Relevant bibliographies by topics / Two-Phase flow including gravity

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  2. Dissertations / Theses
  3. Books
  4. Book chapters
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Academic literature on the topic 'Two-Phase flow including gravity'

Author: Grafiati
Published: 4 June 2021
Last updated: 5 February 2022

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Journal articles on the topic "Two-Phase flow including gravity"

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Salimi, Hamidreza, Karl-Heinz Wolf, and Johannes Bruining. "Negative-Saturation Approach for Compositional Flow Simulations of Mixed CO2/Water Injection Into Geothermal Reservoirs Including Phase Appearance and Disappearance." SPE Journal 17, no. 02 (2012): 502–22. http://dx.doi.org/10.2118/142924-pa.

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Summary Cold mixed CO2/water injection into hot-water reservoirs can be used for simultaneous geothermal-energy (heat) production and subsurface CO2 storage. This paper studies this process in a 2D geothermal homogeneous reservoir, a layered reservoir, and a heterogeneous reservoir represented by a stochastic-random field. We give a set of simulations for a variety of CO2/water-injection ratios. In this process, often regions of two-phase flow are connected to regions of single-phase flow. Different systems of equations apply for single-phase and two-phase regions. We develop a solution approach, called the nonisothermal-negative-saturation (NegSat) solution approach, to solve efficiently nonisothermal compositional flow problems (e.g., CO2/water injection into geothermal reservoirs) that involve phase appearance, phase disappearance, and phase transitions. The advantage of this solution approach is that it circumvents using different equations for single-phase and two-phase regions and the ensuing unstable switching procedure. In the NegSat approach, a single-phase multicomponent fluid is replaced by an equivalent fictitious two-phase fluid with specific properties. The equivalent properties are such that the extended saturation of a fictitious gas is negative in the single-phase aqueous region. We discuss the salient features of the simulations in detail. When two phases are present at the injection side, heterogeneity and layering lead to more CO2 storage compared with the homogeneous case because of capillary trapping. In addition, layering avoids movement of the CO2 to the upper part of the reservoir and thus reduces the risk of leakage. Our results also show that heterogeneity and layering change the character of the solution in terms of useful-energy production and CO2 storage. The simulations can be used to construct a plot of the recovered useful energy vs. maximally stored CO2. Increasing the amount of CO2 in the injection mixture leads to bifurcation points at which the character of the solution in terms of energy production and CO2 storage changes. For overall injected-CO2 mole fractions less than 0.04, the result with gravity is the same as the result without gravity. For larger overall injected-CO2 mole fractions, however, the plot without gravity differs from the plot with gravity because of early breakthrough of a supercritical-CO2 tongue near the caprock. The plot of the useful energy (exergy) vs. the CO2-storage capacity in the presence of gravity shows a Z-shape. The top horizontal part represents a branch of high exergy recovery and a relatively lower storage capacity, whereas the bottom part represents a branch of lower exergy recovery and a higher storage capacity.
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SETA, TAKESHI, KOJI KONO, and SHIYI CHEN. "LATTICE BOLTZMANN METHOD FOR TWO-PHASE FLOWS." International Journal of Modern Physics B 17, no. 01n02 (2003): 169–72. http://dx.doi.org/10.1142/s021797920301728x.

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A lattice Boltzmann method (LBM) for two-phase nonideal fluid flows is proposed based on a particle velocity-dependent forcing scheme. The resulting macroscopic dynamics via the Chapman-Enskog expansion recover the full set of thermohydrodynamic equations for nonideal fluids. Numerical verification of fundamental properties of thermal fluids, including thermal conductivity and surface tension, agrees well with theoretical predictions. Direct numerical simulations of two-phase phenomena, including phase-transition, bubble deformation and droplet falling and bubble rising under gravity are carried out, demonstrating the applicability of the model.
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Chen, Shi Zhong, Yu Hou Wu, Hong Sun, and Hong Tan Liu. "An Improved Two-Phase Flow and Transport Model for the PEM Fuel Cell." Advanced Materials Research 105-106 (April 2010): 691–94. http://dx.doi.org/10.4028/www.scientific.net/amr.105-106.691.

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A two-phase flow, multi-component model has been optimized for a PEM (Proton Exchange Membrane) Fuel Cell. The modeling domain consists of the membrane, two catalyst layers, two diffusion layers, and two channels. Both liquid and gas phases are considered in the entire cathode and anode, including the channel, the diffusion layer and the catalyst layer. The Gravity effect on liquid water was considered in channels. Typical two-phase flow distributions in the cathode gas channel, gas diffuser and catalyst layer are presented. Source term and porosity term were optimized. Based on the simulation results, it is found that two-phase flow characteristics in the cathode depend on the current density, operating temperature, and cathode and anode humidification temperatures. Water mass fraction for the fuel cell with anode upward is higher than that the case with cathode-upward. Liquid water with the case of cathode-upward blocks pores in the gas diffuser layer leading to increasing the concentration polarization. Gravity of liquid water exerts the effect on the water mass fraction in the cathode.
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Zheng, Zhong, and Jerome A. Neufeld. "Self-similar dynamics of two-phase flows injected into a confined porous layer." Journal of Fluid Mechanics 877 (September 2, 2019): 882–921. http://dx.doi.org/10.1017/jfm.2019.585.

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We study the dynamics of two-phase flows injected into a confined porous layer. A model is derived to describe the evolution of the fluid–fluid interface, where the effective saturation of the injected fluid is zero. The flow is driven by pressure gradients due to injection, the buoyancy due to density contrasts and the interfacial tension between the injected and ambient fluids. The saturation field is then computed after the interface evolution is obtained. The results demonstrate that the flow behaviour evolves from early-time unconfined to late-time confined behaviours. In particular, at early times, the influence of capillary forces drives fluid flow and produces a new self-similar spreading behaviour in the unconfined limit that is distinct from the gravity current solution. At late times, we obtain two new similarity solutions, a modified shock solution and a compound wave solution, in addition to the rarefaction and shock solutions in the sharp-interface limit. A schematic regime diagram is also provided, which summarises all possible similarity solutions and the time transitions between them for the partially saturating flows resulting from fluid injection into a confined porous layer. Three dimensionless control parameters are identified and their influence on the fluid flow is also discussed, including the viscosity ratio, the pore-size distribution and the relative contributions of capillary and buoyancy forces. To underline the relevance of our results, we also briefly describe the implications of the two-phase flow model to the geological storage of $\text{CO}_{2}$, using representative geological parameters from the Sleipner and In Salah sites.
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Xie, Fangfang, Xiaoning Zheng, Michael S. Triantafyllou, Yiannis Constantinides, Yao Zheng, and George Em Karniadakis. "Direct numerical simulations of two-phase flow in an inclined pipe." Journal of Fluid Mechanics 825 (July 20, 2017): 189–207. http://dx.doi.org/10.1017/jfm.2017.417.

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We study the instability mechanisms leading to slug flow formation in an inclined pipe subject to gravity forces. We use a phase-field approach, where the Cahn–Hillard model is used to model the interface. At the inlet, a stratified flow is imposed with a specified velocity profile. We validate our numerical results by comparing against previous theoretical models and by predicting the various flow regimes for horizontal and inclined pipes, including stratified flow, slug flow, dispersed bubble flow and annular flow. Subsequently, we focus on slug formation in an inclined pipe and connect its appearance with specific vortical dynamics. A two-dimensional channel geometry is first considered. When the heavy fluid is injected as the top layer, inverted vortex shedding emerges, which periodically impacts on the bottom wall, as it develops further downstream. The accumulation of heavy fluid in the bottom wall causes a back flow that induces rolling waves and interacts with the upstream jet. When the heavy fluid is placed as the bottom layer, the heavy fluid accumulates and initially forms a massive slug at the bottom region, close to the inlet. Subsequently, the heavy fluid slug starts to break into smaller pieces, some of which translate along the pipe. During the accumulation phase, a back flow forms also generating rolling waves. Occasionally, a rolling wave can reach the top of the pipe and form a new slug. To describe the generation of vorticity from the two-phase interface and pipe walls in the slug formation, we study the circulation dynamics and connect it with the resulting two-phase flow patterns. Finally, we conduct three-dimensional (3-D) simulations in a circular pipe and compare the differences between the 3-D flow patterns and its circulation dynamics against the 2-D simulation results.
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Zidane, Ali, and Abbas Firoozabadi. "Fracture-Cross-Flow Equilibrium in Compositional Two-Phase Reservoir Simulation." SPE Journal 22, no. 03 (2017): 950–70. http://dx.doi.org/10.2118/184402-pa.

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Summary Compositional two-phase flow in fractured media has wide applications, including carbon dioxide (CO2) injection in the subsurface for improved oil recovery and for CO2 sequestration. In a recent work, we used the fracture-crossflow-equilibrium (FCFE) approach in single-phase compressible flow to simulate fractured reservoirs. In this work, we apply the same concept in compositional two-phase flow and show that we can compute all details of two-phase flow in fractured media with a central-processing-unit (CPU) time comparable with that of homogeneous media. Such a high computational efficiency is dependent on the concept of FCFE, and the implicit solution of the transport equations in the fractures to avoid the Courant-Freidricks-Levy (CFL) condition in the small fracture elements. The implicit solution of two-phase compositional flow in fractures has some challenges that do not appear in single-phase flow. The complexities arise from the upstreaming of the derivatives of the molar concentration of component i in phase α(cα,i) with respect to the total molar concentration (ci) when several fractures intersect at one interface. In addition, because of gravity, countercurrent flow may develop, which adds complexity when using the FCFE concept. We overcome these complexities by providing an upstreaming technique at the fracture/fracture interface and the matrix/fracture interface. We calculate various derivatives at constant volume V and temperature T by performing flash calculations in the fracture elements and the matrix domain to capture the discontinuity at the matrix/fracture interface. We demonstrate in various examples the efficiency and accuracy of the proposed algorithm in problems of various degrees of complexity in eight-component mixtures. In one example with 4,300 elements (1,100 fracture elements), the CPU time to 1 pore volume injection (PVI) is approximately 3 hours. Without the fractures, the CPU time is 2 hours and 28 minutes. In another example with 7,200 elements (1,200 fracture elements), the CPU time is 4 hours and 8 minutes; without fractures in homogeneous media, the CPU time is 2 hours and 53 minutes.
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van Odyck, Daniel E. A., Sean Lovett, Franck Monmont, and Nikolaos Nikiforakis. "An efficient shock capturing scheme for multicomponent multiphase thermal flow in porous media." Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences 468, no. 2147 (2012): 3413–40. http://dx.doi.org/10.1098/rspa.2012.0152.

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This paper is concerned with multicomponent, two-phase, thermal fluid flow in porous media. The fluid model consists of component conservation equations, Darcy's law for volumetric flow rates and an enthalpy conservation equation. The model is closed with an equation of state and phase equilibrium conditions that determine the distribution of the chemical components into phases. The sequential formulation described in a previous article is used to build a second-order shock capturing scheme for the conservation equations using a primitive-variable-based linear reconstruction. The fluxes at the cell faces are calculated using an approximate Riemann solver. The method is validated and evaluated by means of one- and two-dimensional problems, including a gravity inversion test.
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Ujita, Hiroshi, Satoru Nagata, Minoru Akiyama, Masanori Naitoh, and Hirotada Ohashi. "Development of LGA & LBE 2D Parallel Programs." International Journal of Modern Physics C 09, no. 08 (1998): 1203–20. http://dx.doi.org/10.1142/s0129183198001096.

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A lattice-gas Automata two-dimensional program was developed for analysis of single and two-phase flow behaviors, to support the development of integrated software modules for Nuclear Power Plant mechanistic simulations. The program has single-color, which includes FHP I, II, and III models, two-color (Immiscible lattice gas), and two-velocity methods including a gravity effect model. Parameter surveys have been performed for Karman vortex street, two-phase separation for understanding flow regimes, and natural circulation flow for demonstrating passive reactor safety due to the chimney structure vessel. In addition, lattice-Boltzmann Equation two-dimensional programs were also developed. For analyzing single-phase flow behavior, a lattice-Boltzmann-BGK program was developed, which has multi-block treatments. A Finite Differential lattice-Boltzmann Equation program of parallelized version was introduced to analyze boiling two-phase flow behaviors. Parameter surveys have been performed for backward facing flow, Karman vortex street, bent piping flow with/without obstacles for piping system applications, flow in the porous media for demonstrating porous debris coolability, Couette flow, and spinodal decomposition to understand basic phase separation mechanisms. Parallelization was completed by using a domain decomposition method for all of the programs. An increase in calculation speed of at least 25 times, by parallel processing on 32 processors, demonstrated high parallelization efficiency. Application fields for microscopic model simulation to hypothetical severe conditions in large plants were also discussed.
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Shi, Bohui, Jiaqi Wang, Yifan Yu, Lin Ding, Yang Liu, and Haihao Wu. "Investigation on the Transition Criterion of Smooth Stratified Flow to Other Flow Patterns for Gas-Hydrate Slurry Flow." International Journal of Chemical Engineering 2017 (2017): 1–13. http://dx.doi.org/10.1155/2017/9846507.

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A stability criterion for gas-hydrate slurry stratified flow was developed. The model was based on one-dimensional gas-liquid two-fluid model and perturbation method, considering unstable factors including shear stress, gravity, and surface tension. In addition, mass transfer between gas and liquid phase caused by hydrate formation was taken into account by implementing an inward and outward natural gas hydrates growth shell model for water-in-oil emulsion. A series of gas-hydrate slurry flow experiments were carried out in a high-pressure (>10 MPa) horizontal flow loop. The transition criterion of smooth stratified flow to other flow patterns for gas-hydrate slurry flow was established and validated and combined with experimental data at different water cuts. Meanwhile, parameters of this stability criterion were defined. This stability criterion was proved to be efficient for predicting the transition from smooth to nonsmooth stratified flow for gas-hydrate slurry.
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Lamine, Sadok, and Michael G. Edwards. "Multidimensional upwind schemes and higher resolution methods for three-component two-phase systems including gravity driven flow in porous media on unstructured grids." Computer Methods in Applied Mechanics and Engineering 292 (August 2015): 171–94. http://dx.doi.org/10.1016/j.cma.2014.12.022.

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Dissertations / Theses on the topic "Two-Phase flow including gravity"

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Ngo, Tri Dat. "Mise à l’échelle d’un écoulement diphasique avec gravité dans un milieu géologique hétérogène : application au cas de la séquestration du CO₂." Thesis, Université Paris-Saclay (ComUE), 2016. http://www.theses.fr/2016SACLS005/document.

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Ce travail de thèse porte sur la modélisation mathématique et la simulation numérique de la migration par gravité et capillarité du CO₂ supercritique injecté dans un site de séquestration géologique hétérogène. Les simulations sont réalisées à l'aide du code DuMux. Particulièrement, on s'intéresse à la mise à l'échelle, de l'échelle de la cellule à l'échelle du réservoir, d'un modèle d'écoulement diphasique CO₂ -saumure, au sein d'un milieu stratifié périodique constitué d'un réseau de barrières peu perméables horizontales, continues ou discontinues. La mise à l'échelle est effectuée par la méthode asymptotique à double échelle. Dans un premier temps, on considère le cas d'une colonne verticale parfaitement stratifiée. Un modèle homogénéisé est développé puis validé par simulation numérique pour différentes valeurs du nombre capillaire et du flux incident de CO₂ . La méthode d'homogénéisation est appliquée au cas d'un écoulement dans un milieu bidimensionnel constitué de strates discontinues. Par l'effet de gravité, le CO₂ s'accumule sous les strates peu perméables, ce qui conduit à un problème mathématique local non standard. Cette stratification est modélisée à l'aide de l'approche des courants de gravité. L'approche est étendue au cas des strates semi-perméables et en prenant en compte la capillarité. Le modèle mis à l'échelle est comparé à des simulations numériques effectuées pour différents types de strates, avec ou sans pression capillaire, et sa limite de validité est discutée pour chacun de ces cas. La dernière partie de la thèse est dédiée à l'étude des performances du code DuMux pour simuler par calcul parallèle l'injection et la migration de CO₂ dans des milieux hétérogènes tridimensionnels (milieu périodique stratifié, milieu fluviatile et milieu réservoir SPE10)<br>This work deals with the mathematical modeling and the numerical simulation of the migration under gravity and capillarity effects of the supercritical CO₂ injected into a geological heterogeneous sequestration site. The simulations are performed with the code DuMux. Particularly, we consider the upscaling, from the cell scale to the reservoir scale, of a two-phase (CO₂ -brine) flow model within a periodic stratified medium made up of horizontal low permeability barriers, continuous or discontinuous. The upscaling is done by the two-scale asymptotic method. First, we consider perfectly layered media. An homogenized model is developed and validated by numerical simulation for different values of capillary number and the incident flux of CO₂ . The homogenization method is then applied to the case of a two-dimensional medium made up of discontinuous layers. Due to the gravity effect, the CO₂ accumulates under the low permeability layers, which leads to a non-standard local mathematical problem. This stratification is modeled using the gravity current approach. This approach is then extended to the case of semi-permeable stratas taking into account the capillarity. The upscaled model is compared with numerical simulations for different types of layers, with or without capillary pressure, and its limit of validity is discussed in each of these cases. The final part of this thesis is devoted to the study of the parallel computing performances of the code DuMux to simulate the injection and migration of CO₂ in three-dimensional heterogeneous media (layered periodic media, fluvial media and reservoir model SPE 10)
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Abrishami-Savjublagh, Yoseph. "Numerical computations of dispersed flow and gravity stratified two-phase flow." Thesis, Imperial College London, 1990. http://hdl.handle.net/10044/1/47736.

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Pritchard, David Thomas. "Some problems in two-phase flow : intertidal mudflats and low Reynolds number gravity currents." Thesis, University of Bristol, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.391189.

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Ghrist, Melissa Renee. "Zero gravity two-phase flow regime transition modeling compared with data and relap5-3d predictions." [College Station, Tex. : Texas A&M University, 2008. http://hdl.handle.net/1969.1/ETD-TAMU-2353.

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Supak, Kevin Robert. "Reduced gravity Rankine cycle system design and optimization study with passive vortex phase separation." Texas A&M University, 2007. http://hdl.handle.net/1969.1/ETD-TAMU-2094.

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Liquid-metal Rankine power conversion systems (PCS) coupled with a fission reactor remain an attractive option for space power applications because system specific power and efficiency is very favorable for plant designs of 100 kW(e) or higher. Potential drawbacks to the technology in a reduced gravity environment include two-phase fluid management processes such as liquid-vapor phase separation. The most critical location for phase separation is at the boiler exit where only vapor must be sent to the turbine because blade erosion occurs from high velocity liquid droplets entrained by vapor flow. Previous studies have proposed that rotary separators be used to separate the liquid and vapor from a two phase mixture. However these devices have complex turbo machinery, require kilowatts of power and are untested for high vapor flow conditions. The Interphase Transport Phenomena (ITP) laboratory has developed a low-power, passive microgravity vortex phase separator (MVS) which has already proven to be an essential component of two-phase systems operating in low gravity environments. This thesis presents results from flight experiments where a Rankine cycle was operated in a reduced gravity environment for the first time by utilizing the MVS for liquid and vapor phase separation. The MVS was able to operate under saturated conditions and adjust to system transients as it would in the Rankine cycle by controlling the amount of liquid and vapor within the device. A new model is developed for the MVS to predict separation performance at high vapor flow conditions for sizing the separator at the boiler, condenser, and turbine locations within the cycle by using a volume limiting method. This model factors in the following separator characteristics: mass, pumping power, and available buffer volume for system transients. The study is concluded with overall Rankine efficiency and performance changes due to adding vortex phase separation and a schematic of the Rankine cycle with the integration of the MVS is presented. The results from this thesis indicate the thermal to electric efficiency and specific mass of the cycle can be improved by using the MVS to separate the two phases instead of a rotary separator.
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Emamzadeh, Mohammad. "Modelling of annular two-phase flow in horizontal and vertical pipes including the transition from the stratified flow regime." Thesis, Imperial College London, 2012. http://hdl.handle.net/10044/1/9970.

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The thesis presents a general one-dimensional mathematical model to simulate two-phase, gas-liquid, annular flow in horizontal as well as vertical pipes, and to mechanistically predict the transition from stratified to annular flow in horizontal pipes. The method is based on the transient one-dimensional two-fluid model whereby the two phases are considered as (i) liquid layer and (ii) a mixture of the gas and liquid droplets in which the droplet concentration in the mixture is considered as a flow variable. The model entails the introduction of a scalar transport equation for the conservation of mass of liquid droplets accounting for liquid transfer to and from the film liquid layer. The interface curvature is modelled by a double circle geometric configuration incorporating a new empirical relation for the specification of wetted angle. The droplet exchange rate between the liquid film and gas core is modelled by employing droplet entrainment and deposition rates derived from modifications of models existing in the literature. Using the new model the droplet entrained fraction (E), which is defined as the ratio of the droplet mass flow rate to the total liquid mass flow rate, is computed and validated against different experimental data for both horizontal and vertical pipes. The predictions show good agreement with most of the measurements, being within 30% of the data. This is a significant development since, unlike all other exist- ing models, both horizontal and vertical annular flows can be predicted well with the same model. Moreover, the transition point from the stratified to the annular regimes in horizontal flow can also be predicted and the transition points compare very well with the usual regime boundaries found in existing flow regime maps.
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Narcy, Marine. "Flow boiling in straight heated tube under normal gravity and microgravity conditions." Phd thesis, Toulouse, INPT, 2014. http://oatao.univ-toulouse.fr/13648/1/narcy.pdf.

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Forced convective boiling experiments of HFE-7000 in a vertical heated tube were conducted in earth gravity and under microgravity conditions. The experiment mainly consists in the study of a two-phase flow inside a 6mm diameter sapphire tube uniformly heated through an ITO coating. Measurements of pressure drops, void fraction, and liquid and wall temperatures are performed, along with flow visualisations. Data were collected in normal gravity and during four parabolic flight campaigns providing near weightlessness conditions. Flow visualisations, temperature and pressure signals are analysed to obtain flow patterns, void fraction, wall and interfacial shear stresses, and heat transfer coefficient data. These experimental results and comparisons with other available datasets are used to attempt a modelling of flow boiling in microgravity.
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辻, 義之, Yoshiyuki TSUJI, 幸司 野沢 та ін. "自由界面波上のリップル形成に関する実験的研究". 日本機械学会, 2002. http://hdl.handle.net/2237/9101.

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Wolff, Markus [Verfasser], and Rainer [Akademischer Betreuer] Helmig. "Multi-scale modeling of two-phase flow in porous media including capillary pressure effects / Markus Wolff. Betreuer: Rainer Helmig." Stuttgart : Universitätsbibliothek der Universität Stuttgart, 2013. http://d-nb.info/1044294337/34.

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Kacem, Amine. "Étude expérimentale et numérique d'une nappe liquide en écoulement gravitaire." Thesis, Pau, 2017. http://www.theses.fr/2017PAUU3052/document.

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Nous nous sommes intéressés dans la présente thèse à l’étude de l’écoulement gravitaire de nappesliquides non guidées qui s’écoulent verticalement dans l’air ambiant. Après une synthèse bibliographique,nous avons réalisé une double étude, expérimentale et numérique, en considérant des liquidesde viscosités différentes (allant de 1 à 50 fois celle de l’eau) et de tension superficielle proche de cellede l’eau. Le nombre de Reynolds Rel du liquide a varié de quelques unités à quelques milliers alorsque le nombre de Weber du liquide allait approximativement de 0.1 à 10. Le dispositif expérimentalque nous avons mis en place nous a permis de créer et d’étudier les formes géométriques des nappesliquides. Nous avons employé une méthode expérimentale originale pour mesurer le champ d’épaisseurdes nappes. Nous avons mené, parallèlement aux expériences, des simulations numériques 2D et 3Dinstationnaires et diphasiques (VOF), utilisant le calcul parallèle. Nous avons trouvé que les nappesexpérimentales et numériques deviennent plus courtes (verticalement) et moins épaisses lorsque le débitdiminue. Expérimentalement, lorsque le débit du liquide devient suffisamment faible, des filamentsliquides commencent à apparaître à coté d’une nappe moins large qu’auparavant. Dans le cas desnappes d’eau, cette transition de régime d’écoulement a été précédée de l’apparition systématique detrous dans la partie inférieure des nappes. Pour les autres liquides newtoniens plus visqueux (solutionsaqueuses de glycérine), l’apparition des filaments liquides a été précédée d’une déstabilisation des bourreletsqui délimitent la partie plane des nappes. Nous avons étendu par la suite l’étude expérimentaleà celle de fluides au comportement rhéologique plus complexe en utilisant un liquide non newtonienrhéofluidifiant. Nous avons montré pour ce fluide rhéofluidifiant que le débit associé à la transition versle régime des filaments diminue en comparaison avec celui associé à un liquide newtonien de viscositésimilaire. Cela nous a conduit à suggérer que la présence des propriétés rhéofluidifiantes des nappesliquides peut représenter une solution pour les applications de "coating" pour lesquelles on cherche àproduire des nappes stables et sans percement dans des configurations d’écoulement de faibles débits<br>In this thesis, unguided plane liquid sheets flowing vertically by gravity in an ambient air atmosphereare studied experimentally and numerically. First of all a litterature survey clearly identified themain issues regarding the dynamics and modelling of such flows. Subsequently, different liquids exhibitinga wide range of viscosity (1 to 50 times that of water) and a surface tension close to that of waterwere selected. The liquid flow regimes were characterized by a Reynolds number Rel ranging from afew units to a few thousand while the Weber number Wel was varied between 0.1 to 10. A dedicatedexperimental system was designed and operated to study the relevant sheet features (geometry, thickness)by means of an original optical method. In parallel, finite volume based 2D and 3D simulationsof the flows were undertaken. All rely on the volume of fluid method (VOF) combined with adaptivemeshing. The experimental and numerical sheets became shorter (vertically) and thinner as the massflow rate decreased. Experimentally, when the mass flow rate of the liquid becomes sufficiently low,liquid threads begin to appear next to a narrower sheet than before. In the case of water, this flowregime transition was preceded by the systematic appearance of holes in the lower part of the sheets.For the other more viscous Newtonian liquids (mixtures of water and glycerin), the appearance of theliquid threads was preceded by a destabilization of the rims which delimited the flat part of the sheets.The experimental study was then extended to fluids featuring more complex rheological behavior e.g.by the use of a non-Newtonian shear-thinning fluid. For such a fluid, it was shown that the criticalmass flow rate associated with the transition towards the threads regime was lower than its Newtoniancounterpart of similar viscosity. It is suggested that the presence of shear-thinning properties in liquidsheets may represent a solution for "coating" applications for which stable and non-pierced curtainsin flow configurations of low mass flow rates are targeted
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Books on the topic "Two-Phase flow including gravity"

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McQuillen, John. Reduced gravity gas and liquid flows: Simple data for complex problems. National Aeronautics and Space Administration, Glenn Research Center, 2001.

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Hsu, Yih-Yun. Transport processes in boiling and two-phase systems, including near-critical fluids. American Nuclear Society, 1986.

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Dzenitis, John M. Modelling of micro-gravity two-phase flow regimes. 1988.

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Gabriel, Kamiel S. S. Microgravity Two-phase Flow and Heat Transfer. Springer, 2010.

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A, Platt Jonathan, and United States. National Aeronautics and Space Administration., eds. Prediction of gas-liquid two-phase flow regime in microgravity. National Aeronautics and Space Administration, 1993.

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A, Platt Jonathan, and United States. National Aeronautics and Space Administration., eds. Prediction of gas-liquid two-phase flow regime in microgravity. National Aeronautics and Space Administration, 1993.

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A, Platt Jonathan, and United States. National Aeronautics and Space Administration., eds. Prediction of gas-liquid two-phase flow regime in microgravity. National Aeronautics and Space Administration, 1993.

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A, Platt Jonathan, and United States. National Aeronautics and Space Administration., eds. Prediction of gas-liquid two-phase flow regime in microgravity. National Aeronautics and Space Administration, 1993.

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American Institute of Aeronautics and Astronautics., NASA Glenn Research Center, and Aerospace Sciences Meeting & Exhibit (39th : 2001 : Reno, Nev.), eds. Effects of gravity on concurrent two-phase gas-liquid flows through packed columns. National Aeronautics and Space Administration, Glenn Research Center, 2001.

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Brian, Motil, and NASA Glenn Research Center, eds. Reduced gravity gas and liquid flows: Simple data for complex problems. National Aeronautics and Space Administration, Glenn Research Center, 2001.

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Book chapters on the topic "Two-Phase flow including gravity"

1

van Duijn, C. J., H. Eichel, R. Helmig, and I. S. Pop. "Effective Two-Phase Flow Models Including Trapping Effects at the Micro Scale." In Progress in Industrial Mathematics at ECMI 2006. Springer Berlin Heidelberg, 2008. http://dx.doi.org/10.1007/978-3-540-71992-2_47.

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de Paula, Filipe Fernandes, Thiago Quinelato, Iury Igreja, and Grigori Chapiro. "A Numerical Algorithm to Solve the Two-Phase Flow in Porous Media Including Foam Displacement." In Lecture Notes in Computer Science. Springer International Publishing, 2020. http://dx.doi.org/10.1007/978-3-030-50436-6_2.

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Salmon, Rick. "Introduction to Geophysical Fluid Dynamics." In Lectures on Geophysical Fluid Dynamics. Oxford University Press, 1998. http://dx.doi.org/10.1093/oso/9780195108088.003.0005.

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This second chapter offers a brief introduction to geophysical fluid dynamics—the dynamics of rotating, stratified flows. We start with the shallow water equations, which govern columnar motion in a thin layer of homogeneous fluid. Roughly speaking, the solutions of the shallow-water equations comprise two types of motion: ageostrophic motions, including inertia-gravity waves, on the one hand, and nearly geostrophic motions on the other. In rapidly rotating flow, these two types of motion may, in some sense, decouple. We seek simpler equations that describe only the nearly geostrophic motion. The simplest such equations are the quasigeostrophic equations. In the quasigcostrophic equations, potential vorticity plays the key role: The potential vorticity completely determines the velocity field that transports it, thereby controlling the whole dynamics. We begin by generalizing our previously derived fluid equations to a rotating coordinate frame.
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Ohta, Haruhiko, Paolo Di Marco, and Jungho Kim. "Flow Boiling under Reduced Gravity Conditions." In Encyclopedia of Two-Phase Heat Transfer and Flow II. WORLD SCIENTIFIC, 2015. http://dx.doi.org/10.1142/9789814623285_0013.

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Di Marco, Paolo, Haruhiko Ohta, and Jungho Kim. "Gravity Effects on Pool Boiling Heat Transfer." In Encyclopedia of Two-Phase Heat Transfer and Flow II. WORLD SCIENTIFIC, 2015. http://dx.doi.org/10.1142/9789814623285_0012.

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Mohamed, Zaghdoudi, Maalej Samah, and Mansouri Je. "Theoretical and Experimental Analysis of Flows and Heat Transfer Within Flat Mini Heat Pipe Including Grooved Capillary Structures." In Two Phase Flow, Phase Change and Numerical Modeling. InTech, 2011. http://dx.doi.org/10.5772/19533.

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"Counter Waves in Miscible Two-phase Flow with Gravity (Application to CO2 & H2 Storage)." In Physicochemical Fluid Dynamics in Porous Media. Wiley-VCH Verlag GmbH & Co. KGaA, 2018. http://dx.doi.org/10.1002/9783527806577.ch11.

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Luciani, Sebastien. "Two Phase Flow Experimental Study Inside a Microchannel: Influence of Gravity Level on Local Boiling Heat Transfer." In Evaporation, Condensation and Heat transfer. InTech, 2011. http://dx.doi.org/10.5772/23677.

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Herndon, David N., Celeste C. Finnerty, and Rene Przkora. "Hypermetabolic response to burns." In Burns (OSH Surgery). Oxford University Press, 2019. http://dx.doi.org/10.1093/med/9780199699537.003.0004.

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Large burns are one of the most disastrous injuries today. The survivor experiences a tremendous metabolic response that does not resolve with burn wound healing. This response is seen in patients with burns over more than 30% of the total body surface area (TBSA). Two phases are observed: the 'ebb' phase starts immediately after a burn, lasts for 2–3 days, and is characterized by a “shock state” with decreases in cardiac output and metabolism; the ‘flow’ phase starts approximately 5 days after a burn. This phase can last up to 3 years in paediatric patients with &gt;30% TBSA. The flow phase is characterized by persistent hypermetabolic and inflammatory responses, leading to catabolism and loss of function. Early interventions, including excision and grafting of wounds, enteral feeding, treatment of infections, pharmacological interventions (eg. anabolic hormones, adrenergic receptor antagonists), and exercise, can successfully attenuate this deleterious response.
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Kabeli, Judith, and Peretz Shoval. "Quality Analysis Specifications." In Advances in Database Research. IGI Global, 2005. http://dx.doi.org/10.4018/978-1-59140-471-2.ch013.

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Functional and Object Oriented Methodology (FOOM) combines two essential software-engineering paradigms: the functional (process-oriented) approach and the object-oriented (OO) approach. The two main products of FOOM’s analysis phase are two models: a data model in the form of an initial class diagram and a functional model in the form of OO-DFDs (a hierarchy of data flow diagrams including data classes). We evaluate the quality of these models by comparing them with the quality of equivalent analysis models products by Object-Process Methodology (OPM), which also combines the functional and object-oriented approaches, using a unified diagrammatic notation. The comparison is based on a controlled experiment which measured the correctness of the analysis models (specifications) produced by the two methodologies. The results reveal that the quality of models produced by FOOM is better than those produced by OPM.
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Conference papers on the topic "Two-Phase flow including gravity"

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Wemmenhove, Rik, Erwin Loots, and Arthur E. P. Veldman. "Hydrodynamic Wave Loading on Offshore Structures Simulated by a Two-Phase Flow Model." In 25th International Conference on Offshore Mechanics and Arctic Engineering. ASMEDC, 2006. http://dx.doi.org/10.1115/omae2006-92253.

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The numerical simulation of hydrodynamic wave loading on different types of offshore structures is important to predict forces on and water motion around these structures. This paper presents a numerical study of two-phase flow over a sloping bottom with the presence of breaking waves. The details of the numerical model, an improved Volume Of Fluid (iVOF) method, are presented in the paper. The program has been developed initially to study the sloshing of liquid fuel in satellites. This micro-gravity environment requires a very accurate and robust description of the free surface. Later, the numerical model has been used for calculations of green water loading and the analysis of anti-roll and sloshing tanks, including the coupling with ship motions. The model has been extended recently to take two-phase flow effects into account. Two-phase flow effects are particularly important near the free surface, where loads on offshore structures strongly depend on the interaction between different phases like air and water. Entrapment of air pockets and entrainment of bubble clouds have a cushioning effect on breaking wave impacts. The velocity field around the interface of air and water, being continuous across the free surface, requires special attention. By using a newly-developed gravity-consistent discretisation, spurious velocities at the free surface are prevented. Thus far, the second air phase has been treated as incompressible. Taking compressibility effects into account requires a pressure-density relation for grid cells containing air. The expansion and compression of air pockets is considered as an adiabatic process. The numerical model is validated on several test cases. In this paper special attention will be paid to the impact of a breaking wave over a sloping bottom.
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Colistra, Joshua H., Mahesh V. Panchagnula, Alparslan O¨ztekin, Sudhakar Neti, and John Chen. "Interfacial Dynamics of Two Layer Couette Flow: Gravity Enhanced Kelvin-Helmholtz Instability." In ASME 2005 Fluids Engineering Division Summer Meeting. ASMEDC, 2005. http://dx.doi.org/10.1115/fedsm2005-77459.

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The Couette flow of two immiscible liquids is examined using flow visualization techniques. The flow dynamics are studied as a function of several independent parameters including gravity. The two fluids are initially separated by a sheet of aluminum sufficient in length to ensure that fully developed flow conditions are achieved for both fluids before they come in contact with each other. The experiments are performed for various flowrates of Canola Oil and Polyethylene Glycol (PEG) corresponding Reynolds numbers for Oil and PEG of 0 to 20 and 0.01 to 0.2 respectively. Photographic images of the flow field are recorded and analyzed with the aid of image analysis software to illustrate interfacial dynamics of the flow. A qualitative and quantitative analysis of the flow instability is performed for various inclinations of the test apparatus, including the extreme cases of upward vertical and downward vertical with the horizontal being the baseline test case. Neutral stability curves are identified for the range of variables studied in the experiments. The long wave instability is observed to be very periodic. At the onset of instability, the flow structure is three-dimensional and exhibits wave growth in the flow direction. The wave growth ultimately results in droplet pinch off from the crest of a folded wave. At a constant relative velocity, the wave length is at a minimum when the flow is oriented in the upward vertical direction, opposing gravity. For a given PEG flowrate, the critical Oil flowrate for the onset of interfacial instability decreases as the angle increases. These results indicate gravity enhanced Kelvin-Helmholtz interfacial instability even for low Reynolds numbers. Through a course of systematic variation of flow angles we have been able to separate the effects of inertia, gravity (buoyancy) and viscous shear forces on the wavelength of instability.
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Giese, Tobias, Eckart Laurien, and Wolfgang Schwarz. "Experimental and Numerical Investigation of Gravity-Driven Pipe Flow With Cavitation." In 10th International Conference on Nuclear Engineering. ASMEDC, 2002. http://dx.doi.org/10.1115/icone10-22026.

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Gravity driven pipe flows contain no risk of pump failure and are considered to be reliable even under accident conditions. However, accurate prediction methods are only available for single phase flow. In case of the occurrence of two-phase flow (caused e.g. by boiling or cavitation), a considerable reduction in mass flux can be observed. In this study, an experimental and numerical investigation of gravity driven two-phase pipe flow was performed in order to understand and model such flows. An experiment was conducted to analyse gravity driven flow of water near saturation temperature in a complex pipe consisting of several vertical and horizontal sections. The diameter was 100 mm with a driving height of 13 m between an elevated tank and the pipe outlet. The experiment shows that cavitation leads to formation of steam. The two-phase character of the flow causes a significant reduction of mass flux in comparison to a single phase flow case. The experimental flow rate was reproduced by one dimensional single and two phase flow analysis based on standard one dimensional methods including models for steam formation. The main part of this study consists of a three dimensional CFD analysis of the two phase flow. A three dimensional model for cavitation and recondensation phenomena based on thermal transport processes was developed, implemented and validated against our experimental data. Due to the fact that beside bubbly flow, also the stratified and droplet flow regimes occur, a new approach to model phase interaction terms of the Two-Fluid Model for mass, momentum and energy is presented. Thereby, the transition from one flow regime to another is taken into account. The experimental mass flow rate can be predicted with an accuracy of 10%. The three dimensional analysis of the flow situation demonstrates the influence of pipe elements such as horizontal and vertical sections, bends and valves of the pipe on the mass flux and the steam distribution. The analysis of secondary flows in bends emphases their importance for the steam distribution within the pipe, for the pressure loss and the average mass flux.
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Sou, Akira, Kosuke Hayashi, and Tsuyoshi Nakajima. "Evaluation of Volume Tracking Algorithms for Gas-Liquid Two-Phase Flows." In ASME/JSME 2003 4th Joint Fluids Summer Engineering Conference. ASMEDC, 2003. http://dx.doi.org/10.1115/fedsm2003-45164.

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Qualitative and quantitative evaluations of volume tracking algorithms such as DA, FLAIR, MARS, CIP and VTEMC were conducted. Wide variety of two-dimensional test problems including (1) a circle transported in simple translation and rotational field, (2) a bubble rising in 45° slanted gravity field, (3) zigzag motion of a bubble in a vertical channel, and (4) a bubble rising in a stagnant liquid in axissymmetric cylindrical coordinate were chosen in the present study. As a result of these tests, the superiority of the cell-centered piecewise linear algorithm with the divergence treatment in operator split and especially with embedded micro cells was confirmed. Applicability of these algorithms to three-dimensional problems has to be examined in the future works.
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Wemmenhove, Rik, Roel Luppes, Arthur E. P. Veldman, and Tim Bunnik. "Numerical Simulation of Sloshing in LNG Tanks With a Compressible Two-Phase Model." In ASME 2007 26th International Conference on Offshore Mechanics and Arctic Engineering. ASMEDC, 2007. http://dx.doi.org/10.1115/omae2007-29294.

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The study of liquid dynamics in LNG tanks is getting more and more important with the actual trend of LNG tankers sailing with partially filled tanks. The effect of sloshing liquid in the tanks on pressure levels at the tank walls and on the overall ship motion indicates the relevance of an accurate simulation of the fluid behaviour. This paper presents the simulation of sloshing LNG by a compressible two-phase model and the validation of the numerical model on model-scale sloshing experiments. The details of the numerical model, an improved Volume Of Fluid (iVOF) method, are presented in the paper. The program has been developed initially to study the sloshing of liquid fuel in spacecraft. The micro-gravity environment requires a very accurate and robust description of the free surface. Later, the numerical model has been used for calculations for different offshore applications, including green water loading. The model has been extended to take two-phase flow effects into account. These effects are particularly important for sloshing in tanks. The complex mixture of the liquid and gas phase around the free surface imposes a challenge to numerical simulation. The two-phase flow effects (air entrapment and entrainment) are strongly affected by both the filling ratio of the tank and the irregular motion of the tank in typical offshore conditions. The velocity field and pressure distribution around the interface of air and LNG, being continuous across the free surface, requires special attention. By using a newly-developed gravity-consistent discretisation, spurious velocities at the free surface are prevented. The equation of state applied in the compressible cells in the flow domain induces the need to keep track on the pressure distribution in both phases, as the gas density is directly coupled to the gas pressure. The numerical model is validated on a 1:10 model-scale sloshing model experiment. The paper shows the results of this validation for different filling ratios and for different types of motion of the sloshing tank.
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Mäki, Antti-Juhana, Joose Kreutzer, and Pasi Kallio. "Modeling Drug Delivery in Gravity-Driven Microfluidic System." In ASME 2014 12th International Conference on Nanochannels, Microchannels, and Minichannels collocated with the ASME 2014 4th Joint US-European Fluids Engineering Division Summer Meeting. American Society of Mechanical Engineers, 2014. http://dx.doi.org/10.1115/icnmm2014-21183.

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Human cells cultivated in a microfluidic system provide an interesting alternative for animal experiments in drug screening. For these tests, a pumpless system based on hydrostatic pressure could be used for drug delivery. The objective of this paper is to provide a method to analyze drug distribution in a gravity-driven microfluidic system to reduce the design cycle of these systems. The approach is based on an analytical model combined with a finite element method (FEM). The paper presents simulation of gravity-driven drug delivery in a polydimethylsiloxane (PDMS)-based microfluidic cell culture system. In the study, a simple but commonly used system including two reservoirs, inlet and outlet, connected through a microchannel, is modeled. In the proposed method, time-dependent working pressure based on hydrostatic and capillary pressures is first approximated analytically. Secondly, using the calculated pressure, a velocity profile of single-phase fluid flow is solved across the system using the FEM. Finally, a distribution of a selected drug compound over the system is simulated and analyzed. Based on the results, the initial geometry is improved for better performance. The paper demonstrates how the modified system provides faster and more uniform drug concentration profile on the cells compared to the initial structure.
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Chilamkurti, Yesaswi N., and Richard D. Gould. "Experimental and Computational Studies of Gravity-Driven Dense Granular Flows." In ASME 2015 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2015. http://dx.doi.org/10.1115/imece2015-50762.

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The current paper focusses on the characterization of gravity-driven dry granular flows in cylindrical tubes. With a motive of using dense particulate media as heat transfer fluids (HTF), the study was primarily focused to address the characteristics of flow regimes with a packing fraction of ∼60%. Experiments were conducted to understand the effects of different flow parameters, including: tube radius, tube inclination, tube length and exit diameter. These studies were conducted on two types of spherical particles — glass and ceramic — with mean diameters of 150 μm and 300 μm respectively. The experimental data was correlated with the semi-empirical equation based on Beverloo’s law. In addition, the same flow configuration was studied through three-dimensional computer simulations by implementing the Discrete Element Method for the Lagrangian modelling of particles. A soft-particle formulation was used with Hertz-Mindilin contact models to resolve the interaction forces between particles. The simulation results were used to examine the velocity, shear rate and packing fraction profiles to study the detailed flow dynamics. Curve-fits were developed for the mean velocity profiles which could be used in developing hydrodynamic analogies for granular flows. The current work thus identifies the basic features of gravity driven dense granular flows that could form a basis for defining their rheology.
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Fairweather, M., and J. Yao. "Investigation of Particle-Laden Flow in a Straight Duct Using Large Eddy Simulation." In The 11th International Conference on Environmental Remediation and Radioactive Waste Management. ASMEDC, 2007. http://dx.doi.org/10.1115/icem2007-7029.

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A particle-laden turbulent flow in a square duct is predicted using large eddy simulation (LES). The simulation is performed for a Reynolds number of 35,500, and correctly predicts the existence of secondary flows and their effects on the mean flow. The results are also in good qualitative agreement with experimental data obtained at different Reynolds numbers. One-way coupling is assumed between solid particles and the fluid, and a particle equation of motion, including Stokes drag, lift, buoyancy and gravity force terms, solved using a Lagrangian particle tracking technique. Three sizes of particle (1, 50 and 100 μm) are considered, and results demonstrate that size has a significant effect on particle dispersion and deposition in the duct flow. As particle size increases, therefore, they tend to settle on the floor of the duct, with less dispersion in the fluid phase. The study demonstrates the usefulness of LES for nuclear waste processing applications since secondary flows occur in many practically-relevant flows, and since it is desirable that the two-phase waste mixture is kept as homogeneous as possible to prevent, or at least discourage, the settling out of solid particles to form a bed which can promote pipe blockages.
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Liu, Yujia, Sifan Peng, Nan Gui, Xingtuan Yang, Jiyuan Tu, and Shengyao Jiang. "Experimental Study on Gravity Driven Discharging of Quasi-Two-Dimensional Pebble Bed Based on Mathematical Morphology." In 2020 International Conference on Nuclear Engineering collocated with the ASME 2020 Power Conference. American Society of Mechanical Engineers, 2020. http://dx.doi.org/10.1115/icone2020-16367.

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Abstract The pebbles flow is a fundamental issue for both academic investigation and engineering application in reactor core design and safety analysis. In general, experimental methods including spiral X-ray tomography and refractive index matched scanning technique (RIMS) are applied to obtain the identification of particles’ positions within a three-dimensional pebble bed. However, none of the above methods can perform global bed particles’ position identification in a dynamically discharging pebble bed, and the corresponding experimental equipment is difficult to access due to the complication and high expense. In this research, the experimental study is conducted to observe the gravity driven discharging process in the quasi two-dimensional silos by making use of the high-speed camera and the uniform backlight. A mathematical morphology-based method is applied to the pre-processing of the captured results. After being increased the gray value gradient by the threshold segmentation, the edges of the particles are identified and smoothed by the Sobel algorithm and the morphological opening operation. The particle centroid coordinates are identified according to the Hough circle transformation of the edges. For the whole pebble bed, the self-programmed process has a particle recognition accuracy of more than 99% and a particle centroid position deviation of less than 3%, which can accurately obtain the physical positions of all particles in the entire dynamically discharge process. By analyzing the position evolution of individual particles in consecutive images, velocity field and motion events of particles are observed. The discharging profiles of 5 conditions with different exit are analyzed in this experiment. The results make a contribution to improving the understanding of the mechanism of pebbles flow in nuclear engineering.
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Wu, Yikai, Wenxuan Ju, Yusheng Liu, Fulong Zhao, and Sichao Tan. "Critical Conditions for Secondary Droplets Generated by Droplets Colliding Walls With Different Angles." In 2020 International Conference on Nuclear Engineering collocated with the ASME 2020 Power Conference. American Society of Mechanical Engineers, 2020. http://dx.doi.org/10.1115/icone2020-16864.

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Abstract The single droplet phase change model during motion is developed based on the phenomena description and mechanism comprehension, which including the droplet phase change model as well as the droplet motion model. Then, the calculation of the droplet phase change characteristics during moving in the uniform flow in the gravity separation space is conducted. The results show that when the droplet are evaporating during its moving, the radius will decrease continuously and it will be carried more easily by the steam vapor, which will lead to the larger separation radii of the droplets and the reduced the gravity separation efficiency. In addition, this paper shows the three-dimensional map for the critical separation over the pressure difference and the steam vapor flow velocity, which can contribute to forecast the influence of the droplet phase change on the separation characteristics. The results can be applied in the design of the steam-water separation plants.
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Reports on the topic "Two-Phase flow including gravity"

1

Abdollahian, D., and S. Levy. A Two-Phase Flow and Heat Transfer Model for Zero Gravity. Defense Technical Information Center, 1985. http://dx.doi.org/10.21236/ada156097.

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Mclaughlin, Brian, Derek Gonzalez, Kent Hennessey, Mark Eagar, and Al Murray. Status of Advanced Boundary Layer Code Development for SRM Nozzle Ablation Including Two Phase Flow Effects. Defense Technical Information Center, 2004. http://dx.doi.org/10.21236/ada427803.

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