Letteratura scientifica selezionata sul tema "Spray Flash Evaporation (SFE)"
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Articoli di riviste sul tema "Spray Flash Evaporation (SFE)"
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Berthe, Jean-Edouard, Fabien Schnell, Yannick Boehrer e Denis Spitzer. "Nanocrystallisation of Ammonium DiNitramide (ADN) by Spray Flash Evaporation (SFE)". Propellants, Explosives, Pyrotechnics 43, n. 6 (24 maggio 2018): 609–15. http://dx.doi.org/10.1002/prep.201800039.
Testo completo
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Lobry, Emeline, Jean-Edouard Berthe e Denis Spitzer. "Spray flash evaporation SFE process: Identification of the driving parameters on evaporation to tune particle size and morphology". Chemical Engineering Science 231 (febbraio 2021): 116307. http://dx.doi.org/10.1016/j.ces.2020.116307.
Testo completo
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Coty, Jean-Baptiste, Cédric Martin, Isabella Telò e Denis Spitzer. "Use of Spray Flash Evaporation (SFE) technology to improve dissolution of poorly soluble drugs: Case study on furosemide nanocrystals". International Journal of Pharmaceutics 589 (novembre 2020): 119827. http://dx.doi.org/10.1016/j.ijpharm.2020.119827.
Testo completo
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Okazaki, Takahiro, Zensaku Kawara, Takehiko Yokomine e Tomoaki Kunugi. "Enhancement of MSF Using Microbubbles". International Journal of Chemical Reactor Engineering 13, n. 4 (1 dicembre 2015): 469–75. http://dx.doi.org/10.1515/ijcre-2014-0169.
Testo completoAbstract (sommario):
Abstract Multi Stage Flash (MSF) distillation plants are widely used in saline water desalination. In order to enhance MSF, it is important to increase an evaporation rate in the flashing stage. A spray flash method, in which superheated water jets are injected through nozzles into a depressurized environment to increase the gas/liquid interface area, is a promising technique to make the increase of evaporation rate, which leads directly to the reduction of energy consumption and cost of the MSF plant. In this paper, the introduction of microbubbles into the spray jet as the nucleation sites to increase the evaporation rate of the spray flash is proposed. The spray flash behaviours with/without microbubbles at outside/inside of the nozzle-inside were observed by means of a high speed camera to investigate the mechanism of enhancement of spray flash due to microbubbles. Moreover, the number densities of droplets and bubble volume increase were obtained from visualized images in order to discuss quantitatively on the effects of introduction of microbubbles.
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Ma, Wei, Siping Zhai, Ping Zhang, Yaoqi Xian, Lina Zhang, Rui Shi, Jiang Sheng, Bo Liu e Zonglin Wu. "Research Progresses of Flash Evaporation in Aerospace Applications". International Journal of Aerospace Engineering 2018 (17 dicembre 2018): 1–15. http://dx.doi.org/10.1155/2018/3686802.
Testo completoAbstract (sommario):
Liquid is overheated and evaporated quickly when it enters into the environment with lower saturation pressure than that corresponding to its initial temperature. This phenomenon is known as the flash evaporation. A natural low-pressure environment and flash evaporation have unique characteristics and superiority in high altitude and outer space. Therefore, flash evaporation is widely used in aerospace. In this paper, spray flash evaporation and jet flash evaporation which are two different forms were introduced. Later, key attentions were paid to applications of flash evaporation in aerospace. For example, the flash evaporation has been used in the thermal control system of an aircraft and the propelling system of a microsatellite and oil supply system of a rocket motor. Finally, the latest progresses in the calculation model and numerical simulation of flash evaporation were elaborated.
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Sève, Aymeric, Vincent Pichot, Fabien Schnell e Denis Spitzer. "Trinitrotoluene Nanostructuring by Spray Flash Evaporation Process". Propellants, Explosives, Pyrotechnics 42, n. 9 (7 giugno 2017): 1051–56. http://dx.doi.org/10.1002/prep.201700024.
Testo completo
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Zheng, Lei, Haizhou Xu, Hao Fu, Hua Chen e Wenlong Cheng. "Experiment and simulation study on the characteristics of pressure swirl nozzle flash spray under the influence of superheat". Journal of Physics: Conference Series 2683, n. 1 (1 gennaio 2024): 012036. http://dx.doi.org/10.1088/1742-6596/2683/1/012036.
Testo completoAbstract (sommario):
Abstract The good atomization performance of the pressure swirl nozzle makes it widely used in the fuel injection device of the internal combustion engine. Flash spray caused by fuel inlet superheat can affect spray and combustion characteristics. In this paper, a spray parameter measurement system is set up, combined with phase Doppler particle analysis (PDPA) technology to research the effect of superheat on spray velocity and droplet diameter distribution. To improve the safety of the experiment, Methyl Nonafluorobutyl Ether (HFE7100) with a boiling point of 61°C was used as the spray fluid. The cavitation model and VOF model are used to simulate the pressure swirl nozzle flash spray. The results show that when the temperature changes from 40°C to 60°C, the velocity of spray droplets increases and the particle size decreases under the action of weak evaporation; When the temperature changes from 60°C to 70°C, the evaporation mode is dominated by flash, making the droplet velocity at the spray center greatly increase and the velocity distribution change from saddle-shaped distribution to unimodal distribution. The droplet diameter increases, which may be due to the expansion of the droplet caused by the formation of bubbles inside the droplet under the action of flash.
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Miyatake, Osamu, e Yasuhiro Miki. "Simplified expression for efficiency of spray flash evaporation." KAGAKU KOGAKU RONBUNSHU 13, n. 2 (1987): 252–56. http://dx.doi.org/10.1252/kakoronbunshu.13.252.
Testo completo
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Chen, Mengrong, Yue Xie, Mengjun Gong, Xinyu Zhang e Yong Ren. "Numerical study of spray cooling with flash evaporation". Journal of Physics: Conference Series 2454, n. 1 (1 marzo 2023): 012012. http://dx.doi.org/10.1088/1742-6596/2454/1/012012.
Testo completoAbstract (sommario):
Abstract This work aims to apply Computational Fluid Dynamic (CFD) method to establish a flash evaporation spray cooling (FESC) model to simulate the heating process and find the optimum cooling performance. The heat transfer process during FESC is studied through numerical simulation using commercial code ANSYS FLUENT. The species transport model and the discrete phase model are applied to simulate the multiphase flow and heat transfer process. The turbulence effect is included. The effects of flow rate, nozzle pressure, nozzle angle, and the nozzle orifice size on spray cooling are investigated through analyzing the final surface temperature distributions. This work revealed the mechanism of the heat transfer process in FESC by means of particle tracks and velocity magnitude distribution. The simulated results for the effect of flow rate were compared with other researchers’ previous published experimental results. The comparison shows same trend, which verified the model and the simulation result. The optimum cooling performance is found by analyzing various working conditions. The results show that high flow rate, high nozzle pressure, small nozzle angle and small nozzle orifice can improve the FESC characteristics. The detailed mechanisms of these effects under various working conditions are also discussed. Under giving working conditions, the optimum cooling performance is obtained for the condition where mass flow rate of working fluid is 2L/min, the nozzle pressure is 100MPa, the nozzle angle is 15 degrees and the orifice size of the nozzle is 1mm.
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Ding, Hong Yuan, Peng Deng, Xu Yao Mao e Chao Wu. "Flash Boiling Spray Simulation Based on Void Fraction and Superheat Controlling". Applied Mechanics and Materials 737 (marzo 2015): 289–95. http://dx.doi.org/10.4028/www.scientific.net/amm.737.289.
Testo completoAbstract (sommario):
A new flash boiling spray model whose atomization criterion based on the void fraction and superheat while evaporation model based on the dual-zone method is established to simulate the flashing sprays. The model function is implemented in KIVA program. Flash boiling spray model predicts spray penetration and spray cone angle and its development trend, in good agreement with the experimental results. The model has a good capability in simulating flash sprays at low superheat conditions, which breakup is controlled by void fraction, as well as high superheat transition process. It can also predict flare flashing sprays to some extent at higher superheat conditions.
Tesi sul tema "Spray Flash Evaporation (SFE)"
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Vince, Maxence. "Analyses in situ et approche paramétrique du procédé Spray Flash Evaporation pour l’élaboration d’hexolites". Electronic Thesis or Diss., Strasbourg, 2024. http://www.theses.fr/2024STRAE018.
Testo completoAbstract (sommario):
Les nanodiamants (NDs) font l'objet de recherches intenses dans les domaines biomédical, militaire et de la mécanique quantique. Pour produire ces NDs, le recours à la détonation d'un mélange RDX/TNT, aussi appelé hexolite, est souvent préféré. Cependant, pour produire des NDs aux propriétés physico-chimiques performantes, il est nécessaire d’avoir au préalable des particules fines d’hexolites, et des mélanges intimes et homogènes. Pour parvenir à cela, le laboratoire NS3E a développé le procédé de recristallisation par évaporation flash de spray (Spray Flash Evaporation, SFE). Cependant, l'influence des différentes conditions opératoires du procédé sur les caractéristiques physico-chimiques des particules est encore mal comprise. Améliorer cette compréhension permettrait une plus grande maîtrise des propriétés des particules recristallisées. Cette thèse vise donc, à l'aide d'analyses in situ telles que l'ombroscopie et le PDPA (Phase Doppler Particle Analyzer), à apporter des réponses. Les recherches se structurent en deux axes principaux. Le premier axe explore en profondeur les phénomènes physico-chimiques de l'évaporation flash d'un solvant (acétone) et l'impact du soluté (hexolite) sur le comportement du spray d'acétone. Le second axe porte quant à lui sur la caractérisation des particules d'hexolite, notamment en ce qui concerne leur sensibilité, leur taille et leur morphologie et les raisons qui ont conduit à de telles propriétés par rapport au comportement du sprayNanodiamonds (NDs) are the subject of extensive research in biomedical, military, and quantum mechanics applications. To produce these NDs, the detonation of a RDX/TNT mixture, commonly referred to as hexolite, is frequently employed. However, to achieve NDs with high-performing physicochemical properties, it is essential to begin with finely divided hexolite particles and to ensure that the mixture is both intimate and homogeneous. In pursuit of this goal, the NS3E laboratory has developed a recrystallization process based on Spray Flash Evaporation (SFE). Despite this advancement, the influence of various operating conditions on the physicochemical characteristics of the resulting particles remains poorly understood. Gaining a deeper understanding of these influences would enable more precise control over the properties of the recrystallized particles. This thesis therefore aims to address these issues by employing in situ analytical techniques, such as shadowgraphy and Phase Doppler Particle Analysis (PDPA).The research is organized around two principal axes. The first focuses on an in-depth investigation of the physicochemical phenomena underlying the flash evaporation of a solvent (acetone) and examines how the presence of a solute (hexolite) affects the behavior of the acetone spray. The second axis centers on characterizing the resulting hexolite particles—specifically their sensitivity, size, and morphology—and elucidating the underlying reasons for these properties considering the spray’s behavior
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Fathinia, Farshid. "A study into the effects of spray and jet characteristics on flash evaporation system". Thesis, Edith Cowan University, Research Online, Perth, Western Australia, 2020. https://ro.ecu.edu.au/theses/2342.
Testo completoAbstract (sommario):
Low temperature flash evaporation desalination is a separation system that isolates liquids from other materials when seawater or any fluid undergoes evaporation. Extreme flash evaporation occurs when a low heated liquid is injected into the vacuum area, where the pressure is far below the saturated pressure of the liquid entering the area. This approach of flash evaporation is a key part of this type of system. It has a great potential to develop and improve the implementation of low thermal desalination plants but requires more specific study. Further analysis shows that previous investigations have not given a comprehensive insight into the atomization of sprays or jets in seawater flashing spray desalination. Alternatively, most of the earlier research focused at the macro scale whereby the general process of flashing and its performance was studied. Little or no information is available on the droplet characteristics in spray and jet flash evaporation due to the difficulty of experimental exploration.
In this research study, the effect of operating conditions such as initial temperature, inlet flow rate, superheat degree, nozzle diameter, and salinity of the saltwater on the temperature distribution and evaporation rate of flashing spray is explored and comparisons are made between the results of the present experiments and previous studies. In order to simplify the design of the flash chamber and estimating the evaporation rate, spray angle and droplet size (two important characteristics of spray nozzles) have been analysed using a high-speed camera. These experimental measurements are also compared with mathematical calculation of droplet sizes. In addition, some other experiments have been done to improve the performance of system by utilizing a multi-nozzle head in various arrangements. Investigation of difference between the jet and spray nozzles having single and multiple arrangements is also performed under various operational conditions
The result concluded that flow rate has a different effect on the evaporation rate depending on whether spray or jet flash evaporation is taking place. Increasing the flow rate in sprays leads to higher flash evaporation but lowers the evaporation rate in jets. The spray angle as one of the most important characteristics of the spray is also largely affected by the superheat degree regardless of nozzle type and empirical equation is suggested to correlate this parameter with inlet pressure, saturation pressure. Furthermore, placing nozzles in the farthest distance of each other on the multi-nozzle head leads to maximum 28% performance improvement compared to the conventional single nozzle. At the end of research, it is found that the evaporation rate and gain output ratio of the system using spray nozzle in both single and multiple nozzles are higher than the jet nozzle. This research will contribute to better understanding and development of thermally driven desalination plants.
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Berthe, Jean-Edouard. "Amélioration des explosifs par ajustement de leur balance en oxygène lors de la cristalisation par Evaporation Flash de Spray". Thesis, Strasbourg, 2018. http://www.theses.fr/2018STRAE023/document.
Testo completoAbstract (sommario):
Dans la littérature, que ce soit pour un explosif secondaire ou un matériau composite, une balance en oxygène (BO) proche de 0% est assimilée à de bonnes performances énergétiques (vitesse de détonation, chaleur de décomposition, etc…). L’objectif majeur de cette thèse est d’améliorer les performances énergétiques d’explosifs secondaires courants (RDX, HMX, CL-20) par l’ajout d’un oxydant (DNA) afin d’obtenir un matériau composite avec une BO de -1%. Le mélange intime de ces deux composés est permis par un procédé d’évaporation flash de spray, utilisé habituellement pour réduire la taille de particules des explosifs. Les matériaux composites ont été cristallisés dans les trois cas avec succès, avec la présence d’explosif submicrométrique et de DNA nanostructuré. Un tel résultat a été permis grâce à une meilleure compréhension du procédé, et en conséquence l’ajustement des conditions expérimentales. L’étude de la réactivité de ces matériaux composites montre dans certains cas une désensibilisation, une diminution de la distance de la déflagration à la détonation, ou encore une augmentation de la vitesse de détonation, comparée aux explosifs correspondantsIn literature, for secondary explosive or composite material, an oxygen balance (OB) close to 0% is often linked to good energetic performances (detonation velocity, heat of decomposition, etc.). The main objective of this thesis is to enhance energetic performances of current secondary explosives (RDX, HMX, CL-20) by adding oxidizer (ADN) to obtain a composite material with an OB of -1%. The spray flash evaporation process, usually used for particle size reduction of explosives, enables to obtain an intimate mixture of these two compounds. Composite materials were successfully crystallized in three cases, resulting of submicrometric explosives and nanostructured ADN particles. These results were obtained thanks to a preliminary study for better process understanding and the optimization of experimental conditions. Reactivity studies show some desensitization, shorter distance from deflagration to detonation, and/or higher detonation velocity, compared to corresponding explosives
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Pessina, Florent. "Toward particle size reduction by spray flash evaporation : the case of organic energetic crystals and cocrystals". Thesis, Strasbourg, 2016. http://www.theses.fr/2016STRAE031/document.
Testo completoAbstract (sommario):
La cristallisation en continu de nanoparticules énergétiques est un défi de longue date. Le Spray Flash Evaporation (SFE) est une technique majeure développée et brevetée en interne, pour la production en continu de matériaux énergétiques submicroniques ou nanométriques ; la technologie se base sur la surchauffe d’un solvant pulvérisé dans le vide et s’évaporant de manière flash. Ce présent travail de recherche a pour but de comprendre et contrôler la cristallisation au sein du procédé SFE. Le RDX et le cocristal CL-20:HMX 2:1 sont étudiés. La sursaturation, concernant le SFE, est une fonction du temps et de l’espace liée aux tailles et vitesses de gouttes : elle fut variée par un anti-solvant et par l’amélioration du SFE avec un système double buse. Ensuite, PVP 40K et PEG 400 ont été utilisés afin de contrôler la nucléation et la croissance. Les particules ont pu être ajustées d’une taille de 160 nm à 5 µm, avec des morphologies facettées ou sphériques et avec des sensibilités moindresThe continuous formation of nanosized energetic material is a long-standing challenge. Spray Flash Evaporation (SFE) is a major technique, internally developed and patented, for continuously producing energetic materials at submicron or nano scale; it relies on the superheating of a solvent sprayed into vacuum and thus flashing. This present research project aims to understand and control the crystallisation occurring in the SFE process. RDX and the cocrystal CL-20:HMX 2:1 was studied overcome the limited in situ characterizations also. The supersaturation is a function of time and space in SFE, linked to the size distribution and velocity of droplets. Supersaturation was raised with an anti-solvent and by the enhancement of the SFE with a dual nozzle system. Then PVP 40K and PEG 400 were successfully used to alter the nucleation and the growth. The particles were subsequently tuned from 160 nm spheres to 5 µm grains and were less sensitive, especially toward electrostatic discharge
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Le, Brize Axel. "Etude de la nanostructuration de matériaux énergétiques multi-composants pour application aux poudres propulsives à sensibilités réduites". Thesis, Strasbourg, 2017. http://www.theses.fr/2017STRAE020/document.
Testo completoAbstract (sommario):
Les travaux de thèse présentés dans ce manuscrit ont porté sur l’élaboration et la caractérisation de poudres propulsives à sensibilités réduites. Ceci a été effectué par l’utilisation de matériaux énergétiques relativement insensibles ainsi que par l’emploi du procédé de Spray Evaporation Flash (SFE). Ce dernier a permis d’obtenir des poudres nanostructurées de composition ternaire. La caractérisation de ces poudres propulsives par spectroscopie Raman a permis de mettre en évidence le mécanisme de plastification de la nitrocellulose par les plastifiants employés. Des analyses de microscopie électronique à balayage ont été menées pour étudier la granulométrie de ces échantillons. Leur caractérisation par diffraction des rayons X a permis d’étudier leur structure et leur cristallisation. Des mesures de calorimétrie différentielle à balayage, des essais de tirs en tubes et en bombe manométrique, ainsi que des mesures de sensibilités à divers types de sollicitations, ont permis de montrer que les poudres obtenues sont particulièrement insensiblesThe PhD thesis presented in this manuscript focused on the elaboration and characterization of propellants with reduced sensitivities. This was accomplished by the use of relatively insensitive energetic materials, in conjunction with the application of the Spray Flash Evaporation (SFE) process. The latter made it possible to obtain nanostructured propellants of ternary composition.The characterization of these propellants by Raman spectroscopy revealed the mechanisms ruling the plasticization of nitrocellulose by the plasticizers used. Scanning electron microscopy analyzes were conducted to determine the particle size of these samples. Their characterization by X-ray diffraction allowed to study their structure and their crystallization. These propellants were shown to be particularly insensitive through analyses by differential scanning calorimetry,pyrotechnic tests in tubes and manometric vessels as well as sensitivity measurements to various types of solicitations
Capitoli di libri sul tema "Spray Flash Evaporation (SFE)"
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Gärtner, Jan Wilhelm, Daniel D. Loureiro e Andreas Kronenburg. "Modelling and Simulation of Flash Evaporation of Cryogenic Liquids". In Fluid Mechanics and Its Applications, 233–50. Cham: Springer International Publishing, 2022. http://dx.doi.org/10.1007/978-3-031-09008-0_12.
Testo completoAbstract (sommario):
AbstractRocket engine manufacturers attempt to replace toxic, hypergolic fuels by less toxic substances such as cryogenic hydrogen and oxygen. Such components will be superheated when injected into the combustion chamber prior to ignition. The liquids will flash evaporate and subsequent mixing will be crucial for a successful ignition of the engine. We now conduct a series of DNS and RANS-type simulations to better understand this mixing process including microscopic processes such as bubble growth, bubble-bubble interactions, spray breakup dynamics and the resulting droplet size distribution. Full scale RANS simulations provide further insight into effects associated with flow dynamic such as shock formation behind the injector outlet. Capturing these gas dynamic effects is important, as they affect the spray morphology and droplet movements.
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Rees, Andreas, e Michael Oschwald. "Experimental Investigation of Transient Injection Phenomena in Rocket Combusters at Vacuum with Cryogenic Flash Boiling". In Fluid Mechanics and Its Applications, 211–31. Cham: Springer International Publishing, 2022. http://dx.doi.org/10.1007/978-3-031-09008-0_11.
Testo completoAbstract (sommario):
AbstractThe substitution of the toxic hydrazine in current high-altitude rocket engines like upper stages or reaction control thrusters by green propellants is a major key driver in the current technology development of rocket propulsion systems. Operating these kind of rocket engines at high-altitude leads to a sudden pressure drop in the liquid propellants during their injection into the combustion chamber with a near-vacuum atmosphere prior to ignition. The resulting superheated thermodynamic state of the liquid causes a fast and eruptive evaporation which is called flash boiling. The degree of atomisation is important for a successful ignition and a secure operation of the rocket engine. The development and operation of a cryogenic high-altitude test bench at DLR Lampoldshausen enables the systematical experimental characterization of cryogenic flash boiling due to its ability to adjust and control the injection parameters like temperature, pressure or geometry. Several test campaigns with liquid nitrogen (LN2) were performed using two optical diagnostic methods: First, flash boiling LN2 spray patterns were visualised by means of high-speed shadowgraphy and, secondly, we determined the droplet size and velocity distributions in strongly superheated LN2 sprays with the help of a laser-based Phase Doppler system (PDA). The experimental data generated within these measurement campaigns provide defined boundary conditions as well as a broad data base for the numerical modelling of cryogenic flash boiling like e.g. the publications [8, 9].
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Schwartz, C., M. Comet, F. Schnell e D. Spitzer. "The Properties of Detonating Compositions Prepared from Submicron KClO4 and TiH2". In Future Developments in Explosives and Energetics, 158–63. Royal Society of Chemistry, 2023. http://dx.doi.org/10.1039/9781839162350-00158.
Testo completoAbstract (sommario):
A new kind of THKP was prepared by combining submicron potassium perchlorate made by the Spray Flash Evaporation (SFE) process with titanium hydride. Spray Flash Evaporation is based on flash evaporation to manufacture nanoparticles. The solvated product is nebulized in a chamber, which is maintained under vacuum, thanks to an atomization nozzle. The sudden fall of pressure induces a flash evaporation of the solvent and then crystallization of the product in the form of nanosized particles. This process was used on potassium perchlorate in order to produce nanosized particles of this product. This new type of potassium perchlorate prepared by SFE shows a particle size ranging from 50 to 400 nm. With this submicron sized potassium perchlorate, a better oxidation of titanium hydride was observed and also a transition to detonation in the THKP. This detonation transition was noted when the THKP is placed in a small diameter tube (3 mm) in loose powder. In the same time, the detonation velocity of this type of THKP increased to a value of approximatively 1250 m/s with a porosity of 86%. In comparison, micron sized potassium perchlorate in THKP tested in the same condition, no transition to detonation was observed and sometimes combustion stops. The sensitivities of THKP prepared with submicron sized potassium perchlorate are relatively high with an impact sensitivity of 44.7 J, a friction sensitivity of 192 N and an electrostatic discharge sensitivity of 34.7 mJ. THKP mixtures prepared from submicron potassium perchlorate can be classified as low-sensitivity primary explosives.
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Schwartz, C., M. Comet, F. Schnell e D. Spitzer. "The Properties of Detonating Compositions Prepared from Submicron KClO4 and TiH2". In Future Developments in Explosives and Energetics, 158–63. Royal Society of Chemistry, 2023. http://dx.doi.org/10.1039/9781788017855-00158.
Testo completoAbstract (sommario):
A new kind of THKP was prepared by combining submicron potassium perchlorate made by the Spray Flash Evaporation (SFE) process with titanium hydride. Spray Flash Evaporation is based on flash evaporation to manufacture nanoparticles. The solvated product is nebulized in a chamber, which is maintained under vacuum, thanks to an atomization nozzle. The sudden fall of pressure induces a flash evaporation of the solvent and then crystallization of the product in the form of nanosized particles. This process was used on potassium perchlorate in order to produce nanosized particles of this product. This new type of potassium perchlorate prepared by SFE shows a particle size ranging from 50 to 400 nm. With this submicron sized potassium perchlorate, a better oxidation of titanium hydride was observed and also a transition to detonation in the THKP. This detonation transition was noted when the THKP is placed in a small diameter tube (3 mm) in loose powder. In the same time, the detonation velocity of this type of THKP increased to a value of approximatively 1250 m/s with a porosity of 86%. In comparison, micron sized potassium perchlorate in THKP tested in the same condition, no transition to detonation was observed and sometimes combustion stops. The sensitivities of THKP prepared with submicron sized potassium perchlorate are relatively high with an impact sensitivity of 44.7 J, a friction sensitivity of 192 N and an electrostatic discharge sensitivity of 34.7 mJ. THKP mixtures prepared from submicron potassium perchlorate can be classified as low-sensitivity primary explosives.
Atti di convegni sul tema "Spray Flash Evaporation (SFE)"
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Qiu, Shuyi, Shangning Wang, Xuesong Li, Min Xu e Mohamed Nour. "Quantitative Analysis of Fuel Film Formation and Evolution Following Spray Impingement". In SAE 2024 Vehicle Powertrain Diversification Technology Forum. 400 Commonwealth Drive, Warrendale, PA, United States: SAE International, 2025. https://doi.org/10.4271/2025-01-7045.
Testo completoAbstract (sommario):
<div class="section abstract"><div class="htmlview paragraph">Flash boiling spray has exhibited remarkable atomization performance by utilizing the sudden alterations in the thermodynamic state of the fluid during injection. The notable evaporation properties of flash boiling spray provide potential remedies for the problem of fuel film adhesion resulting from spray-wall impingement, especially during cold starts in reciprocating engines. Multi-hole injectors, which are often employed, frequently experience spray collapse under flash boiling conditions. The collapsing spray impinging a wall involves a complex multi-phase coupling mechanism. Once the spray impinges the wall, the heat and mass transfer between the wall and the adhering liquid film complicates the predictability of the fuel film characteristics. The quantitative evaluation of fuel film is crucial for studies on wall impingement. Nonetheless, the quantitative measurement of phase change fuel films necessitates addressing multiple problems, including evaporation and vapor phase interference. This work utilizes Mie scattering photography and Laser-Induced Exciplex Fluorescence (LIEF) techniques to examine the multi-plume spray impingement process. The impacts of the flash boiling superheat index and wall temperature were examined, alongside a quantitative analysis of the evolutions in the thickness, area, mass, and temperature of the adherent fuel film. The study results indicate that the spray collapses at a low superheat index. High fuel temperature diminishes liquid volume flux, hence reducing the mass of droplet impinging on the wall. The mass of the deposited fuel film reduces with an increase in fuel temperature, but low plate temperatures hinder evaporation and increase the mass of fuel film. The interplay of impinging droplets and evaporation governs fuel film’s thickness and temperature. Under flare flash boiling conditions, even with a plate temperature of -25°C, the adhered film comprising merely 4% of the total injected fuel.</div></div>
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Liu, Yifu, Yang Yu, Xinghui Hou e Zhijun Wu. "Effects of Water Addition on Flash-Boiling Spray of Gasoline and Gasoline/Water Mixtures". In WCX SAE World Congress Experience. 400 Commonwealth Drive, Warrendale, PA, United States: SAE International, 2023. http://dx.doi.org/10.4271/2023-01-0307.
Testo completoAbstract (sommario):
<div class="section abstract"><div class="htmlview paragraph">To improve the thermal efficiency and inhibit the knock tendency of gasoline direct injection (GDI) engines, water injection technology has a bright application prospect. Utilize gasoline/water mixture as a way to realize this technology can lower the cost of modifying the engines and bring potential for better spray qualities. Hence it is essential to give deep insight into the effects of water on spray atomization, evaporation and mixture formation for gasoline/water mixtures. A spray synchronous measurement experimental system with a single hole nozzle is used to investigate the spray morphology, spray width and droplet size distribution of gasoline/water mixtures sprays under different water volume fractions (0 %, 20 %, 35 %) and different initial fuel temperatures (50 °C~ 130 °C). There are critical temperatures of 80 °C(G100), 100 °C(G80) and 120 °C(G65), above which the ‘collapsed’ spray appears. Noticeably, unlike the collapsed spray caused by jet-jet interactions in the multi-hole nozzles. In this article, the referred ‘collapsed’ spray has a smoother and more curved leading edge. The ‘collapsed’ spray pattern appears because finer droplets appear at high-temperature conditions and the aggregations of small droplets are rarer. The study of the spray width shows that the influence of water is two-sided and more evident under flash boiling conditions. The intensity of spray ‘collapse’ increases with fuel temperature and decreases with water volume fraction. Spray width variation within the axial of 5 mm is revealed by calculating heterogeneous nucleation rate and is mainly related to bubble growth and breakup under flash boiling conditions. The microscopic exploration demonstrates when spray enters flash boiling state, Sauter mean diameter (SMD) falls slightly. However, when fuel temperature reaches the critical temperature, spray enters ‘collapsed’ state and SMD drops drastically. For instance, when G80 spray transforms into flash boiling and ‘collapsed’ state, SMD decreases by 6.05 % and 61.43 % respectively.</div></div>
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Schmehl, Roland, e Johan Steelant. "Flash-Evaporation of Oxidizer Spray During Start-Up of an Upper-Stage Rocket Engine". In 39th AIAA/ASME/SAE/ASEE Joint Propulsion Conference and Exhibit. Reston, Virigina: American Institute of Aeronautics and Astronautics, 2003. http://dx.doi.org/10.2514/6.2003-5075.
Testo completo
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Shen, Li, e Felix Leach. "Effect of Ambient Pressure on Ammonia Sprays Using a Single Hole Injector". In WCX SAE World Congress Experience. 400 Commonwealth Drive, Warrendale, PA, United States: SAE International, 2024. http://dx.doi.org/10.4271/2024-01-2618.
Testo completoAbstract (sommario):
<div class="section abstract"><div class="htmlview paragraph">Ammonia has received attention as an alternative hydrogen carrier and a potential fuel for thermal propulsion systems with a lower carbon footprint. One strategy for high power density in ammonia applications will be direct injection of liquid ammonia. Understanding the evaporation and mixing processes associated with this is important for model development. Additionally, as a prior step for developing new injectors, it is of interest to understand how a conventional gasoline direct injection (GDI) injector would behave when used for liquid ammonia without any modifications. Pure anhydrous ammonia, in its liquid form, was injected from a single hole GDI injector at a fuel pressure of 150 bar into an optically accessible constant volume chamber filled with nitrogen gas for ammonia spray measurements. The chamber conditions spanned a wide range of pressures from 3 − 15 bar at an increment of 1 bar or 2 bar between the test points. These conditions lead to sprays which are both flash boiling and non-flash boiling as well as in a transition region. Spray morphology studies were performed based on high-speed backlit images recorded at 10 kFPS. Droplet size distributions for the bulk spray were simultaneously measured using a laser diffraction technique at the same sampling rate. The results show that at a higher ambient pressure, shorter spray penetration lengths and smaller spray spread widths are observed compared to those at lower pressures. While these macroscopic spray geometrical parameters change gradually at different ambient pressures, the droplet size distribution undergoes a slightly more abrupt transition across the saturation vapor pressure at chamber temperature. These results provide a fundamental dataset for liquid ammonia injection and could be used to validate against simulation data or to build surrogate models.</div></div>
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Guo, Guangyu, Hongling Deng, Chao Zhu e Zhiming Ji. "Non-Volatile Fraction Effects in Dispersed Vacuum Spray Flash Evaporation". In ASME 2020 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2020. http://dx.doi.org/10.1115/imece2020-23506.
Testo completoAbstract (sommario):
Abstract Spray flash evaporation has been widely used in spray cooling and thermal distillation as a technology of heat/mass transfer enhancement. In a vacuum spray flash process, the vapor is instantly extracted by vacuuming, while the supersaturated droplets are further cooled by the continued spray flash until becoming saturated or discharged. Hence, in the evaporator, non-equilibrium exists not only in the flash evaporation driven by the pressure difference between droplet and ambient but also in the temperatures of yields, namely, generated vapor and discharged liquid with or without precipitates. To deeper understand such interesting thermal non-equilibrium between two phases in a spray flash evaporation of salty water, this paper establishes a multi-component spray flash evaporation model which coupled with diffusivity effect of non-volatile fraction, as well as the influence of spray polydispersion. An experimental system is also set up for evaporative coefficient determination, as well as model validation. The theoretical and experimental results meet a good agreement. It indicates the salinity and the superheat level of inlet feed have substantial impacts on such thermal non-equilibrium phenomenon of the temperature difference between the extracted vapor and the discharged liquid residue.
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Guo, Guangyu, Chao Zhu e Zhiming Ji. "CFD SIMULATION OF ISOLATED SPRAY FLASH EVAPORATION WITH ACTIVE VAPOR EXTRACTION". In 5th Thermal and Fluids Engineering Conference (TFEC). Connecticut: Begellhouse, 2020. http://dx.doi.org/10.1615/tfec2020.fip.032143.
Testo completo
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Wang, Huihui, Dan Zhang, Shuran Zhao e Jiping Liu. "Experimental Study on Evaporation properties during Spray Flash of Aqueous NaCl Solution". In The 5th World Congress on Momentum, Heat and Mass Transfer. Avestia Publishing, 2020. http://dx.doi.org/10.11159/enfht20.171.
Testo completo
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Ji, Can, Lin Cheng, Naihua Wang e Zhigang Liu. "SYSTEM DESIGN AND EXPERIMENTAL INVESTIGATION ON HIGHTEMPERATURE AND HIGH-PRESSURE SPRAY FLASH EVAPORATION". In International Heat Transfer Conference 16. Connecticut: Begellhouse, 2018. http://dx.doi.org/10.1615/ihtc16.mpf.023342.
Testo completo
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Chen, Hao, Min Xu, Gaoming Zhang, Ming Zhang e Yuyin Zhang. "Investigation of Ethanol Spray From Different DI Injectors by Using Two-Dimensional Laser Induced Exciplex Fluorescence at Potential Cold-Start Condition". In ASME 2010 Internal Combustion Engine Division Fall Technical Conference. ASMEDC, 2010. http://dx.doi.org/10.1115/icef2010-35090.
Testo completoAbstract (sommario):
The spray evaporation of gasoline and ethanol fuel was investigated qualitatively through the use of the planar laser induced exciplex fluorescence (PLIEF) technique in a constant volume chamber. The effect of fuel temperature and ambient pressure on spray evaporation was identified over a range of conditions. Both a swirl injector and a multi-hole injector were examined for each of the two fuels. A coevaporative mixture of benzene and triethylamine (TEA) was used as a fluorescent seeding material to study the evaporation processes of ethanol fuel. A mixture of fluorobenzene (FB) and diethylmethylamine (DEMA) in n-hexane, which has been proved to be a suitable seeding material for LIEF measurement, allowed for the investigation of the evaporation processes of gasoline fuel mixture. Remarkable spray evaporation processes were observed for both gasoline and ethanol fuel by increasing fuel temperature or by reducing ambient pressure to a vacuum. Especially after achieving flash-boiling, the vapor distribution of multi-plume spray increases dramatically, and the vapor phase of spray from swirl injector gathers to the centerline of injector by increasing the superheated degree. The collapsing of both liquid and vapor phases of n-hexane is stronger than that of ethanol spray for both swirl and multi-hole injectors.
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Golliher, Eric L., e Shi-chune Yao. "Exploration of Impinging Water Spray Heat Transfer at System Pressures Near the Triple Point". In ASME 2013 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/imece2013-66872.
Testo completoAbstract (sommario):
The heat transfer of a water spray impinging upon a surface in a very low pressure environment is of interest to cooling of space vehicles during launch and re-entry, and to industrial processes where flash evaporation occurs. At very low pressure, the process occurs near the triple point of water, and there exists a transient multiphase transport problem of ice, water and water vapor. At the impingement location, there are three heat transfer mechanisms: evaporation, freezing and sublimation. A preliminary heat transfer model was developed to explore the interaction of these mechanisms at the surface and within the spray.