The Experts below are selected from a list of 108 Experts worldwide ranked by ideXlab platform
T.r. Blake - One of the best experts on this subject based on the ideXlab platform.
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Gas jets in fluidized media, turbulent diffusion flames, and Condensing Vapor jets in liquids
Powder Technology, 1996Co-Authors: T.r. BlakeAbstract:Abstract Dimensional analysis and similitude is used to examine the integral characteristics of turbulent diffusion flames, jets in fluidized media, and Condensing Vapor jets. Data such as flame length, momentum flux and mass entrainment for these disparate jets are described in a common dimensionless frame. This, entrainment in turbulent diffusion flames permits an estimate of the particle entrainment in gas jets in fluidized media. Conversely, since the penetration length of gas jets in fluidized media is affected by the gas to solid density ratio, similitude permits an assessment of flame to ambient density ratio upon turbulent diffusion flame length.
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An examination of flame length data from vertical turbulent diffusion flames
Combustion and Flame, 1993Co-Authors: T.r. Blake, M. McdonaldAbstract:Abstract Literature data on the length of turbulent diffusion flames is examined for the buoyancy through momentum dominated regimes. This data is interpreted through an ad hoc dimensional analysis where the length scale is the Thring-Newby theoretical lateral flame dimension. The nondimensional flame length is shown to be a function of a density weighted Froude number (inverse Richardson number) and a flame to ambient density ratio. Experimental observations on gas turbulent diffusion flames are combined with data for Condensing Vapor jets and jets in liquid metal combustion. The latter measurements extend the data base and offer new insights into the mechanisms affecting turbulent diffusion flames.
Robert A Hiller - One of the best experts on this subject based on the ideXlab platform.
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numerical modeling of inert gas Condensing Vapor thermoacoustic engines
Journal of the Acoustical Society of America, 2003Co-Authors: W. V. Slaton, Richard Raspet, Robert A HillerAbstract:Recent theoretical work by Slaton and Raspet et al. describe the acoustic propagation equation [J. Acoust. Soc. Am. 114, 1414–1422] and the second‐order enthalpy and mass transport equations [J. Acoust. Soc. Am. 114, 1423–1430] for an inert gas‐Condensing Vapor mixture in a porous medium with an imposed temperature gradient. The acoustic propagation and enthalpy transport equations show that the Vapor diffusion effects in the mixture are analogous to the heat diffusion effects in the thermoacoustics of inert gases, and that these effects occur in parallel with the heat diffusion effects in the wet system for proper choice of inert gas and Vapor. Writing the acoustic propagation equation as two coupled first‐order differential equations in terms of the volumetric velocity and acoustic pressure amplitude and utilizing the conservation of enthalpy in the stack allows the system of equations to be solved numerically by interfacing with the well‐established thermoacoustic modeling code, DeltaE. Modeling of var...
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Theory of inert gas-Condensing Vapor thermoacoustics: propagation equation.
The Journal of the Acoustical Society of America, 2002Co-Authors: Richard Raspet, W. V. Slaton, Craig J. Hickey, Robert A HillerAbstract:The theory of acoustic propagation in an inert gas-Condensing Vapor mixture contained in a cylindrical pore with wet walls and an imposed temperature gradient is developed. It is shown that the Vapor diffusion effects in the mixture are analogous to the heat diffusion effects in the thermoacoustics of inert gases, and that these effects occur in parallel with the heat diffusion effects in the wet system. The Vapor diffusion effects can be expressed in terms of the thermoviscous function F(λ) used in the theory of sound propagation of constant cross-section tubes. As such, these results can be extended to any shape parallel-walled tube. The propagation equations predict that the temperature gradient required for onset of sound amplification in a wet-walled prime mover is much lower than the corresponding temperature gradient for an inert gas prime mover. The results of a measurement of the onset temperature of a simple demonstration prime mover in air with a dry stack and with a stack wetted with water provide a qualitative verification of the theory.
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Theory of inert gas-Condensing Vapor thermoacoustics: Transport equations a)
2002Co-Authors: W. V. Slaton, Craig J. Hickey, Richard Raspet, Robert A HillerAbstract:~Received 20 November 2001; revised 3 July 2002; accepted 11 July 2002!The preceding paper @J. Acoust. Soc. Am. 112, 1414–1422~2002!# derives the propagation equationfor sound in an inert gas-Condensing Vapor mixture in a wet-walled pore with an imposedtemperature gradient. In this paper the mass, enthalpy, heat, and work transport equations necessaryto describe the steady-state operation of a wet-walled thermoacoustic refrigerator are derived andpresented in a form suitable for numerical evaluation. The requirement that the refrigerator operatein the steady state imposes zero mass flux for each species through a cross section. This in turn leadsto the evaluation of the mass flux of Vapor in the system. The Vapor transport and heat transport areshown to work in parallel to produce additional cooling power in the wet refrigerator. An idealizedcalculation of the coefficient of performance~COP! of a wet-walled thermoacoustic refrigerator isderived and evaluated for a refrigeration system. The results of this calculation indicate that thewet-walled system can improve the performance of thermoacoustic refrigerators. Severalexperimental and practical questions and problems that must be addressed before a practical devicecan be designed and tested are described. © 2002 Acoustical Society of America.@DOI: 10.1121/1.1508114#PACS numbers: 43.35.Ud @MRS#
W. V. Slaton - One of the best experts on this subject based on the ideXlab platform.
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numerical modeling of inert gas Condensing Vapor thermoacoustic engines
Journal of the Acoustical Society of America, 2003Co-Authors: W. V. Slaton, Richard Raspet, Robert A HillerAbstract:Recent theoretical work by Slaton and Raspet et al. describe the acoustic propagation equation [J. Acoust. Soc. Am. 114, 1414–1422] and the second‐order enthalpy and mass transport equations [J. Acoust. Soc. Am. 114, 1423–1430] for an inert gas‐Condensing Vapor mixture in a porous medium with an imposed temperature gradient. The acoustic propagation and enthalpy transport equations show that the Vapor diffusion effects in the mixture are analogous to the heat diffusion effects in the thermoacoustics of inert gases, and that these effects occur in parallel with the heat diffusion effects in the wet system for proper choice of inert gas and Vapor. Writing the acoustic propagation equation as two coupled first‐order differential equations in terms of the volumetric velocity and acoustic pressure amplitude and utilizing the conservation of enthalpy in the stack allows the system of equations to be solved numerically by interfacing with the well‐established thermoacoustic modeling code, DeltaE. Modeling of var...
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Theory of inert gas-Condensing Vapor thermoacoustics: transport equations.
The Journal of the Acoustical Society of America, 2002Co-Authors: W. V. Slaton, Craig J. Hickey, Richard Raspet, R. A. HillerAbstract:The preceding paper [J. Acoust. Soc. Am. 112, 1414-1422 (2002)] derives the propagation equation for sound in an inert gas-Condensing Vapor mixture in a wet-walled pore with an imposed temperature gradient. In this paper the mass, enthalpy, heat, and work transport equations necessary to describe the steady-state operation of a wet-walled thermoacoustic refrigerator are derived and presented in a form suitable for numerical evaluation. The requirement that the refrigerator operate in the steady state imposes zero mass flux for each species through a cross section. This in turn leads to the evaluation of the mass flux of Vapor in the system. The Vapor transport and heat transport are shown to work in parallel to produce additional cooling power in the wet refrigerator. An idealized calculation of the coefficient of performance (COP) of a wet-walled thermoacoustic refrigerator is derived and evaluated for a refrigeration system. The results of this calculation indicate that the wet-walled system can improve the performance of thermoacoustic refrigerators. Several experimental and practical questions and problems that must be addressed before a practical device can be designed and tested are described.
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Theory of inert gas-Condensing Vapor thermoacoustics: propagation equation.
The Journal of the Acoustical Society of America, 2002Co-Authors: Richard Raspet, W. V. Slaton, Craig J. Hickey, Robert A HillerAbstract:The theory of acoustic propagation in an inert gas-Condensing Vapor mixture contained in a cylindrical pore with wet walls and an imposed temperature gradient is developed. It is shown that the Vapor diffusion effects in the mixture are analogous to the heat diffusion effects in the thermoacoustics of inert gases, and that these effects occur in parallel with the heat diffusion effects in the wet system. The Vapor diffusion effects can be expressed in terms of the thermoviscous function F(λ) used in the theory of sound propagation of constant cross-section tubes. As such, these results can be extended to any shape parallel-walled tube. The propagation equations predict that the temperature gradient required for onset of sound amplification in a wet-walled prime mover is much lower than the corresponding temperature gradient for an inert gas prime mover. The results of a measurement of the onset temperature of a simple demonstration prime mover in air with a dry stack and with a stack wetted with water provide a qualitative verification of the theory.
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Theory of inert gas-Condensing Vapor thermoacoustics: Transport equations a)
2002Co-Authors: W. V. Slaton, Craig J. Hickey, Richard Raspet, Robert A HillerAbstract:~Received 20 November 2001; revised 3 July 2002; accepted 11 July 2002!The preceding paper @J. Acoust. Soc. Am. 112, 1414–1422~2002!# derives the propagation equationfor sound in an inert gas-Condensing Vapor mixture in a wet-walled pore with an imposedtemperature gradient. In this paper the mass, enthalpy, heat, and work transport equations necessaryto describe the steady-state operation of a wet-walled thermoacoustic refrigerator are derived andpresented in a form suitable for numerical evaluation. The requirement that the refrigerator operatein the steady state imposes zero mass flux for each species through a cross section. This in turn leadsto the evaluation of the mass flux of Vapor in the system. The Vapor transport and heat transport areshown to work in parallel to produce additional cooling power in the wet refrigerator. An idealizedcalculation of the coefficient of performance~COP! of a wet-walled thermoacoustic refrigerator isderived and evaluated for a refrigeration system. The results of this calculation indicate that thewet-walled system can improve the performance of thermoacoustic refrigerators. Severalexperimental and practical questions and problems that must be addressed before a practical devicecan be designed and tested are described. © 2002 Acoustical Society of America.@DOI: 10.1121/1.1508114#PACS numbers: 43.35.Ud @MRS#
George Yadigaroglu - One of the best experts on this subject based on the ideXlab platform.
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turbulence and heat exchange in Condensing Vapor liquid flow
Physics of Fluids, 2008Co-Authors: Djamel Lakehal, Marco Fulgosi, Sanjoy Banerjee, George YadigarogluAbstract:Turbulence and heat exchange during condensation of a Vapor stream countercurrently flowing to a subcooled liquid stream in a slightly inclined channel has been investigated by direct numerical simulation (DNS). Condensation rates and imposed pressure gradients have been varied, and capillary-gravity waves have been allowed to develop at the (deformable) Vapor-liquid interface. These simulations extend our previous DNS of turbulence and scalar exchange in stratified gas-liquid flows without condensation. The previous studies indicated that for conditions in which the gas-liquid interface remained continuous, i.e., did not “break,” scalar exchange rates on both the gas and liquid sides were largely determined by sweeps which brought high momentum fluid from the bulk flow to the interface. As sweep frequencies were found to scale with interfacial friction velocities, scalar exchange coefficients could be parametrized with a surface renewal theory. The issue addressed in the current work is how these finding...
Julio M. D’arcy - One of the best experts on this subject based on the ideXlab platform.
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Condensing Vapor Phase Polymerization (CVPP) of Electrochemically Capacitive and Stable Polypyrrole Microtubes.
ACS applied materials & interfaces, 2017Co-Authors: Luciano M. Santino, Erica Hwang, Yifan Diao, Hongmin Wang, Qisheng Jiang, Srikanth Singamaneni, Julio M. D’arcyAbstract:We introduce a novel Condensing Vapor phase polymerization (CVPP) strategy for depositing microtubes of the conducting polymer polypyrrole; these serve as one-dimensional hollow microstructures for storing electrochemical energy. In CVPP, water droplets are structure-directing templates for polypyrrole microtubes. Water Vapor condensation and polymerization occur simultaneously-conformal coatings of microtubes deposit on porous substrates such as hard carbon fiber paper or glass fiber filter paper. A mechanistic evolution of the microtubular morphology is proposed and tested based on the mass transport of water and monomer Vapors as well as on the reaction stoichiometry. A coating of PPy microtubes is characterized by a high reversible capacitance of 342 F g-1 at 5 mV s-1 throughout 5000 cycles of cyclic voltammetry and a low sheet resistance of 70.2 Ω □-1. The open tubular structure is controlled in situ during synthesis and leads to electrodes that exhibit electrochemical stability at high scanning rates up to 250 mV s-1 retaining all stored charge, even after extensive cycling at 25 mV s-1.