Fundamentals of Multiphase Flows
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Multiscale Computational Fluid Dynamics
energies Review Multiscale Computational Fluid Dynamics Dimitris Drikakis 1,*, Michael Frank 2 and Gavin Tabor 3 1 Defence and Security Research Institute, University of Nicosia, Nicosia CY-2417, Cyprus 2 Department of Mechanical and Aerospace Engineering, University of Strathclyde, Glasgow G1 1UX, UK 3 CEMPS, University of Exeter, Harrison Building, North Park Road, Exeter EX4 4QF, UK * Correspondence: [email protected] Received: 3 July 2019; Accepted: 16 August 2019; Published: 25 August 2019 Abstract: Computational Fluid Dynamics (CFD) has numerous applications in the field of energy research, in modelling the basic physics of combustion, multiphase flow and heat transfer; and in the simulation of mechanical devices such as turbines, wind wave and tidal devices, and other devices for energy generation. With the constant increase in available computing power, the fidelity and accuracy of CFD simulations have constantly improved, and the technique is now an integral part of research and development. In the past few years, the development of multiscale methods has emerged as a topic of intensive research. The variable scales may be associated with scales of turbulence, or other physical processes which operate across a range of different scales, and often lead to spatial and temporal scales crossing the boundaries of continuum and molecular mechanics. In this paper, we present a short review of multiscale CFD frameworks with potential applications to energy problems. Keywords: multiscale; CFD; energy; turbulence; continuum fluids; molecular fluids; heat transfer 1. Introduction Almost all engineered objects are immersed in either air or water (or both), or make use of some working fluid in their operation. -
(2020) Role of All Jet Drops in Mass Transfer from Bursting Bubbles
PHYSICAL REVIEW FLUIDS 5, 033605 (2020) Role of all jet drops in mass transfer from bursting bubbles Alexis Berny,1,2 Luc Deike ,2,3 Thomas Séon,1 and Stéphane Popinet 1 1Sorbonne Université, CNRS, UMR 7190, Institut Jean le Rond ࢚’Alembert, F-75005 Paris, France 2Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, New Jersey 08544, USA 3Princeton Environmental Institute, Princeton University, Princeton, New Jersey 08544, USA (Received 12 September 2019; accepted 13 February 2020; published 10 March 2020) When a bubble bursts at the surface of a liquid, it creates a jet that may break up and produce jet droplets. This phenomenon has motivated numerous studies due to its multiple applications, from bubbles in a glass of champagne to ocean/atmosphere interactions. We simulate the bursting of a single bubble by direct numerical simulations of the axisymmetric two-phase liquid-gas Navier-Stokes equations. We describe the number, size, and velocity of all the ejected droplets, for a wide range of control parameters, defined as nondimensional numbers, the Laplace number which compares capillary and viscous forces and the Bond number which compares gravity and capillarity. The total vertical momentum of the ejected droplets is shown to follow a simple scaling relationship with a primary dependency on the Laplace number. Through a simple evaporation model, coupled with the dynamics obtained numerically, it is shown that all the jet droplets (up to 14) produced by the bursting event must be taken into account as they all contribute to the total amount of evaporated water. A simple scaling relationship is obtained for the total amount of evaporated water as a function of the bubble size and fluid properties. -
Collisional Granular Flows with and Without Gas Interactions in Microgravity
COLLISIONAL GRANULAR FLOWS WITH AND WITHOUT GAS INTERACTIONS IN MICROGRAVITY A Dissertation Presented to the Faculty of the Graduate School of Cornell University in Partial Ful¯llment of the Requirements for the Degree of Doctor of Philosophy by Haitao Xu August 2003 c 2003 Haitao Xu ° ALL RIGHTS RESERVED COLLISIONAL GRANULAR FLOWS WITH AND WITHOUT GAS INTERACTIONS IN MICROGRAVITY Haitao Xu, Ph.D. Cornell University 2003 We studied flows of agitated spherical grains in a gas. When the grains have large enough inertia and when collisions constitute the dominant mechanism for momentum transfer among them, the particle velocity distribution is determined by collisional rather than by hydrodynamic interactions, and the granular flow is governed by equations derived from the kinetic theory. To solve these equations, we determined boundary conditions for agitated grains at solid walls of practical interest by considering the change of momentum and fluctuation energy of the grains in collisions with the wall. Using these condi- tions, solutions of the governing equations captured granular flows in microgravity experiments and in event-driven simulations. We extended the theory to gas-particle flows with moderately large grain in- ertia, in which the viscous gas introduces an additional dissipation mechanism of particle fluctuation energy. When there is also a mean relative velocity between the gas and the particles, the gas gives rise to particle fluctuation energy and to mean drag. Solutions of the resulting equations compared well with Lattice- Boltzmann simulations at large to moderate Stokes numbers. However, theoretical predictions deviated from simulations at small Stokes number or at large particle Reynolds number. -
SPEAKERS TRANSPORTATION CONFERENCE FAA COMMERCIAL SPACE 15TH ANNUAL John R
15TH ANNUAL FAA COMMERCIAL SPACE TRANSPORTATION CONFERENCE SPEAKERS COMMERCIAL SPACE TRANSPORTATION http://www.faa.gov/go/ast 15-16 FEBRUARY 2012 HQ-12-0163.INDD John R. Allen Christine Anderson Dr. John R. Allen serves as the Program Executive for Crew Health Christine Anderson is the Executive Director of the New Mexico and Safety at NASA Headquarters, Washington DC, where he Spaceport Authority. She is responsible for the development oversees the space medicine activities conducted at the Johnson and operation of the first purpose-built commercial spaceport-- Space Center, Houston, Texas. Dr. Allen received a B.A. in Speech Spaceport America. She is a recently retired Air Force civilian Communication from the University of Maryland (1975), a M.A. with 30 years service. She was a member of the Senior Executive in Audiology/Speech Pathology from The Catholic University Service, the civilian equivalent of the military rank of General of America (1977), and a Ph.D. in Audiology and Bioacoustics officer. Anderson was the founding Director of the Space from Baylor College of Medicine (1996). Upon completion of Vehicles Directorate at the Air Force Research Laboratory, Kirtland his Master’s degree, he worked for the Easter Seals Treatment Air Force Base, New Mexico. She also served as the Director Center in Rockville, Maryland as an audiologist and speech- of the Space Technology Directorate at the Air Force Phillips language pathologist and received certification in both areas. Laboratory at Kirtland, and as the Director of the Military Satellite He joined the US Air Force in 1980, serving as Chief, Audiology Communications Joint Program Office at the Air Force Space at Andrews AFB, Maryland, and at the Wiesbaden Medical and Missile Systems Center in Los Angeles where she directed Center, Germany, and as Chief, Otolaryngology Services at the the development, acquisition and execution of a $50 billion Aeromedical Consultation Service, Brooks AFB, Texas, where portfolio. -
General@ Electric Space Sciences Laboratory Theoretical Fluid Physics Section
4 3 i d . GPO PRICE $ CFSTI PRICE(S) $ R65SD50 Microfiche (MF) , 7.3, We53 July85 THE STRUCTURE OF THE VISCOUS HYPERSONIC SHOCK LAYER SPACE SCIENCES LABORATORY . MISSILE AND SPACE DIVISION GENERAL@ ELECTRIC SPACE SCIENCES LABORATORY THEORETICAL FLUID PHYSICS SECTION THE STRUCTURE OF THE VISCOUS HYPERSONIC SHOCK LAYER BY L. Goldberg . Work performed for the Space Nuclear Propulsion Office, NASA, under Contract No. SNPC-29. f This report first appeared as part of Contract Report DIN: 214-228F (CRD), October 1, 1965. Permission for release of this publication for general distribution was received from SNPO on December 9, 1965. R65SD50 December, 1965 MISSILE AND SPACE DIVISION GENERAL ELECTRIC CONTENTS PAGE 1 4 I List of Figures ii ... Abstract 111 I Symbols iv I. INTRODUCTION 1 11. DISCUSSION OF THE HYPER NIC CO TTINUI 3 FLOW FIELD 111. BASIC RELATIONS 11 IV . BOUNDARY CONDITIONS 14 V. NORMALIZED SYSTEM OF EQUATIONS AND BOUNDARY 19 CONDITIONS VI. DISCUSSION OF RESULTS 24 VII. CONCLUSIONS 34 VIII. REFERENCES 35 Acknowledgements 39 Figures 40 1 LIST OF FIGURES 'I PAGE 1 1 1. Hypersonic Flight Regimes 40 'I 2. Coordinate System 41 3. Profiles Re = 15, 000 42 S 3 4. Profiles Re = 10 43 S 3 5. Profiles Re = 10 , f = -0.4 44 S W 2 6. Profiles Re = 10 45 S 2 7. Profiles Re = 10 , f = do. 4 46 S W Profiles Re = 10 47 8. s 9. Normalized Boundary Layer Correlations 48 10. Reduction in Skin Friction and Heat Transfer with Mass 49 Transfer 11. Normalized Heat Transfer 50 12. Normalized Skin Friction 51 13. -
Nucleate-Boiling Heat Transfer to Water at Atmospheric Pressure
Scholars' Mine Masters Theses Student Theses and Dissertations 1966 Nucleate-boiling heat transfer to water at atmospheric pressure H. D. Chevali Follow this and additional works at: https://scholarsmine.mst.edu/masters_theses Part of the Chemical Engineering Commons Department: Recommended Citation Chevali, H. D., "Nucleate-boiling heat transfer to water at atmospheric pressure" (1966). Masters Theses. 2971. https://scholarsmine.mst.edu/masters_theses/2971 This thesis is brought to you by Scholars' Mine, a service of the Missouri S&T Library and Learning Resources. This work is protected by U. S. Copyright Law. Unauthorized use including reproduction for redistribution requires the permission of the copyright holder. For more information, please contact [email protected]. NUCLEATE-BOILING HEAT TRANSFER TO WATER AT ATMOSPHERIC PRESSURE BY H. D. CHEV ALI - 1 &J '-I 0 ~~ A THESIS submitted to the faculty of THE UNIVERSITY OF MISSOURI AT ROLLA in partial fulfil lment of the requirements for the Degree of MASTER OF SCIENCE IN CHEMICAL ENGINEERING Roll a, Missouri 1966 Approved by / (Advisor ) ii ABSTRACT The purpose of this investigation was to study the hysteresis effect, the effect of micro-roughness and orientation of the heat-trans fer surface, and the effect of infra-red-radiation-treated heat-transfer surfaces on the nucleate-boiling curve. It has been observed that there exists no hysteresis effect for water boiling from a cylindrical copper surface in the nucleate-boiling region over the range studied. The nucleate-boiling curve has been found to be independent of micro-roughness and orientation of the heat transfer surface. There was no detectable change in the nucleate-boil ing characteristics of the heat-transfer surface when the surface was treated with infra-red radiation. -
Multiphase Turbulence in Bubbly Flows: RANS Simulations
This is a repository copy of Multiphase turbulence in bubbly flows: RANS simulations. White Rose Research Online URL for this paper: http://eprints.whiterose.ac.uk/90676/ Version: Accepted Version Article: Colombo, M and Fairweather, M (2015) Multiphase turbulence in bubbly flows: RANS simulations. International Journal of Multiphase Flow, 77. 222 - 243. ISSN 0301-9322 https://doi.org/10.1016/j.ijmultiphaseflow.2015.09.003 © 2015. This manuscript version is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0/ Reuse Unless indicated otherwise, fulltext items are protected by copyright with all rights reserved. The copyright exception in section 29 of the Copyright, Designs and Patents Act 1988 allows the making of a single copy solely for the purpose of non-commercial research or private study within the limits of fair dealing. The publisher or other rights-holder may allow further reproduction and re-use of this version - refer to the White Rose Research Online record for this item. Where records identify the publisher as the copyright holder, users can verify any specific terms of use on the publisher’s website. Takedown If you consider content in White Rose Research Online to be in breach of UK law, please notify us by emailing [email protected] including the URL of the record and the reason for the withdrawal request. [email protected] https://eprints.whiterose.ac.uk/ 1 Multiphase turbulence in bubbly flows: RANS simulations 2 3 Marco Colombo* and Michael Fairweather 4 Institute of Particle Science and Engineering, School of Chemical and Process Engineering, 5 University of Leeds, Leeds LS2 9JT, United Kingdom 6 E-mail addresses: [email protected] (Marco Colombo); [email protected] 7 (Michael Fairweather) 8 *Corresponding Author: +44 (0) 113 343 2351 9 10 Abstract 11 12 The ability of a two-fluid Eulerian-Eulerian computational multiphase fluid dynamic model to 13 predict bubbly air-water flows is studied. -
Out There Somewhere Could Be a PLANET LIKE OURS the Breakthroughs We’Ll Need to find Earth 2.0 Page 30
September 2014 Out there somewhere could be A PLANET LIKE OURS The breakthroughs we’ll need to find Earth 2.0 Page 30 Faster comms with lasers/16 Real fallout from Ukraine crisis/36 NASA Glenn chief talks tech/18 A PUBLICATION OF THE AMERICAN INSTITUTE OF AERONAUTICS AND ASTRONAUTICS Engineering the future Advanced Composites Research The Wizarding World of Harry Potter TM Bloodhound Supersonic Car Whether it’s the world’s fastest car With over 17,500 staff worldwide, and 2,800 in or the next generation of composite North America, we have the breadth and depth of capability to respond to the world’s most materials, Atkins is at the forefront of challenging engineering projects. engineering innovation. www.na.atkinsglobal.com September 2014 Page 30 DEPARTMENTS EDITOR’S NOTEBOOK 2 New strategy, new era LETTER TO THE EDITOR 3 Skeptical about the SABRE engine INTERNATIONAL BEAT 4 Now trending: passive radars IN BRIEF 8 A question mark in doomsday comms Page 12 THE VIEW FROM HERE 12 Surviving a bad day ENGINEERING NOTEBOOK 16 Demonstrating laser comms CONVERSATION 18 Optimist-in-chief TECH HISTORY 22 Reflecting on radars PROPULSION & ENERGY 2014 FORUM 26 Electric planes; additive manufacturing; best quotes Page 38 SPACE 2014 FORUM 28 Comet encounter; MILSATCOM; best quotes OUT OF THE PAST 44 CAREER OPPORTUNITIES 46 Page 16 FEATURES FINDING EARTH 2.0 30 Beaming home a photo of a planet like ours will require money, some luck and a giant telescope rich with technical advances. by Erik Schechter COLLATERAL DAMAGE 36 Page 22 The impact of the Russia-Ukrainian conflict extends beyond the here and now. -
Convective Boiling Heat Transfer and Two-Phase Flow Characteristics
International Journal of Heat and Mass Transfer 46 (2003) 4779–4788 www.elsevier.com/locate/ijhmt Convective boiling heat transfer and two-phase flow characteristics inside a small horizontal helically coiled tubing once-through steam generator Liang Zhao, Liejin Guo *, Bofeng Bai, Yucheng Hou, Ximin Zhang State Key Laboratory of Multiphase Flow in Power Engineering, XiÕan Jiaotong University, Xi’an Shaanxi 710049, China Received 15 February 2003; received in revised form 8 June 2003 Abstract The pressure drop and boiling heat transfer characteristics of steam-water two-phase flow were studied in a small horizontal helically coiled tubing once-through steam generator. The generator was constructed of a 9-mm ID 1Cr18Ni9Ti stainless steel tube with 292-mm coil diameter and 30-mm pitch. Experiments were performed in a range of steam qualities up to 0.95, system pressure 0.5–3.5 MPa, mass flux 236–943 kg/m2s and heat flux 0–900 kW/m2. A new two-phase frictional pressure drop correlation was obtained from the experimental data using ChisholmÕs B-coefficient method. The boiling heat transfer was found to be dependent on both of mass flux and heat flux. This implies that both the nucleation mechanism and the convection mechanism have the same importance to forced convective boiling heat transfer in a small horizontal helically coiled tube over the full range of steam qualities (pre-critical heat flux qualities of 0.1–0.9), which is different from the situations in larger helically coiled tube where the convection mechanism dominates at qualities typically >0.1. Traditional single parameter Lockhart–Martinelli type correlations failed to satisfactorily correlate present experimental data, and in this paper a new flow boiling heat transfer correlation was proposed to better correlate the experimental data. -
Prediction of Critical Heat Flux (CHF) for Vertical Round Tubes with Uniform Heat Flux in Medium Pressure Regime
Korean J. Chem. Eng., 21(1), 75-80 (2004) Prediction of Critical Heat Flux (CHF) for Vertical Round Tubes with Uniform Heat Flux in Medium Pressure Regime W. Jaewoo Shim† and Joo-Yong Park Department of Chemical Engineering, Dankook University, Seoul 140-714, Korea (Received 2 July 2003 • accepted 8 November 2003) Abstract−The description of critical heat flux (CHF) phenomena under medium pressure (10 bar≤P≤70.81 bar) regime is complex due to the large specific volume of vapor and the effect of buoyancy that are inherent in the con- ditions. In this study, a total of 2,562 data points of CHF in uniformly heated round vertical tube for water were collected from 5 different published sources. The data consisted of the following parameter ranges: 93.7≤G (mass ≤ 2 ≤ ≤ ≤ ≤ ≤ ≤ 2 flux) 18,580 kg/m s, 0.00114 D (diameter) 0.03747 m, 0.008 L (length) 5 m, 0.26 qc (CHF) 9.72 MW/m , and −0.21≤L (exit qualities)≤1.09. A comparative analysis is made on available correlations, and a new correlation is presented. The new CHF correlation is comprised of local variables, namely, “true” mass quality, mass flux, tube diameter, and two parameters as a function of pressure only. This study reveals that by incorporating “true” mass quality in a modified local condition hypothesis, the prediction of CHF under these conditions can be obtained quite accurately, overcoming the difficulties of flow instability and buoyancy effects. The new correlation predicts the CHF data are significantly better than those currently available correlations, with average error 2.5% and rms error 11.5% by the heat balance method. -
Expedition 16 Adding International Science
EXPEDITION 16 ADDING INTERNATIONAL SCIENCE The most complex phase of assembly since the NASA Astronaut Peggy Whitson, the fi rst woman Two days after launch, International Space Station was fi rst occupied seven commander of the ISS, and Russian Cosmonaut the Soyuz docked The International Space Station is seen by the crew of STS-118 years ago began when the Expedition 16 crew arrived Yuri Malenchenko were launched aboard the Soyuz to the Space Station as Space Shuttle Endeavour moves away. at the orbiting outpost. During this ambitious six-month TMA-11 spacecraft from the Baikonur Cosmodrome joining Expedition 15 endeavor, an unprecedented three Space Shuttle in Kazakhstan on October 10. The two veterans of Commander Fyodor crews will visit the Station delivering critical new earlier missions aboard the ISS were accompanied by Yurchikhin, Oleg Kotov, components – the American-built “Harmony” node, the Dr. Sheikh Muzaphar Shukor, an orthopedic surgeon both of Russia, and European Space Agency’s “Columbus” laboratory and and the fi rst Malaysian to fl y in space. NASA Flight Engineer Japanese “Kibo” element. Clayton Anderson. Shukor spent nine days CREW PROFILE on the ISS, returning to Earth in the Soyuz Peggy Whitson (Ph. D.) TMA-10 on October Expedition 16 Commander 21 with Yurchikhin and Born: February 9, 1960, Mount Ayr, Iowa Kotov who had been Education: Graduated with a bachelors degree in biology/chemistry from Iowa aboard the station since Wesleyan College, 1981 & a doctorate in biochemistry from Rice University, 1985 April 9. Experience: Selected as an astronaut in 1996, Whitson served as a Science Offi cer during Expedition 5. -
Two-Phase Modeling of Granular Sediment for Sheet Flows and Scour
TWO-PHASE MODELING OF GRANULAR SEDIMENT FOR SHEET FLOWS AND SCOUR. A Dissertation Presented to the Faculty of the Graduate School of Cornell University in Partial Fulfillment of the Requirements for the Degree of Doctor of Philosophy by Laurent Olivier Amoudry January 2008 c 2008 Laurent Olivier Amoudry ALL RIGHTS RESERVED TWO-PHASE MODELING OF GRANULAR SEDIMENT FOR SHEET FLOWS AND SCOUR. Laurent Olivier Amoudry, Ph.D. Cornell University 2008 Even though sediment transport has been studied extensively in the past decades, not all physical processes involved are yet well understood and repre- sented. This results in a modeling deficiency in that few models include complete and detailed descriptions of the necessary physical processes and in that mod- els that do usually focus on the specific case of sheet flows. We seek to address this modeling issue by developing a model that would describe appropriately the physics and would not only focus on sheet flows. To that end, we employ a two-phase approach, for which concentration- weighted averaged equations of motion are solved for a sediment and a fluid phase. The two phases are assumed to only interact through drag forces. The correlations between fluctuating quantities are modeled using the turbulent viscosity and the gradient diffusion hypotheses. The fluid turbulent stresses are calculated using a modified k−ε model that accounts for the two-way particle-turbulence interaction, and the sediment stresses are calculated using a collisional granular flow theory. This approach is used to study three different problems: dilute flow modeling, sheet flows and scouring. In dilute models sediment stresses are neglected.