measured with these configurations were correlated by a simple, three-parameter correlation with a relative standard deviation (RSD) of 11%. The performance and behavior of the ejector in less stable configurations are discussed and the recommendations for the design of optimally operating units are provided. Finally, the correlation is tested against available literature data. The ejectors with comparable geometry agree well with the proposed correlation (within 20% RSD). The reasonable agreement with the discussed differences is found for other literature data. This comparison results in the validation of the proposed correlation to provide a safe prediction of minimal gas entrainment in units of various geometries, orientation and operating conditions.

This paper presents an experimental investigation on the interactions of a deflected submerged jet into a liquid pool with its above interface in the absence and presence of an additional lighter liquid. Whereas the former is a free surface flow, the latter mimics a situation of two stratified liquids where the liquid-liquid interface is disturbed by large-scale motions in the liquid pool. Such configurations are encountered in various industrial applications and, in most cases, it is of major interest to avoid the entrainment of droplets from the lighter liquid into the main flow. Therefore, it is important to understand the fluid dynamics in such configurations and to analyze the differences between the cases with and without the additional liquid layer. To study this problem, we applied time-resolved particle image velocimetry experiments with high spatial resolution. A detailed data analysis of a small layer beneath the interface shows that although the presence of an additional liquid layer stabilizes the oscillations of the submerged jet significantly, the amount of kinetic energy, enstrophy, and velocity fluctuations concentrated in the proximity of the interface is higher when the oil layer is present. In addition, we analyze the energy distribution across the eigenmodes of a proper orthogonal distribution and the distribution of strain and vortex dominated regions. As the main objective of this study, these high-resolution time-resolved experimental data provide a validation platform for the development of new models in the context of the volume of fluid-based large eddy simulation of turbulent two-phase flows.

Objectives To determine the effect of liquid gas fraction (LGF), sclerosant type and concentration, and filter use on foam bubble size and count. Methods Sclerosant foam microstructure was investigated using light microscopy for a range of LGFs (1 + 2, 1 + 4 and 1 + 8), for both sodium tetradecyl sulphate (STS) and polidocanol (POL), at a range of concentrations (0.5–3%), with and without the addition of micro-filters. Foam was generated using a modified Tessari method and placed into wells for analysis by light microscopy. Foam microscopic morphology was photographically documented, and bubble diameters and counts were quantified. Results Spherical bubbles were observed at lower LGF and a trend towards polyhedral morphology was observed at the higher LGF of (1 + 8). The higher gas content in LGF led to larger but fewer bubbles. POL bubble diameters appeared to be more influenced by concentration than STS with smaller bubbles observed at higher concentrations of POL. The mean bubble diameters were slightly larger for STS than POL at the highest concentration of 3% but smaller at lower concentrations of 1% and 1.5%. Conclusions LGF is the primary determinant of bubble diameter and count. In contrast to STS, POL concentration influences the foam bubble size with smaller bubbles generated at higher concentrations of POL and larger bubbles appearing at low concentrations of this agent.

The mass transfer and energy efficiency in the “batch” and “Circulating” gliding arc configuration reactors for the direct discharges and degradation of pollutants in the aqueous solution have been investigated. The mass transfer characterization and energy efficiency in this study showed that the “Batch” configuration would be more efficient than the “Circulating” reactor. The difference between these reactors is due to the plasma (gas)–solution (liquid) contact time, therefore the gas–liquid transfer phenomenon. The lowest value of pH (2.5) and high temperature obtained in the “Batch” reactor contributes to better nitrogen oxides (NOx) transfer and solubility consequently the high conversion of the phenol in this reactor configuration (100% after 10 min of treatment) relative to that obtained in the circulating reactor (≈ 50% after 30 min) with pH 4.7.

The theoretical model of main performance indicators of diesel locomotive engines using natural gas is exposed. According to the model, the heat released during the combustion of mixed fuel can be determined. The composition of natural gas, which is indicated in the passport when refueling a diesel locomotive, is taken into account. Thus, it became possible to adjust the program of regulating the fuel supply control system according to the operating modes of a diesel locomotive engine by introducing a composition coefficient. The results of analyzing the variation range in the net calorific value of gas during the conversion of diesel locomotives for using the natural gas as a motor fuel are presented. As exposed, the variation range in the net calorific value at various examined fields varies up to 32.4%. The so-called net calorific value of diesel fuel and natural gas combustion is suggested to be considered for operating diesel locomotive engines with liquid gas fuel, in addition to atmospheric conditions.

This study was conducted based on Davis's extended technology acceptance model (TAM) (1989) and survey data of 486 petroleum and liquefied gas enterprises in Vietnam on their intention to apply using a total quality management (TQM) system. Research results show that factors such as (1) Perception of the effectiveness of TQM; (2) Perception of the effectiveness of the convenience in using TQM; and (3) Perception of the effectiveness of TQM compared to the old system which has a positive impact on the intention to apply the total quality management system in petroleum and liquefied petroleum gas enterprises in Vietnam. Besides, the perception of decision-makers on issues related to quality management in these enterprises also has a direct influence on the perception of the TQM usability and indirect effect of the intention to use TQM application in these enterprises.

Loss circulation is a common problem in geothermal drilling due to naturally fractured formation and depleted reservoir pressure. This problem might lead to another problem such as a stuck pipe. In some cases, LCM is not effective in curing loss in a naturally fractured formation and cannot be used to cure loss circulation in the production zone. One of the methods that can be used to prevent loss circulation and also preventing reservoir damage in geothermal drilling is underbalanced drilling or aerated drilling. In an underbalanced or aerated drilling operation, the ratio of air injection rate ad liquid rate is critical to ensure the cutting carrying capacity while preventing hole problems. Usually, computer simulations are used to determine the safe gas-liquid rate limit due to the complexity of the multiphase flow in an underbalanced drilling system. Since the simulation software is not always available, a simpler and reliable method is needed to determine the gas-liquid rate limit in aerated drilling. the purpose of this paper is to design the operating window of the gas-liquid rate ratio in aerated drilling. the purpose of this paper is to design the operating window of gas-liquid rate ratio in aerated drilling using a simple yet reliable method such as the Guo-Ghalambor Liquid-Gas Rate Window method. The result of this research is a gas-liquid rate envelope that can be used to promote good cutting transport, preventing formation and borehole damaged while preventing loss circulation in geothermal well.

Due to discrepancies observed between many experimental results and predictions from the Bell–Cameron–Lucas–Washburn (BCLW) imbibition equation, the BCLW equation was often modified by considering the effects of pore/throat characteristics. As previous works mainly focused on liquid–gas systems, the effects of the viscosity ratios are neglected. In this study, the nonwetting-/wetting-phase-viscosity ratio ( $$ \Psi $$ ) is varied by four orders of magnitude (0.018 to 8), which covers the common fluid viscosity in waterflooded tight reservoirs. Capillaries with irregular cross sections (namely, complex capillaries), which are recognized to more representative for porous media, are used to theoretically study imbibition kinetics in both the liquid–gas and liquid–liquid system. To considering the effects of viscosity ratio, we propose a modified imbibition equation based on the Poiseuille law and a piecewise method to calculate the equivalent radius for complex capillaries. The predictivity of the new imbibition equation is mathematically validated in varying viscosity ratios and geometries characteristics (such as the radius levels and the numbers/length ratios of radius levels). The study proves that an equivalent straight capillary can globally predict imbibition behaviors in complex capillaries. Except for a few scenarios, the equivalent radius of the straight capillary is affected by capillary geometries and viscosity ratios. Only in the early stage of imbibition ( $$ l_{x} /l \le 0.12\Psi /\left( {\Psi - 1} \right) $$ ), the modified imbibition equation can be expressed as a power-law relation (i.e., $$ l_{x} /l \propto \frac{1}{\Psi }t^{\alpha } $$ ) as $$ {\Psi } $$ is higher than 1. In general, it is more suitable to express the imbibition equations in a quadratic form, especially for liquid–liquid imbibition systems.

We propose a wireless soft actuator controlled thermally by millimeter-wave irradiation. The actuator is composed of low boiling point liquid sealed in a soft bellows. By irradiating high-power millimeter-waves, the liquid can be evaporated to generate a strong mechanical force. We characterize the force and work extracted from the bellows as a function of the liquid volume and temperature. We then demonstrate the wireless actuation by irradiating a millimeter-wave on the bellows. We also evaluate its dynamic response by modulating the millimeter-wave. Our approach provides novel usage and design space of soft actuators.

Rapid phase transitions occurring with a sharp increase in a specific volume can be accompanied by explosive gas-dynamic phenomena. A model is presented for calculating shock waves generated in the atmosphere during an explosion of a liquid gas pressure reservoir, based on the assumption of a thermodynamically equilibrium state of a vapor–liquid mixture in which both vapor and liquid have equal velocities and are in a state of saturation at local pressure. The spherically symmetric expansion of a boiling liquid cloud is calculated, pressure profiles under various initial conditions are compared, and the primary shock wave parameters are validated according to the results of available experimental data. Two-dimensional calculations of shock waves during the fracture of a cylindrical tank near the underlying surface at various degrees of filling are presented.

Understanding liquid motion in nanoenvironment is of fundamental importance in nanofluidics-based systems. While the liquid outflow from hydrophobic nanochannels can significantly affect system performance, its underlying mechanism remains unclear so far. Here, we present an experimental study of the gas-phase effect on liquid outflow behavior from hydrophobic nanochannels in a liquid nanofoam (LN) system. Four LN samples, consisting of same liquid-solid composition but different amounts of the gas phase, are characterized by cyclic quasi-static compression tests. A remarkable difference in the LN system reusability has been observed, indicating that the liquid outflow behavior is highly sensitive to the amount of the gas phase. As the gas amount increases, the degree of liquid outflow from hydrophobic nanochannels is considerably promoted. This promotive effect is because of the suppression of gas outflow and acceleration of bubble nucleation in the nanochannels. These fundamental findings open a new perspective on liquid outflow behavior and can facilitate the design of reusable nanofluidics-based energy absorbers.

Railway transportation of liquefied petroleum gases in special tank wagons requires special attention to safety on the railway. A new method for analyzing the scenario of tank cars of liquefied hydrocarbon gases is proposed. It is based on the methodology for calculating the behavior of a rail tank car with liquefied gas in a fire. This method simulates processes using the «Fobot» software package. This mathematical model considers a metal tank with LPG, the outer surface of which contains a heat-insulating layer consisting of a layer of a porous non-combustible material (mineral wool) and a foaming fire-retardant paint. With the help of “Fobot”, calculations of an emergency situation were made using various methods of fire protection. Certain patterns were deduced, conclusions were drawn to assess the degree of elaboration of this topic. The possibilities for improving this complex have become known, as well as the ability to design various emergency situations using all kinds of fire-fighting materials and technically improved devices.

It is known that the suspended liquid droplets in clouds can generate electrostatic charges, which finally results in the lightning. However, the detailed mechanism related to the contact-electrification process on the liquid-gas (L-G) interfaces is still poorly understood. Here, by introducing an acoustic levitation method for levitating a liquid droplet, we have studied the electrification mechanism at the L-G interface. The tribo-motion between water droplets and air induced by the ultrasound wave leads to the generation of positive charges on the surface of the droplets, and the charge amount of water droplets (20 μL) gradually reaches saturation within 30 s. The mixed solid particles in droplets can increase the amount of transferred charge, whereas the increase of ion concentration in the droplet can suppress the charge generation. This charge transfer phenomenon at L-G interfaces and the related analysis can be a guidance for the study in many fields, including anti-static, harvesting rainy energy, micro/nano fluidics, triboelectric power generator, surface engineering, and so on. Moreover, the surface charge generation due to L-G electrification is an inevitable effect during ultrasonic levitation, and thus, this study can also work for the applications of the ultrasonic technique.

Summary High-viscosity liquid two-phase upward vertical flow in wells and risers presents a new challenge for predicting pressure gradient and liquid holdup due to the poor understanding and prediction of flow pattern. The objective of this study is to investigate the effect of liquid viscosity on two-phase flow pattern in vertical pipe flow. Further objective is to develop new/improve existing mechanistic flow-pattern transition models for high-viscosity liquid two-phase-flow vertical pipes. High-viscosity liquid flow pattern two-phase flow data were collected from open literature, against which existing flow-pattern transition models were evaluated to identify discrepancies and potential improvements. The evaluation revealed that existing flow transition models do not capture the effect of liquid viscosity, resulting in poor prediction. Therefore, two bubble flow (BL)/dispersed bubble flow (DB) pattern transitions are proposed in this study for two different ranges of liquid viscosity. The first proposed transition model modifies Brodkey's critical bubble diameter (Brodkey 1967) by including liquid viscosity, which is applicable for liquid viscosity up to 100 mPa·s. The second model, which is applicable for liquid viscosities above 100 mPa·s, proposes a new critical bubble diameter on the basis of Galileo's dimensionless number. Furthermore, the existing bubbly/intermittent flow (INT) transition model on the basis of a critical gas void fraction of 0.25 (Taitel et al. 1980) is modified to account for liquid viscosity. For the INT/annular flow (AN) transition, the Wallis transition model (Wallis 1969) was evaluated and found to be able to predict the high-viscosity liquid flow pattern data more accurately than the existing models. A validation study of the proposed transition models against the entire high-viscosity liquid experimental data set revealed a significant improvement with an average error of 22.6%. Specifically, the model over-performed existing models in BL/INT and INT/AN pattern transitions.

International audience

La producción de petróleo en el Ecuador ha involucrado durante varios años la quema de gas asociado sin que este sea entregado en su totalidad a la entidad responsable de transformarlo en productos como GLP y gasolina natural. En consecuencia, existe una pérdida energética en el proceso que conlleva a una pérdida económica para el estado. Por lo tanto, en este estudio se presenta la metodología necesaria para simular la condición de operación óptima en los separadores de producción de la Central de Procesos Aguarico, la misma que represente la máxima ganancia económica de comercialización de petróleo y gas licuado, optimizando el recurso energético. Para el desarrollo del estudio se emplea los softwares Aspen Hysys® y PIPESIM, que conjuntamente con la información proporcionada por Petroamazonas EP, permiten simular la condición actual de operación del campo para posteriormente realizar un análisis de sensibilidad sobre la presión de operación del separador y su efecto en los caudales de gas y petróleo. A pesar de que, a medida que se incrementa la presión de operación del separador, el flujo de petróleo y gas disminuyen, el estudio demuestra que existe un punto que maximiza la ganancia monetaria referida a la comercialización de petróleo y gas licuado, e inclusive, representa el límite de la captación de gas a la entrada del compresor que direcciona el flujo al Complejo Industrial Shushufindi (CIS). La modificación del set de presión actual a un valor de 29 psig, conllevaría a un incremento de $ 11 936,26 asociado a la comercialización de petróleo y GLP por día de operación. Del mismo modo, se reduce la cantidad de gas asociado que se envía a las antorchas, generando un menor efecto de contaminación por combustión.

In this paper, literature data of 719 materials on the enthalpy of evaporation hv and boiling temperature Tb, including calculated entropy of evaporation sv, have been analyzed regarding systematic correlations in phase change liquid-gas. It has been observed that several groups of materials exist that form clusters with an almost linear correlation in an hv – sv/R graph. One such cluster is formed by the metallic elements. A second cluster is formed by the halogens, the noble gases, and most of the diatomic molecules. A third cluster is formed by the linear alcanes. The knowledge about these clusters can be used to improve rules to predict certain values like in group-contribution methods, and maybe also to identify a common microscopic origin. Additionally, the analysis has shown that many materials have sv/R deviating significantly from the Trouton constant. Deviations are more frequent to higher values, and deviations are more pronounced in compounds with few atoms. A chemical reaction upon evaporation has been identified in 12 cases; the formation of larger compounds upon condensation seems to be the main reason for exceptionally high values of sv/R. The analysis thus led to a deeper understanding of the physical and chemical origins on the atomic and molecular level.

Diffraction of terahertz radiation on ultrasound in liquefied sulfur hexafluoride at room temperature was observed for the first time. The dependences of the diffraction efficiency on the sound frequency, angle of incidence, and amplitude of radio-frequency electrical signal applied to a piezo-transducer were studied. Deflection of diffracted radiation by an angle of $\text{10}^\circ$ was observed. It was found that the diffraction efficiency at room temperature is significantly (four times) higher than the one at 14 $^\circ$ C known from the literature. The obtained and published data on the acousto-optic diffraction in liquefied sulfur hexafluoride contradict the well-known theory.

Aiming at the problems of low system efficiency and high energy consumption of nodes in the current explosion-proof control system for liquefied gas tank leakage, a data fusion-based explosion-proof control system for liquefied gas tank leakage is designed. The function design of the explosion-proof control system for liquefied gas tank leakage is completed through personal information management, authority management, basic data management, detection and alarm design and control design. In software design, data fusion algorithm is used to fuse the underlying data of the system, which saves data traffic and ensures the normal functioning of the mobile terminal. The specific step is to use the local estimation of each independent sensor in the multi-sensor network, give each sensor a weighted value according to the approximation of the true value, and finally integrate all local estimates to get the whole system. Through function design and software design, the design of explosion-proof control system for liquefied petroleum gas tank leakage is realized. The experimental results show that the system has the advantages of low node energy consumption and high system efficiency.

In this investigation, UniSim software and the Soave-Redlich-Kong (SRK) thermodynamic model were utilized to study flooding in a Naphta stripping column. The objective of this study was to evaluate the impact of increasing feed flowrate from a design load of 121 m3/hr. to 165 m3/hr. on the performance of the plate column. In order to study only flooding in the column, UniSim software was run by keeping the LPG (Liquefied Gas petroleum) and Naphta products within the required specifications. According to the original design specifications of the stripping column, it should not be operated at high feed rates and differential pressure must not exceed 600 mbar. For the purpose of simulation, this value corresponds to a maximum allowable flooding percentage of 85%. The simulation results show that the flooding percentage was 144.5% in the case under study and 83.7% for the design case. Flooding occurred in all parts of the column with diameters of 2 m and 2.7 m. For the case under investigation, the reflux to feed ratio was reduced from 0.45 (design case) to 0.2. The originality of this investigation is the utilization of the temperature profile in the column as a tool to detect the plates where flooding could take place. The column temperature profile during the case under study suggests instability in the plates between trays 5 to 15. It is therefore suspected that flooding takes place mainly between those plates.

The proposed solution relates to fluidics and can be used, for example, in the extraction of oil and gas, the collection and preparation of oil, gas and water, the extraction of methane from methane beds, oil refining. The technical result is to increase the efficiency of a liquid-gas ejector by ensuring its work in the field of rational concentrations and salt composition, in which the intensification of energy exchange between the working fluid and the ejected gas is achieved. The essence of the proposed solution: the method of operation of a liquid-gas ejector involves injecting a working fluid with a power pump into the ejector nozzle, pumping gas with an ejector, creating, dispersing and increasing the pressure of a gas-liquid mixture with an ejector using aqueous solutions of salts as a working fluid. The values of the concentration and composition of salts in the working fluid are maintained within the range of rational concentrations and composition of salts, in which increased values of the efficiency of the ejector are achieved. Salts are added to the weakly mineralized aqueous solutions, and the highly mineralized aqueous solutions are diluted with fresh water. As the working fluid, the formation and/or incidentally produced waters of oil, gas, gas condensate and methane-coal deposits, which are aqueous solutions of salts, are used if the composition and concentration of salts in the produced and/or incidentally produced waters are within the range of rational concentrations and composition of salts in which provides an increase in the efficiency of the ejector. The boundaries of the field of rational concentrations and salt composition are preliminarily determined by laboratory bench studies.

Superhydrophobic microchannels have evolved recently as an accepted strategy to mitigate the hydrodynamic resistance tendered in micro-constrictions. In this work, hydrodynamics of a hydrophobic microchannel realized by entrapping air in the cavities located between transversely oriented ribs is numerically investigated. An interface formed between the liquid and air/vapor in the confinement facilitates a resistance free slipping surface for the flowing water. The shape of the meniscus is determined by the pressure difference between air and liquid and is classified as convex, flat, and concave depending on the protrusion angle. Several applications require a long hydrophobic channel in which the liquid pressure decreases lengthwise; consequently the interface shape changes as well. In this regard, a mathematical model is proposed to predict the protrusion angle at a specific distance from the inlet of microchannel. This is incorporated in the computational fluid dynamics (CFD) simulations to define the static geometry of the interface which is varying throughout the length of the channel. Moreover, the boundary is treated as a combination of flat no-slip and curved shear-free regions to mimic the ribs and cavities. Further, the evolution of interface morphology is captured using the volume-of-fluid (VOF) scheme by considering a static contact angle at the solid surface to check the validity of the suggested model. Dynamically evolved protrusion angle is measured for various liquid–gas interface pressures and it is observed that the theoretical scaling proposed by Laplace and Young is well obeyed. Though CFD–VOF simulation scheme is an effective tool for predicting the pressure dependent liquid–gas meniscus and concurrent hydrodynamics of the ribbed microchannel, it is resource intensive. The present study demonstrates that the developed model for static boundary may be adopted alternatively to predict the hydrodynamics of a long hydrophobic microchannel by saving computational resources.

An innovative study on liquid hydrogen diffusion in time-dependent mixed convection flow is carried out in the presence of magnetic field effects. In fact, this is the first approach to analyze such flow problems, and also this is the first research paper to study the non-uniform heat sink/source and nonlinear chemical reaction in the presence of liquid hydrogen diffusion. Initially, the governing equations are reduced to dimensionless form by using non-similar transformations and are linearized by applying quasilinearization technique. Then, the finite difference approximation is utilized to discretize the resulting equations. The mixed convection is analyzed along with exponentially stretching surface through various graphs on profiles as well as gradients. The results display that the non-uniform heat source parameter increases the fluid velocity as well as temperature, and the magnetic parameter reduces the friction at the wall. Specifically, the skin friction coefficient decreases about 40% in the presence of magnetic field. The mass transfer rate increases for high-order chemical reaction and for destructive chemical reaction rate. The mass transfer rate is found to be high for the diffusion of liquid nitrogen than that for the diffusion of liquid hydrogen. In fact, the mass transfer rate increases about 22% for the diffusion of liquid nitrogen. This study can assist the design engineers who are working in pertain to the diffusion of liquid gases in mixed convection regimes. Also, the obtained data in the present study can be more useful for future investigations about time-dependent mixed convection nanofluid flow problems.

International audience; The boiling liquid expanding vapour explosion (BLEVE) is well known but not well understood. Some still argue about what comes first, the BLEVE or the vessel rupture. Some believe the BLEVE is triggered by some pressure transient inside the vessel and this causes a superheat limit explosion which causes the vessel to rupture. Others believe it is the vessel rupture by some weakening process that leads to the BLEVE. This paper will provide evidence that the latter description that is correct for most, if not all BLEVEs observed in practice. This paper describes small scale experiments of aluminum tubes that were weakened by machining a thinned wall area over a specified length. The tubes were filled to a desired level with liquid propane and then the propane was uniformly heated electrically until the tubes failed. The failure pressures ranged from 10 to 33 bar. The tube was instrumented to capture failure characteristics (pressure, temperature) and consequences: blast overpressure and imaging of the propane cloud and shock around the vessel; ground force under it; transient pressure and imaging of the boiling process inside the vessel. The work was done to improve our understanding of the fluid – structure interactions during the fire heat induced failure of a pressure vessel holding a pressure liquefied gas. We were specifically interested in the near field hazards including blast overpressure and ground force. This paper will focus on the early milliseconds of the process where the vessel begins to open and a shock wave is formed and moves out into the surroundings. The imaging reveals presence of a Mach shock at the exit of the vessel at the early stage of the opening. A chronology of the event also shows that the lead shock is generated early in the explosion process, and is long gone before the liquid starts boiling, arguing that vapour expansion is the main contributor to the first shock overpressure.

Gallium–indium eutectic (eGaIn) is a liquid metal being explored in a number of applications because of its high thermal/electrical conductivity and favorable deformability. A key function regulati...

In this research, we constructed the exact travelling and solitary wave solutions of the Kudryashov–Sinelshchikov (KS) equation by implementing the modified mathematical method. The KS equation describe the phenomena of pressure waves in mixtures liquid-gas bubbles under the consideration of heat transfer and viscosity. Our new obtained solutions in the shape of hyperbolic, trigonometric, elliptic functions including dark, bright, singular, combined, kink wave solitons, travelling wave, solitary wave and periodic wave. We showed the physical interpretation of obtained solutions by three-dimensional graphically. These new constructed solutions play vital role in mathematical physics, optical fiber, plasma physics and other various branches of applied sciences.

The thermal‐hydraulic performance of printed circuit heat exchanger (PCHE) through an experimental vaporization process of supercritical nitrogen was investigated. The inlet temperature of supercritical nitrogen was controlled between 113 K and 129 K, while its pressure was controlled between 4.5 MPa and 6 MPa. The mass of supercritical nitrogen corresponds to the turbulent state on the cold side of PCHE, which was maintained at 299.94 kg/h. A numerical processing of the same supercritical nitrogen flow through a single channel of PCHE cold side was presented. The numerical results were validated by comparison with the experimental data. Both experimental and numerical results showed that the increased inlet supercritical nitrogen pressure improved the heat transfer performance and pressure drop decreased with increasing the pressure at the PCHE cold side. Furthermore, the Fanning friction coefficient (f) and the Nusselt number (Nu) of supercritical nitrogen flow obtained by numerical simulation and empirical correlation were compared.

We considered the physicochemical regularities and analytical capabilities of separation methods based on the manifestation of capillary effects in hydrophobic microporous media, namely, liquid–gas chromatography with a stationary gas phase in the pores of a solid-phase substrate and a mass-exchange process in liquid–gas and liquid–liquid systems, carried out in a biporous matrix. The advantages of these methods compared to conventional mass-exchange processes in the same systems in terms of higher efficiency and a possibility of the separation of substances in a continuous mode are shown.

Natural gas liquefaction cycles require high amounts of shaft power and any effort for decreasing power consumption of these cycles is a subject of interest. Among natural gas liquefaction cycles, N 2 and N 2 /CH4 cycles with CO2 pre-cooling are attractive due to their simplicity. The novel work here is that two above cycles are first modified. Then by choosing the ratio of power consumption to the liquefied gas molar flow rate (Specific Energy Consumption, SEC) as the objective function and 13 design parameters for N 2 -CO 2 cycle and 12 design parameters for N 2 /CH 4 -CO 2 cycle, these cycles are optimized. Results of the above procedure showed decrease in both SEC and the total annual cost in comparison with those for similar cycles published in open literature. Two modified and optimized N 2 -CO 2 and N 2 /CH 4 -CO 2 liquefaction cycles showed 5.25% and 3.62% decrease in specific energy consumption and 9.4% and 16% decrease in exergy destruction respectively. The total cost of two above cycles also decreased for 0.5% and 1.2% respectively.

The formation of equilibrium liquid–gas interfaces in single- and two-component Lennard-Jones systems has been reproduced by molecular-dynamics simulation. The second component in the two-component system is a volatile impurity. The initial state is created by bringing in contact homogeneous liquid and gas phases having equal temperatures, pressures, and chemical potentials. The times required to establish equilibrium values of pressure, composition, shape and thickness of an interfacial layer, relative adsorption, and surface tension have been evaluated by the simulation. The calculations have been carried out at a temperature close to the triple point temperature of a solvent. It has been found that, in the course of relaxation, the maximum dynamic surface tension exceeds the equilibrium value by a factor of 1.2–1.6, while the relaxation time increases from 10 to 100 ns as the concentration of the volatile component in the solution grows to 0.25. In the two-component system with a limited volume of the gas phase, an equilibrium interfacial layer is formed in two stages. At the first stage, the volatile component is transferred into the interfacial layer from the near-surface regions of the liquid and gas phases. When an equilibrium partial density of the volatile component in the gas phase is achieved, the second stage begins, at which the surface layer is mainly supplied with liquid-phase particles. As a result, the relaxation times of relative adsorption and surface tension substantially increase. The role of the dynamic surface tension in the process of nucleation has been discussed.

The efficiency of photovoltaic (PV) panels is a function of temperature. Efficiency decreases by 0.5%°K−1 after 25°C. Phase change material (PCM) technology due to its ability to store and transmit...

This paper deals with the mathematical study of the small motions of a system formed by a cylindrical liquid column bounded by two parallel circular rings and an internal cylindrical column constituted by a barotropic gas under zero gravity. From the equations of motion, the authors deduce a variational equation. Then, the study of the small oscillations depends on the coerciveness of a hermitian form that appears in this equation. It is proved that this last problem is reduced to an auxiliary eigenvalues problem. The discussion shows that, under a simple geometric condition, the problem is a classical vibration problem. Â

An ammonia self-managed vaporization propulsion (ASVP) system for micro-nano satellites is presented. Compared with a normal cold gas or liquefied gas propulsion system, a multiplex parallel sieve type vaporizer and related vaporization control methods are put forward to achieve self-managed vaporization of liquefied propellant. The problems of high vaporization latent heat and incomplete vaporization of liquefied ammonia are solved, so that the ASVP system takes great advantage of high theoretical specific impulse and high propellant storage density. Furthermore, the ASVP operation procedure and its physical chemistry theories and mathematical models are thoroughly analyzed. An optimal strategy of thrust control is proposed with consideration of thrust performance and energy efficiency. The ground tests indicate that the ASVP system weighs 1.8 kg (with 0.34-kg liquefied ammonia propellant) and reaches a specific impulse of more than 100 s, while the power consumption is less than 10 W. The ASVP system meets multiple requirements including high specific impulse, low power consumption, easy fabrication, and uniform adjustable thrust output, and thus is suitable for micro-nano satellites.

In the framework of the complete formulation of the conjugate problem, the liquid–gas flow structure arising upon local heating using thermal sources is investigated numerically. The two-layer system is confined by solid impermeable walls. The Navier–Stokes equations in the Boussinesq approximation in the ‘streamfunction–vorticity’ variables are used to describe the media motion. The dynamic conditions at the interface are formulated in terms of the tangential and normal velocities, while the temperature conditions at the external boundaries of the system take into account the presence of local heaters. The influence of the number of heaters and heating modes on the dynamics and character of the appearing convective regimes is analysed. The steady and commutated heating modes for one and two heaters arranged at the lower boundary are investigated. The heating initiates convective and thermocapillary mechanisms causing the fluid motion. Transient regimes with the successive formation of two-vortex, quadruple-vortex and two-vortex flows are observed before the stabilization of the system in the uniform heating mode. A stable thermocapillary deflection appears at the interface above the heater. The commutated mode of heating entails oscillations of the interface with a change in the deflection form and the formation of travelling vortices in the fluids. The impact of particular mechanisms on the flow patterns is analysed. The paper presents typical distributions of the velocity and temperature fields in the system and the position of the interface for the considered cases.