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A simplified and a numerical mathematical models of gas cooling and water heating in a thin turbulent bubbling layer on a tray with cross-phase flow are presented. The thermal efficiency of gas cooling is found using the ideal displacement model, and the temperature profile in the liquid phase is found from the solution of a cell model or a two-dimensional differential equation of convective heat exchange with an interfacial heat source. Examples of calculating the efficiency of water cooling of gas with different humidity on sieve and valve trays are given. The results of calculations of the thermal efficiency of gas cooling depending on the height of the gas–liquid layer, as well as on the gas velocity in the column are compared with known experimental data. Conclusions are drawn about the adequacy of the mathematical model and of the developed algorithm for calculating the heat and mass transfer characteristics of the bubbling layer. Comparative characteristics of the thermal efficiency of sieve and valve trays are given depending on the gas velocity and different heights of the liquid column. The influence of the variable mass of valves along the length of the tray on the increase in thermal efficiency is shown. Conclusions are drawn on the most efficient designs and modes of operation of bubbling trays. [ABSTRACT FROM AUTHOR]

The article is dedicated to describing the research of different ways, appliances and solutions for flammable gas supply, transportation and cooling, performed in terms of authors' PhD theses, related to pyrolysis gas production and application for electric power production. The main idea of this research is the investigation of opportunities of application of modern simple generally used technological solutions on pyrolysis gas power plants for the above mentioned units design. The research is related to different ways of pyrolysis gas cooling and also to the ways of the gas supply from gas generator to the consumer. Another goal is to create a systematic approach to the automation of pyrolysis gas production and transportation onto future pyrolysis gas powered electric power plants. [ABSTRACT FROM AUTHOR]

For sustainable low-carbon cities, using sustainable urban energy system solutions is imperative. CO2-based bionanofluid is one proposed energy system solution that is sustainable and environmentally friendly. This paper examines the thermal-hydraulic and entropy production properties of mango bark/CO2 nanofluid for industrial-inclined gas cooling applications. The influence of gravitational force (in terms of tube inclination angle), volume fraction, and Reynolds number on the heat transfer, pressure drop, and entropy production of CO2-based mango bark nanofluids in laminar flow through a circular aluminum tube are numerically studied. The bionanofluid flows through a tube with an inner radius of 2.25 mm, a length of 970.0 mm, and an initial temperature of 320.0 K. A constant heat flux of −10.0 W/m2 is applied to the flow at its walls. The laminar flow regime with Reynolds numbers of 100, 400, 700, and 1000 are subjected to flow inclinations of ±90°, ±60°, ±45°, ±30°, and 0° and bionanofluid volume fractions of 0.5%, 1.0%, and 2.0%. Results show that ±45° tube inclination angle offers the optimal heat transfer coefficient, maximum pressure drop, and minimum total entropy production rates for Re > 100; however, for Re = 100, these occur at the inclination angle of −30° and +60°. The pressure drop shows less sensitivity to the inclination angle; however, it offers peak values at the same inclination angles as the heat transfer coefficient for the respective Reynolds number values. The maximum thermal enhancements due to gravitational effect are 42%, 93.98%, 121.28%, and 150% for Reynolds numbers of 100, 400, 700, and 1000, respectively, while that due to nanofluid volume fraction are less than 16%.

The optimal process parameters of a gas-cleaning plant used to achieve and exceed its design efficiency are presented. The optimization conditions for the process parameters are determined. A situation schematic of static pressure (vacuum) measured at the design process parameters of the gas-cleaning system in the circuit of gas flues and process units is presented. One of the main causes of unstable operation of "dry" gas-cleaning systems is the lack of data on optimal process parameters. Such situations include changes in the properties of supplied alumina, gas-distribution balance, emergency shutdowns of one or more cleaning modules, etc. The results of study and testing of optimal gas cleaning parameters at one of the Russian aluminum plants under various operating conditions of gas-cleaning systems to ensure stable environmental performance of aluminum production are discussed. The case of emergency shutdown of two or more gas-cleaning modules is additionally examined. The test results show that when two or more modules fail or are shut down, the cleaning efficiency is not achieved when removing gaseous fluorine. Therefore, in such situations, it is necessary to increase the amount of fed alumina to 7.5 t/h and to increase the recycle rate to 3. [ABSTRACT FROM AUTHOR]

The work contains a numerical solution of the scientific and technical problem of the determination of the efficiency of packed scrubbers during condensation cooling and purification of the dispersed phase of gases in the process of a stationary film liquid flow through regular and chaotic contact devices. A system of differential equations with partial derivatives of the conjugate transfer of heat, the mass of water vapor, and the dispersed phase in the packing layer is written. The heat and mass transfer and the transfer of dispersed particles between the gas and liquid phases are taken into account with volume source terms of the interfacial transfer, averaged over the local volume of the layer. Expressions are given to determine the source parameters. The results of the numerical solution of the system of equations in terms of the temperature and moisture content fields and comparison with known experimental data are presented. The dependence of the efficiency of gas purification from a finely dispersed phase on the gas velocity is shown. Comparative characteristics of packings, as well as scientific and technical solutions for the modernization of scrubbers introduced in the industry, are given. [ABSTRACT FROM AUTHOR]

The relevance of the study is caused by the need to improve the efficiency of the allocation of valuable components from natural gas in field conditions.The existing gas treatment technologies of gas condensate fields are characterized by a low degree of extraction of propane-butane and ethane fractions. It is known that natural gases of the Valanginian and Achimov deposits contain a large number of components necessary for petrochemical products. Field preparation of natural gas of gas condensate fields is usually based on low-temperature separation technology, where the extraction of liquid hydrocarbons from gas stream occurs by reducing the temperature by throttling, followed by separation of gas and liquid phases in independent separators. The technology has low efficiency and is limited by dependence on high pressures. The article deals with the issue of retrofitting gas treatment plants with small-sized high-performance equipment that provides deep cooling of the medium and simultaneous separation into components. The aim of the work is theoretical study of high-speed processes of natural gas preparation, numerical experiment for establishing the influence of the main parameters of the equipment on efficiency of separation of high-molecular components from methane. Objects: complex gas treatment plants of gas condensate fields, mean values of gas composition, critical parameters and derivative values of which correspond to the conditions of the Northern fields. Methods: construction of a mathematical model that takes into account gas component composition, determination of distribution of temperature, pressure, velocity, density and the Mach number of gas in a high-speed separator with separation into components. Results. The authors have proposed the technology of obtaining lower temperatures required for complex gas treatment of gas condensate fields. It is implemented on the basis of gas-dynamic high-speed technology with the use of the Ranque–Hilsh tube and Laval nozzle. The calculated dependences of extraction of propane-butane and ethane fractions on the achieved low temperatures are established.

To discuss a suitable porous structure for helium gas cooling under high heat flux conditions of a nuclear fusion divertor, we first evaluate effective thermal conductivity of sintered copper-particles in a simple cubic lattice by direct numerical heat-conduction simulation. The simulation reveals that the effective thermal conductivity of the sintered copper-particle highly depends on the contacting state of each particle, which leads to the difficulty for the thermal design. To cope with this difficulty, we newly propose utilization of a unidirectional porous tube formed by explosive compression technology. Quantitative prediction of its cooling potential using the heat transfer correlation equation demonstrates that the heat transfer coefficient of the helium gas cooling at the pressure of 10 MPa exceeds 30,000 W/m2/K at the inlet flow velocity of 25 m/s, which verifies that the unidirectional porous copper tubes can be a candidate for the gas-cooled divertor concept.

This article presents a method for calculating the dynamics of fluid motion in a two-stage hybrid energy machine with a gas cap. The developed method is based on the Bernoulli energy conservation equation, taking the linear hydraulic resistances, local hydraulic resistances, and inertial forces into account. The expressions for the current coordinate values of the liquid levels and pressures in the gas cap apply to the second stage compressor section and the first stage pump section. The developed method of calculation can be used for the analysis of working processes in compressor machines based on the principle of the liquid piston. [ABSTRACT FROM AUTHOR]

• Quadrupole-ToF-SIMS was applied with gas cluster ion beam (GCIB). • Ar-GCIB sputtered 1,2-Distearoyl-sn-glycero-3-phosphocholine (DSPC) sample. • He or N2 gas of varied pressures was used at travelling-wave ion guide. • DSPC mass spectra and ion yields in MS and MS/MS modes were measured. • Secondary ion or fragment energy was cooled depending on the gas and pressure. The work was aimed at using gas to cool the secondary ions emitted from gas cluster ion beam (GCIB) bombardment of biosamples for lowering the ion energy distribution and thus enhancing the detection sensitivity for secondary ion mass spectrometry (SIMS). An Ar-cluster ion source at energy in an order of keV was installed with the Q-ToF (Quadrupole Time-of-Flight) premier at the Quantum Science and Engineering Center, Kyoto University. The main component of the Q-ToF premier consisted of a travelling-wave ion guide, a mass filter quadrupole lens, a travelling-wave collision cell, and a ToF analyzer. A 1,2-Distearoyl-sn-glycero-3-phosphocholine (DSPC) sample was used in the study on cooling the secondary ions at the travelling-wave ion guide by using helium and molecular nitrogen gas. The DSPC sample was impinged with primary Ar-cluster ions at energy 10 keV and sputtered for secondary ions in an energy range from zero to several hundred eV. Sputtering-emitted secondary ions were extracted to the Q-ToF mass spectrometer. The experiment was carried out to measure DSPC secondary ion mass spectra in two modes at varied pressures of helium or molecular nitrogen gas. The first mode was the MS mode and the other was the MS/MS mode which defined the m / z = 790.6 Da for the protonated molecule at the mass filter quadrupole lens. The experiment found that the secondary ion yields (SIYs) in the MS mode reached the maximum at 2.0 and 0.35 Pa for helium and molecular nitrogen, respectively. In the MS/MS mode, the SIYs reached the maximum at 2.5 and 0.35 Pa for helium and molecular nitrogen, respectively, and however, some fragments could not be eliminated by the cooling molecular nitrogen gas. The cooling of the secondary ions for lowering the energy distribution and the transverse direction of the secondary ions by using helium was more effective and stable than by using molecular nitrogen. [ABSTRACT FROM AUTHOR]

Gas cooling is a technique used by firefighters to reduce the dangers posed by the hot smoke in enclosure fires and, to thereby approach a fire while keeping their escape route safe. The technique includes bursts of water from a fog nozzle producing small droplets into the hot gases. The purpose of this work was to experimentally investigate the effects of gas cooling. A total of 44 tests were conducted in an 1800 × 1200 × 1200 mm room with an added fire room sizing 1200 × 760 × 1200 mm. A gas burner with a RHR of approximately 90 kW was used as a heat source. Four different nozzles were used, differing in droplet size, flow, and spray pattern. Also, reach, number of bursts and open time of the nozzles varied between tests. In this paper, six of the test with the most important and pronounced results were used for comparison. Conclusions from the tests included that nozzles producing droplets with a median diameter of approximately 500 µm delivered in multiple short burst with time in between bursts kept as short as possible were most effective for gas cooling. However, overall in this experimental setup taking all droplets sizes into consideration, a single longer burst performed slightly better than several short bursts as a similar temperature reduction is achieved in 1/3rd of the time of 5 short bursts and gases are cooled over a larger part of the room. The volume of the smoke was not observed to change significantly due to gas cooling. [ABSTRACT FROM AUTHOR]

For sustainable low-carbon cities, using sustainable urban energy system solutions is imperative. CO 2 -based bionanofluid is one proposed energy system solution that is sustainable and environmentally friendly. This paper examines the thermal-hydraulic and entropy production properties of mango bark/CO 2 nanofluid for industrial-inclined gas cooling applications. The influence of gravitational force (in terms of tube inclination angle), volume fraction, and Reynolds number on the heat transfer, pressure drop, and entropy production of CO 2 -based mango bark nanofluids in laminar flow through a circular aluminum tube are numerically studied. The bionanofluid flows through a tube with an inner radius of 2.25 mm, a length of 970.0 mm, and an initial temperature of 320.0 K. A constant heat flux of -10.0 W/m 2 is applied to the flow at its walls. The laminar flow regime with Reynolds numbers of 100, 400, 700, and 1000 are subjected to flow inclinations of ±90°, ±60°, ±45°, ±30°, and 0° and bionanofluid volume fractions of 0.5%, 1.0%, and 2.0%. Results show that ±45° tube inclination angle offers the optimal heat transfer coefficient, maximum pressure drop, and minimum total entropy production rates for Re > 100; however, for Re = 100, these occur at the inclination angle of -30° and +60°. The pressure drop shows less sensitivity to the inclination angle; however, it offers peak values at the same inclination angles as the heat transfer coefficient for the respective Reynolds number values. The maximum thermal enhancements due to gravitational effect are 42%, 93.98%, 121.28%, and 150% for Reynolds numbers of 100, 400, 700, and 1000, respectively, while that due to nanofluid volume fraction are less than 16%., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper, (© 2023 Published by Elsevier Ltd.)