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The jet impingement flash technology represents a paramount research subject in the domain of heat and mass transfer. To augment its commercial potential, the conjunction of annular multi‐aperture jet impingement with negative pressure flash evaporation is introduced in this study. The employment of an annular nozzle array is integral to the enhancement of the heat and mass transfer efficiency between the phases. The Realizable k‐ε model is used in this study. The negative pressure flash vaporization model was also developed by introducing a mass source term and an energy source term based on the Mixture model. The flow characteristics are characterized using numerical simulation. Additionally, the λ2 vortex identification criterion is investigated the vortex structure. The simulation results exhibit good agreement with experimental findings, demonstrating that a higher initial vacuum leads to a stronger flashing effect and a more chaotic movement of the flow group within the flow field. Thus, this study provides a reference method for the structural design and optimization of annular symmetric jet impingement negative pressure deammonia chemical equipment for engineering applications. [ABSTRACT FROM AUTHOR]

This paper proposes a fast cooling technology called flash evaporation or flashing to overcome cooling problems. Flashing is a pressure-driven phase change phenomenon widely studied because of its complex physics and numerous applications. An experimental system is fabricated to study the efficiency of the proposed process by considering water as a working fluid. A transparent acrylic column is used as the flash chamber, enabled with a high-speed camera to visualize and capture this fast and complex process. Experiments have been carried out with various initial temperatures from 65 °C to 80 °C, initial vacuum tank pressure ranging from 11.32 kPa to 41.32 kPa, and initial water heights of 80 mm and 140 mm. The flashing phenomenon is divided into two stages based on its effectiveness. From the present study, it becomes apparent that the drop in the temperature increases with the initial temperature and decreases with increasing vacuum tank pressure. The cooling rate is improved by 49.1% by increasing the initial pool temperature by 23%. The present study demonstrates an effective application of the flashing process in areas requiring high cooling rates and rapid vapour generation, such as refrigeration and drying.

Vacuum-based deposition of halide perovskites receives a lot of attention for its proven scalability and conformal depositions. Co-evaporation has remarkable success, but efficiencies continue to lag behind their solution-based counterparts. This is in part attributed to the complex sublimation behavior of some organic ammonium precursor salts and the increased complexity of the absorber materials, requiring the use of four or more sources in a conventional co-evaporation setup. The latter has driven work into single-source methods with flash evaporation presented as one such method. However, flash evaporation processes typically evaporate all material in a single batch, leading to short deposition times at high temperatures. Particle sputtering effects seen at these high temperatures drive processes toward low temperatures where prolonged exposure causes degradation. Here, a pulse-driven incremental powder feeding system is presented. This method is capable of stable flash evaporation rates for >1 h, with controlled rates as low as 1.5 Å per pulse (±0.89). The feasibility of this method is demonstrated for three different perovskite compositions: FAPbBr3, MAPbI3, and FA1-xMAxPbSnI3:SnF2. Furthermore, FAPbBr3 and MAPbI3 are integrated into all vacuum-processed thin-film solar cells leading to power conversion efficiencies (PCE) of ~4% and 10%, respectively. [ABSTRACT FROM AUTHOR]

With the continuous improvement of environmental protection requirements，zero emissions technology becomes an important path to achieve the use of sewage resources. A fiber optic product factory in Jiangsu was chosen as object，the process flow and operation of MVR evaporation crystallization technology to treat saline wastewater by MVR evaporation crystallization technology for the treatment of salty wastewater produced was introduced. Furthermore，the economy of the system was analyzed. It is hoped to understand the actual processing effect of the MVR evaporation crystallization technology in zero emissions technology，and provide a reference for the design and operation of zero discharge projects in domestic wastewater. The project was based on the principle of MVR process，using external plate heat exchanger and flash evaporator to form an evaporation crystallization system. The results showed that the actual processing capacity of the evaporation crystallization system was 48 t/d，the system salt rejection rate was 99.23%，the condensate index reached the reuse index in the plant，the recovery rate was 93.47%，and the purity of the waste salt produced by crystallization was 96%. It met the first-class standard of industrial wet salt of Industrial Salt（GB/T 5462—2015），and the cost of water treatment per ton was 65.03 yuan. The evaporation crystallization technology of MVR was applied in the treatment of salt-containing wastewater，which was energy saving and environmental protection，and no pollutants were discharged，achieving the near-zero discharge of industrial wastewater.

Copyright of Industrial Water Treatment is the property of CNOOC Tianjin Chemical Research & Design Institute and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

To further improve the quality of antioxidant 6PPD products, differential analysis and comparison are conducted through continuous tracking and comparison of similar domestic products. The effect of reaction temperature, circulating hydrogen content and high ketone content on the quality of antioxidant 6PPD products is investigated, and the production process is optimized. At the same time, the influence of temperature, vacuum degree, material quantity and other factors on the separation effect is studied, and the flash evaporation process is optimized. The production process optimization results have achieved good application effects in the production equipment, achieving the goal of improving the quality of antioxidant 6PPD. [ABSTRACT FROM AUTHOR]

Different from a gas expander, there is a phase change from liquid to vapor called the flash inside the two-phase expander. But, same with the gas expander, only the vapor phase expands and pushes the rotation of the expander to output power in the two-phase expander. It means that the amount of the vapor is increased during the expansion by the flash. Obviously, the flash rate of the working fluid from liquid to vapor is critical to the expansion power recovery. In this paper, an experiment system with water as the working fluid was established to study the heat transfer characteristics of flash evaporation during the two-phase expansion process. The flash was controlled inside a flash chamber, under the initial temperature from 100 ℃ to 130 ℃, and the initial liquid level height from 110 mm to 175 mm. The pressure evolution of the flash evaporation was limited by the pressure regulating valve. The obtained results showed that the level of the instant liquid superheat was positively associated with the flash rate of evaporation. The temperature drop rate behaved negatively correlated with the instant superheat, while higher the instant superheat resulted in faster liquid temperature reduction. Both the liquid-vapor heat transfer coefficient and the instant flash rate were increased with the increase of instant superheat. Generally, the peak of instant superheats occurred earlier than that of instant flash rate and instant heat transfer coefficient. The instant superheat level was increased and affected by the initial temperature and initial liquid level height.

Flash evaporation processes are widely adopted in the desalination, food processing, waste heat recovery and other industries for heat extraction or product separation. In this paper, a pressure-driven phase transition model is developed by improving the Lee model and combined with the VOF (Volume of Fluid) method to numerically simulate the flash evaporation process. In this modified Lee phase transition model, the driving force for the rates of the local phase transition is calculated using the local temperature and static pressure magnitude. Numerical simulations are carried out in a water-circulating flash chamber and compared with the experimental results to obtain the values of the time relaxation parameters. And the non-equilibrium fraction of the outlet water can be effectively obtained under different conditions of flow rate, inlet temperature and initial liquid level height. The time relaxation factor takes values from 0.195 to 0.43 (Pout,v = 19.9 kPa) and from 0.31 to 0.92 (Pout,v = 31.2 kPa) with increasing superheat. In addition, the model can effectively represent the evolution of the unstable flow flash evaporation from the initial rapid boiling state to dynamic equilibrium. [ABSTRACT FROM AUTHOR]

Flash evaporation processes are widely used in petroleum, food, chemical, power, and other industries to separate products or extract heat. The liquid is often entrained by non-condensing gas components. This study develops a multiphase, multicomponent, and pressure-driven phase-change-coupled model to numerically study water flash evaporation with non-condensing CO2. The model includes the mass, momentum, energy, volume of fluid (VOF), species transport, turbulence (RNG k-ε), modified phase-change Lee, and non-condensing CO2 release governing equations. The steam generation rate and mechanism for pure water and different concentrations of CO2 are considered. The results show that the numerical model can accurately predict the flash evaporation process and has high accuracy compared with the experimental data. Both the dissolved and entrained CO2 that are released can severely disturb the flow field, leading to an increase in the steam generation rate. Under a 1–10% volume concentration of dissolved CO2 and 0.0661–0.1688% mass concentration of entrained CO2, the maximum increase ratio of steam generation can reach 20%. [ABSTRACT FROM AUTHOR]

The performance of organic Rankine cycle (ORC) is poor due to the high irreversible losses in evaporator. To improve system performance, organic Rankine single flash cycle (ORSFC) and organic Rankine double flash cycle (ORDFC) are proposed, in which the traditional evaporation process is split into incomplete evaporation and flash evaporation. Thermal and exergetic efficiencies are taken as the objective functions, and the effects of the related operating parameters and the number of the flash stage on the thermodynamic performance of the system is conducted. The results show that for the ORSFC and ORDFC, in the direction of the rise of the heat source temperature, the net power output increases, the optimal evaporation temperature and flash temperature corresponding to different performance criteria also gradually increase. Besides, the dryness of the evaporator outlet is inversely proportional to the net power output, while it is directly proportional to the system efficiencies. When the dryness increases by 0.1, the net power output of the ORSFC and ORDFC decreases by an average of 148.5 kW, the thermal efficiency and exergetic efficiency of the ORSFC and ORDFC increase by an average of 0.56% and 1.37%, respectively. Moreover, with the flash stages increase, the performance criteria are improved at different magnitude. When a specific thermodynamic parameter is optimized, the ORDFC always obtains the best value for this parameter. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Dalian University of Technology / Dalian Ligong Daxue Xuebao is the property of Journal of Dalian University of Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Numerical study has been conducted to investigate shock waves generated by flashing water jet. This study presents results of a numerical simulation of flash evaporation phenomena occurring when a jet of superheated water is injected through a nozzle into low-pressure water vapor. Due to the sudden pressure drop, flashing takes place, and the sensible heat of the water converts into latent heat of evaporation. The multiphase flow field in the evaporation zone and induced shock waves are explored via a 2D transient investigation in Ansys Fluent. The Mixture model is applied with slip velocities to model the non-homogeneous multiphase flows. Resulting distributions of the fluid properties velocity, Mach number, pressure, liquid volume fraction, density, and in addition to speed of sound inside the flashing chamber at different time steps are presented and discussed. The results show that once the superheated water is injected, it flashes immediately and generates a shock wave. The primary and reflected shock waves are characterized by discontinuous fluid properties in a narrow region across the shock. The generated shock waves are moving shock waves and can be useful to transfer energy directly between fluids without using mechanical components such as pistons or vaned impellers, which can be exploited in industrial and technological applications such as utilizing resulting shock waves in creating useful compression.

Wort boiling is the most energy intensive stage in the brewing process. Novel wort boiling systems have been explored to reduce primary energy consumption and improve wort quality and beer flavor stability. Low thermal stress boiling is proposed for wort boiling, but the content of dimethyl sulphide (DMS) in the wort may exceed the required product threshold. A single spinning cone evaporator (SCE) is proposed to enhance the separation of DMS and minimise the energy consumption for wort boiling. The performance of a SCE was evaluated by measurement of fluid flow, ratio of DMS removal, wort self-evaporation ratio based on sensible heat, and thermal efficiency. The results show that use of a spinning cone evaporator, reduced DMS by up to 90% with 2.1% wort self-evaporation ratio with less primary heat consumption. The SCE operation exceeds the evaporation of a gravity film cone. Under reduced pressure, the spinning cone evaporator was less effective in DMS removal. [ABSTRACT FROM AUTHOR]

This paper presents an experimental study on spray flash evaporation occurring in a superheated water jet injected through a short nozzle into a vacuum chamber. The study presents shock waves as one of significant consequences that can be produced by flash evaporation, which can be utilize for creating useful compression. The experimental study is carried out with the liquid water initially at a pressure of 101325 Pa, and a temperature ranging from 40 °C to 100 °C, and the backpressure (vacuum pressure) ranging from 4000 Pa to 10000 Pa. The experimental set-up includes Schlieren technique utilizing a high-speed camera to capture images of the flashing and the generated shock wave. The Schlieren photographs were mathematically filtered using the Image Processing and Analysis in Java to show the induced shock wave structure. The results show that increasing the initial water temperature accelerates and enhances the flash evaporation. Full flashing generating a shock wave takes place at high initial liquid temperature and low backpressure.

Japan has a huge geothermal resource with geothermal power generation capacity of about 550 MWe. The hot water geothermal resources in Japan are mostly in the range of 53-120 °C. Hot spring thermal energy conversion (STEC) can provide a stable power output so introduction of small-scale STEC based on organic Rankine cycle (ORC) is expected. Hybrid hot spring thermal energy conversion (H-STEC) is a combination of distillation and ORC; thus, it is able to produce electric power and water to supply the cooling tower simultaneously. H-STEC has a flash chamber to prevent scaling in heat exchangers due to the supersaturated Ca, Si, and so on. The system characteristics of H-STEC are such that power output and supplied water ratio can be clarified by using parametric analysis, however, there has been no significant research proving such in actual experiments. In this study, the system characteristics of H-STEC were clarified by using a small-scale demonstration equipment. Pumped hot spring water was used as the heat source of H-STEC where the hot spring water was delivered after heat utilization. To evaluate the available power for a power generation system using a finite heat source, the maximum power output and the maximum power efficiency were defined. The maximum power efficiency is the ratio of the gross power to the maximum power. The maximum gross power was 15.9 kW, and the maximum power efficiency was 22.1%. The condensed water from evaporator could supply 100% of the water consumption in the cooling tower.

Eggshells and eggshell membranes have high‐value recycling applications and have been widely used in pharmaceutical, chemical, and food research. The separation of eggshells and eggshell membranes is a prerequisite to efficiently using both. Therefore, the pressure‐vacuum experiment equipment was designed. In this study, research on the separation of eggshells and eggshell membranes from waste eggshells using the pressure‐vacuum experiment equipment was carried out. The flash evaporation experiment process controlled the experimental factors to obtain a sufficient moisture content between the eggshell and eggshell membrane with vigorous flash evaporation. The effects of experimental factors such as superheat (5–10°C), temperature (50–70°C), initial pressure (0.6–0.8 MPa), pressurization time (0–40 min), and particle size (6–8 mm) on the separation rate were investigated in the pressure‐vacuum experiment process. Through single‐factor and orthogonal experiments, it was found that the separation rate was most affected by changes in temperature, initial pressure, and particle size, followed by the interaction of temperature and particle size. The experimental results suggested that the optimum separation of eggshell membranes from eggshells was achieved at higher superheat, higher temperature, higher initial pressure, medium pressurization time, and smaller particle size. Through optimization by response surface methodology, the optimal conditions for the separation of eggshells and eggshell membranes using the flash evaporation method were determined as 15°C of superheat, 70°C of temperature, 0.8 MPa of initial pressure, and 6 mm of particle size. Flash evaporation method is an effective and environmentally friendly method, which provides a new solution for the recycling of waste eggshells. Practical Application: In this study, pressure‐vacuum experiment equipment was utilized to reuse of waste eggshells, and an innovative and environmentally friendly method of eggshell membrane and eggshell separation was established. The pressure‐vacuum experiment equipment has a simple structure and low energy consumption. The results of flash evaporation experiments are instructive for further in‐depth studies on the separation of eggshells and eggshell membranes. Furthermore, the separation of eggshells and egg membranes by flash evaporation is of great research value. Most importantly, the separated eggshells and eggshell membrane are available for high‐value applications in food, chemical, and biological fields. [ABSTRACT FROM AUTHOR]

An FM-NM film (FM - ferromagnetic metals: Fe, Ni, Co; NM - conductive metals: Al, Cu, Ag, Au, etc.) is a type of magnetic nanogranular material with properties of metal-matrix nanocomposite or metastable crystalline alloys material systems. It is believed possible to deposit these films using vapor quenching techniques, for which flash evaporations are included. This study aims to find whether approaches and practices of the flash co-evaporation (FcoE) technique for creating magnetic nanogranular thin films are possible and realistic. This work introduces some technical basis, the thermodynamics of evaporation of related materials for the establishment of the FcoE technique, and some structural and magnetic properties of the FcoE deposited Co-NM films (NM = Ag, Al, Cu). The FcoE technique seems less applicable to such thin films so far. So, this technique is expected to contribute to the enrichment of deposition techniques for nanostructured material systems. Since then, a nanogranular film technology based on the FcoE technique applied to the FM-NM-type immiscible metal alloys, whose constituents are not thermodynamically identical, has been preliminarily set up. This technique is expected to provide another simple and efficient way to generate magnetic nanogranular or metal-matrix nanocomposite materials for research in nanoelectronics and spintronics. [Display omitted] • FcoE is a flash-style protocol for the simultaneous evaporation of different solids. • XRD, TEM, SEM confirm Co-NM films as two-phase heterostructures in an NP morphology. • SPM, GMR data are valid additional demonstrations for the presence of Co NPs/clusters. • Co NPs/clusters of the Co-NM films deposited by FcoE reach no more than 10 nm in size. • Co–Ag(Cu, Al) films are typically a metastable alloy or a magnetic MMNC category. [ABSTRACT FROM AUTHOR]

• Visual observation of two-phase mixture during flash evaporation. • Void fraction measurements using capacitance probe. • Correlation of data. Flashing is a pressure driven phase change phenomenon. It is widely studied due to its richness in physics and applications such as in desalination, in nuclear industry to name a few. Dynamic flashing is a situation wherein the pressure drop for flashing is initiated through the flow of liquid. A recently developed novel desalination system [ 1 ] utilizes combined dynamic flashing and vapor separation through tangential injection for producing potable water. An understanding of dynamic flashing in a tube with reference to the novel desalination system could help with its optimization. In this work, dynamic flashing of tap water occurring in a clear quartz square tube was studied. The pressure and temperature measurements along the tube were made and analyzed for different inlet flowrates and initial liquid temperatures. The pressure and temperature values showed increasing gradients along the tube indicating increased vapor production or flashing for increasing flowrates and initial liquid temperatures. The vapor production from flashing and the resulting flow regimes along the tube were tracked and identified through high-speed imaging. Visual observations showed complex flow regimes with bubbles nucleating and growing throughout the tube due to flashing. Most of the bubble formation was observed in the bulk with little nucleation on the glass tube wall. Void fraction measurements along the tube based on capacitance impedance technique were performed to supplement the visual observations which showed increasing void fraction along the tube matching the observed flow regimes from vapor production. [ABSTRACT FROM AUTHOR]

Flash evaporation processes are widely adopted in the desalination, food processing, waste heat recovery and other industries for heat extraction or product separation. In this paper, a pressure-driven phase transition model is developed by improving the Lee model and combined with the VOF (Volume of Fluid) method to numerically simulate the flash evaporation process. In this modified Lee phase transition model, the driving force for the rates of the local phase transition is calculated using the local temperature and static pressure magnitude. Numerical simulations are carried out in a water-circulating flash chamber and compared with the experimental results to obtain the values of the time relaxation parameters. And the non-equilibrium fraction of the outlet water can be effectively obtained under different conditions of flow rate, inlet temperature and initial liquid level height. The time relaxation factor takes values from 0.195 to 0.43 (Pout,v = 19.9 kPa) and from 0.31 to 0.92 (Pout,v = 31.2 kPa) with increasing superheat. In addition, the model can effectively represent the evolution of the unstable flow flash evaporation from the initial rapid boiling state to dynamic equilibrium.

Flash evaporation processes are widely used in petroleum, food, chemical, power, and other industries to separate products or extract heat. The liquid is often entrained by non-condensing gas components. This study develops a multiphase, multicomponent, and pressure-driven phase-change-coupled model to numerically study water flash evaporation with non-condensing CO2. The model includes the mass, momentum, energy, volume of fluid (VOF), species transport, turbulence (RNG k-ε), modified phase-change Lee, and non-condensing CO2 release governing equations. The steam generation rate and mechanism for pure water and different concentrations of CO2 are considered. The results show that the numerical model can accurately predict the flash evaporation process and has high accuracy compared with the experimental data. Both the dissolved and entrained CO2 that are released can severely disturb the flow field, leading to an increase in the steam generation rate. Under a 1–10% volume concentration of dissolved CO2 and 0.0661–0.1688% mass concentration of entrained CO2, the maximum increase ratio of steam generation can reach 20%.

Numerical study has been conducted to investigate shock waves generated by flashing water jet. This study presents results of a numerical simulation of flash evaporation phenomena occurring when a jet of superheated water is injected through a nozzle into low-pressure water vapor. Due to the sudden pressure drop, flashing takes place, and the sensible heat of the water converts into latent heat of evaporation. The multiphase flow field in the evaporation zone and induced shock waves are explored via a 2D transient investigation in Ansys Fluent. The Mixture model is applied with slip velocities to model the non-homogeneous multiphase flows. Resulting distributions of the fluid properties velocity, Mach number, pressure, liquid volume fraction, density, and in addition to speed of sound inside the flashing chamber at different time steps are presented and discussed. The results show that once the superheated water is injected, it flashes immediately and generates a shock wave. The primary and reflected shock waves are characterized by discontinuous fluid properties in a narrow region across the shock. The generated shock waves are moving shock waves and can be useful to transfer energy directly between fluids without using mechanical components such as pistons or vaned impellers, which can be exploited in industrial and technological applications such as utilizing resulting shock waves in creating useful compression. [ABSTRACT FROM AUTHOR]

This paper presents an experimental study on spray flash evaporation occurring in a superheated water jet injected through a short nozzle into a vacuum chamber. The study presents shock waves as one of significant consequences that can be produced by flash evaporation, which can be utilize for creating useful compression. The experimental study is carried out with the liquid water initially at a pressure of 101325 Pa, and a temperature ranging from 40 °C to 100 °C, and the backpressure (vacuum pressure) ranging from 4000 Pa to 10000 Pa. The experimental set-up includes Schlieren technique utilizing a high-speed camera to capture images of the flashing and the generated shock wave. The Schlieren photographs were mathematically filtered using the Image Processing and Analysis in Java to show the induced shock wave structure. The results show that increasing the initial water temperature accelerates and enhances the flash evaporation. Full flashing generating a shock wave takes place at high initial liquid temperature and low backpressure. [ABSTRACT FROM AUTHOR]

Copyright of Experimental Technology & Management is the property of Experimental Technology & Management Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

• A quick-opening simulation module is designed, and a moveable measuring rod is used to measure the exterior space pressure. • The physical change process at different depressurization phases corresponds to the pressure variation curve are obtained. • Some parameters like depressurization rate and liquid superheat degree are measured and calculated in various cases. • The relaxation time before flash evaporation strongly affects the pressure variation inside the pipe and the back pressure. Pressurized pipeline transportation systems are widely used in various industries for fluid delivery, energy exchange and transmission. When the pipeline system loses pressure because of the rupture or fracture of the pipe, the contained fluid, like hot water, will rapidly flow out of the system and may be accompanied by flashing, which may lead to severe consequences to the pipeline system itself and the surrounding instrument. Based on the designed test bench for separated discharge experiments, this paper uses the toughened glass disc crushed by a hammer to realize the full opening of the pipe after it breaks. The test section is a 50 mm nominal stainless steel pipe about 1600 mm long. Several high-precision piezoelectric sensors are placed along the pipe and the outside space near the rupture point with a data acquisition frequency of up to 20 kHz. Pressure distribution and time trends are obtained inside and outside the pipe during the rapid blowdown process with various initial pressures and subcooling degrees. The characteristics of different stages in depressurization are identified, and some other vital parameters, such as the rate of depressurization and liquid superheat, are also calculated and analyzed. In addition, some variation rules are also given using nondimensionalization of parameters. Moreover, some large pressure pulses are observed in the exterior space, presumably due to the formation of shock waves caused by the flashing of superheated fluid. These data all help to understand the hot water blowdown process with flash evaporation at not high pressures and provide more accurate insights into using boundary model with back pressure changes and phase transition relaxation time in system analysis code calculations. [ABSTRACT FROM AUTHOR]

In this study, thin films-based thermoelectric generators (TEG) were fabricated using the flash evaporated copper sulfide films and radio frequency (RF) sputtered ITO films, deposited on 26 × 76 mm2 glass substrates. After careful study of the Seebeck coefficient of both films, without and with annealing at 350 °C, the open-circuit voltage for the eight junctions was studied as a function of the temperature gradient. Applying a temperature gradient of 40 K, the obtained maximum voltage is shown to be 10.9 mV, which increases to 15.6 mV by annealing. The internal resistance of the TEG remains unchanged, possibly due to the inverse evolution of resistivity during the annealing process of the CuS and ITO films. The obtained outputpower is 13 nW for the as-deposited films and increases to 26.2 nW by annealing. • ITO/CuS thin films based thermoelectric generators were fabricated. • Flash evaporated copper sulphide films and radio frequency sputtered ITO films were used. • Open-circuit voltage for the eight junctions was studied. • The generated power is 13 nW for the as-deposited films and increases to 26.2 nW by annealing. [ABSTRACT FROM AUTHOR]

The scarcity of clean and safe water is one of the most perilous glitches faced by the world. The pure drinking water resources across the world are depleting progressively due to rapid industrialization and growth in population. The conceivable solution for this problem is converting the available seawater into pure drinking water through several techniques of desalination. In the stream of desalination, many prodigious endeavours are in evolution to increase the reliability of the process by cutting down the principal and maintenance costs. Among several desalination approaches, low-temperature thermal desalination (LTTD) is an intriguing and advancing trend in the desalination process by using low temperatures and pressures in a range similar to ambient temperatures and vacuum pressures. The LTTD technique is operated by taking the energy input from waste heat, thermoclines and renewable energy sources. However, the operating temperatures of the LTTD system are less than 50 °C. The development of this particular LTTD process driven by renewable energy sources has gone through various stages, based on the water–energy demands, environmental concerns and technological progressions. In this article, the historical developments of the LTTD process using several renewable and non-renewable energy sources have been reviewed. Finally, some future recommendations for further developments in this approach are discussed. This article paves the path for the researchers working in desalination to choose an appropriate LTTD approach that is more viable and sustainable than the conventional desalination systems. [ABSTRACT FROM AUTHOR]

Hydrothermal carbonization (HTC) is a promising and effective technology for upgrading the fuel quality of high‐moisture organic wastes. However, a large amount of energy is required to heat the feedstock to high temperature for HTC. Therefore, the maximum waste heat should be recovered to increase the energy efficiency of the HTC process. In this work, a flash‐organic Rankine cycle (FSPG‐ORC) system was coupled after HTC to recover the heat contained in the HTC slurry product. Various operating factors including the flashing temperature, the HTC temperature, the solid‐water ratio (S/W) of the feedstock, and the organic working fluids in the ORC section were studied to obtain their influences on thermodynamic performance of the coupled system. Results indicated that the net power (Wnet) of the FSPG‐ORC system increased from 185.64 to 774.30 kW through the increase of the HTC temperature from 160 to 280°C. In addition, the Wnet and exergy efficiency of the FSPG‐ORC system also increased with increasing the flashing temperature of HTC slurry product. The coupled FSPG‐ORC system converted waste heat to electric energy and increased the energy efficiency of the HTC process. [ABSTRACT FROM AUTHOR]

Copyright of Iraqi Journal of Chemical & Petroleum Engineering is the property of Republic of Iraq Ministry of Higher Education & Scientific Research (MOHESR) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

A novel route of a single flash thermal evaporation technique has been used for deposition of Cu(In,Ga)Se2. This route allows the deposition of stoichiometric CIGS layers direct from powder elements without selenization or any treatment. Structure, optical properties and surface morphology of the deposited films at various substrate temperatures have been investigated using X-ray diffraction (XRD) analysis, Raman spectroscopy, photospectroscopy, Scanning electron microscopy (SEM) and Atomic force microscopy. The structure and the optical properties of deposited films depend on the substrate temperatures which play crucial rule on the stoichiometry of the film by changing mainly the content of selenium. Increasing the substrate temperature improved the crystallinity of the films and the best stoichiometric film has been found at 220°C, the grain size increased from 146 to 286 Å, Whereas, the band gap reduced to 1.37 eV.

This contribution presents results from entrainment measurements in a forced circulation flash evaporator which was designed to systematically investigate the droplet entrainment under real evaporating conditions. Operating pressures in a range of 100 to 800 mbar(a) and temperature differences between 5 and 55 K were conducted. Gas load factors up to fG = 4.0 Pa0.5 were achieved with glycerol‐water and water as evaporating liquids. A conductivity measurement was used to determine the absolute entrained liquid and entrainment ratios. The results show an exponential behavior between entrainment, gas load factor, and heat flux due to superimposing effects. Investigation on the pressure drop across the orifice plate showed no influence for operation at gas load factors of fG < 2.5 Pa0.5. [ABSTRACT FROM AUTHOR]

• The influence of vacuum degrees and superheat degrees was considered. • A sphere model was established to reveal features of flash evaporation. • The initial diameters had more significant impact on drop rate of temperature. • The evaporation rate increased with the decrease of pressures. The effect of depressurized ambient condition on spray flash atomization process was of great importance. However, the process of droplet atomization and flash in depressurized environment was complex and coupled with a variety of physical and thermal behaviors. Thus, characteristics of jet flash atomization evaporation under a depressurized condition were mainly investigated in our present work. The experimental analysis and mathematical method were both adopted in order to consider the influence of factors (vacuum degree and superheat degree) on the spatial distribution of near-field region and the flash evaporation characteristics of far-field region. In particular, a laser particle sizer instrument was used to measure the droplets characteristics in the near-field region and a single sphere model of droplet was established to reveal features of flash evaporation process in the far-field region by the analysis of momentum transfer, heat transfer and mass transfer. The results showed that the droplets size distribution in the axial direction exhibited a fine uniform state, while it showed a disordered distribution in the radial direction of the near-field region analysis. In terms of the far-field region, velocity gradient still existed in far field according to the model analysis. The initial diameter had a more significant impact on drop rate of temperature reported at the initial temperature. Moreover, droplets with smaller diameter had a tendency to possess greater evaporation rate and this progress could be enhanced as decreasing the ambient pressure. The coupling process of jet atomization and flash evaporation could accelerate the temperature change process obviously and simultaneously thus promote the mass transfer. [Display omitted] [ABSTRACT FROM AUTHOR]

[Display omitted] • A method of solar-driven spray flash evaporation assisted by microencapsulated phase change material (MPCM) is proposed for solution regeneration. • The spray flash evaporation experimental platform working with NaCl-MPCM suspension is constructed. • The regeneration amount per unit mass flow rate of the NaCl-MPCM suspension is 24.8 g/kg, which is about 19 % higher than that of the NaCl solution. • This study aims to provide guidance for the efficient utilization of solar-driven flash evaporation assisted by MPCM. Solution regeneration belongs to a separation and purification technology for multi-component liquid systems, which is involved in many fields such as liquid desiccant air-conditioning, desalination, and sewage treatment. Solar-driven evaporation technology has enormous energy-saving potential in solution regeneration, but it has the disadvantages of instability and slow regeneration rate. In this work, the method of solar-driven spray flash evaporation assisted by microencapsulated phase change material (MPCM) is proposed for solution regeneration. The spray flash evaporation experimental platform working with NaCl-MPCM suspension is constructed, and the spray characteristics and heat and mass transfer characteristics of NaCl-MPCM suspension are examined under different operating parameters. The results show that the addition of MPCM to the solution can significantly improve its equivalent specific heat capacity, which mitigates dispersed and discontinuous defects of solar energy. Furthermore, it can effectively reduce the severe temperature drop of the solution during the flash evaporation process, which ensures a high driving potential difference between the solution and flash evaporation environment. It is worth mentioning that under the same operating conditions, the regeneration amount per unit mass flow rate of the NaCl-MPCM suspension (w MPCM = 10 wt%) is 24.8 g/kg, which is about 19 % higher than that of the NaCl solution. Additionally, the flash performance of the NaCl-MPCM suspension can be further improved by reducing the initial fluid velocity at the nozzle or the flash evaporation pressure. This study aims to provide guidance for the efficient utilization of solar-driven flash evaporation assisted by MPCM. [ABSTRACT FROM AUTHOR]

Low-rank coal drying plays a crucial role in achieving clean and efficient coal utilization. This study introduces steam flash drying, a novel method specifically designed for upgrading low-rank coal. Unlike conventional drying techniques, steam flash drying utilizes steam as the heat medium, generating a certain amount of condensation. This paper presents a comprehensive analysis of the calculated condensate quantity and the experimental measurement of coal particles' water-holding capacity to determine the initial moisture content before drying. Furthermore, the study investigates the steam flash drying effect on different-sized coal particles at a temperature of 497 K. The findings demonstrate that particles above 3 mm have lower water-holding capacity. The initial moisture content is determined by the particles' water-holding capacity and the combined raw coal water content and condensate content. The research reveals a diminishing flash-drying effect with increasing particle size, characterized by a rapid decrease followed by a gradual decline, observed at a critical point of 6 mm. By strategically adjusting the particle size distribution and employing mixing techniques, the coal drying effect can be significantly enhanced by 22%, ultimately leading to a remarkable 17% increase in processing capacity per unit volume. As a result, this study provides a theoretical foundation and optimization strategies for the clean and efficient utilization of coal through steam flash drying. [Display omitted] • A novel steam flash drying method utilizing steam as the heat medium was proposed. • An initial moisture content model was developed, incorporating both condensed water and water-holding capacity. • Steam flash drying proves effective for upgrading coarse-grained coal particles. • Strategic adjustment of particle size distribution enhances drying efficiency for 3-0 mm particles and boosts processing capacity. [ABSTRACT FROM AUTHOR]

Single‐source flash evaporation method has recently gained attention for its potential as a rapid and solvent‐free deposition method for producing organic–inorganic halide perovskite (OHP) films in large‐scale. However, due to a complex nature of the different experimental parameters involved in the deposition process, it is not straightforward to obtain the optimal condition for producing high‐quality OHP films. In this study, this problem is tackled by employing the design‐of‐experiment (DoE) process, which is an efficient statistical analysis for finding an optimized condition with a minimized number of experiments. The DoE process is used for optimizing the responsivity of the OHP photodetector devices against the input variables used in the deposition that yielded an enhanced responsivity of 112.2 mA W−1, which is up to an order of magnitude higher than that of the unoptimized devices. The experimental results using the DoE method provide not only the conditions required for enhancing the device performance but also the guidelines for improving the overall film quality through exploring the variable space of the flash evaporation technique. [ABSTRACT FROM AUTHOR]

According to the wet purified gas with a water molar fraction about 0.09% and the volume flow between 96×10³ m³ and 106×10³ m³, the TEG circulation rate is between 2.50 t/h and 2.85 t/h, and the water dew point of the exported product gas is below -19 ℃, which meets the water dew point requirements. When the steam consumption of TEG reboiler was between 529 kg/h and 549 kg/h, the TEG mass fraction increased from 96.9% to 99.7% after regeneration. In order to avoid the process defects such as unstable TEG regenerative heat source, serious scaling of poor solvent post-cooled tube heat exchanger, the dehydration process was optimized:(1) The self-produced 3.8 MPa medium-pressure steam was used as heat source to ensure stable TEG regeneration temperature and make it easy to adjust. The relation curve between the steam consumption and TEG reboiler temperature was fitted to provide a reference for adjustment. (2) The direct flash process without preheating of rich TEG was adopted to reduce the preheating process of rich liquid and remove most of light hydrocarbon components in rich TEG, so as to reduce energy consumption and cost while meeting the requirements of dehydration unit. (3)The TEG lean liquid after-cooler from shell and tube heat exchanger was replaced to corrugated plate heat exchanger made of stainless steel. The heat exchanger ran smoothly for a long time and the replacement frequency of heat exchanger accessories reduced. [ABSTRACT FROM AUTHOR]

This work discusses the influence of spray or feeder nozzle orientation on the production rate, non-equilibrium temperature difference (NETD), water quality, and flash efficiency of the evaporator of 100 m³/d capacity low-temperature thermal desalination plant. To investigate this, the flash evaporator of the Kavaratti LTTD plant was taken for the study which is located at UT Lakshadweep Islands. This plant is being operated continuously for supplying potable drinking water to the local Island community. In the present work totally three different nozzle orientations (upward, downward, horizontal) were tested for the performance analysis of the flash evaporation. Experimental studies were conducted for different operating conditions and relevant data were collected for comparative analysis. It was observed that the orientation of the feeder or spray nozzle significantly influences the production rate, NETD, product water quality, and flash efficiency in the evaporator, and the mechanism responsible for variation in the performance of flash evaporation with respect to feeder orientation is also discussed. Upward nozzle delivers a good performance of up to 1.4 times the evaporation rate, 85%--90% flash efficiency, and lowest thermal loss (NETD) of 0.69°C to 0.75°C compared to horizontal and downward nozzle orientations. As far as product water quality is concerned, the downward-facing nozzle gives better quality or low salinity product water than the other two nozzle orientations. [ABSTRACT FROM AUTHOR]

• The flow of R600a through capillary tubes was visualized with a high-speed camera. • The flow was found to be a predominantly inhomogeneous slug flow. • FEP and copper capillaries provide a similar pressure drop and mass flow rate. • A discrete jump in the vaporization point was achieved by creating imperfections. • Different surface textures could influence the homogeneity of the flow. This paper presents the results of an experimental study of the flow visualization of the refrigerant R600a through a capillary tube with an internal diameter of 0.8 mm made from a FEP (fluorinated ethylene propylene) polymer that was installed in a small-scale, vapor-compression refrigeration system. The main purpose of the study was to determine the flow patterns of the refrigerant flow in capillary tubes under different operating conditions and to verify whether the results obtained using a FEP tube are representative for the flow of a refrigerant in copper capillary tubes. The results of the study revealed that the two-phase refrigerant flow in the FEP capillary tubes consists predominantly of slug flow. These slugs continuously expand while traveling downstream. It was also found that different operating conditions can have a strong influence on the frequency of the vapor bubbles' formation and their growth. In addition, an experimental study of the effect of local or global imperfections on the inner surface of the FEP tube was performed. In some cases the imperfections increased the number of vapor-bubble inception points, which caused a homogenization of the two-phase flow. [ABSTRACT FROM AUTHOR]

Summary: This study is purposed to conduct experimental investigation into the characteristics of vacuum flash evaporation with nanofluid under adsorption conditions, with the effects of nanoparticle concentration, surfactant concentration, and nanofluid stability taken into consideration. By measuring absorbency, solute concentration, and sedimentation graph, a new nanofluid with excellent dispersion was developed for the vacuum ice‐making system. It has been demonstrated that the low concentration of additive is conductive to not only the maintenance of vacuum but also the generation of binary ice. For nanofluid, there are two distinct freezing stages in the process of vacuum flash evaporation. The supercooling stage of nanofluid is delayed with the increase of surfactant concentration, whereas the TiO2 nanofluid applied to the vacuum ice‐making system under adsorption shows stability. Moreover, it is indicated that, for the vacuum ice‐making system with TiO2 nanofluid, the pH level is around 8.5, the surfactant is sodium dodecyl benzene sulfonate‐span 60 (SDBS‐SPAN), the ratio of SDBS to SPAN is about 10:7, the concentration of TiO2 nanoparticle is around 0.20 wt%, and the ratio of TiO2 nanoparticle to SDBS‐SPAN is about 10:5. Compared with pure water, undercooling is reduced by 77.92%; the ice packing factor and thermal conductivity are increased by 40.61% and 67.27%, respectively. The results of test and analysis can be applied to conduct further research on vacuum flash evaporation. [ABSTRACT FROM AUTHOR]

Shape memory alloy coating on an optical fiber plays an important role in developing novel active thermal sensors in the field of microelectromechanical systems. In this article, a detailed analysis of NiTi alloy deposited over plastic optical fiber was discussed. A detailed investigation of the morphological, structural, and thermal properties of the NiTi-coated optic fiber was conducted. The uniformity, crystallinity, transformation temperatures, and thermal stability of the coatings were measured using differential scanning calorimetry, scanning electron microscopy, X-ray diffraction, and thermogravimetric analysis, respectively. Also, an electrical actuation setup thermo-mechanical test was conducted through Joule heating in which different voltages at varying loads have been used. The sensor characteristic–based parameters (time response and sensitivity) were also calculated. The article presents a complete analysis of experimental results showing the properties and performances of the plastic optical fiber after coating with shape memory alloy. [ABSTRACT FROM AUTHOR]

A novel route of a single flash thermal evaporation technique has been used for deposition of Cu(In,Ga)Se2. This route allows the deposition of stoichiometric CIGS layers direct from powder elements without selenization or any treatment. Structure, optical properties and surface morphology of the deposited films at various substrate temperatures have been investigated using X-ray diffraction (XRD) analysis, Raman spectroscopy, photospectroscopy, Scanning electron microscopy (SEM) and Atomic force microscopy. The structure and the optical properties of deposited films depend on the substrate temperatures which play crucial rule on the stoichiometry of the film by changing mainly the content of selenium. Increasing the substrate temperature improved the crystallinity of the films and the best stoichiometric film has been found at 220°C, the grain size increased from 146 to 286 Å, Whereas, the band gap reduced to 1.37 eV. [ABSTRACT FROM AUTHOR]

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In this study, we employed the flash evaporation method to deposit thin films of pure copper sulfide and cobalt-doped copper sulfide. We focused on evaluating the influence of cobalt content, ranging from zero to 9 % , on the structural, optical, electrical, and thermoelectric characteristics of the synthesized thin films. Our findings indicate that the passage from the copper-rich (covellite phase to the digenite or djurleite phases) can be carried out by annealing or by doping. Raman's investigation supports the discovered phase and shows that the A 1g (LO) mode intensity drops with doping. The gap energy was found to decrease by increasing the percentage of cobalt. The annealing at 350 °C resulted in good thermoelectric properties, while the dominance of the djurleite phase, resulted in the highest Seebeck coefficients. [ABSTRACT FROM AUTHOR]