Дисертації з теми "Droplet Collision"
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Blancher, Roman Adrien. "Numerical simulations of high speed droplet collision." Thesis, Georgia Institute of Technology, 2002. http://hdl.handle.net/1853/19127.
Повний текст джерелаFujimoto, Hitoshi. "Flow fields of air-liquid droplet two-phase mixture and collision dynamics of a droplet on a surface." Kyoto University, 1995. http://hdl.handle.net/2433/160775.
Повний текст джерелаKyoto University (京都大学)
0048
新制・論文博士
博士(工学)
乙第8868号
論工博第2977号
新制||工||996(附属図書館)
UT51-95-D461
(主査)教授 八田 夏夫, 教授 鈴木 健二郎, 教授 赤松 映明
学位規則第4条第2項該当
Liu, Muyuan [Verfasser], Dieter [Akademischer Betreuer] Bothe, and Cameron [Akademischer Betreuer] Tropea. "Numerical Study of Head-on Binary Droplet Collisions: Towards Predicting the Collision Outcomes / Muyuan Liu ; Dieter Bothe, Cameron Tropea." Darmstadt : Universitäts- und Landesbibliothek Darmstadt, 2017. http://d-nb.info/1148650261/34.
Повний текст джерелаEnuguri, Venkata Kotaiah Shiva Teja, and Sri Harsha Karra. "Colliding Drops in Spray Dryers." Thesis, Blekinge Tekniska Högskola, Institutionen för maskinteknik, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:bth-17386.
Повний текст джерелаGe, Yang. "3D numerical study on droplet-solid collisions in the Leidenfrost regime." Connect to resource, 2005. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1124291953.
Повний текст джерелаTitle from first page of PDF file. Document formatted into pages; contains xxi, 225 p.; also includes graphics (some col.). Includes bibliographical references (p. 218-225). Available online via OhioLINK's ETD Center
Wunsch, Dirk. "Theoretical and numerical study of collision and coalescence - Statistical modeling approaches in gas-droplet turbulent flows." Thesis, Toulouse, INPT, 2009. http://www.theses.fr/2009INPT031H/document.
Повний текст джерелаCoalescence in a droplet cloud is studied in this work by means of direct numerical simulation of the turbulent gas flow, which is coupled with a Lagrangian tracking of the disperse phase. In a first step, a collision detection algorithm is developed and validated, which can account for a polydisperse phase. This algorithm is then implemented into an existing code for direct numerical simulations coupled with a Lagrangian tracking scheme. Second, simulations are performed for the configuration of homogeneous isotropic turbulence of the fluid phase and a disperse phase in local equilibrium with the fluid. The influence of both droplet inertia and turbulence intensity on the coalescence rate of droplets is discussed in a pure permanent coalescence regime. First results are given, if other droplet collision outcomes than permanent coalescence (i.e. stretching and reflexive separation) are considered. These results show a strong dependence on the droplet inertia via the relative velocity of the colliding droplets at the moment of collision. The performed simulations serve also as reference data base for the development and validation of statistical modeling approaches, which can be used for simulations of industrial problems. In particular, the simulation results are compared to predictions from a Lagrangian Monte-Carlo type approach and the Eulerian 'Direct Quadrature Method of Moments' (DQMOM) approach. Different closures are validated for the coalescence terms in these approaches, which are based either on the assumption of molecular-chaos, or based on a formulation, which allows to account for the correlation of droplet velocities before collision by the fluid turbulence. It is shown that the latter predicts much better the coalescence rates in comparison with results obtained by the performed deterministic simulations
Aziz, Shiraz Dean. "Impact velocity and surface temperature effects on the collision of a molten tin droplet on a solid surface." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape11/PQDD_0005/MQ40963.pdf.
Повний текст джерелаAyala, Orlando. "Effects of turbulence on the collision rate of cloud droplets." Access to citation, abstract and download form provided by ProQuest Information and Learning Company; downloadable PDF file 6.00 Mb , 236 p, 2005. http://wwwlib.umi.com/dissertations/fullcit/3181864.
Повний текст джерелаSchröder, Simon [Verfasser]. "Stochastic Methods for Fiber-Droplet Collisions in Flow Processes / Simon Schröder." München : Verlag Dr. Hut, 2013. http://d-nb.info/1045988073/34.
Повний текст джерелаPlanchette, Carole. "Collisions de gouttes asymétriques." Phd thesis, Université Paris-Est, 2011. http://tel.archives-ouvertes.fr/tel-00647892.
Повний текст джерелаAmani, Ahmad. "Numerical simulation of Newtonian/non-Newtonian multiphase flows : deformation and collision of droplets." Doctoral thesis, Universitat Politècnica de Catalunya, 2019. http://hdl.handle.net/10803/667419.
Повний текст джерелаLa naturaleza compleja de los flujos multifásicos, particularmente en presencia de reologías no newtonianas, limita la aplicabilidad del análisis teórico de ecuaciones físicas y también de los experimentos de laboratorio. Por lo tanto, las técnicas de dinámica de fluidos computacional (CFD) son esenciales para estudiar estos problemas. A pesar de los avances en las técnicas de simulación numérica en esta área durante la última década, la aplicabilidad de estos enfoques está limitada por los desafíos que aparecen en las aplicaciones específicas, y se debe considerar de forma particular cada uno de estos problemas. La presente tesis tiene como objetivo la solución numérica tridimensional de los problemas de flujo multifase newtoniano / no newtoniano en el contexto del enfoque de discretización de volúmenes finitos con aplicaciones en diferentes procesos naturales e industriales. Esta tesis está organizada en cinco capítulos. El primer capítulo proporciona una introducción y la motivación de este trabajo. También presentamos alguna aplicación de esta tesis en procesos industriales, seguida de una corta introducción al grupo de investigación del CTTC, los objetivos y el resumen de la tesis. En el capítulo 2, utilizando un método CLS, se realiza una simulación numérica directa (DNS) tridimensional de colisión de gotitas binarias. Se introduce un nuevo enfoque de estabilización de lamella para resolver numéricamente la capa delgada de fluido ("lamella") que aparece durante muchos regímenes de colisión. Este enfoque demuestra ser numéricamente eficiente y preciso en comparación con los datos experimentales, con una importante reducción de costos computacionales en casos tridimensionales. Las herramientas numéricas introducidas se validan y verifican con diferentes resultados experimentales para diferentes casos de colisión en los que se observa un muy buen acuerdo. Además, para todos los casos estudiados en este capítulo, se proporciona un estudio detallado de los balances de energía. En el capítulo 3, se estudia en detalle la física de una sola gota sometida a flujo de cizallamiento, con un enfoque principal en el efecto de la viscosidad en el confinamiento crítico de las paredes. Primero, validamos la capacidad de las herramientas numéricas para capturar la física correcta de la deformación de las gotitas. Este capítulo continúa con el estudio tridimensional DNS de las deformaciones subcríticas (estado estable) y supercríticas (ruptura) de la gota para un amplio rango de confinamiento de paredes en diferentes relaciones de viscosidad. Los resultados indican la existencia de dos regiones de estado estable en un gráfico de una relación de confinamiento de las paredes y la viscosidad, que están separados por una región de ruptura. En general, estos logros indican un potencial importante del enfoque actual para simular la deformación y ruptura de las gotitas, en aplicaciones de la ciencia de la dispersión y los procesos de mezcla. En el capítulo 4, con la ayuda de la experiencia adquirida en los capítulos anteriores, se utiliza un método CLS de volumen finito para resolver numéricamente los problemas de flujo multifase no newtonianos. Las principales áreas desafiantes de la simulación numérica de fluidos multifásicos no newtonianos incluso el seguimiento de la interfaz, la conservación de masa de las fases, los problemas de pequeños paso de tiempo encontrados por los fluidos no newtonianos, las inestabilidades numéricas relacionadas con el problema del alto número de Weissenberg (HWNP), inestabilidades fomentadas por una baja relación de viscosidad de disolvente a polímero en fluidos viscoelásticos y las inestabilidades encontradas por las tensiones superficiales son discutidos y se proporcionan tratamientos numéricos adecuados para el método propuesto. El método numérico se valida para diferentes tipos de fluidos no newtonianos, utilizando diluyentes de cizallamiento, espesamiento de cizallamiento y fluidos viscoelásticos utilizando mallas estructuradas y no estructuradas, donde los resultados extraídos se comparan con los datos analíticos, numéricos y experimentales disponibles en la literatura.
Coppens, François M. G. J. "Ultrafast quantum dynamics of doped superfluid helium nanodroplets." Thesis, Toulouse 3, 2018. http://www.theses.fr/2018TOU30145/document.
Повний текст джерелаIn this thesis we investigate two aspects of the dynamics of atomic impurities interacting with superfluid helium (He) nanodroplets, namely the photo-excitation of alkalis on a nanodroplet and the doping process of nanodroplets hosting quantised vortices with noble gas atoms. For the theoretical investigations we use He density functional theory and its time-dependent version. The first aspect involves a joint experimental and theoretical collaboration that focusses on the photo-excitation of the alkali rubidium (Rb). Alkalis are a very interesting probe of He droplets since they reside in their surface region, where it has been argued that almost 100% Bose-Einstein condensation could be achieved due to a density that is lower than in bulk superfluid He. In our simulations we find that states excited to the 5p and 6p manifold desorb at very different timescales, separated by 2 orders of magnitude (~100 ps and ~1 ps for 5p and 6p respectively). This is in good agreement with experimental results where the desorption behaviour of photo-excited Rb atoms is determined using a femtosecond pump-probe scheme. However, in our simulations excitation to the 5pPi_{3/2}-state results in a surface-bound RbHe exciplex, contrary to the experimental case where the RbHe exciplex desorbs from the droplets surface. Introducing spin-relaxation from Pi_{3/2} to Pi_{1/2} into the simulations, the RbHe exciplex is able to desorb from the droplet's surface, which resolves this contradiction. The second aspect concerns a purely theoretical investigation that is inspired by recent work of Gomez and Vilesov et al., where quantised vortices were visualised by doping He nanodroplets with silver atoms, subsequently "soft landing" them on a carbon screen. Electron-microscope images show long filaments of silver atom clusters that accumulated along the vortex cores. Also the formation of quantum-vortex lattices inside nanodroplets is evidenced by using X-ray diffractive imaging to visualise the characteristic Bragg patterns from xenon (Xe) clusters trapped inside the vortex cores. First, head-on collisions between heliophilic Xe and a He nanodroplet made of 1000 He atoms are studied. The results are then compared with the results of a previous study of an equivalent kinematic case with cesium (Cs), which is heliophobic. Xe acquires a "snowball" of He around itself when it traverses the droplet and much more kinetic energy is required before Xe is able to pierce the droplet completely. When it does, it takes away some He with it, contrary to the Cs case. Next, collisions between argon (Ar)/Xe and pristine superfluid He nanodroplets are performed for various initial velocities and impact parameters to determine the effective cross-section for capture. Finally, the simulations are then repeated for droplets hosting a single quantised vortex line. It is observed that the impact of the impurities induces large bending and twisting excitations of the vortex line, including the generation of helical Kelvin waves propagating along the vortex core. We conclude that Ar/Xe is captured by the quantised vortex line, although not in its core. Also we find that a He droplet, hosting a 6-vortex line array whose cores are filled with Ar atoms, results in added rigidity to the system which stabilises the droplets at low angular velocities. Our simulations involving droplets hosting quantum vortices open the way to further investigations on droplets hosting an array of vortices, involving multiple impurities
Meng, Kejie. "MECHANISTIC STUDIES OF PROTON-COUPLED ELECTRON TRANSFER REACTIONS INVOLVING ANTIOXIDANTS." VCU Scholars Compass, 2018. https://scholarscompass.vcu.edu/etd/5498.
Повний текст джерелаGai, Guodong. "Modeling of water sprays effects on premixed hydrogen-air explosion, turbulence and shock waves Modeling pressure loads during a premixed hydrogen combustion in the presence of water spray Numerical study on laminar flame velocity of hydrogen-air combustion under water spray effects Modeling of particle cloud dispersion in compressible gas flows with shock waves A new formulation of a spray dispersion model for particle/droplet-laden flows subjected to shock waves Particles-induced turbulence: a critical review of physical concepts, numerical modelings and experimental investigation A new methodology for modeling turbulence induced 1 by a particle-laden flow using a mechanistic model." Thesis, Normandie, 2020. http://www.theses.fr/2020NORMIR14.
Повний текст джерелаThis PhD dissertation is dedicated to develop simple models to investigate the effect of water spray system on the premixed hydrogen-air combustion in the nuclear power plants. Specific simple models are developed to describe the water droplet evaporation in the flame, particle cloud dispersion after the shock wave passage, and turbulence length scale evolution with the presence of a water spray. A methodology is proposed to evaluate the spray evaporation effects on the propagation of the turbulent hydrogen flame inside a closed volume and a simple model is developed for the quantification of the laminar velocity deceleration with the droplets evaporation inside the flame. An analytical model is proposed for the prediction of particle cloud dispersion after the shock passage in the one-way formalism and another analytical model is dedicated to describe the spray-shock interaction mechanism and predict the appearance of a particle number density peak using the two-way formalism. A review of the important criteria and physical modelings related to the particle-induced turbulence modulation is given and a mechanistic model is used for the estimation of the turbulent integral length scales induced by the injection of particle clouds. These developed numerical models can be coupled to implement in the large-scale numerical simulations of the spray system effects on the accidental hydrogen explosions in the nuclear power plants
高天冀. "Droplets-Collision Analysis and Droplet-Generator Development." Thesis, 1999. http://ndltd.ncl.edu.tw/handle/64196574472669709072.
Повний текст джерелаHsu, Yu-Lin, and 許祐霖. "Parallel MD Simulation of Droplet-Droplet Collision Dynamics." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/70380682800938471128.
Повний текст джерела國立交通大學
機械工程系所
94
Abstract Collision dynamics between two nanoscale argon droplets with the same diameter of ~10nm under vacuum and pressurized environment is simulated using a parallelized cellular molecular dynamics (PCMD) simulation code. Simulation results show that the collision dynamics between two droplets can be very complicated, which strongly depends upon the magnitude of the background pressure, the relative inertia (or collision velocity) and impact parameter. These phenomena include bouncing, direct coalescence, stretching coalescence, stretching separation and shattering. Regime maps at different background pressures are constructed for the first time to the best knowledge of the author. Analysis of snapshots of molecular distribution, fragment size distribution, surface tension on droplet surfaces and energy transfer process during collision are used to explain the complicated collision dynamics. The research is divided into two phases, which is described as follows. In the first phase, a PCMD code is developed on memory-distributed parallel machines (e.g., PC-cluster system) by taking advantage of link-cell data structure, which is often used for fast search in constructing the Verlet list. Dynamic spatial domain decomposition using multi-level graph-partitioning technique is employed to enforce the load balancing among processors. A simple threshold scheme (STS), in which workload imbalance is monitored and compared with some threshold value during the runtime, is proposed to decide the proper time for repartitioning the domain. Results show that the parallel efficiency using one million L-J atoms reaches 57%, 35% and 65%, respectively, for condensed, vaporized and supercritical test cases at 64 processors of HP clusters at NCHC. In the second phase, the above developed PCMD code using L-J (12-6) potential is used to study the collision dynamics between two nanoscale droplets under vacuum and pressurized environments. Test conditions will include variations of the impact parameter (0-8 nm), relative velocity of droplets (20-1500 m/s), background gas pressure (0, 0.055 and 0.55 atm; ¥, 2312.3 and 216.9) and the background gas temperature is 216K. Observed phenomena can be categorized as bouncing, direct coalescence, stretching coalescence, stretching separation and shattering. Distributions of these regimes, as a function of relative velocity and impact parameter, are constructed for the first time for different background gas pressures. The simulation results under vacuum condition show that disruption, fragmentation and shattering can be easily observed at higher relative velocities, while direct coalescence can only be found at lower relative velocities. However, with the existence of background gas, disruption and fragmentation can only be observed at higher velocities than those under vacuum conditions. Bouncing at very low velocity (10-30 m/s) can be clearly observed under pressurized environments, which coincides with previous findings. In addition, stretching coalescence is observed for the first time at intermediate relative velocity and impact parameter under pressurized environment. Effects of the relative velocity, impact parameter and ambient pressure to the collision process are discussed in detail using the concept of the separable rotational energy and the vibration energy of the largest cluster during collision.
Chen, Jen-Chun, and 陳任鈞. "Surfactant Effect on Binary Droplet Collision." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/51355354266008558009.
Повний текст джерела臺灣大學
機械工程學研究所
98
The droplets collision dynamics with different surfactant and viscous fluids are investigated. The high speed camera and reliable measuring methods facilitate the experimental procedures. Depending on the two independent factors of Weber number and impact parameter, the consequences of droplets collision can be categorized into five distinct regimes: (Ⅰ) coalescence after minor deformation, (Ⅱ) bouncing, (Ⅲ) coalescence after substantial deformation, (Ⅳ) reflective separation and (Ⅴ) stretching separation, and it reveals that the viscosity, surfactant types and concentrations all have great influences on regime diagrams, especially the finding of the extensive bouncing regime and the retardant occurrence of separation regime. It is because the Marangoni effect which is motivated by the surfactant gradient could manifestly affect droplet interfacial behaviors. However, these induced transformations will dominate over the microscopic situations such as droplet bouncing but become trivial in the macroscopic conditions such as droplet separation phenomena.
Liu, Muyuan. "Numerical Study of Head-on Binary Droplet Collisions: Towards Predicting the Collision Outcomes." Phd thesis, 2017. https://tuprints.ulb.tu-darmstadt.de/7018/1/Thesis_final.pdf.
Повний текст джерелаTseng, Yu-Jen, and 曾煜仁. "High-Speed Binary Droplet Collision with DifferentOhnesorge number." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/50961029992377667114.
Повний текст джерела國立臺灣大學
機械工程學研究所
96
In this study, we investigate the phenomena of droplet-droplet collision with different Ohnesorge number in a head-on collision condition, i.e., the impact number is zero. It aims at observing the phenomena of droplet collision and discussing the physical phenomena of that under a head-on situation. In addition, we try to find a different way from the original one to generate high-speed droplets. Instead of using a compressor to inject a liquid jet and then cutting it off into several droplets by a rotating disk, we simply let the accelerating air move through a tube and carry the droplets into high speed. One of the main goals of this experiment is to take clear photographs whether in lower Weber number or in higher one. The other is to achieve a relative high Weber number about 5100. On the other hand, we discuss how Ohnesorge number influences the droplet collision. Break-up phenomenon is observed in high-speed droplet collision. The Z-We and We-W figures which illustrate the trends of break-up diameter, break-up boundary, and splattering boundary are also obtained in this thesis, where Z indicates the Ohnesorge number and W is the non-dimensional parameter of the diameter of droplet with respect to the break-up diameter. Keywords: droplet collision, high-speed droplet, impact number, Ohnesorge number, Webber number
Munnannur, Achuth. "Droplet collision modeling in multi-dimensional engine spray computation." 2007. http://www.library.wisc.edu/databases/connect/dissertations.html.
Повний текст джерелаHung, Chun-Yu, and 洪諄宇. "Fluid properties and material effects on droplet-film collision." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/37311073873602877028.
Повний текст джерела國立臺灣大學
機械工程學研究所
97
An investigation in droplet-film collision is experimentally conducted. The phenomena of a drop impinging upon a liquid layer are categorized into five characteristics including absorption, central jet, secondary droplet, multiple droplets, and closed crown. Four regime thresholds are defined to segregate these five characteristics. By changing the viscosity and the surface tension of the fluids, a peninsular trend is summarized, which describes the behaviour of these specific thresholds. The sheeting-splashing threshold is postponed when the viscosity of the fluid is increased, and is advanced if the surface tension of the solution is decreased. Moreover, the material effect on the droplet-film collision is discussed. The turning point of each threshold arises with higher Weber number when the aluminum plate is replaced for the acrylic plate.
HSIEH, WAN-TING, and 謝宛庭. "Physical model of rotational separation in binary droplet collision." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/fn5je4.
Повний текст джерела國立臺灣大學
機械工程學研究所
106
Identical droplet-droplet collisions were studied, with emphasis on the criterion for boundary transition between regimes of rotational separation and regimes of coalescence. Based on the confirmatory experimental results and the numerical simulation outcomes, two types of motion in the regimes of rotational separation were found to co-exist:region of interaction and the region outside of the region of interaction. The former is oscillating; the latter is rotating. The above two motions achieve good coherence that can overcome the bonding forces at critical time is the fragmentation criterion. A physical model is established and found to agree well with the experimental data. Further analyzing the criterion for reflexive separation and stretching separation, we based the physical model of the rotation separation on head-on reflexive separation and stretching separation. We constructed two new physical models for these two regimes after making some modifications. Both physical models and experimental results are in good agreement. By means of the physical models we established, we observed that the critical time of head-on reflexive separation is the very time while the region of interaction is stretching. On the other hand, the critical time of rotation separation is the second times while the region of interaction is stretching. This outcome is consistent with the previous study that rotational separation is second reflexive separation.
Li, Szu Yun, and 李祠澐. "Design of Droplet Generator Driven by piezoelectric Transducer and Experiments of Micro Droplet Collision on Surface." Thesis, 2002. http://ndltd.ncl.edu.tw/handle/21337473190846115072.
Повний текст джерела國立臺灣大學
機械工程學研究所
90
This article is targeting on a PZT driven droplet generator to proceed the structure design, analysis and performance tests, as well as the observation of micro-droplet impacting on a plate. The structure characteristics of the droplet generator are simulated by finite analysis software ANSYSTM. And, the droplet formulating processes are simulated by MEMS analysis software MEMCADTM. After that, the designed PZT driven droplet generator is fabricated and set up. To compare and verify the results of experiment and analysis, the performance of the whole system and the characteristics of formulating droplet are experimentally tested. As to the micro-droplet impacting on a plate, there have been plenty of related literatures. However, restricted by the experiment and observation equipments, few of the past studies conducted the micrometer scale droplet research. In terms of the application of high technological industries, the size of the droplet is getting more and more minute. Therefore, the understanding of dynamic characteristics of micro droplet is of great urgency. This research used the PZT driven droplet generator to produce micro-droplet, took the observation of the micro-droplet impacting on a plate and probed into its observed results. This research integrated the research method of droplet generator equipments in the former part and the characteristic of the micro-droplet formulated by the equipments in the latter part to build up a complete procedure for design, analysis, and test of the micro-droplet generator. As a result, they can help the application of the equipments in all industries and research fields to meet all kinds of needs.
Yang, Xing-Xiong, and 楊幸雄. "The Collision Phenomena of Water Droplet Adding with the Surfactant." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/72903354928744418548.
Повний текст джерела國立臺灣大學
機械工程學研究所
96
The boundaries of droplet collision phenomena are defined by Weber number and Impact parameter, namely(I) coalescence after minor deformation, (II) bouncing, (III) coalescence after substantial deformation, (IV) coalescence followed by separation for near head-on collisions, and (V) coalescence followed by separation for off-centre collisions. According to earlier investigation, bouncing collision of water is not observed at 1 atm. Air. In this experiment, the surfactant, Triton X100, is dissolved in water in order to change the surface tension. Observing its collision phenomena, we can find bouncing collision and the boundaries of collision is changed. The influence of the surface tension on the boundaries of droplet collision will be discussed in this experiment.
Chou, Kun-Yi, and 周坤毅. "The Effect of Surface Tension Difference on Binary Droplet Collision." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/56561849287172880500.
Повний текст джерелаMing-Huang, Tsai, and 蔡銘煌. "Collision Characteristics and Investigation of a Droplet with a hemispherical film." Thesis, 2003. http://ndltd.ncl.edu.tw/handle/27732119248502373363.
Повний текст джерела國立臺灣大學
機械工程學研究所
91
In the study we investigated the phenomena of liquid-droplet impact the solid surface and displayed a certain appearance of the semicircle liquid film on the solid surface after impact. It was generated single steady liquid droplet by means of Ink-jet printing method. After liquid droplet detaches from generator and impacted through around air at room temperature and pressure. The kind of liquid droplet was distilled water and solid surface of impact was plastic. The method of study was we changed single liquid droplet size and impacted solid surface by different velocity. At the same time, we used a hemispherical liquid film was formed after liquid droplet impact solid surface, then fixed first liquid droplet size (static hemispherical droplet)and steady. To make changes in velocity and size of liquid droplet which impinging hemispherical liquid film (which size was greater, equal, and smaller). Therefore, first liquid droplet may regard as a hemispherical liquid film, and observes behavior of liquid droplet impacted hemispherical liquid film on the solid surface, and the outcome compared with model of single liquid droplet impacted on the solid surface. Primary parameters on experiment were size and impact velocity of liquid droplet. Finally, the sum and substance of experiment provided interaction of liquid droplet on the solid surface. Besides the result, in the experiment we found single liquid droplet impacted the solid surface, which produced a condition that had air bubbles were encompassed in hemispherical liquid film and made qualitative analysis.
Shen, Zheng. "Phase transfer in a collision between a droplet and solid spheres." Thesis, 2008. http://library1.njit.edu/etd/fromwebvoyage.cfm?id=njit-etd2008-024.
Повний текст джерелаLu, Chi-Ru, and 呂季儒. "Binary droplet collision: 1. Off-center separation revisited2. Surfactant(Span 80) effect on collision behavior of hydrocarbon fuels." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/17715109984241906703.
Повний текст джерела國立臺灣大學
機械工程學研究所
99
An experimental investigation of binary droplet collision dynamics was conducted, with emphasis on the off-center separation outcomes and surfactant effect on collision behavior of hydrocarbon fuels. First, six kinds of hydrocarbon fluid and Span 80/hydrocarbon fluid were used in the experiment. The results show that collision outcomes of hydrocarbon droplets exhibit six distinct regimes, namely (I) coalescence after minor deformation, (II) bouncing, (III) coalescence after substantial deformation, (IV) reflective separation, (V) stretching separation and, (VI) second reflexive separation. Then we base on a basic droplet collision model with some assumption properly to explain the second reflexive separation. The other part of the study, we will analyze the critical Weber number of the Span 80 /hydrocarbon and silicone oil /hydrocarbon to prove that viscosity is the only factor affected by Span 80. Finally, we conclude that higher viscosity will promote droplet bouncing but become trivial as it reaches a critical value.
Mitra, Subhasish. "Droplet particle interaction in a flowing gas stream." Thesis, 2016. http://hdl.handle.net/1959.13/1315709.
Повний текст джерелаDroplet-particle collision interaction in a flowing gas stream is one of the major phase interaction phenomena in a wide class of multiphase process applications such as spouted bed coating, fluid catalytic cracking unit, fluid coking process for bitumen upgrade process etc. that govern the process performance to a significant extent. Such interactions are manifestations of complex hydrodynamics involving competing interplay of various forces e.g. viscous, capillary, inertial and gravity coupled with simultaneous heat and mass transport process which involves further complexity of phase change. Depending on the size ratio of the droplet-particle pair, relative velocity, physical properties, temperature difference, surface roughness and hydrophobicity; a number of different outcomes are possible which presumably affect the associated transport phenomena to a significant extent. For instance, inefficient contact of atomized feed droplets and hot catalyst particles adversely affects the desired product yield in a fluid catalytic cracking unit. Motivated by a dearth of knowledge in this field, the present research aims at investigating some of these interaction mechanisms with specific focus on the single droplet-particle system to broaden the mechanistic understandings using both non-invasive optical technique (high speed imaging) and numerical modelling wherever applicable. Based on the droplet-particle size ratio (Δ), there different systems were studied: Δ < 1, Δ > 1 and Δ ~ 1. For Δ < 1 system, normal collision behaviour of different fluids namely water, isopropyl alcohol and acetone was studied on a highly thermally conductive stationary brass particle surface in the temperature ranging from normal atmospheric condition (20 °C) to film boiling regime (250 °C - 350 °C) at different impact velocities (0.34 - 1.67 m/s) of droplets using high speed imaging technique. With increasing impact velocity (Weber number), three distinct outcomes were noted – deposition or wetting behaviour at normal atmospheric condition to nucleate boiling regime and then rebound and disintegration in the film boiling regime. In the impact dynamics, broadly two distinct phases were observed – inertia-dominated spreading or advancing phase and surface tension dominated recoiling or receding phase below disintegration limit and only spreading phase above this limit. Specifically in the film boiling regime, a critical Weber number range was determined wherein the transition from rebound to disintegration regime occurs. Two important parameters were quantified – maximum wetted contact area and droplet-particle contact time that governs the collision induced heat transfer process. Using image analysis, maximum spreading parameter was quantified to characterise the wetted area and correlated with impact Weber numbers using a general functional form. Also an analytical expression was suggested to determine this parameter on spherical surface based on an energy balance approach which showed reasonable agreement with experimental measurements. Also determined were a spreading kinetics of two functional forms – power law and recovery type exponential; both of which predicted the spreading trend well. Measured contact times were observed to have inverse dependency on the impact Weber number. Below limit of disintegration, a power law form of contact time as a function of Weber number was obtained which predicted the trend well and also confirmed a general form of contact time in film boiling regime with little dependency on the system characteristics. No such functional form could be established in the disintegration regime wherein contact time appears to be almost independent of Weber number. A 3D computational fluid dynamics (CFD) model based on volume of fluid (VOF) method was developed using the FLUENT platform to simulate the droplet deformation behaviour during impact for Δ < 1. It was shown that the temporal evolution of complex droplet shapes depends critically on the contact angle boundary condition and use of dynamic contact angle improves the prediction compared with static contact angle. It was observed experimentally that in film boiling regime, contact angle hysteresis was minimal due to presence of the insulating vapour film at solid-liquid interface which enhances surface hydrophobicity. Also the effect of contact line velocity and surface temperature on the contact angle variation was found to be insignificant. Based on this observation, it was further shown that in film boiling regime, CFD model could predict the dynamics based on a static contact angle in the limit of super-hydrophobicity and a free slip wall boundary condition to account for the vapour film which reasonably agreed with the experiments both qualitatively and quantitatively. Also studied experimentally for the Δ < 1 system, was in-flight collision interactions between a number of small droplets and a larger particle at different droplet (Weber number ≈ 3.0 – 26) and particle (Reynolds number ≈ 14 – 46) impact velocities where both were in the moving state. The droplets were observed to undergo inelastic collision resulting into complete deposition onto the particle surface in lower Weber number cases and forming a thin film in the higher Weber number cases. The measured film thickness normalized by particle radius was found to be in the range of 0.033 -0.314. Also during collision, significant deflection in the particle trajectory was noted especially at higher droplet velocity. However the angle of deflection was observed to decrease when the relative velocity between droplet and particle was decreased. A force balance model was developed accounting for the impact behaviour during collision to predict the particle trajectory and velocity. The model predicted outcomes were in good agreement with the experimental measurements when the angle of deflection was small however larger deviations were noted when angle of deflections were relatively large. The deviations were attributed to a number of factors such as uncertainty in droplet size due to in-flight coalescence, loss of droplet momentum due to coalescence on particle surface and intricate rotational motion during impact which were not completely accounted in the model. For a Δ > 1 system, collision interactions between a small particle and a larger stationary supported spherical cap droplet were investigated at different particle impact velocities (Weber number ≈ 1.4 - 33). Two outcomes were noted – particle capture or retention at interface and penetration through the droplet interface. A one dimensional model was developed based on force balance approach to predict these collision outcomes. Effect of different competing forces namely gravity, virtual mass, buoyancy, drag, capillary and pressure were analysed. Among others, the capillary force was noted to have dominating effect however effect of the drag force was also observed to be significant when impact velocity was increased. The earlier mentioned CFD model was modified to include the effect of particle motion utilizing a dynamic meshing technique. Using a static contact angle and no-slip wall boundary conditions, the CFD model predicted outcomes were in reasonable agreement with the high speed visualizations and force balance model predictions. Also investigated for the Δ > 1 system was the collision interactions between a small particle and a stationary liquid film confined in a capillary tube using different diameters of particle and impact velocities since the complete penetration behaviour of the impacting particle could not be studied with a supported droplet. Three different outcomes were noted based on the impact Weber number - particle capture/retention at top interface; particle capture or retention at bottom interface and complete penetration through both interfaces. A criterion was developed based on the energy balance approach to predict the collision outcomes. In complete penetration cases, the particle was observed to entrain a certain amount of liquid mass with it which was explained by the end-pinching mechanism of ligament breakup. A model based on the energy balance approach was developed to quantify this liquid mass carryover. Also an empirical correlation was obtained to correlate the liquid mass carryover and the particle Bond number. A sensitivity analysis on the predictions of CFD model was performed using different contact angle boundary conditions – advancing, static and receding contact angle which could only predict a specific instance of the outcome well and not the overall outcome. The simulated particle trajectory and velocity were compared with the experimental measurements. Also the contributions of pressure force and viscous force predicted by the CFD model were analysed to explain the collision outcomes wherein pressure force was found be higher than the corresponding viscous force by at least an order of magnitude. The Δ ~ 1 system was studied experimentally for normal collision between an impacting droplet and a stationary particle where two outcomes were noted – deposition in lower Weber number cases and film formation in higher Weber number cases. Also studied here was the interaction behaviour in higher Weber cases involving heat transfer. The film was observed to rupture when the film reached a limiting thickness due to intense vaporization involving nucleate boiling at the apex point of the particle. This system was also studied computationally using a coupled level-set and volume of fluid (CLSVOF) CFD model using different combinations of droplet-particle size ratio, impact Weber number and impact parameter (collision angle). Three distinct outcomes were noted – deposition, ripping and coating and skirt scattering in the increasing order of impact Weber number which reasonably agreed with the predictions of LBM model previously reported by Gac and Gradon (2014). In both ripping and coating and skirt scattering outcomes, separation of ligaments was explained by the end-pinching mechanism. It was shown that all outcomes are governed by a competition between surface energy and kinetic energy and while higher surface energy favours deposition, higher kinetic energy leads to separation. Force analysis reveals that both pressure force and viscous force increases when impact Weber number is increased. Rise of these forces occur specifically in the early phase of interaction followed by a sharp decay in higher Weber number cases indicating separation of liquid ligament from particle surface. Also investigated was the effect of impact parameter (collision angle) which was shown to be critical for droplet-particle interaction. Increase in impact parameter leads to significant decrease in contact area of liquid-solid interface which consequently results in inefficient momentum transfer. This was evident by the corresponding decrease in the magnitude of both force and strain rate. In continuation with this study, a droplet-particle collision induced heat transfer model was developed applicable for FCC environment. The model computes the heat transfer coefficient based on a conductive heat transfer mechanism involving wetted contact area and droplet-particle contact time based on the interaction mechanism of Δ < 1 system. The model also includes volume fraction of droplets and solid particles to account for the multiphase environment. The developed heat transfer sub-model was incorporated into a lumped parameter vaporization model to compute vaporization times for typical gas-oil feed droplets. Computed vaporization times were compared with the predictions of other heterogeneous vaporization models reported in literature and found to be in reasonable agreement. Finally, a multi-particle system involving injection of an acetone jet in a bubbling fluidized bed of Geldart A-B particles was briefly studied to understand the collision interactions of droplets in a multi-particle environment involving vaporization. Several interesting phenomena like jet breakup into multiple droplets, re-suspension of solid particles due to vapour explosion, droplet shape deformation, coalescence, levitation and nucleate boiling were noted. Also evolution of the vapour concentration profile in freeboard region was visualized using Schlieren imaging technique. Numerically, a two-way coupled Eulerian-Lagrangian CFD model was developed using the FLUENT platform to simulate the jet vaporization process using user defined source terms for heat transfer between the liquid jet and the bed. Simulated vaporization phenomenon qualitatively agreed with experimental observations and captured the key feature of the vaporization process indicating diffusing nature of vapour concentration profile from bed surface to bulk. The CFD model also indicated significant reduction of local bed temperature which indirectly explained the presence of particle agglomerates found in the experiment.
Hung, Chih-Lung, and 洪誌隆. "On the viscous effect in binary droplet collision using glycerol solutions and nanofluids." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/n846c3.
Повний текст джерела國立臺灣大學
機械工程學研究所
103
The viscous and nanoparticle effect on droplet-droplet collision behavior at ambient conditions were studied experimentally. Glycerol solutions and silica nanofluids were used as working liquid providing viscosities in the range from 0.93 to 15.94 mPa‧s. The droplet image and collision history were recorded on a video recorder by using a strobe light synchronized with the droplet generator with various phase differences. The collision outcomes in terms of Weber number and the impact parameter could be categorized into six distinct regimes: (I) coalescence after minor deformation, (II) bouncing, (III) coalescence after substantial deformation, (IV) reflexive separation, (V) stretching separation and, (VI) rotational separation. It is shown that, by varying the viscosity of the glycerol solution through its concentration, the border between bouncing and coalescence were shifted toward lower impact parameter until bouncing appears on head-on with increasing viscosity and verified empirical correlation for the onset of reflexive separation for high viscosity fluids. Furthermore, it was found the collision behavior of 1% weight percentage concentration nanofluids was the same with water and separation occurred at higher Webber number with increasing concentration.
Yeh, Szu-I., and 葉思沂. "Droplet Collision, Coalescence, Mixing, and Reaction on the Textured Surface with Wettability Gradient." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/52922715874068926472.
Повний текст джерела國立臺灣大學
應用力學研究所
103
Digital microfluidics attracts much attention for its prospective applications to revolutionize biological laboratory procedures by allowing efficient assays with great versatility, small sample consumption and short detection duration. Droplets collision, colalescence and mixing behavior with different viscosities and surface tensions are the basic and important research in the development process of digital microfluidics. The aim of this study is to buildup the performance of bio-chemical detection device using droplet-based microfluidics. We manipulated the droplet on the self-assambled textured surface and investigated the different droplet coalescence profile, internal flow field inside the coalesced droplet, and mixing behavior inside the coalesced droplet caused by different characteristic (viscosity and surface tension) of fluids. We also investigated the difference of fluid mixing and reaction inside the droplet, and we show a simple and maneuverable method of digital microfluidics to modulate a biochemical reaction with a ternary droplet collision using a simple chemical reaction and DNA fluorescence resonance-energy transfer (FRET) test. We utilized micro-PIV and confocal microscopy to measure the coalescence process, internal flows, and mixing patterns of droplets with different viscosities and surface tensions after a head-on collision between a moving droplet and a stationary droplet on a wettability gradient surface. The results indicate that the mixing is driven sequentially by interior convection and diffusion once the two droplets touch each other; the convection endures less than 100 ms but dominates more than 60 % of the mixing. For the collision of droplets of identical surface tension, the surface tension affects the coalescence behavior; for the collision of droplets with distinct surface tension, the coalescence behavior and mixing quality depend on the colliding arrangement of stationary and moving droplets. We also used a high-speed camera to observe the color changing reaction inside a coalesced droplet. Compare to the traditional dye-mixing test, the chemical reaction inside the coalesced droplet facilitated the mixing of two counter-reactive fluids and was more than hundred times as efficient as the unreactive fluids mixing inside the coalesced droplet. Instead of mixing, chemical reaction inside a coalesced droplet is worth attention to the applications of digital microfluidic open-system. In droplet coalescence process, the characteristic of fluids and the ratio of volumes of two droplets caused different droplet coalescence profile especially the necking-curvature which affects the shape of the material interface between the two droplets in an initial phase. Capsules are used to protect, control and deliver drugs to the specific tissue. In recent year, multilayer microcapsules and nanocapsules are under review as multifunctional delivery systems. In this study, we also show a simple and maneuverable method to modulate the bio-chemical reaction for digital microfluidics on the surface by ternary droplet collision. The coalescence behavior and mixing quality are significantly concerned with the arrangement and configuration of different droplets on a droplet-based microfluidic system. This work significantly contributes to the understanding of droplet mixing and reaction in droplet-based microfluidic systems. Instead of mass transfer and mixing, chemical reaction inside a coalesced droplet is worth attention for digital microfluidic open-system. This work illustrates a correlation between the growth and evolution of chemical reaction and the profile (necking-curvature) of a coalesced droplet, which is also a significant reference in droplet-based microfluidic systems for biochemical use. Furthermore, the moduration of initial time and initial point of reaction inside the coalesced droplet is greater development potential on bio-chimical detection and cell-drug interaction test specifically.
Liao, Ming-Wei, and 廖明威. "Front-Tracking Method and Volume of Fluid Method Numerical Simulations for Binary Droplet Collision." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/23198302899923379656.
Повний текст джерела國立臺灣大學
機械工程學研究所
97
This study focuses on numerical simulation for binary droplets collision. We compare the numerical results with the experimental ones by front-tracking method and volume of fluid (VOF) method. Front-tracking method is controlled artificially by prescribing the rupture of the inter-drop film in multiphase flow, and the simulation results are consistent with the experimental ones. In high-speed droplet collision, the surface tension force damping option in VOF increases the viscosity in the vicinity of the interface, which damps the capillary wave effect that is invariably generated at the interface by the surface tension. In the view of physics, the droplets are not supposed to rupture in the separation regime. Therefore, if the surface tension force damping option is selected, the droplet does not rupture during the collision. The simulation condition of head-on collision of binary equal-size droplets is set. Water and tetradecane are used to be the liquid phases to predict the phenomena of droplet collision under the atmosphere. We examine the feasibility of droplet collision simulation with VOF in CFD-ACE solver. The 3D simulation results of high-speed droplet collision are obtained by VOF.
Hu, Jin-Ruei, and 胡金瑞. "Analyses on the Collision Behaviors of Gashol Fuel Droplet Impinging on a hot surface." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/38887415361327359392.
Повний текст джерела崑山科技大學
機械工程研究所
99
The dynamic behaviors of alcohol fuel droplets impinging on the hot surface were investigated. The alcohol fuel were made from 85% to 97% of unlead gasoline and various concentration of alcohol , which were 3%,5%,10% and 15% of mathanol, ethanol or butanol. Alcohol Fuel droplets impinging on a hot surface were tested under a smooth surface, two altitudes (10cm and 15cm), two kinds of hot plate temperatures (100℃ and 200℃). The observation was achieved by using high speed digital camera. When the surface temperature was at 100℃, the experimental results showed that the phenomenon of fuel droplets were spread, recoiling, split, shock, boiling then stable. At 200℃, the fuel droplets were more intense and became spread, boiling, evaporating, splashing, and jumping up from the surface. We also found that M3, E3 and B3 had more strong evaporated phenomena than the others when the surfface temperature was at 200℃. At high surface temperature, the viscosity and surface tension of the alcohol fuel decreased and the diffusive diameter of droplets increased. At last, we found that the evaporating phenomena happened on B15 but M15 and E15 when the surface temperature reached 200℃. Comparing the physical properties of M15, E15 and B15, we found that butanol had higher energy density, low heat of vaporation and high specific energy as well. The low heat of evaporation might be the reason why B15 was easy to get evaporating. With the three physical properties, butanol might become better additive instead of ethanol or be the better energy substitute.
Dev, Narendra. "Interaction behavior and droplet characteristics of multi-injector sprays." Thesis, 2020. https://etd.iisc.ac.in/handle/2005/4483.
Повний текст джерелаPinto, Pedro Miguel Moreira. "Collision Dynamics of a Single Droplet onto a Heated Dry Surface: Jet Fuel and HVO Mixtures." Master's thesis, 2021. http://hdl.handle.net/10400.6/11695.
Повний текст джерелаA preocupação com o ambiente levou o ser humano a desenvolver novos combustíveis alternativos para reduzir a poluição e mitigar a emissão de gases de efeito de estufa. O setor de transporte aéreo e a queima de combustíveis fósseis é responsável por grande parte da poluição. Por conseguinte, introduzir novas formas sustentáveis de fornecer energia, como os biocombustíveis, é de elevada importância. Contudo, de modo a tornar estes novos meios de energia mais eficientes e seguros, é necessário realizar estudos relativos à injecção de combustíveis nas câmaras de combustão e ao impacto de gotas. Este estudo é focado numa investigação experimental sobre o impacto de gotas numa superfície sólida quente. O principal objectivo deste trabalho é analisar a influência da temperatura da superfície na morfologia do impacto de uma única gota e observar os possíveis resultados. Para isso, nestes ensaios experimentais foram utilizadas misturas de Jet Fuel e HVO (Óleo Vegetal Hidroprocessado). Os fluidos utilizados foram: água (como grupo de controlo), 100% Jet A-1, 75% Jet A-1 e 25% NExBTL, 50% Jet A-1 e 50% de NExBTL, e 100% NExBTL. Estas misturas seguem os requisitos da aviação civil, no qual têm que conter um mínimo de 50% de jet fuel. O presente trabalho estuda os efeitos de impacto de uma gota em função da temperatura da superfície para diferentes fluidos. A energia de impacto foi mantida constante. Portanto, o número de Weber nesta experiência foi fixado em W e = 320, tendo variado ou o diâmetro da gota ou a velocidade de impacto. Além disso, foram escolhidas diferentes temperaturas da superfície, que variam entre Tw = 25ºC e Tw = 330ºC, para procurar obter cada fenómeno de impacto e caracterizar a morfologia do mesmo. As dinâmicas de impacto foram capturadas utilizando uma câmara digital de alta velocidade e as imagens foram processadas digitalmente. Foi possível observar os regimes de calor para todos os fluidos, bem como alguns adicionais para as misturas de 75% jet fuel - 25% HVO e 50% jet fuel - 50% HVO.
Wang, Po-Sheng, and 王柏勝. "Effect of Molecular Weight on Nanoscale Droplet Collisions Using Molecular Dynamics Simulation." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/09731168974729304045.
Повний текст джерела國立交通大學
機械工程系所
95
In this thesis, Parallelized cellular molecular dynamics (PCMD) to simulate two droplets consist of Helium or Xenon in nanoscale and adopt the L-J (12-6) potential to discuss the behavior and effects when two droplets collide in vacuum. In the simulation, parameters which influence the behavior of collision primarily involve the relative velocity between droplets, the impact parameter and the material we use. The simulation in this context sets the relative velocity of helium atom range from 250 m/s to 750 m/s, the relative velocity of xenon atom range from 250 m/s to 2250 m/s, and the impact parameters all range from 0 to 8.75 nm. By the way of visualization program “pvwin” we can observe several behavior of simulation as follow: Direct Coalescence, Stretching Coalescence, Stretching Separation, and Shattering. The greater the relative velocity and impact parameters are, the more obvious separation and rotation the droplets display after collision. Furthermore differences in material will affect the degree of shattering after collision. And we can compare the results with literature before to study the behavior and the change of energy in different molecular weights after the collision of droplets in the collision of droplets in nanoscale.
Collins, David. "A stochastic bulk model for turbulent collision and coalescence of cloud droplets." Thesis, 2016. http://hdl.handle.net/1828/7413.
Повний текст джерелаGraduate
0725 0608 0405
davidc@uvic.ca
Kai-Lung, Huang, and 黃凱倫. "An Experimental Investigation on The Burning Characteristics of Collision-Merged Multiple Fuel Droplets." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/87791638940907607434.
Повний текст джерела國立臺灣大學
機械工程學研究所
93
Experiment applies Ink-Jet Printing method to generate dual free droplet streams and collided along their path as they fall. Then the collided droplets will fall into the combustion chamber freely and some collision states and burning characteristics are investigated. We use n-hexadecane, methanol, ethanol, and propanol in the first part of this experiment, and then use hexadecane and ethanol-MTBE(or beneze)-premixture in the second part. Then we will compare the results of these two parts. According to our experiment results, the combustion states of non-mixable n-hexadecane/methanol droplets is always micro-explosion in adhesive mode. The occurrence of micro-explosion will increase burning rate. In discussion on the n-hexadecane and methanol, we find strong micro-explosion and the zone of micro-explosion in 40%~90% in n-hexadecane volume ratio probably. In the second part of this experiment, we find that if we join the MTBE or beneze of the suitable volume ratio, can increase burning state. But if we join too much MTBE or beneze, it will make immiscible droplets become to multiple miscible droplets.
Ling-Chieh, Kung, and 孔令杰. "An experimental investigation on the burning charactistics of collision-merged diesel fuel droplets." Thesis, 2004. http://ndltd.ncl.edu.tw/handle/03370895575102913691.
Повний текст джерела國立臺灣大學
機械工程學研究所
92
Experiment applies Ink-Jet Printing method to generate dual free droplet streams and collided along their path as they fall. Then the collided droplets will fall into the combustion chamber freely and some collision states and burning characteristics are investigated. We use diesel fuel, methanol, and water in the first part of this experiment, and use diesel fuel and water-methanol-premixture in the second part. Then we will compare the results of these two parts. According to the experiment results, the combustion states of water and diesel fuel are water droplet micro-explosion and extinction. The probability of the occurrence of micro-explosion will increase when the water droplet size decrease. In discussion on the diesel fuel and methanol we find strong and unstable micro-explosion. In the second part of this experiment, we find the difference of the concentration of water-methanol-premixture will affect the droplet collision and burning state.
Tsai, Cheng-Feng, and 蔡承豐. "An Experimental Investigation on the Burning Characteristics of Collision-Merged Bio-Diesel Fuel Droplets." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/64677106496020237389.
Повний текст джерела臺灣大學
機械工程學研究所
95
Experiment applies Ink-Jet Printing method to generate dual free droplet streams and collided along their path as they fall. Then the collided droplets will fall into the combustion chamber. We can observe the characteristics of combustion : ignition delay、burning time、burning rate、flame shrinking and micro-explosion. We use diesel fuel, bio-diesel, and water in the first part of this experiment. In different droplet size, oxygen volume fraction observe the characteristics of combustion and micro-explosion. Use bio-diesel and methanol, ethanol in the second part. Then we can observe the characteristics of premixture and collision. According to the experiment results, the combustion states of water and bio-diesel are water droplet micro-explosion and extinction. The probability of the occurrence of micro-explosion will increase when the water droplet size decrease. Then find flame shrinking in this experiment. The methanol, ethanol and bio-diesel collision、combustion、micro-explosion stability better than diesel.
Clark, Michael. "Femtoscopic signatures of small QGP droplets in proton-lead collisions at the Large Hadron Collider." Thesis, 2019. https://doi.org/10.7916/d8-t50g-tn57.
Повний текст джерела