Unsteady thermal response of the condensed-phase fuel adjacent to a reacting gaseous boundary layer

1971 ◽  
Vol 13 (1) ◽  
pp. 529-539 ◽  
Author(s):  
J.S. T'ien ◽  
W.A. Sirignano
Keyword(s):  
Boundary Layer ◽  
Condensed Phase ◽  
Thermal Response

scholarly journals Modelling multi-phase halogen chemistry in the remote marine boundary layer: investigation of the influence of aerosol size resolution on predicted gas- and condensed-phase chemistry

2009 ◽  
Vol 9 (2) ◽  
pp. 5289-5320 ◽  
Author(s):  
D. Lowe ◽  
D. Topping ◽  
G. McFiggans
Keyword(s):  
Boundary Layer ◽  
Gas Phase ◽  
Condensed Phase ◽  
Significant Influence ◽  
Marine Boundary Layer ◽  
Turnover Rates ◽  
Gas Phase Chemistry ◽  
Size Dependent ◽  
Multi Phase ◽  
Phase Chemistry

Abstract. A coupled box model of photochemistry and aerosol microphysics which explicitly accounts for size-dependent chemical properties of the condensed-phase has been developed to simulate the multi-phase chemistry of chlorine, bromine and iodine in the marine boundary layer (MBL). The model contains separate seasalt and non-seasalt modes, each of which may be composed of 1–16 size-sections. By comparison of gaseous and aerosol compositions predicted using different size-resolutions with both fixed and size-dependent aerosol turnover rates, it was found that, for halogen-activation processes, the physical property initialisation of the aerosol-mode has a significant influence on gas-phase chemistry. Failure to adequately represent the appropriate physical properties can lead to substantial errors in gas-phase chemistry. The size-resolution of condensed-phase composition has a less significant influence on gas-phase chemistry.

Fluid-Thermal Response of Spherical Dome Under a Mach 6.59 Laminar Boundary Layer

AIAA Journal ◽  
2012 ◽  
Vol 50 (12) ◽  
pp. 2791-2808 ◽  
Author(s):  
Christopher M. Ostoich ◽  
Daniel J. Bodony ◽  
Philippe H. Geubelle
Keyword(s):  
Boundary Layer ◽  
Laminar Boundary Layer ◽  
Thermal Response ◽  
Spherical Dome

scholarly journals Transient Thermal Response of Turbulent Compressible Boundary Layers

2011 ◽  
Vol 133 (8) ◽  
Author(s):  
Hongwei Li ◽  
M. Razi Nalim ◽  
Charles L. Merkle
Keyword(s):  
Boundary Layer ◽  
Steady State ◽  
Laminar Flow ◽  
Thermal Boundary Layer ◽  
Thermal Response ◽  
Thermal Conditions ◽  
Steady State Solution ◽  
Similarity Transformations ◽  
Keller Box Method ◽  
Transient Thermal

A numerical method is developed with the capability to predict transient thermal boundary layer response under various flow and thermal conditions. The transient thermal boundary layer variation due to a moving compressible turbulent fluid of varying temperature was numerically studied on a two-dimensional semi-infinite flat plate. The compressible Reynolds-averaged boundary layer equations are transformed into incompressible form through the Dorodnitsyn–Howarth transformation and then solved with similarity transformations. Turbulence is modeled using a two-layer eddy viscosity model developed by Cebeci and Smith, and the turbulent Prandtl number formulation originally developed by Kays and Crawford. The governing differential equations are discretized with the Keller-box method. The numerical accuracy is validated through grid-independence studies and comparison with the steady state solution. In turbulent flow as in laminar, the transient heat transfer rates are very different from that obtained from quasi-steady analysis. It is found that the time scale for response of the turbulent boundary layer to far-field temperature changes is 40% less than for laminar flow, and the turbulent local Nusselt number is approximately 4 times that of laminar flow at the final steady state.

scholarly journals On the Boundary Layer Equations with Phase Transition in the Kinetic Theory of Gases

2021 ◽  
Vol 240 (1) ◽  
pp. 51-98
Author(s):  
Niclas Bernhoff ◽  
François Golse
Keyword(s):  
Boundary Layer ◽  
Boltzmann Equation ◽  
Half Space ◽  
Condensed Phase ◽  
Existence And Uniqueness ◽  
Hard Sphere ◽  
Stat Phys ◽  
Type Solution ◽  
Boundary Layer Equations ◽  
Detailed Presentation

AbstractConsider the steady Boltzmann equation with slab symmetry for a monatomic, hard sphere gas in a half space. At the boundary of the half space, it is assumed that the gas is in contact with its condensed phase. The present paper discusses the existence and uniqueness of a uniformly decaying boundary layer type solution of the Boltzmann equation in this situation, in the vicinity of the Maxwellian equilibrium with zero bulk velocity, with the same temperature as that of the condensed phase, and whose pressure is the saturating vapor pressure at the temperature of the interface. This problem has been extensively studied, first by Sone, Aoki and their collaborators, by means of careful numerical simulations. See section 2 of (Bardos et al. in J Stat Phys 124:275–300, 2006) for a very detailed presentation of these works. More recently, Liu and Yu (Arch Ration Mech Anal 209:869–997, 2013) proposed an extensive mathematical strategy to handle the problems studied numerically by Sone, Aoki and their group. The present paper offers an alternative, possibly simpler proof of one of the results discussed in Liu and Yu (2013).

scholarly journals Modelling multi-phase halogen chemistry in the remote marine boundary layer: investigation of the influence of aerosol size resolution on predicted gas- and condensed-phase chemistry

2009 ◽  
Vol 9 (14) ◽  
pp. 4559-4573 ◽  
Author(s):  
D. Lowe ◽  
D. Topping ◽  
G. McFiggans
Keyword(s):  
Boundary Layer ◽  
Gas Phase ◽  
Condensed Phase ◽  
Significant Influence ◽  
Marine Boundary Layer ◽  
Turnover Rates ◽  
Gas Phase Chemistry ◽  
Size Dependent ◽  
Multi Phase ◽  
Phase Chemistry

Abstract. A coupled box model of photochemistry and aerosol microphysics which explicitly accounts for size-dependent chemical properties of the condensed-phase has been developed to simulate the multi-phase chemistry of chlorine, bromine and iodine in the marine boundary layer (MBL). The model contains separate seasalt and non-seasalt modes, each of which may be composed of 1–16 size-bins. By comparison of gaseous and aerosol compositions predicted using different size-resolutions with both fixed and size-dependent aerosol turnover rates, it was found that, for halogen-activation processes, the physical property initialisation of the aerosol-mode has a significant influence on gas-phase chemistry. Failure to adequately represent the appropriate physical properties can lead to substantial errors in gas-phase chemistry. The size-resolution of condensed-phase composition has a less significant influence on gas-phase chemistry.

Microcalorimeters for X-Ray Spectroscopy

1988 ◽  
Vol 102 ◽  
pp. 41
Author(s):  
E. Silver ◽  
C. Hailey ◽  
S. Labov ◽  
N. Madden ◽  
D. Landis ◽  
...  
Keyword(s):  
High Resolution ◽  
High Efficiency ◽  
Thermal Response ◽  
Low Noise ◽  
High Resolution Spectroscopy ◽  
Superconducting Transition ◽  
Sapphire Substrates ◽  
Laboratory Plasmas ◽  
Adiabatic Demagnetization ◽  
Theoretical Predictions

The merits of microcalorimetry below 1°K for high resolution spectroscopy has become widely recognized on theoretical grounds. By combining the high efficiency, broadband spectral sensitivity of traditional photoelectric detectors with the high resolution capabilities characteristic of dispersive spectrometers, the microcalorimeter could potentially revolutionize spectroscopic measurements of astrophysical and laboratory plasmas. In actuality, however, the performance of prototype instruments has fallen short of theoretical predictions and practical detectors are still unavailable for use as laboratory and space-based instruments. These issues are currently being addressed by the new collaborative initiative between LLNL, LBL, U.C.I., U.C.B., and U.C.D.. Microcalorimeters of various types are being developed and tested at temperatures of 1.4, 0.3, and 0.1°K. These include monolithic devices made from NTD Germanium and composite configurations using sapphire substrates with temperature sensors fabricated from NTD Germanium, evaporative films of Germanium-Gold alloy, or material with superconducting transition edges. A new approache to low noise pulse counting electronics has been developed that allows the ultimate speed of the device to be determined solely by the detector thermal response and geometry. Our laboratory studies of the thermal and resistive properties of these and other candidate materials should enable us to characterize the pulse shape and subsequently predict the ultimate performance. We are building a compact adiabatic demagnetization refrigerator for conveniently reaching 0.1°K in the laboratory and for use in future satellite-borne missions. A description of this instrument together with results from our most recent experiments will be presented.

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